CHUVA International Workshop 08-10 May 2013 São Paulo

Transcrição

CHUVA International Workshop
08-10 May 2013
São Paulo, Brazil
WEDNESDAY MAY 08th, 2013
Time
9:00
Abstract
Number
Open
Session
Title
Authors
L. Machado, C. Morales, D. Vila, M. A. Silva Dias, G.
Fisch, R. Albrecht, J. Cohen, E. Nascimento, M.
Sakamoto
The CHUVA Field Campaign: Overview
NUMERICAL MODELING SESSION #1
9:30
1.1
HRLAMENS - A PILOT PROJECT ON ENSEMBLE PREDICTION USING HIGH RESOLUTION LIMITED AREA
MODELS
C. Cunningham, C. Saulo, W. Anabor, G.
Camponogara, J.-P. Chaboureau, M. A. Silva Dias, S.
Freitas, Y. García Skabar, L. Machado, E.
Nascimento, M. Nicolini, M. Pulido, J. Ruiz, P. Salio,
D. Santos, M. Saucedo, R. Stockler, E. Vendrasco
9:45
1.2
Modeling cloud and rainfall formation near Belem and Santa Maria with OLAM (Ocean Land Atmosphere
Model)
R. R. Silva, A. Gandu, J. Cohen, R. Haas
10:00
1.3
Modeling cloud and rainfall formation near Fortaleza with OLAM (Ocean Land Atmosphere Model)
A. Gandu, R. R. Silva, R. Haas, A. Costa
10:15
1.4
10:30-11:00
High Resolution Model-Satellite-Radar Space and Time Scale Cloud Organization: The Santa Maria Case
Study.
COFFEE BREAK
L. Machado, J.-P. Chaboureau.
11:00
1.5
MODEL INTERCOMPARISON FOR EVENTS OCURRED AT SANTA MARIA SUL EXPERIMENT
L. Amaral, C. Eichholz, V. Virpiccinini
C. Matsudo, C. Saulo, C. Cunningham, W. Anabor, G.
Camponogara, J.-P. Chaboureau, M. A. Silva Dias, S.
Freitas, Y. García Skabar, L. Machado, E.
Nascimento, M. Nicolini, M. Pulido, J. Ruiz, P. Salio,
D. Santos, M. Saucedo, R. Stockler , E. Vendrasco
11:15
1.6
H
11:30
1.7
Validation of the BRAMS high resolution simulations by satellite radiance comparison
R. Negri, L. Machado
11:45
1.8
M. Illha, V. Anabor
12:00
1.9
December 10, 2012 MCS during CHUVA campaign: event forecast-ability using WRF
Evaluation of precipitation simulated over middle-latitude land by CPTEC AGCM single-column model
(SCM)
LUNCH BREAK
12:15-14:00
14:00
1.10
14:15
1.11
C
E
CHUVA S
M
Analysis of precipitation in operational simulations of WRF in case of intense convection over Rio Grande
do Sul State: Case Study December 11, 2012
WRF MODEL ASSESSMENT TO THE WIND PROFILE AND THERMODYNAMIC CHARACTERISTICS DURING
THE CHUVA PROJECT ALCANTARA STATION 2010
S. Figueroa, E. Ramirez, P. Kubota
D. Daniel, D. Custódio, P. Oliveira, E. Nascimento, V.
Anabor, E. Piva, F. Puhales
A. Silva, G. Fisch
14:30
1.12
EVALUATION OF A BIN CLOUD MODEL USING DATA FROM CHUVA PROJECT FOR FORTALEZA, CEARA
G. Almeida, L. Franklin, J. Leal Jr.
BOUNDARY LAYER AND SURFACE PROCESSES SESSION
14:45
2.1
Spatial distribution of meteorological variables during severe weather events in CHUVA-Sul
15:00
2.2
Could LIDAR methods automatically detect the top of ABL? Case studies for Santa Maria / CHUVA-SUL
15:15
2.3
15:30-16:00
A comparative analysis between daily cycles of shortwave radiation from CHUVA Experiments at Vale do
Paraíba and Santa Maria
COFFEE BREAK
16:00-17:30
ROUND TABLE - Dataset Control, Numerical Modeling, Boundary Layer and Surface Processes
18:00-19:30
ICE BREAK COCKTAIL
G. Silva, O. Acevedo, P. Oliveira, H. Zimmermann, E.
Nascimento
G. Moreira, E. Landulfo, L. Peres, G. Mariano, R.
Bourayou
,
T. Kaufmann G. Fisch
Moderators: G. Fisch, M. A. Silva Dia, S. Freitas, C.
Cunningham
Datasets: radiosondes, balloons, tower, meteo
statins, modeling
THURSDAY MAY 09th, 2013
Time
Abstract
Number
Title
Authors
CLOUD PROCESSES AND PRECIPITATION SESSION #1
9:00
3.1
GNSS Observations of Deep Convective Timescales in the Amazon
D. K. Adams, S. Gutman, K. Holub, D. Pereira
9:15
3.2
PRELIMINARY STUDIES OF THE APPLICATION OF GNSS TO PRECIPITATION NOWCASTING
L. Sapucci, L. Machado, I. Costa, L. Avanco
9:30
3.3
Relationship between Amazon biomass burning aerosols and rainfall over La Plata Basin
G. Camponogara, M. A. F. Silva Dias, G. G. Carrió
9:45
3.4
I. Costa, L. Machado
10:00
3.5
10:15
3.6
Preparation of a filter to correct drop size distributions of Parsivel disdrometer based on the particle
speed limitation
Weather radar systems and techniques at different frequencies and polarizations for quantitative
precipitation estimation and severe weather monitoring
Radar calibration
10:30-11:00
L. Baldini, V.Chandrasekar, R. Bechini
C. Morales, R. Albrecht, T. Biscaro
COFFEE BREAK
11:00
3.7
ICE WATER PATH STUDY USING PASSIVE MICROWAVE SENSORS DURING THE CLOUD LIFE CYCLE
R. Braga, D. Vila
11:15
3.8
Characterization of the microphysics of ice using CHUVA X-band radar and TMI and MADRAS brightness
temperatures
A. Martini , N. Viltard, L. Machado, T. Biscarro
11:30
3.9
The Cloud and Rain Liquid Water Characteristics of Different Precipitation Regimes in Brazil
A. Calheiros, L. Machado
11:45
3.10
AEROSOLS IMPACTS ON CLOUD DYNAMICS
M. Cecchini, L. Machado
12:00
3.11
Cirrus clouds observation in Santa Maria, Rio Grande do Sul during the experiment Chuva Sul.
B. Barja, H. Barbosa, R. Bourayou
12:15
3.12
12:30-14:00
SEVERE STORM DURING THE CAMPAIGN OF PROJECT CHUVA IN THE CITY OF BELÉM
I. Mello , J. Cohen
LUNCH BREAK
14:00
3.13
14:15
3.14
INFLUENCE OF LOCAL CIRCULATION ON SPATIAL AND TEMPORAL DISTRIBUTION OF THE PRECIPITATION
NEAR THE NEGRO AND SOLIMÕES RIVERS CONFLUENCE REGION
Micro Squall Line in Belem region
14:30
3.15
Space and time Characteristics of Convective clouds during chuVa campaigns
W. Lima, L. Machado
14:45
3.16
SSMI/S Satellite Rainfall Retrievals during CHUVA-GLM Experiment
D. Vila, N. Viltard, L. Machado, W. Lima
15:00
3.17
Use of CHUVA data to improve and validate the BRAIN rain retrieval algorithm
N. Viltard, L. Machado, D. Vila
Moderators: L. Machado, N. Viltard, D. Vila, L.
Baldini
Datasets: raingauges, DSD, MRR, radars,
radiometer
15:15-16:30
ROUND TABLE - Dataset Control, Cloud Processes and Precipitation
16:30-17:00
COFFEE BREAK
M. Santos, M. A. Silva Dias, E. Freitas
T. Amaral Neto, J. Cohen, L. Machado
FUTURE FIELD EXPERIMENTS
17:00
4.1
17:30
4.2
Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5)
Interactions between urban and forest emissions in Manaus, Amazonia: The Brazilian component of
GoAmazon
17:45
4.3
Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems
(ACRIDICON)
18:00
4.4
RELAMPAGO: following CHUVA steps....
19:00
S. T. Martin
P. Artaxo, M. A. Silva Dias
M. Wendisch, L. Machado, U. Pöschl, K. Longo, M.
Andreae, P. Artaxo, D. Rosenfeld, M. Silva Dias, H.
Schlager, G. Fisch, A. Ehrlich, A. Manzi, B. Stevens,
R. Souza
P. Salio, S. Nesbitt, D. Cecil, T. Lang, L. Machado, R.
Albrecht, E. Nascimento
SOCIAL EVENT (To be determined...)
FRIDAY MAY 10th, 2013
Time
Abstract
Number
8:15
5.1
8:30
5.2
8:45
5.3
9:00
5.4
9:15
5.5
Title
CLOUD ELECTRIFICATION PROCESSES SESSION
SYNOPTIC AND THERMODYNAMIC CHARACTERIZATION OF SPRITE PRODUCING CONVECTIVE SYSTEMS
OBSERVED IN
DURING THE CHUVA SUL CAMPAIGN
Space-time Evolution of Sprite Producing Thunderstorms During CHUVA Sul Campaign in 2012
Calibration of correction factors for the daily lightning quantities of starnet network using data from Field
Mill, Belém campaign, CHUVA Project.
Lightning activity associated to Amazonian coastal squall lines: a casestudy
Thunderstorms and lightning activity in São Paulo metropolitan area during CHUVA-GLM Vale do Paraiba
field experiment
Authors
R. Anchayhua, R. Azambuja, F. São Sabbas, A. Morais
F. T. São Sabbas, R. Azambuja, R. Anchayhua, A.
Morais
W. Moreira Frota, B. Rocha, J. de Sá, L. Dentel, J.
Pissolato Filho
L. Dentel, B. Rocha, J. Souza, R. Holle, J. Saraiva
R. Albrecht, C. Morales, R. Blakeslee, J. Bailey, S.
Goodman, H. Höller, E. Anselmo, J. Neves, E. Mattos,
T. Biscaro, L. Machado
9:30
5.6
Characteristics of the X-Band Polarimetric Radar Associated With the Lightning Electrical Activity
E. Mattos, L. Machado
9:45
5.7
Lightning and Polarimetric Radar Behavior of Incipient Thunderstorms in CHUVA
10:00
5.8
I
E. Williams, E. Mattos, L. Machado, A. Saraiva
M. Lacerda, C. Morales, E. Anselmo, R. Albrecht, W.
Rocamora, K. Fernandes, R. Jaques
10:15-10:45
P
C
L
P
CHUVA B
C
COFFEE BREAK
LIGHTNING DETECTION SYSTEMS SESSION #1
R. Blakeslee, J. Bailey, L. Carey, S. Goodman, S.
Rudlosky, R. Albrecht, C. Morales, E. Anselmo, J.
Neves
M. Bateman, S. Goodman, R. Blakeslee, R. Albrecht,
J. Bailey, D. Mach
H. Höller, H.-D. Betz, C. Morales, R. Blakeslee, J.
