Land Surface Temperature Observations

Land Surface Temperature Observations
EUMETSAT Land Surface Analysis SAF
GMES Geoland-2
Isabel F. Trigo
Instituto de Meteorologia
Thanks to the LSA SAF and Geoland-2 Teams
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
Outline
LST from Geostationary platforms
Ø  SEVIRI/MSG retrievals (LSA SAF)
ü  Algorithm
ü  LST uncertainties
ü  Availabitiy & Distribution
Ø  Towards Global Coverage (Geoland2)
ü  GOES; MTSAT - Algorithm & constraints
Ø  