Bailey, R. Albrecht
10:45
6.1
São Paulo Lightning Mapping Array (SP-LMA): Network Assessment and Analyses for Intercomparison
Studies and GOES-R Proxy Activities
11:00
6.2
Additions to the GLM proxy data set from CHUVA measurements
11:15
6.2
Ground-based and space-borne lightning observations during CHUVA
11:30
6.4
Using Lightning Mapper Array to evaluate the lightning detection signatures at VLF, LF and VHF systems
C. Morales, R. Albrecht
11:45
6.5
12:00
6.6
ANALYSIS OF THE TLS200 NETWORK DEPLOYED DURING THE CHUVA CAMPAIGN IN BRAZIL
O
R
O
L
I
S
G
Lightning Observations at VLF, LF, and VHF Frequencies
12:15
6.7
A. Nag, M. Murphy, R. Said
K. Cummins, R. Blakeslee, L. Carey, J. Bailey, M.
Bateman, S. Goodman
H. Zheng, R. Holzworth, M. Hutchins, J. Brundell, S.
,
Heckman O. Pinto Jr.
12:30-14:00
Performance Comparison between Different Lightning Datasets during CHUVA Campaign
LUNCH BREAK
14:00
6.8
14:15
6.9
14:30
6.10
14:45
6.11
15:00
6.12
15:15
6.13
LIGHTNING DETECTION SYSTEMS SESSION #2
COMPARATIVE ANALYSIS OF BRASILDAT TOTAL LIGHTING NETWORK FOR THE VALE DO PARAIBA CHUVA
CAMPAIGN
Electrostatic fields observed during the CHUVA campaign
RAMMER NETWORK OBSERVATIONS DURING THE SUMMER OF 2011/2012
15:30-16:00
Upward lightning observations from towers in São Paulo, SP, Brazil and comparison with Lightning
Location Systems data
Data Analysis of upward lightning in Jaragua Peak
On the relation between return stroke peak current provided by lightning location systems and its peak
luminosity obtained from high-speed video cameras Preliminary results
COFFEE BREAK
16:00-18:00
ROUND TABLE ON CLOUD ELECTRIFICATION PROCESSES AND LIGHTNING DETECTION SYSTEMS
WORKSHOP ENDS
K. Naccarato, O. Pinto Jr
E. Anselmo, C. Morales, J. Neves, G. Beneduzi, M.
Lacerda, R. Albrecht
,
A. Saraiva O. Pinto Jr, G. Zepka, E. Lu, L. Campos, L.
Antune, J. Alves, T. Buzato
M. Saba, A. Paiva, K. Naccarato, C. Schumann, R.
Albrecht, M. Ferro
C. Schumann, M. Saba, M. Ferro, A. Paiva, R. Jaques
L.. Campos, J. Alves, A. Saraiva, E. Williams, O. Pinto
Jr.
Moderators: C. Morales, R. Albrecht
Dataset: field-mills, LLS, fast/slow antennas, highspeed cameras
WRF MODEL ASSESSMENT TO THE WIND PROFILE AND
THERMODYNAMIC CHARACTERISTICS DURING THE CHUVA
PROJECT – ALCANTARA STATION 2010
Adaiana F. G. da Silva1; Gilberto F. Fisch1,2
1
Instituto Nacional de Pesquisas Espaciais (INPE), Centro de Previsão do Tempo e Estudos
Climáticos (CPTEC), São José dos Campos, SP, Brasil
2
Departamento de Ciência e Tecnologia Aeroespacial (DCTA), Instituto de Aeronáutica e
Espaço (IAE), São José dos Campos, SP, Brasil
O Centro de Lançamento de Alcântara (CLA) é considerado o “portal brasileiro para o
espaço”. De lá podem ser lançados satélites de telecomunicação, coleta de dados
ambientais, sensoriamento remoto, entre outras aplicações, através do Veículo Lançador
de Satélites (VLS), bem como são realizados experimentos científicos (por exemplo, de
microgravidade) por meio de foguetes de sondagem fabricados no Brasil (VSB30,
VS40, etc.), como parte integrante do Programa Espacial Brasileiro (AEB, 2012).
As características do vento podem impactar direta e profundamente a trajetória de um
foguete, podendo desviá-lo, causar imprevistos e até mesmo acidentes. Por este motivo
é muito importante conhecer o regime de vento local em termos das características do
perfil vertical. Não apenas seus padrões climatológicos, mas também suas condições
exatas no momento do lançamento são cruciais para a segurança da operação. Podem-se
verificar as condições meteorológicas através de medidas observacionais instantâneas
imediatamente antes do lançamento, mas neste momento todo o equipamento já deve
estar montado, checado e preparado. Um complemento para o prognóstico da
determinação do vento é a previsão feita a partir de modelagem numérica. Observações
realizadas com antecedência geram as condições iniciais necessárias para simular a
dinâmica da atmosfera e representar o estado futuro a partir do tempo presente. Os
modelos regionais refinam a grade dos modelos globais (105 m) para meso (104 m e 105
s) ou micro-escala (103 m e 103 s). Desta forma, através das condições iniciais e de
contorno fornecidas pelos modelos globais, é possível captar as interações locais e ter
uma melhor representação regional ou até mesmo pontual. Neste trabalho, o modelo
atmosférico WRF (Weather Research and Forecasting), núcleo ARW (Advanced
Research WRF), foi escolhido por se tratar do estado-da-arte em modelos numéricos
(CARVALHO et al., 2012), além de ser um software moderno, livre, de código aberto,
fácil manipulação e pela liberdade na configuração das simulações em termos de
parâmetros numéricos, físicos e dinâmicos, o que permite grande adequação ao estudo
específico. A importância da utilização deste modelo está também no desenvolvimento
de uma autonomia operacional do Setor de Meteorologia do CLA para a realização de
previsões locais às vésperas de uma operação de lançamento.
Na região equatorial, onde o CLA está localizado, o regime de ventos é dominado pelos
ventos alísios, que são fortes, persistentes e predominantemente de leste, com uma
rotação sazonal de nordeste (época chuvosa) para sudeste (época seca), em função do
posicionamento da Zona de Convergência Intertropical (ZCIT). Além disto, por se
localizar próximo ao oceano, o CLA também sofre influências do efeito de brisa
marítima, a qual é intensificada no período de seca da região. (FISCH, 1999)
Em específico, este trabalho teve como objetivo principal avaliar a performance do
modelo WRF na previsão do vento no CLA através da comparação dos resultados
gerados pelo modelo com dados de radiossondagens para o período de 19 a 25 de março
de 2010, representativo do período chuvoso da região, caracterizado por ventos mais
fracos. O período seco da região, com ventos fortes, também foi abordado no trabalho
completo de dissertação de Mestrado que deu origem a esse resumo. Entretanto, como
dados do Projeto Chuva foram utilizados somente para a avaliação do período chuvoso,
somente este será tratado aqui.
As radiossondagens foram obtidas da campanha realizada durante o Projeto Chuva
GPM 2010, INPE – estação Alcântara). As medidas foram realizadas nos 4 horários
sinóticos diários (00:00, 06:00, 12:00 e 18:00 UTC), com o aparelho da marca Vaisala,
modelo RS92-SVG.
O modelo WRF foi inicializado com dados gerados pela previsão do modelo global
GFS, do National Center of Atmospheric Research (NCEP), com resolução espacial de
0,5° x 0,5° (aproximadamente 55 x 55 km para a latitude local) e temporal de 6 horas,
disponíveis em http://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/. Os dados do
terreno foram fornecidos pelo United States Geological Survey (USGS) (disponíveis
em: http://www.mmm.ucar.edu/wrf/src/wps_files/geog.tar.gz), com resolução espacial
de 30” de arco. Todas as simulações foram realizadas com 42 níveis na vertical, três
domínios quadrados e centralizados no CLA com dimensões de 900, 264 e 76 km2
(Figura 1), sendo um domínio mãe e dois aninhados, com comunicação bidirecional de
dados entre eles. O espaçamento da grade do domínio maior foi de 9x9 km, reduzindo
na proporção de 3 até a grade de 1x1 km no domínio menor, com passos de tempo de
45, 15 e 5 s para os domínios 1, 2 e 3, respectivamente. Simulações foram iniciadas a
cada 12 horas (às 00 e às 12 UTC), com tempo de integração de 72 horas, incluso o
tempo inicial de spin-up de 6 horas.
A camada de interesse deste estudo é até os primeiros 5000 m, pois esta é a altura em
que pode ocorrer influência do vento na determinação da trajetória de veículos em
lançamento (FISCH, 1999).
Figura 1 – Configuração de tamanhos dos domínios aninhados.
Em geral, para avaliar quantitativamente a acurácia de modelos numéricos, utilizam-se
métricas estatísticas para comparar e quantificar dados observados e simulados. Para a
comparação dos dados observados com as saídas do modelo WRF foram utilizadas três
métricas estatísticas diferentes: bias (absoluto), RMSE e índice de Willmott (d)
(WILLMOTT, 1981) para as variáveis velocidade (Vel) e as componentes U e V,
calculados da seguinte forma:
Viés 
bias
1 n
  P  O
n i 1
EQM 
RMSE
1 n
2
 n  P  O 
 i 1

n
d  1
(1)
 P  O
(2)
2
i 1
n
  P  O  O  O 
2
(3)
i 1
onde: n = número de níveis verticais; P = previsão, O = observação, O = média das
observações, no caso, valor médio da camada.
geralmente na forma de atrasos do modelo em relação à observação, de 1 a 2 horas ou
mais. Quando ocorreu o posicionamento correto de núcleos de chuva, sua intensidade
foi sempre muito subestimada pelo modelo. Devido à metodologia utilizada, não foi
possível quantificar com precisão a quantidade de chuva subestimada.
Um exemplo que merece destaque foi a forte precipitação observada pelo radar sobre o
CLA durante 15 horas praticamente ininterruptas, das 16 UTC do dia 21 às 07 UTC do
dia 22 de março de 2010, com núcleos de até 60 dBz, equivalente a aproximadamente
100 mm/h. Nenhuma das rodadas que incluíram este intervalo temporal foi capaz de
representar tal evento extremo. Somente após o cessar das chuvas observadas o modelo
começou a representar fortes núcleos aos arredores do CLA, mas representando no
máximo 30 mm/h e deslocados, já que o núcleo principal foi observado sobre o CLA
(Figura 3). Nestes horários já não há mais nenhuma precipitação significativa observada
pelo radar. É possível que o modelo global (GFS) tenha carregado este atraso em seus
arquivos de previsão, utilizados como dados de entrada.
Figura 3 – Campos de precipitação acumulada (WRF) e imagens de radar em raio 30 km. Forte
núcleo de precipitação sobre o CLA. Modelo não representou.
A Figura 4a mostra o campo das 13 UTC do dia 22 de março. Analisando as imagens de
radar em horários próximos, tanto anteriores quanto posteriores, percebeu-se que os
núcleos se assemelhavam com as observações do sistema que passou pela região de
Alcântara entre 10 e 12 UTC. Ou seja, o modelo WRF representou a chuva com atraso
de aproximadamente 2 horas. Isto pode ser um indicativo de que as nuvens estavam se
deslocando mais rapidamente do que calculado pelo modelo WRF, mostrando uma
defasagem temporal.
a
b
c
Figura 4 – Atraso temporal na rodada das 00 UTC do dia 22 de março. Evolução do sistema no
WRF (esquerda) e observada pelo radar.
Como conclusões, obteve-se que o modelo WRF consegue representar o perfil do vento
no CLA de forma razoável, dentro de suas limitações. Os valores alcançados pelo índice
de Willmott foram considerados satisfatórios de acordo com limites encontrados em
outros estudos. Porém, não foi possível concluir que, depois de passado certo tempo de
integração numérica (em intervalo de horas), as simulações tivessem apresentado um
mesmo tipo de comportamento padrão em termos de melhora ou piora da qualidade de
previsão.
Em geral, o modelo superestimou a velocidade do vento médio observado na camada
em até 2,0 m/s, com média de 0,70 m/s. Mesmo assim, acredita-se que, dentre as opções
de parametrizações da CLP disponíveis, a escolhida para a realização deste trabalho
(MYNN2,5) se mostrou eficiente para os objetivos a que foi definida, ou seja,
representar a distribuição de momentum local de acordo com as características da
estação.
O modelo WRF, com a configuração default de microfísica de nuvens, não consegue
capturar a presença de chuva em termos de posicionamento e intensidade. Este tema
deve ser ainda melhor estudado em trabalhos futuros.
AGÊNCIA ESPACIAL BRASILEIRA (AEB). Plano Brasil: defesa geopolítica
tecnologia inovação. Disponível em: <http://planobrasil.com/2011/12/19/perto-decompletar-18-anos-agencia-espacial-brasileira-tenta-novo-recomeco/>. Acesso em: 03
abr. 2012.
CARVALHO, D.; ROCHA, A.; GÓMEZ-GESTEIRA, M.; SANTOS, C. A sensitivity
study of the WRF model in wind simulation for an area of high wind energy.
Environmental Modelling & Software, v. 33, p. 23-34, 2012.
FISCH, G. Características do perfil vertical do vento no Centro de Lançamento de
foguetes de Alcântara (CLA). Revista Brasileira de Meteorologia, v. 14, n. 1, p. 1121, 1999.
GISLER, C. A. F. Análise do perfil de vento na camada limite superficial e sistemas
meteorológicos atuantes no Centro de Lançamento de Alcantâra. 2009. 143 p.
(INPE-16079-TDI/1536). Dissertação (Mestrado em Meteorologia) - Instituto Nacional
de Pesquisas Espaciais, São José dos Campos, 2009. Disponível em:
<http://urlib.net/sid.inpe.br/mtc-m18@80/2009/04.24.12.33>. Acesso em: 31 out. 2011.
WILLMOTT, C. J. On the validation of models. [S.l: s.n.], 1981.
The Cloud and Rain Liquid Water Characteristics of Different
Precipitation Regimes in Brazil
Alan J. P. Calheiros1
and
Luiz A. T. Machado 2
1
[email protected], [email protected]
1,2
Instituto Nacional de Pesquisas Espaciais, Centro de Previsão de Tempo e Estudos
Climáticos, Cachoeira Paulista, SP, Brazil
ABSTRACT
Between 2010 and 2012, the CHUVA project collected information regarding cloud and
rain trends in different precipitation regimes in Brazil. CHUVA had four field
campaigns, located in the North, Northeast and Southeast regions of Brazil, covering the
semi-arid, Amazonas, coastal and mountain regions. The purpose of this study is to
present statistics related to the integration of cloud and rain liquid water and the profiles
for different cloud types and regimes. The synergy of several instruments allows us to
describe the cloud process characteristics and to classify rain events. Microwave
radiometer, LiDAR, radar, and disdrometer were employed in this study. The rain type
classification was made using vertical profiles of reflectivity (VPR) and polarimetric
variables from dual-polarization radar (XPOL). The profiles and integrated cloud liquid
water (ILWC) was retrieved with a microwave ground-based radiometer using a neural
network. For rainy conditions, the profiles from the liquid water content (LWCR) and
their integrated (ILWR) properties were estimated by Micro Rain Radar (MRR) and
XPOL VPRs. For non-precipitating clouds, the ILWC values were larger for the sites in
Northeast Brazil near the coast than for the other regions. For rainy cases, distinct LWCR
profiles and ILWR were observed for different rain classifications and regions with a
distinctive rainfall regime. The ILWR for the convective systems show the highest
values, followed by stratiform and warm systems. The clouds in the Vale do Paraiba
and Belem showed the largest reflectivity in the mixed and glaciated layers,
respectively. In contrast, the coastal sites show larger values of cloud and rain liquid
water content for non-precipitating and warm clouds. The Vale and Belem clouds
present the deepest clouds and larger convective cloud liquid water. Several analyses
are presented, describing the cloud process and the differences among the regions.
CHUVA International Workshop, May 8-10, 2013
ANALYSIS OF THE TLS200 NETWORK DEPLOYED DURING
THE CHUVA CAMPAIGN IN BRAZIL
Amitabh Nag1, Martin J. Murphy1, and Ryan K. Said1
1
Vaisala Inc., Louisville, Colorado, USA
Abstract: The CHUVA campaign was held in the vicinity of São Luiz do Paraitinga, Brazil
from October 2011 to March 2012. One of the objectives of the CHUVA lightning mapping
campaign was to perform measurements of total lightning activity, map lightning channels,
and characterize in detail the lightning discharges in the region. Vaisala installed a five sensor
network consisting of its TLS200 Total Lightning Sensor which combines very high
frequency (VHF) interferometry with low frequency (LF) magnetic direction finding and
time-of-arrival technologies. The network operated from January through March 2012 and
detected total lightning activity over a region with a radius of approximately 100 km around
São Paulo. During this period several severe thunderstorms occurred in the region. The
TLS200 network detected a total of 294810 cloud-to-ground flashes in January through
March, 2012. A larger number of cloud-to-ground flashes occurred during February than in
January and March. Various characteristics of the lightning activity, including cloud-toground flash density, peak current distribution, and the ratio of cloud and cloud-to-ground
discharges, were examined. Our analysis also illustrates the cloud lightning mapping
capability of the VHF part of the TLS200 sensor.
Cloud lightning detection performance of a lightning locating system is inherently difficult to
quantify. Cloud lightning flashes or ICs may last from several hundred milliseconds to about a
second. They may have several vertical and horizontal branches that can extend several
kilometers or more spatially. The electromagnetic radiation field signature of an IC flash
measured at distances of several tens of kilometers or more typically consists of a few tens to
hundreds of electromagnetic field pulses spread over the entire duration of the flash.
Typically, pulses in cloud discharges have amplitudes that are smaller than that of first return
strokes in cloud-to-ground discharges. Cloud flash detection efficiency is defined as the
percentage of the total number of IC flashes occurring in a certain period of time over a
certain geographical area that are detected by a network. An IC flash is said to be “detected”
if at least one pulse in the flash is detected and reported by the network. Similarly, cloud pulse
detection efficiency is defined as the percentage of the total number of pulses in all cloud
flashes (again, in a certain period of time over a certain geographical area) that are detected
and reported by the network. However, obtaining a ground-truth estimate of the total number
of cloud pulses is not practical due to the range of pulse amplitudes, and it is much more error
prone than obtaining a ground-truth estimate of the total number of cloud flashes. Hence
cloud flash detection efficiency of a lightning detection network is the only practical statistic.
To improve cloud flash detection efficiency, an increase in sensor sensitivity (that is, higher
gain and/or lower threshold) is required due to the tendency of cloud pulses to have lower
amplitudes than return strokes. Cloud lightning detection at LF, where fewer sensors can be
used to cover a given area, is considered to have growing importance. Given this, our
objective is to quantify the cloud lightning detection capabilities of the TLS200 network
deployed in CHUVA, particularly flash detection efficiency and spatial mapping capability at
LF and VHF, respectively.
RAMMER NETWORK OBSERVATIONS DURING THE SUMMER OF 2011/2012
A. C. V. Saraiva1; O. Pinto Jr.1; G. S. Zepka1; E. S. A. M. Luz1; L. Z. S. Campos1; L.
Antunes1; J. Alves1; T. S. Buzato1
1. INPE - National Institute for Space Research, São José dos Campos, São Paulo,
Brazil.
The RAMMER Project (Automated Multi-camera Network for Monitoring and Study of
Lightning) is a network of automatically triggered high-speed cameras, designed to
observe lightning flashes in the region of São José dos Campos-SP, Brazil. The
cameras were assembled in weatherproof boxes with all equipment necessary to
automatically trigger lightning flash events with the help of a photo sensor. Their
initial set up provided high-speed videos of 2500 frames per second at 1200 x 500
pixels. They were strategically positioned to cover a total area of ~1000 km^2 and a
common area of ~70 km^2. All cameras may capture flashes occurring inside the
common area almost at the same time. The videos recorded simultaneously can be
used for tridimensional reconstruction of the lightning channel. During the summer of
2011/2012, it was conducted the first campaign with two cameras operating
continuously, and a third camera set up during some events. This first campaign was
conducted in collaboration with a joint experiment with several institutions called
CHUVA Project (Cloud processes of the main precipitation systems in Brazil: A
contribution to cloud resolving modeling and to the Global Precipitation
Measurement). Examples of analysis made with RAMMER data and other sensors
installed during the CHUVA experiment will be shown. Among the examples there is
an important study on the formation of bipolar flashes, a study of luminosity versus
peak current, some observations of the same flash by two cameras, and the
detection efficiency of the LLS (Lightning Location System) networks. As for the
detection efficiency analysis, the high-speed camera data can be used as ground
truth to evaluate the performance of the networks installed during the CHUVA
experiment.
Abstract for CHUVA International Workshop
8-10th May 2013
Audrey Martini (LATMOS)
(1)
(2)
(2)
N. Viltard , L. A. Toledo Machado , T. Biscarro
(1)
(2)
LATMOS,
INPE
Characterization of the microphysics of ice using CHUVA X-band radar and TMI and
MADRAS brightness temperatures
CHUVA campaign is aimed at deploying a series of instruments in various locations over
Brazil in order to better characterize the various rain regimes. Among those instruments, the XBand dual polarization Doppler radar has a polarimetric capability, allowing us to get information
using the combination of the various
polarimetric variables measured by the radar, it is possible to access to a certain extent the type
of particles that were observed within a given radar bin. Simultaneously, the radar classically
gives the surface rain associated with those particles and the various regions of the rain system.
Megha-Tropiques is a Franco-Indian satellite to study the water and energy cycle in the
of its main instrument MADRAS. The latter is a 9-channel passive microwave radiometer
dedicated mainly to precipitation retrieval. Bauer et al (2005) showed that the most critical
source of uncertainties in the precipitation retrieval over land comes from the ice microphysics
characteristics. In the framework of the Megha-Tropiques mission we tried to improve the
parameterization of precipitating ice in the radiative transfer model used to performed the
retrieval of rain from the measured brightness temperatures.
The aim of this study is not to get more into the details of particles classification but
rather to test if the radar PID can be somewhat correlated to the 85 GHz brightness
temperature in order to explain the effect of particles density and the ice content on the
scattering. The knowledge of the properties of the ice precipitations is a very important
information in order to retrieve accurately the rain from a vector of microwave brightness
temperatures (Tb), particularly over land where the surface emissivity masks most of the
rain/precipitation contribution for all frequencies below ~40 GHz.
The next step will be to build a database of cases in various situations: oceanic, continental,
coastal using CHUVA data set over Brazil.
Title: Cirrus clouds observation in Santa Maria, Rio Grade do Sul during the experiment Chuva Sul.
Authors: Boris Barja(1), Henrique Barbosa(1), Riad Bourayou(2).
(1) Physics Institute. University of Sao Paulo. Sao Paulo, SP, Brazil.
(2) Center for Lasers and Application Nuclear and Energy Research Institute (IPEN/CNEN),
Sao Paulo, SP, Brazil .
Abstract:
Cirrus clouds are an interesting point in the research of the atmosphere due their behavior and the effect
on the earth radiation budget. They can affect the atmospheric radiation budget by reflecting the incoming
solar radiation and absorbing the outgoing terrestrial radiation. Also, this cloud type is involved in the
dehydration of the upper troposphere and lower stratosphere. So, it is interesting to increment the
measurements of this type of clouds from the ground.
During November and December 2012, through the CHUVA-SUL campaign, measurements with lidar in
Santa Maria, Rio Grande do Sul were conducted. The system installed in Santa Maria site (29.8 °S; 53.7 °W,
100 m asl) was a single elastic-backscatter lidar using the wavelength of 532 nm. Some days with cirrus
clouds lidar measurements were detected. Four days with presence of cirrus cloud are showed in the
present study. These days, 7, 8, 19 and 28 November 2012, was selected due the persistence of cirrus
clouds over many hours.
The raw retrieval lidar signals and inverted backscatter coefficient profiles were analyzed for the selected
days. Base and top height was obtained by analysis of raw signal and backscatter coefficient. Extinction
coefficient profiles were obtained by the assumption of the lidar ratio. Cirrus cloud optical depth (COD)
values were calculated, from the integration of the extinction coefficient between the base and top
altitudes of the cirrus clouds.
Title
Calibration of correction factors for the daily lightning quantities of starnet
network using data from Field Mill, Belém campaign, CHUVA Project.
Authors
Willamy Moreira Frota1,4, Brigida Ramati Pereira da Rocha2-3, José Alberto Silva de Sá2,
Laure Madeleine Dentel3,José Pissolato Filho4
1 Eletronorte
2 UFPA- Programa de Pós-Graduação em Engenharia Elétrica
3 SIPAM Sistema de Proteção da Amazônia, CTO/BE, Belém-PA
4 UNICAMP
Abstract
During the CHUVA project, Belém Campaign, models developed by Sá et
al, 2011 (1.2) were used to forecast severe thunderstorms. These models
use starnet network data for forecasting severe thunderstorms with
lightning occurrence. During the period of Belém campaign some of the
sensors of the starnet network had operational problems causing erros
in the measured daily lightning quantities and affecting the performance
of the forecast models. To optimize the forecast model, dynamic
calibration factors for starnet network were developed taking into account
the status of the network every 15 minutes; these factors were calibrated
against field data observed by field mill in Belém. With the use of
corrected data the forecast model had a success rate higher than 70%
throughout the experiment.
References:
1. Sá, José Alberto S., ALMEIDA, Arthur da Costa, ROCHA, B. R. P., MOTA,
Maria Aurora S., SOUZA, José Ricardo Santos de, 2011, Lightning Forecast
Based on Hourly Evolution of the Convective Available Potential Energy
(CAPE) In: XIV International Conference on Atmospheric Electricity, Rio de
Janeiro. Anais do XIV International Conference on Atmospheric Electricity.
Rio de Janeiro
2. Sá, José Alberto S., ALMEIDA, Arthur da Costa, da Rocha, B.R.P., SOUZA,
José Ricardo Santos de; 2011; Recurrent Self-Organizing Map for Severe
Weather Patterns Recognition In: Recurrent Neural Network
ed.Croacia : INTECH, v.1
Data Analysis of upward lightning in Jaragua Peak
Carina Schumann, Marcelo Magalhães Fares Saba, Marco Antônio Ferro, Amanda Romão de Paiva,
Robson Jaques
Observations of upward lightning from tall objects have been reported since 1939. Interest in this subject has
grown recently, some of it because of the rapid expansion of wind power generation. Also, with the increasing
number of tall buildings and towers, there will be a corresponding increase in the number of upward lightning
flashes from these structures. Reports from recent field observations are beginning to address the nature of
upward lightning initiation, but much still needs to be learned. Examples are studies of upward lightning from
towers in winter thunderstorms in Japan (Wang and Takagi, 2010; and Lu et al., 2009) and summer
thunderstorms in Europe (Miki et al., 2005; Flache et al., 2008; and Diendorfer et al., 2009; Zhou et al., 2011)
and in North America (Mazur and Ruhnke, 2011; Hussein et al., 2011; Warner, 2011, and Warner et al., 2011).
During CHUVA Campaign, a combination of high-speed video and standard definition video were used to
record upward lightning flashes from multiple towers in Sao Paulo, a city located in southeastern Brazil with a
population over 10 million people, an average elevation of around 800 meters above sea level, and a flash
density of 15 flashes/km2.year. The upward flashes initiated from two towers located on top of a 300 m tall hill.
The heights of the towers were 130 m and 90 m. In this work, observations of 15 upward flashes made with
these assets were analyzed along video observations, different Lightning Location Systems, electric field
sensors and a lightning mapping array (LMA).
CHUVA Radar Measurements: Calibration and Attenuation Issues
Carlos A. Morales1, Rachel Albrecht2 and Thiago Biscaro2
1
Universidade de São Paulo (USP)
2
Instituto Nacional de Pesquisas Espaciais (INPE)
Although the Mobile X-Band Dual Polarization weather radar employed in the 3 CHUVA field
campaigns has been calibrated by Gemmatronik, the transmitted power is not updated in the
radar equation and the calibration curve (power x signal) needs to be checked frequently.
Furthermore, radome wetting could also cause some attenuation especially at the X-band
frequency. Due to these artifacts it is important to evaluate the quality of such measurements,
thus in this study we employ the methodology developed by Anagnostou et al. (2001) to
retrieve the performance of CHUVA weather radar against the consolidate measurements of
TRMM-PR. Finally, we will check if the rain attenuation algorithm used in the Gemmatronik
software is able to recover the signal during some moderate to severe raining systems.
Using Lightning Mapper Array to evaluate the lightning detection signatures at VLF, LF and
VHF systems
Carlos A. Morales1 and Rachel Albrecht2
1
Universidade de São Paulo (USP)
2
Instituto Nacional de Pesquisas Espaciais (INPE)
During the CHUVA-GLM field campaign 10 lightning detection networks were measuring the
lightning activity in the São Paulo area. This unprecedented field campaign aloud a great
opportunity for understanding the different lightning detection technologies, because
assuming that the Lightning Mapper Array (LMA) can capture all the electromagnetic
irradiated sources through a lightning discharge (breakdown, step leader, return stroke and
dart leaders), it is possible to correlate in space and time what the VLF, LF and VHF lightning
detection systems are really measuring, i.e., are they measuring sferics, leaders, return
strokes, sources or a complete lightning channel. For this presentation we are going to use a
case study on February 10th, 2012, where the Lightning Imaging Sensor (LIS) onboard the
TRMM satellite observed a storm in the São Paulo city. Coincident 90 seconds LIS
measurements were compared with LMA, LINET, Vaisala-TLS200, EarthNetwork-BrazilDat,
IMPACT/LPATS-RINDAT, ATDNet, STARNET, WWLLN, Vaisala-GLD360. In a preliminary analysis,
the total lightning systems (LMA, LINET, TLS-200 and EarthNetwork) were very comparable in
time, i.e., they had coincident time measurements, for the VLF and LF systems that were
designed to measure mainly cloud to ground discharges, we did find some differences, i.e.,
sometimes all measure and most of the time just one or two. As for the presentation, we will
be exploring these differences and spatial distribution that could provide insights on the type
of discharges been observed.
HRLAMENS - A PILOT PROJECT ON ENSEMBLE PREDICTION USING HIGH
RESOLUTION LIMITED AREA MODELS
Cunningham, Christopher (1); Saulo, Celeste (2,3,4); Anabor, Wagner (5); Camponogara, Gláuber
(6); Chaboureau, Jean-Pierre (7); Faus da Silva Dias, Maria Assunção (6); Ferreira, Márcio (1);
Freitas, Saulo (1); García Skabar, Yanina (1,4,8); Machado, Luiz (1); Matsudo, Cynthia (9);
Nascimento, Ernani (5); Nicolini, Matilde (2,3,4); Pulido, Manuel (4,10); Rodrigues, Joyce (1); Ruiz,
Juan (2,3,4); Salio, Paola (2,3,4); Santos, Daniel (5); Saucedo, Marcos (2,4); Stockler , Rafael (1);
Vendrasco, Eder (1)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
Instituto Nacional de Pesquisas Espaciais (INPE) - Centro de Previsão de Tempo e Estudos Climáticos (CPTEC), Cachoeira Paulista,
Brasil
Centro de Investigaciones del Mar y la Atmósfera (CONICET-UBA), Argentina
Dpto Cs. de la Atmósfera y los Océanos, F CEyN, Universidad de Buenos Aires, Argentina
UMI- IFAECI (CNRS/UBA/CONICET), Argentina
Universidade Federal de Santa Maria (UFSM), Brasil
Departamento de Ciências Atmosféricas, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo
L
A
U
T
CNRS T
F
e
Facultad de Agronomía, Universidad de Buenos Aires, Argentina
Servicio Meteorológico Nacional, Argentina
Department of Physics, FACENA, Universidad Nacional del Nordeste, Corrientes, Argentina
ABSTRACT
The Center for Weather Forecast and Climate Studies (CPTEC), the University of Buenos Aires (UBA) and the
Federal University of Paraná (UFPR) have been working on a project with focus on prediction of high impact
weather events in the La Plata Basin (LPB). This project had been assembled following the framework of a Research
and Development (ReD) project of the World Weather Research Program (WWRP). A recommendation from the
Joint Scientific Committee-WWRP of adding a high-resolution component to the project, motivated a proposal for
a mutual collaboration between CHUVA and LPB-ReD projects, which was presented and accepted by the occasion
of the first CHUVA workshop. The main objective of the present work is to describe the details of this cooperative
effort of combining global and high resolution models in an multi-model, multi-boundary ensemble that operates
during the Sta. Maria campaign of the CHUVA project. The ensemble is composed of a core of 5 model
configurations (2 executions of the BRAMS model plus 3 of the WRF model), which were integrated using CPTEC's
supercomputing facilities, plus four other configurations, which were integrated on the participating institutions
facilities. This core was designed to be driven by selected members of global Ensemble Prediction Systems (CPTEC
and NCEP) and also to be homogeneous in domain size, horizontal and vertical resolution (2 km of grid space and
41 levels). Partner institutions participating in the project (WRF-UBA-UNNE, WRF-Argentina SMN, WRF-UFSM and
MESO-NH-LA) have assisted the multi-model composition with their own model configurations. A selection
procedure based on spatial pattern resemblance was developed to choose one member, likely the best one, to
drive the high resolution LAM. Some insights on the role of the large scale, represented by the EPS boundary
conditions, on the quality of the forecast are given. A companion work will give details an assessment of this
intercomparison focused on precipitation forecasts quality during 4 particular events, when organized convection
has been observed
High resolution model intercomparison for Convective Events during CHUVA Santa María Matsudo, Cynthia(1); Saulo, Celeste(2,3,4); Cunningham, Christopher (5), Anabor, Wagner (6); Camponogara, Gláuber (7); Chaboureau, Jean Pierre (8); Faus da Silva Dias, Maria Assunção(7); Freitas, Saulo (5); García Skabar, Yanina(1,4,9); Machado, Luiz (5); Nascimento, Ernani (6); Nicolini, Matilde (2,3,4); Pulido, Manuel (4,10); Ruiz, Juan (2,3,4); Salio, Paola (2,3,4); Santos, Daniel (6); Saucedo, Marcos (2,4); Stockler , Rafael (5); Vendrasco, Eder (5) Affiliation: (1)
Servicio Meteorológico Nacional, Argentina (2)
Centro de Investigaciones del Mar y la Atmósfera (CONICET UBA), Argentina (3)
Dpto Cs. de la Atmósfera y los Océanos, F CEyN, Universidad de Buenos Aires, Argentina (4)
UMI IFAECI (CNRS/UBA/CONICET), Argentina. (5)
Instituto Nacional de Pesquisas Espaciais (INPE) Centro de Previsão de Tempo e Estudos Climáticos (CPTEC), Cachoeira Paulista, Brasil. (6)
Universidade Federal de Santa Maria (UFSM), Brasil. (7)
Departamento de Ciências Atmosféricas, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo (8)
Laboratoire d’Aerologie, Universite de Toulouse and CNRS, Toulouse, France. (9)
Facultad de Agronomía, Universidad de Buenos Aires, Argentina. (10)
Department of Physics, FACENA, Universidad Nacional del Nordeste, Corrientes, Argentina. Abstract: CHUVA Santa María took place between November 6 and December 22, 2012. In order to provide high resolution operational forecasts during this period, several institutions designed specific model runs centered around Santa María, Brazil. Besides the interest of providing operational forecasts, the researchers of the participant institutions discussed model settings aimed at generating a high resolution model ensemble for the first time over South America. This ensemble includes 9 members, with varying resolution from 2 km to 48 km grid spacing, though most of them lie in the 4 2 km range. Particular model settings based in the WRF model (e.g. those adopted by UFSM, CPTEC, UBA UNNE, Argentina SMN) have been chosen in order to analyze the effect of alternative boundary conditions, grid resolution and planetary boundary layer parameterization. In turn, other models (e.g. BRAMS, MESO NH) have also been employed in order to compare different model performance. This work provides an assessment of this intercomparison focused on precipitation forecasts quality during 4 particular events, when organized convection has been observed. Besides subjective comparison of forecasted and observed accumulated precipitation fields; temporal precipitation variability, at each point where disdrometers and/or automated stations are available, will be analyzed and varied performance metrics will be presented. 1234567689A8BCDE7B7F3F79287289BDC3F7923486743F792689A88728E36D89A8
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SSMI/S Satellite Rainfall Retrievals during CHUVA-GLM Experiment
Daniel Vila, Nicolas Viltard, Luiz A. Machado, Wagner F. Lima
This research effort regards the properties of the rain regimes over Brazil and the retrieval of
instantaneous rain itself from passive microwave radiometers on board low-orbiting satellites
like DMSP/SSMI/S. This study is conducted in the framework of the CHUVA-GLM campaign
(Vale do Paraiba) which is aimed at deploying a series of instruments in various locations over
Brazil in order to better characterize the various rainfall regimes.
The performance of two different algorithms, the Bayesian Rain retrieval Algorithm Including
Neural network (BRAIN) and Goddard Profile algorithm (GPROF), were carried out through a
comparison between SSMI/S retrievals and radar data during November 2011 - March 2012
over the Vale do Paraiba region (15 S - 31 S, 37 W - 57 W).
GNSS Observations of Deep Convective Timescales
in the Amazon
David K. Adams
Centro de Ciencias de la Atmósfera,
Universidad Nacional Autonoma de México,
D.F., México
and
Programa de Pós Graduação em Clima e
Ambiente, Universidade do Estado do
Amazonas, Manaus, Amazonas, Brazil
Seth I. Gutman and Kirk L. Holub,
Earth System Research Laboratory,
National Atmospheric and Oceanic
Administration, Boulder, CO, USA
Dulcineide S. Pereira
Programa de Pós Graduação em Clima e
Ambiente, Universidade do Estado do
Amazonas, Manaus, Amazonas, Brazil
In the tropics, deep precipitating convection dominates the weather and climate. Deep convection
determines and is determined by the spatial/temporal distribution of water vapor resulting from
complex interactions and feedbacks. However, observational systems, both surface-based and satellitebased, for the tropics tend to be inadequate for observing the convective-water vapor relationship,
particularly for scales below mesoscale. For example, to understand the shallow-to-deep convective
transition and organization on the mesoscale in the tropics and their relationship to the water vapor
distribution, high frequency (~10 minutes), all weather observations are absolutely necessary. GNSS
meteorology offers a durable, frequent, all-weather relatively inexpensive measures of column water
vapor/precipitable water vapor. In this study, we utilize GNSS PWV for determining deep convective
water vapor convergence time scales for the equatorial tropics, namely, Manaus in the central Amazon
Basin. For a 3.5-year period, 320 observed deep convective events were analyzed. Two water vapor
convergence timescales are observed ; a roughly 8 hour period of weak water vapor convergence and a
strong non-linear shallow-to-deep transition time scale of 4 hours. Within the 4 hour shallow-to-deep
transition timescale, identifiable structure also exists. Maximum water vapor convergence is observed
within 1 hour of the maximum precipitable water vapor value. During this final hour, rapid deep cloud
growth and initiation of heavy precipitation occurs. This 4-hour shallow-to-deep transition time scale
shows strikingly little variation, even when conditioned upon PWV values, diurnal vs. nocturnal
convection, or measures of convective intensity (e.g., minimum cloud top temperature) . This suggest
that the shallow-to-deep transition time is an intrinsic property of convection. The longer 8 hour
timescale does show some conditional dependency on different measures of convective intensity or
thermodynamic environment.
Analysis of these water vapor convergence time scales is currently being carried out for the CHUVA
Belem GNSS Dense Network data set. Unlike Manaus, forcing in Belem is strongly associated with
sea-breezes, providing an opportunity to examine the shallow-to-deep transition under different forcing.
Result from this analysis as well as from Manaus will be presented. We argue that the GNSS-derived
water vapor convergence time scale is valuable, not only for identify intrinsic characteristic of deep
convection, but also for providing a metric for numerical modeling of deep tropical convection.
CHUVA Manaus and GoAmazon2014 will provide and unprecedented opportunity to understand the
shallow-to-deep transition in a Tropical continental region.
Lightning and Polarimetric Radar Behavior of Incipient Thunderstorms in CHUVA
Earle Williams, MIT; Enrique Mattos, CPTEC; Luiz Machado, CPTEC; Antonio Saraiva, INPE
Movies of radar PPI scans made at 6-minute intervals with the X-band polarimetric radar at UNIVAP
during the wet season of 2011-2012 have been used to identify 20 incipient isolated thunderstorms on
five different storm days (November 10-13, March 13). A number of different lightning networks
(BrazilDat, Lightning Mapping Array (LMA), Vaisala TLS200 and GLD360, LINET) have been used to
characterize the lightning in each incipient storm. The 3D radar and lightning histories have been
followed in each case from the initial radar echo to the first cloud-to-ground (CG) lightning flash. The
sequence of events is remarkably reproducible and consistent with earlier studies in the Northern
Hemisphere: initial radar echo, initial LMA radiation, initial intracloud (IC) flash, and initial CG flash (all
negative polarity). The mean time interval from initial radar echo to first CG flash is 44 minutes, with a
minimum time of 18 minutes and a maximum time of 78 minutes. The typical radar-measured storm
diameter at the time of the initial CG flash is 15 km. In two storm cases, no CG flash was attained, but
only IC flashes. In those cases, the maximum radar-measured diameter is only 7-8 km at the time of the
lightning. These findings support the idea that a sufficiently extended charge reservoir is needed to
enable a bridging of the nominal 5-7 km vertical distance between main negative charge center and
ground by the initial CG flash. Of the 18 initial CG flashes, 16 of them (89%) are single-stroke flashes.
This finding is consistent with the idea that when the main charge reservoir is compact, the positive
leader intruding negative space charge is unable to continue its progression to stress the cutoff channel
to ground and provide for a second stroke. Profiles of differential reflectivity are underway in the
developing thunderstorms to distinguish negative ZDR values (associated with conical graupel) from
positive ZDR values (associated with large raindrops below the freezing level and with supercooled
drops above the freezing level.) The microphysical nature of the initial radar echo will also be diagnosed
with this dual-pol method.
Characteristics of the X-Band Polarimetric Radar Associated With the Lightning
Electrical Activity
1
Enrique Vieira Mattos, 1Luiz Augusto Toledo Machado
1
Center for Weather Forecast and Climate Studies (CPTEC)
National Institute of Space Research (INPE), Brazil
This work have the objective of the evaluate the impact of cloud microphysics on the
intensity of lightning electrical activity. As part of the fourth field campaign from
CHUVA project called CHUVA-Geostationary Lightning Mapper-Paraíba Valley
(CHUVA-GLM-Vale) has been used data from November 2011 to March 2012 on the
Paraíba Valley in the Sao Paulo state, Brazil. Data of the horizontal reflectivity factor
(Zh) and vertical (Zv), differential reflectivity (Zdr), specific differential phase (Kdp) and
the correlation coefficient (
hv)
from X-pol Radar; VHF sources from Lightning Mapper
Array (LMA) and intra-cloud and cloud-to-ground lightning from Brasildat have been
used. We have applied for all period data the correction of attenuation (for dBZ and Zdr
variables), correction when has precipitation over of the radar (for dBZ, case called
correction of wet radome) and correction of Zdr for the bias that exists when the radar
points vertically. Analysis of the vertical profile from polarimetric variables was
combined with different classes of electrical intensity of VHF sources like: (i) Weak,
(ii) Moderate and (iii) Higher occurrence. An higher LMA occurrence was associated
with an homogeny reflectivity vertical distribution, with higher values of reflectivity
both inside of cloud warm and cold region. To differential reflectivity higher the
intensity of electrical activity the distribution shifts for negative values of Zdr and close
the height of the 7 Km. The variable Kdp showed the same behavior of Zdr and for
correlation factor distribution there was many events inside of warm cloud region.
Analysis of mean profile also showed that higher electrical activity is correlated with
existence of vertically oriented ice or conical graupel inside cold cloud region (Zdr more
negative) and associated with fewer variability of hydrometeors kind (higher correlation
factor). Furthermore the vertical distribution of VHF source has showed an classic
electrical bipolar structure found in typical cloud for all the class of VHF sources. So in
this way, this currently being determined the distribution pattern of polarimetrics
variable for both centers of electrical charge. The same analysis has been done for
negative and positive cloud-to-ground strokes and intra-cloud lightning.
Evandro M. Anselmo1*
Carlos A. Morales Rogriguez1
Moacir Lacerda2
Rachel Albrecht3
1 - Institute of Astronomy, Geophysics and Atmospheric Sciences of USP
2 - Federal University of Mato Grosso do Sul
3 - National institute for Space Research - INPE
Electrostatic fields observed during the CHUVA campaign
Observing the Electric Field Mill measures during a thunderstorm, is notable the
increased of electrostatic field associated with the electrification processes before the
lightning occurrence. On CHUVA experiment, electrostatic field measurements were
done by Field Mill network on 3 sites: in Belém – PA where the Field Mill network
had 3 sensors, Vale do Paraíba – SP with 4 sensors and finally in Santa Maria – RS
that had the network with 5 sensors. Based on Electric Field Mill measures, the
lightning occurrence was identify and studied the frequency of occurrence of electrical
field values for 2 minutes before of each discharge. Values above 2000 V/m are most
common in Belém – PA and Santa Maria – RS than Vale do Paraíba – SP. In Belém –
PA the thunderstorms charge centers were often negative while in the Vale do Paraíba
– SP and Santa Maria – RS, the polarity positive or negative, were more balanced.
*
[email protected]
Space-time Evolution of Sprite Producing Thunderstorms During CHUVA Sul Campaign in
2012
F. T. São Sabbas, R. Azambuja, R. Anchayhua, A. Morais
Instituto Nacional de Pesquisas Espacias - INPE
Av. dos Astronautas, 1.758, Jd da Granja
São José dos Campos, SP, Brazil, 12227-010
During the months of November and December of 2012 the CHUVA Project performed the
southern component of its campaigns, designated as CHUVA Sul. During this campaign, a suite of
meteorological sensors was installed in the southernmost state of Brazil, Rio Grande do Sul. In
order to perform observations of Transient Luminous Events – TLEs, as part of this campaign, a
team from the Atmospheric and Space Electrodynamical Coupling – ACATMOS group of INPE set
up optical observation sites at the headquarters of Anti-Granizo Fraiburgo-AGF company in Lebon
Regis, Santa Catarina State, and at SIMEPAR radar site, near Curitiba, Paraná State.
TLE is the generic term adopted to designate optical emissions excited in the upper atmosphere
above thunderstorms as a consequence of intense electric fields of lighting discharges. They are of
low luminosity, 100s of kR – 10ths of MR, therefore only observable at night, and of short duration,
few ms to few 100s of ms. They signal the electrodynamical coupling between the atmospheric
layers and sprites are the most spectacular of these events.
In the nights of 18-19/11/12 e 10-11/12 sprites above Rio Grande do Sul were recorded from the
AGF site. A total of 17 sprites were recorded during these observations. This paper will present
preliminary results describing the temporal and spatial evolution of the thunderstorms that
generated the observed sprites. The work was performed using IR and Water Vapor images from
the GOES 12 weather satellite, lightning data from the BrasilDAT network, and estimated locations
of the sprites. We will present preliminary information on the life cycle of the storm, its expansion
rate and the estimated overshooting of the cloud tops. We will also show the initial results of the
relationship between the sprites and the lightning by identifying the cloud top regions above which
sprites were generated, as well as the regions where the parent lightning may have withdraw charge
from. Other aspects of this research, further characterizing the sprites observed, the parent lightning,
the synoptic and thermodynamical scenario that led to the formation of the sprite producing
thunderstorms and further details of the internal structure of the storms based on radar data will be
presented in different papers from the co-authors of this work.
EVALUATION OF A BIN CLOUD MODEL USING DATA FROM CHUVA
PROJECT FOR FORTALEZA, CEARA
Gerson P. ALMEIDA² , Levi M. FRANKLIN¹,², João Bosco V. LEAL JUNIOR²,
1-Secretatia de Educação do Ceará, SEDUC
2- Universidade Estadual do Ceara, UECE
Abstract.
This study evaluated a bin cloud model, and compares results from simulations
using data form the CHUVA project. Atmospheric conditions were taken from
soundings performed in Fortaleza in April 2011. We compare rainfall rate to
observations at four sites in Fortaleza. The analysis was performed in a
qualitative way, ie, observation or not of rainfall. It is shown that the bin cloud
model can represent appropriately most of the observation.
Description of the model.
The model is that described in Costa (1995), Almeida (1997), Costa et al.,
(2000) e Almeida e Santos (2007). On the cloud model advection is evaluated
using the scheme of Bott (1989 a, b). An iteractive numerical procedure is used
to calculate the stream function, using the vorticity equation as defined by Stone
(1968) and Jacobs (1972).
For turbulence closure we use a first order
Smagorinsky (1963), Soong e Ogura (1973)
scheme, according to
We modified the model domain from 80x80 up to 230x230 grid points, with grid
spacing of 80 meters both on the horizontal and vertical domain. Cloud
Condensation Nuclei (CCN) were represented by 178 categories, with dry
diameters ranging from 12 nm up to 15.2 m. The corresponding activation
supersaturations ranging from 2.8% to 0.0% (ALMEIDA e SANTOS 2007).
The bin cloud model uses 100 drops categories, with diameters ranging from
2.0 m to 1.0 (COSTA et al., 2000).
Cloud microphysical process (activation, condensation/evaporation, collision
coalescence and collisional break up) modify drop size distribution function and
are evaluated using a modified Kovetz and Olund (1969) method. The
condensation process is calculated using a semi lagrangean scheme, as
defined by Kogan (1991), producing realistic values for supersaturation.
The model boundaries are defined as rigid, without slipping. To avoid numerical
instability, absorbing levels are imposed at upper and lateral levels of the
model.
CCN distribution is evaluated for three regimes: maritime, polluted and
, where
intermediate. The three distributions follow the relation
is
, and are constants, and is the supersaturation
the concentration in
in . Values for and are: 245 and 0.33 for the maritime regime; 1275 and
0.72 for the intermadiate regime; and 2450 and 0.9569 for the polluted one.
Methodology
Comparisons were performed for 10 soundings, evaluating the accumulated
precipitation simulated in 60 minutes.
We performed a simulation control to evaluate the accumulated precipitation.
Additional simulations were, then, compared the simulation control, varying the
number of grid points and smoothing the data point of the sounding.
For simulations presented here the model was configured with 150x150 grid
points and we chose a maritime regime for the CCN distribution. The
simulations of 1 hour was performed using a dynamic time steep of 5 second,
and a microphysical time step of 0.25 seconds.
We also carried out several simulations to evaluate the cloud evolution as a
function of the sounding smoothing process. The smoothing is needed to
mitigate spikes in thermal inversions.
RESULTS.
The cloud model can qualitatively represent about 45% of all precipitation
events observed on the four collecting sites when the simulation control was
used.
Using smoothed sounding increase the representation to 54% of precipitation
events observed on the four observational sites.
Increasing grid point domain also increase the representation to 66% of the
precipitation events
The figures below represent the simulation control for those days that produced
precipitation. (a) April 9, 2011 at 05:37 UTC, (b) April 9, 2011 at 12:01 UTC, (c)
April 9, 2011 at 18:01 UTC, (d) April 10, 2011 at 17:56 UTC, (e) April 11, 2011
at 11:41 UTC, (f), April 11, 2011 at 17:36 UTC, (g), April 11, 2011 at 23:36 UTC,
(h) April 12, 2011 at 11:48 UTC
(a)
(e)
(b)
(f)
(c)
(g)
(d)
(h)
CONCLUSIONS.
The bin cloud model is able to represents qualitatively the amount of
precipitation produced during observation of Projeto CHUVA in Fortaleza. In
some events a quantitatively representation was also achieved.
REFERENCES.
ALMEIDA, G. P. Microfísica explícita para um modelo de nuvem quente convectiva,
Dissertação de Mestrado, Departamento de Física, Universidade Federal do Ceará,
107 pp. 1997.
ALMEIDA, G.P.; R. R. SANTOS. Modeling the relation between CCN and the vertical
evolution of cloud drop size distribution in convective clouds with parcel model. Revista
Brasileira de Meteorologia. v. 22, n. 3, p. 313 - 321, 2007.
BOTT, A. A positive definite advection scheme obtained by nonlinear renormalization
of the advective fluxes. Monthly Weather Review. v. 117, p. 1006–1015, 1989a.
BOTT, A. A positive definite advection scheme obtained by nonlinear renormalization
of the advective fluxes. Monthly Weather Review. v. 117, p. 2633-2636, 1989b.
COSTA, A. A. Desenvolvimento de modelo bidimensional, axi-simétrico, de nuvem
quente com microfísica parametrizada. Dissertação de Mestrado, Departamento de
Física, Universidade Federal do Ceará. 135 pp.1995.
COSTA A. A.; ALMEIDA, G. P.; SAMPAIO, A. J. C. A bin microphysics cloud model
with high order, positive definite advection. Atmospheric Research. v. 55 p. 225-255,
2000.
EASTER, R. C. Two modified versions of Bott’s positive definite numerical advection
scheme. Monthly Weather Review. v. 121, p. 297–304, 1993.
JACOBS, D.A.H. The strongly implicit procedure for numerical solution of parabolic and
elliptic partial differential equations. Central Electricity Research Laboratory. 1972.
KOGAN, Y. L. The simulation of a convective cloud in a 3-D model with explicit
microphysics: Part I. Model description and sensitivity experiments. Journal of the
Atmospheric Sciences. v. 48, p. 1160–1189. 1991.
KOVETZ, A.; OLUND, B. The Effect of Coalescence and Condensation on Rain
Formation in a Cloud of Finite Vertical Extent. Journal of the Atmospheric Sciences. v.
26, n. 5P2, p. 1060-1065, 1969.
SMAGORINSKY, J. General circulation experiments with the primitive equations. I the
basic experiment. Monthly Weather Review. v. 91, p. 99-164, 1963.
SOONG, S. T.; Y. OGURA. A comparison between axisymmetric and Slabsimmetric
cumulus cloud models. Journal Atmospheric Sciences. v. 30, p. 879-893, 1973.
STONE, H. L. Iterative solution of implicit approximation of multidimensional partial
differential equations. SIAM Journal Numerical Analysis. v. 5, p. 530–558, 1968.
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Could LIDAR methods automatically detect the top of ABL? – Case
studies for Santa Maria / CHUVA-SUL
Gregori de A. Moreira¹, Eduardo Landulfo¹, Lucas Vaz Peres2, Glauber Mariano3, Riad
Bourayou¹
¹ Center for Lasers and Applications, IPEN , Sao Paulo, Brazil
2 Laboratório de Troposfera/Estratosfera - Ozônio - Radiação Ultravioleta – PMOA/CRS/INPE – MCT,
Brazil
3 Glauber Lopes Mariano, Professor - Meteorology Department at Universidade Federal de Pelotas,
Pelotas-RS
The data presented here were obtained using measurements performed during the CHUVA-SUL
campaign. The current authors list indicates, for divulgation inside the project, the main actors of this
study.
Introduction
The Planetary Boundary Layer (PBL) is the region of troposphere situated in
its lower part. Due to its direct contact with the surface and it's responsible for
the main energy exchanges with the Atmosphere [5], influencing directly the
climate. Therefore, the understanding of its behavior and the main factors that
influence the PBL are very important to allow for a reasonable description and
comprehension of the main process occurring at low altitude. The LIDAR
technique has been appointed by many authors as one of the best tools to
investigate the PBL thanks to its good spatial and time resolutions, besides
enabling the realization of data capture without to influence the study
object.[1,2,3]
The main objective of this work is to perform a comparison of the behavior of
three algorithms (Gradient Method,
Wavelet Covariance Transform and
Richardson’s Number) retrieving the height of the PBL and to correlate the
atmospheric conditions with their respective performance.
Methodology
A case study is performed on relevant days of the multi-instrument campaign
CHUVA-SUL held 2012, in the city of Santa Maria – Rio Grande do Sul - Brazil.
In this campaign a mobile LIDAR system was used for data capture. The
analysis of the ABL height was done with three mathematical algorithms: the
Gradient Method (GM), using the derivative of logarithm, the WCT (Wavelet
Covariance Transform); and finally the method of the Richardson Number,
which used for validation purposes, as it depends solely on radiossounding.
•
Gradient Method (GM) In this case was used the derivative of logarithm
the LIDAR signal corrected with the square of height (12345 3 6 4:
7
89A212345 3 6 4
73
which minimum value is the top of ABL [2].
•
Wavelet Covariance Transform (WCT) This method consists in
detection of change in range-corrected signal by the realization of the
covariance between the wavelet function and the LIDAR signal corrected with
the height 212345 3 6 4. It is very important that the function chosen has
characteristics similar to the analyzed signal. For this case the most indicated
function is the Haar wavelet [1].
where b and a are the vertical translation and dilatation of function, respectively
(values given in literature [5]), and z is the height. To this method, the point
where the function has its maximum corresponds to the top of ABL.
•
Richardson’s Number (RN) This algorithm does not depend of the
LIDAR data, but it depends of radio-sounding data. The RN is obtained from the
following equation:
BCD E 3
F234 FD F 234²
A
where: z is the height, g is the value of gravity, F is the average value of
potential temperature of layer, F234 is the potential temperature in z point, FD is
the potential temperature at ground level and U (z ) is the wind speed at the
altitude z. The altitude of the top of PBL is the first point where BCD is below
0.25. Note that due to the low resolution of the radio-sounding data at low
altitude, the Richardson number was determined using interpolated profiles,
thus delivering an indicative rather than strict reference value.
Cases study
Stable Conditions
On November 29th the atmosphere presented stable conditions with high
clouds and a well defined PBL (Fig 1-A). These conditions facilitated the
detection of the PBL top by all algorithms. The WTC didn’t need parameter
value departing from their standard values, but the profile was most detailed for
low values to b (for example b = 10). The GM and WCT presented results close
to each other, correlating well with the NR (Fig. 1-B).
12
32
Fig. 1 - Day with stable conditions - A: Profile LIDAR -
B: Comparison among the three methods.
Day with Sublayers
On November 8th some aerosol sublayers inside the PBL were observed,
difficulting the retrieval of the LIDAR algorithms (GM and WCT) because initially
they could not discriminate the sublayers from the top of ABL (Fig. 2-A). To
solve this problem, it was necessary to adopt a threshold value [1] in two
methods.
In order to look for the optimal performance of the algorithms, we performed
retrievals using several values for the threshold (Fig. 2-B). Values for the WCT
ranged from 0.0 to 0.8, while they ranged from -0.01 to -0.001for the GM. For
the GM, an intermediate value (-0.005) was sufficient for a robust differentiation
of the sublayers from the top of PBL. Lower values induced an excessive loss of
information. The WCT behaved as expected for low values to b (for example b
= 10), allows a great detail in profile. A high value of a was necessary (for
example a = 200) for the maximum to become more pronounced, thus
facilitating the discrimination. A low value of the threshold (0.2) is enough to
differentiate the sublayers from the top of PBL, without noticeable loss of
information.
12
32
Fig. 2 - Day with sublayers - A: LIDAR profile – B: Comparison between three methods.
Turbulent Day
The last case is the day November 9th, where clouds and some sublayers
where detected by the LIDAR near the supposed top of the PBL (Fig. 3-A), and
in such a quantity that the algorithms were at first confounded; It was then
necessary to refine the analysis with other values of the parameters. For GM,
only the lowest value of the threshold helped obtaining a height to top of ABL
near the one inferred by NR, at the cost of loss of stability. The WCT presented
results partially satisfactory only for great values to b. A high value for a helped
the transition from PBL to free troposphere become more pronounced, thus
facilitating the detection.
High values for the threshold, enabling greater differentiation between
sublayers and top of ABL, had to be used, at the cost of resolution loss (Fig. 3B).
12
32
Fig. 3 - Turbulent Day - A: LIDAR profile – B: Comparison between three methods.
Conclusion
GM and WCT retrieved PBL heights within the range of RN. It was also
observed that in cases of cloudiness or in the presence of sublayers, their
performance is reduced or deceiving, but could be revived using threshold
values or adapting their specific parameters, especially for the WCT algorithm.
For turbulent days, the choice of the parameters appears to be critical, as we
saw that a little variation can generate a big difference in the results, but basic
trends could be extracted and value ranges could be identificated. This study
could constitute a further step towards an automated PBL height detection
where the choice of adequate parameters for WCT could be assisted by a
rough analysis of the quantity of perturbing sublayers (to define the ranges of
the threshold and parameters a and b of the WCT), and a minimization method
taking into account the history of the LIDAR profiles (to assert PBL height
retrieval continuity).
References
[1] BAARS, H., ANSMANN, A., ENGELMANN, R., and ALTHAUSEN, D.
Continuous monitoring of the boundary-layer top with LIDAR. Atmospheric
Chemistry and Physics 8 (2008), 7281- 7296.
[2] DAVIS, K. J., GAMAGE, N., HAGELBERG, C. R., and KIELME, C. An
objective method for deriving atmospheric structure from airbone lidar
observations. Journal of Atmospheric And Oceanic Technology 17 (2000), 1455
– 1468
[3] MATOS, C. A. D., TORRES, A. S., LANDULFO, E., NAKAEMA, W. M.,
UEHARA, S. T., SAWAMURA, P., and JESUS, W. D. Estudo de camada limite
planetária com o uso de um lidar de retroespalhamento em São Paulo, Brasil.
In Anais XIII Simpósio Brasileiro de Sensoriamento Remoto (2007).
[4] Stull, R. B. An Introduction to Boundary Layer Meteorology. Kluwer
Academic Publishers, 1988.
[5] WALLACE, J. M., and HOBBS, P. V. Atmospheric Science - An
Introductory Survey. Academic Press, 2006.
Spatial distribution of meteorological variables
during severe weather events in CHUVA-Sul
Guilherme Marqueri da Silva1 , Otávio Acevedo1 , Pablo Oliveira1 , Hans Zimmermann1 ,
Ernani Nascimento1
1
UFSM - Santa Maria - Rio Grande do Sul
A 7-station meteorological micronet started to operate in August 2012 in a steep topography region around Santa Maria, RS. Five of the stations were deployed across the
steepest slope, along a North-South oriented line, from a hilly area to plainlands, over
which the altitudinal difference was slightly over 300 m. The other two stations were
installed in intermediate altitudes, one to the East and the other to the West of the remaining 5 stations. Variables observed in each station are precipitation, air pressure,
temperature, humidity, wind speed, direction and gusts, each collected every 2 minutes.
The micronet operated during the period of Chuva-Sul project, conducted at the Santa
Maria region, from November to December 2012. The present study aims at characterizing severe weather events from August 2012 to March 2013. Variables such as pressure
rise, temperature drop, wind gust and total rainfall, along with their respective times of
occurrence are compared among the 7 stations for each of the events that occurred along
the period. It allows characterizing with detailed precision the typical evolution of these
events in the region, and how the topography influenced it.
1
Performance Comparison between Different Lightning Datasets
during CHUVA Campaign
Hao Zheng1, Robert H. Holzworth1, Michael L. Hutchins1, James B. Brundell2,
Stan Heckman3 and Osmar Pinto, Jr.4
(1 Earth and Space Sciences, University of Washington, Seattle, WA 98195)
(2 ULTRAMSK, Dunedin, 9013 New Zealand)
(3 Earth Networks, Germantown, MD 20876)
(4 INPE, Sao Jose dos Campos, SP, Brazil)
From Nov. 2011 to Mar. 2012, we compared lightning data from the Brazilian Total
Lightning Network (BTLN), World Wide Lightning Location Network (WWLLN) and other
lightning networks in the CHUVA region, which is centered at Sao Paulo, Brazil with a
radius of 666 km. A 0.5° box in latitude and longitude and 2 ms time window was used
as the criteria. Assuming BTLN observed most of the lightning strokes in this region, we
calculated the detection efficiency of the other networks. Also, we compared the
difference of detection efficiency on land and on ocean among these networks. For the
location accuracy, we found that most of the networks give the same result, but some
showed an obvious offset. The peak current detected by different networks was also
compared, including Cloud-to-Ground and In-Cloud lightning. At last, we calculated the
relation between VLF energy (WWLLN) and the peak current (BTLN), which is found to
be a relationship similar to that result found in the in the USA.
CHUVA International Workshop, 2013, Sao Paulo, Brazil
Abstract
Ground-based and space-borne lightning observations during CHUVA
H. Höller1, H.-D. Betz2,3, C. Morales4 , R.J. Blakeslee5, J.C. Bailey6, R.I. Albrecht7
(1) Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre,
Oberpfaffenhofen, Germany
(2) Physics Department, University of Munich, Germany
(3) Nowcast GmbH, Munich, Germany
(4) Universidade de São Paulo, Instituto de Astronomia, Geofisica e Ciências Atmosféricas,
São Paulo, Brazil
(5) NASA Marshall Space Flight Center, Huntsville, USA
(6) University of Alabama, Huntsville, USA
(7) Instituto Nacional de Pesquisas Espaciais (INPE), Cachoeira Paulista, Brazil
Future geostationary satellite systems will offer a variety of improved observing capabilities
which will be extremely useful for many applications like numerical weather forecasting,
nowcasting of severe weather, climate research or hydrology. The future payloads will
include the optical lightning imagers LI on MTG (Meteosat Third Generation) and GLM
(Geostationary Lightning Mapper) on GOES-R (Geostationary Operational Environmental
Satellite - R Series). Proper interpretation of these optical data requires a better
understanding of what components of a flash are to be seen from space and how these
observations relate to ground based radio frequency observations.
For assessing the future performances and benefits of a geostationary lightning sensor this
study takes advantage of the comprehensive lightning data sets obtained from the recent
CHUVA field experiment performed in Brazil (CHUVA - Cloud processes of tHe main
precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM
(GlobAl Precipitation Measurement)). During the rainy season of 2011-2012 a large number
of ground based lightning detection systems was set up in the Sao Paulo area as part of the
CHUVA-GLM Vale do Paraíba campaign. In the present study we look at the detailed radio
frequency (RF) based observation from LINET (Lightning detection network operated by
DLR, nowcast and USP) observing strokes in the VLF/LF (very low and low frequency)
range, the LMA (Lightning Mapping Array) from NASA observing RF sources in the VHF
(very high frequency) range and the TRMM-LIS (Tropical Rainfall Measuring MissionLightning Imaging Sensor) optical space borne lightning imager. The LIS is used as a
reference instrument for the future geostationary sensors. Thus it is possible to study the
relations between the RF and optical signals from lightning in detail and to assess the
performance of the future geostationary observations from a set of proxy satellite data
generated from the ground based observations.
In confirmation of previous studies, it was found that often a direct temporal coincidence of
RF signals (LINET strokes) and optical pulses (LIS groups) exists. The short baseline
configuration of LINET allowed observing the strokes mapping the flash branches similar to
LMA, but by locating the limited number of strong cloud strokes rather than a large number of
weak source points from leader steps. An initial breakdown phase of vertically propagating
sources can often be found in LINET and LMA data. The higher level LINET and LMA signals
have higher probability to be optically detected. Lower level LINET and LMA signals are
optically detected from above in case of missing high level precipitation as inferred from
radar observations provided by USP.
SEVERE STORM DURING THE CAMPAIGN OF PROJECT CHUVA IN THE
CITY OF BELÉM
Ivan B. FIUZA de MELLO 1 , Júlia C. PAIVA COHEN 2
1
Graduated in Meteorology at UFPA - Belém - Pará - [email protected]
2
Meteorology Faculty UFPA - Belém - Pará - [email protected]
ABSTRACT:This paper analyzes the development of a severe storm formed during the
afternoon of June 7, 2011 in the northwestern state of Maranhão that propagated toward
the city of Belém, when the Project Chuva campaign was being held in this city. During
the passage of this storm in Belém it was observed intense rain, strong winds and heavy
thunderstorms that caused material losses in the city. During the life cycle of this storm
there was a center of maximum velocity of wind-driven in the direction of propagation
of this storm. It was observed a reduction in temperature and humidity during the
passage of this storm in the experimental area of the Project Rain. It was also carried out
numerical simulation of this storm and the results were purchasable those found in the
observed data.
1 - INTRODUCTION
The constant atmospheric instability in Amazon Basin due to the wide
availability of heat, moisture and energy, creates ideal weather conditions for the
formation of severe storms in different scales, such as mesoscale convective systems
(YOSHIDA, 2002). Mesoscale convective systems (MCS) are classified into three subscales: meso- (200-2000 km), meso- (20-200 km) and meso- (2-20 km)
(ORLANSKI, 1975).
To study and understand the dynamics of mesoscale convective systems in the
Amazon region, the first experimental mesoscale campaigns were performed in the
1980s, such as the ABLE-2b, which, in addition to the network data collection on the
scale of the Amazon basin also included the installation of a mesoscale network in the
Manaus region (HARISS, 1988). With the arrival of the LBA, mesoscale campaigns
were conducted in various regions of the Amazon Basin (SILVA DIAS, 2002, 2004;
FITAZJARRALD, et. al. 2008), providing the elucidation of various aspects of
mesoscale phenomena. However, there is still much to advance the understanding of the
physics
of
an
internal
storm,
and
Project
Chuva
(http://chuvaproject.cptec.inpe.br/portal/br/) allows that questions that are still in hold
about the subject, in Brazil, may be better understood.
During the days of May 30 th to July 2th 2011, a Project Chuva campaign was
carried out in Belém do Pará, where several convective systems were observed, as well
as squall lines, isolated convection and severe storms, such as supercells.
Supercells are deep convective systems, formed from the difference of
temperature and pressure between two air masses. The period of formation of these cells
occurs at the end of the afternoon, a time when the atmosphere is most unstable, with
atmospheric turbulence and the presence of clouds with great vertical development
(CB).
The supercells presents a characteristic of been isolated clouds from other cloud
systems, whose base extends nearby the proximities of the surface, the presence of gust
fronts and mamattus clouds, intense areas of rain and a change in flow direction of the
prevailing wind in the region where the system is acting. Analyzes and studies suggest
that these systems may be classified as MCS, by having physical and visual
characteristics of a mesocyclone at low levels. (DAVIES, 1986).
Thus, the main objective of this work is to analyze the formation and
propagation of a mesoscale convective system that formed in the northwestern state of
Maranhão and spread westward, entering the state of Pará, with maximum activity
recorded on the town Belém, for subsequent dissipation in Marajó Island.
2 –METHODOLOGY
Figure 1 shows the location of the instruments installed by Project Chuva in
Belém area. In the experimental site of Outeiro, located inside Belém area, temperature,
humidity and wind data were collected such as data from rain gauges and disdrometers
in order to analyze the impact of the passage of this storm.
At Belém airport, on that occasion, radiosondes were launched four times at 00,
06, 12, and 18 UTC, throughout the campaign period. The radiosonde launched at 18
UTC on 7th June is the atmospheric condition before the arrival of the storm in Belém,
while the one launched at 00 UTC of June 8th, shows the environment after the storm.
Images from GOES-12 satellite were used to analyze the life cycle of the storm since its
formation in northwest Maranhão until the moment it hit the city of Belém. When this
system reached Belém area, it was used dual polarization X-band data from the radar
installed in UFPA, which allowed a more detailed analysis of the storm, both
horizontally and vertically.
The NCEP reanalysis also were used to investigate the large-scale environment
where they developed this convective system.
Figure 1 - Location of meteorological instruments used during the Project Rain in the
Belém region.
The Brazilian version of the Regional Atmospheric Modeling System (BRAMS)
(PIELKE, 1992 and COTTON, 2003) was used to verify mainly the structure of the
storm that reached the Project Chuva area in Belém when the collected data by Project
Chuva was available which allowed to calibrate the results acquired by the numerical
simulations.
The BRAMS is a three-dimensional model consisting of a set of equations
prognostic, including dynamic and thermodynamic microphysics hydrometeors, which
are numerically solved using finite difference scheme. This model contains interactions
with several submodels that simulate the exchange of heat and water interfaces in soilvegetation-atmosphere (WALKO, 2000); turbulent processes in the surface layer
(LOUIS, 1979), processes in turbulent boundary layer (MELLOR; YAMADA, 1982);
transfer of solar and thermal radiation and its interaction with hydrometeors
(HARRINGTON, 1997), and cloud and precipitation microphysics (WALKO, 2000).
The simulation of this storm has been developed using a grid whose horizontal
resolution was 9 km, with an array of 135x99x40 points. 27 were considered in the
vertical levels of the atmosphere, the first being equal to 50 meters and the next
increased by a factor of 1.1, when compared to the previous level until 1000 and then
remains constant up to the top of the model.
The NCEP reanalysis, vegetation data from INPE, the global topography data
from the United States Geological Survey (USGS) data and sea surface temperature
(SST) from NOAA were used as initial and boundary condition of the model.
The model integration was 18 hours, from 12 UTC on 7th June 2011 until 06
UTC on June 8th, 2011, which covers the period of training, development and
dissipation of convective cell.
3 - RESULTS AND DISCUSSION
3.1 LIFE CYCLE OF THE STORM
Figure 2 shows the life cycle of the storm from its formation until its
dissipation. This convective system formed in the west coast state of Maranhão at 14
UTC on 7th June 2011 (not showed), two hours later there is an intensification of this
convection that spread westward along the coast, reaching Belém area around 20 UTC
of the same day (Figure 2c). The arrival of this convective cell in Belém area caused
heavy rain with flooding, felling billboards and trees, among other disorders. This storm
continued its spread reaching Marajó Island at 23:30 UTC, occurred where its
dissipation (Fig. 2e).
Figure 3 below shows the reflectivity in dBZ radar dual polarization X-band
when the convective system was in the region of Belém, at 20:14 UTC on June 7th,
2011.
Figure 4 shows the vertical profile of the storm at 20:30 UTC on June 7 th, 2011,
the city of Belém. Note that the top of the storm reached a vertical development of up to
13 km altitude. The regions of higher reflectivity were inside the storm between the
surface and the first 5 km altitude, near 40 dBZ, indicating the regions of more intense
activity of the system.
a) 16 UTC June 7th 2011
b) 18 UTC June 7th 2011
c) 20 UTC June 7th 2011
d) 22 UTC June 7th2011
e) 23:30 UTC June 7th 2011
Figure 2 - Life cycle of convective cell since its formation in the state of Maranhão,
until its dissipation in the region of Marajó.
Figure 3 - Image of the X band radar 20:14 UTC.

฀฀
฀ 

฀฀ ฀
฀  ฀ ฀฀
    
   


฀ ฀   ฀
 Figure
฀  ฀฀4฀-
฀ 
 
฀
 ฀ ฀
    



Range
Height Indicator of the convective cell approaching the radar in UFPA
on June 7 , 2011, at 20:30 UTC.

th

฀

3.2 LARGE SCALE ENVIRONMENT
The Figure 5 shows the flow of the wind at the level of 925 hPa, obtained from
the NCEP reanalysis, from 12 UTC on 7th June 2011 to the 00 UTC on June 8th, 2011.
Note a center of maximum wind speed, whose orientation was east-west along the coast.
At the time of 18 UTC, when the storm was at one of its peaks of activity, there is a
greater intensity in the flow of the wind compared to the time before and after the
training period during which the storm was dissipating. It is possible that this flow
southeast has promoted the spread of this storm from Maranhão to Belém area.
(a) Before - 12 UTC June 7th 2011
(b) During - 18 UTC June 7th 2011
(c) After - 00 UTC June 8th 2011
Figure 5 - Flow of wind at 925 hPa and isotacas (lines) at different stages of the
convective cell: (a) Before (12 UTC June 7th, 2011), (b) During (18 UTC June 7th, 2011)
(c) After (00 UTC June 8th, 2011).
Figure 6a shows the zonal wind changes before and after the passage of the
storm over the region of Belém, when two east jets are observed, with the first one at
500 meters and the second at 7 km in height. In both jets, there is an intensification of
the same after the storm, leaving emphasize that this difference is relatively small for
the jet located at 7 km. The meridional wind at low levels showed up before moving
south of Belém by the storm, and moving to the northeast after exceeding the capital of
Pará (Figure 6b). The air temperature cooling air shows with the storm, particularly
close to the surface. The profile of relative humidity shows at low levels an increase of
moisture with the passage of this storm.
a - Zonal wind
b–Meridional wind
c - Air temperature
d– Relative humidity
Figure 6 –Profile of (a) zonal wind component, (b) meridional wind component, (c) air
temperature, (d) relative humidity before (June 7th, 2011 at 18 UTC) and after (June 8th,
2011 at 00UTC) of the passage of the storm in Belém.
3.3 IMPACT OF THE STORM IN BELÉM METROPOLITAN REGION
฀฀


The precipitation rate estimated by disdrometers Parsivel and Joss was up to
100mm/h and 60 mm/h, respectively, characterizing the arrival of the storm in the
region of Belém around 20:30 UTC (Figure 7). On this day, the rain gauges installed in
Outeiro did not record the data. The passage of this convective system over Outeiro
caused a drop in temperature of around 4°C and air humidity of approximately 5%,
 the cooling and increased
indicating that the arrival of this storm on the site caused
humidity air close to the surface (Figure 8a).
 The distribution of wind speed shows a gust front that
 preceded the arrival of the
storm
฀
฀฀

฀





฀




฀
 thecooler

and whose origin is associated with downdrafts that bring
and drier air
levels
















฀
฀

฀

above. (Figure 8b). The passage of this storm also promoted a shift in wind
direction that prior to the passage, had a predominant component of north becoming
south after passing the region of Outeiro.

  ฀ 
฀฀ 


฀

฀
฀
  
Figure
7
–Precipitation
rate
estimated
by
disdrometers
parsivel,
joss

฀

  


฀
    
  and
installed
at
the
site
of
Outeiro
during
the
passage
of
the
convective
cell.
 
฀฀

rain gauges

(a)
(b)
Fonte: Boletim Meteorológico
Fonte: INPE/CPTEC (2013)
Figure 8 - (a) Temperature and relative humidity changes and (b) the wind during the
passage of convection in Outeiro.
 
฀ ฀ 
฀ ฀ ฀ ฀    
฀ ฀  
   ฀ ฀
฀ ฀ ฀฀ ฀฀
 ฀  ฀ 
    ฀ ฀ ฀฀ ฀
฀        
    
 



 ฀ ฀  
Figure 8 - (a) Temperature and relative humidity changes and (b) the wind during the
passage of convection in Outeiro.
3.4 NUMERICAL SIMULATION
3.4.1 Horizontal Structure
Figure 9 shows the rate of precipitation and wind at the level of 76.8 meters,
when the system was getting in the region of Belém, at 23:30 UTC. It is observed that
the simulations captured the storm's development since its formation in Maranhao, until
its dissipation in the state of Pará, and his arrival in the Belém area was three hours late
in relation to the observed. The wind was predominantly from the northeast along the
coast of Pará, entering into the river through the east side of the island Marajó. It points
out the generated precipitation rate when the convection was in the region of Belém, of
the order of 100 mm / h, i.e. comparable to that found by disdrometer Parsivel (Figure
7).
(a) June 7th 2011 at 18 UTC
(b) June7th2011 at 23:30 UTC
Figure 9 - Horizontal Wind (m/s) at the level of 24.4 meters and rain rate obtained
through the cloud microphysics (mm/ h): (a) at the beginning of the formation of
convective cell (June 7th, 2011 the 18 UTC). (b) Development of convective cell over
the region of Belém (June 7th, 2011 23:30 UTC).
3.4.2 Vertical Structure
Figure 10 shows the vertical profile of the condensate and of the zonal wind,
with the vertical wind found through BRAMS. Here, we can observe the structure of the
storm similar to that observed in the radar (Figure 4). The top of the storm reached 10
km, whereas the observed was 13 km. Moreover, it is observed that the most active
region of this system was located until the level of 5 km, as observed on the radar data
(Figure 6).
Figure 10 - Vertical profile of horizontal wind (m/s) and vertical multiplied by 10
(vector) and cloud mixing ratio (g/kg) in latitude 01.889oS on June 7th, 2011, at 23:30
UTC.
4 - CONCLUSIONS
The main objective of this work was to study the development of a storm that
originated in the northwest of the state of Maranhão and spread west to reach the city of
Belém do Pará. This study was based on data collected during the Project Chuva
campaing in Belém, and the results of a simulation with BRAMS, with the following
main conclusions:
• The large scale flow showed a center of maximum wind speed on the northeast of
Brazil, whose direction was east-northeast, coincident with the direction of propagation
of the convective cell formed in Maranhão, which hit the region of Belém as a severe
storm, causing significant material damage to the population of the state capital.
• The passage of this storm in the experimental area of Project Chuva showed a drop in
temperature and an increase in the humidity, the one associated with the current vertical
descent which is responsible of bringing cooler and dry air to average levels.
• The numerical simulation of this storm was compatible with the observed results,
highlighting intense rain rate, maximum storm intensity localized to the level of 5 km,
drop in temperature and increase in humidity with the storm in Belém. Therefore, even
if the horizontal resolution of this simulation was 9 km, it was possible to follow the
development of the convective cell, the same as the rate of rainfall generated by the
model was similar to that reported by the disdrometers.
• It was found that studied the storm proved a supercell, since their physical and
dynamical characteristics met the main requirements typical of this classification:
isolated storm, presence of mamattus clouds, strong gust fronts, areas of intense
precipitation and change in direction of the prevailing wind.
5 - REFERENCES
DAVIES, J. Tornado dynamics. Thurderstorm morphology and dynamics. 2a ed,
Ed.E.Kessler, University of Oklahoma Press, p.197-236. 1986.
FITZJARRALD, D. R.; R. K. SAKAI.; O. L. L. MORAES.; R. C. de OLIVEIRA.; O.
C. ACEVEDO.; M, J. CZIKOWSKY.;T. BELDINI. Spatial and temporal rainfall
variability near the Amazon-Tapajós confluence. Journal of Geophysical Research G:
Biogeosciences, v.114, p.1. 2008.
HARRISS, R. C., S. C., WOFSY, M. GARSTANG, E. V. BROWELL, C. B. MOLION,
R. J. MCNEAL, J. M. HOELL, R. J. BENDURA, S. M. BECK, R. L. NAVARRO, J. T.
RILEY, E R. L. SNELL: The Amazon Boundary Layer Experiment (ABLE 2A):
Dryseason 1985. J. Geophys. Res., 93, p.1351-1360. 1988.
INSTITUTO NACIONAL DE PESQUISAS ESPACIAIS (INPE/CPTEC). Boletim
Meteorológico. Disponível em:
http://chuvaproject.cptec.inpe.br/portal/belem/br/relatorio.html. 2013. Acesso em
02.02.2013.
INSTITUTO NACIONAL DE PESQUISAS ESPACIAIS (INPE/CPTEC).
Comportamento
da
temperatura.
Disponível
em:
http://chuvaproject.cptec.inpe.br/portal/belem/br/relatorio.html. Acesso em 10.01.2013.
ORLANSKI, I.A Rational subdivision of scales for atmospheric processes.Bulletin of
the American Meteorological Society, v.56, n. 5, p.527-530. 1975.
SILVA DIAS, M. A. F.A Case study of Convective Organization into Precipitating Lines
on Southwest Amazon during the WETAMC and TRMM-LBA.Journal of Geophysical
Research, v.107, p.8078. 2002.
YOSHIDA, M. C. Estudo de células convectivas em Rondônia durante o experimento
WETAMC-LBA/TRMM. 2002. Dissertação (Mestrado do Curso de Pós-Graduação em
Meteorologia) -INPE 16238 -TDI/1554, SP. 2002.
CHUVA International Workshop
Preparation of a filter to correct drop size distributions of Parsivel
disdrometer based on the particle speed limitation
Izabelly Carvalho da Costa1; Luiz Augusto Toledo Machado2
1. Centro Nacional de Monitoramento e Alertas de Desastres Naturais - CEMADEN
2. Instituto Nacional de Pesquisas Espaciais – INPE
[email protected], [email protected]
The disdrometer is an instrument which measures the droplet size distribution, this
measurement can be used to estimate the rainfall intensity (mm/h), radar reflectivity
(mm6.m-3) close to ground and concentration of droplets (m-3.mm-1) for each diameter
class. The most common are the impact disdrometer (Joss-Waldvogel) and optical
disdrometer (Parsivel and Thies). The optical disdrometer has a light beam and when
the rainfall particle passes through this beam, the received signal decreases. The extent
of this reduction is related to the particle size and duration of reduction is related to the
fall velocity. The Joss-Waldvogel Disdrometer measuring the raindrops size distribution
through an electromechanical spectrometer, where the drops levied on an area of 50
cm2. The comparison between three different disdrometers Krajewski et al. (2006) was
performed during the DEVEX experiment (Disdrometer EValuation EXperiment). To
performance evaluation of each disdrometer were done comparing rain rate, drop size
distribution and particle velocity data. The comparison results indicate that in general all
the instruments showed satisfactory performance. However, small differences were
observed between the disdrometer data, especially during intense precipitation events,
with a significant overestimation of Parsivel in precipitation rate. In his study the same
comparison was performed and also an overestimation has been observed for the field
experiments of the CHUVA Project. This difference may be associated to the fact that
large rain particles when precipitate, collide with the instrument and is subdivided into
several smaller droplets, causing high levels of concentration in small diameters classes.
When this occurs the droplets pass through the beam at a speed greater than that
expected for these small broken droplets. In this study the Joss-Waldvogel disdrometer
was used as reference and a filter was developed with the purpose of eliminating
inconsistent data measured by Parsivel in order to bring similar concentration of rain
drops values from different types of disdrometers. Results are presented for two
disdrometers, a Joss-Waldvogel and a Parsivel, installed in IEAv site during the
CHUVA Project, at Vale do Paraíba - SP, which occurred from 30 October 2011 to 18
March 2012. Based on these data we calculated the average speeds and standard
deviations for each class of diameter. A filter was developed using the expected fall
speed for each droplet size and only droplets sizes. In the domain of the expected
terminal velocity and the standard deviation for each class of diameter were considered
to compute the concentration. We have tested several intervals as function of the

CHUVA International Workshop 08-10 May 2013 São Paulo

Transcrição

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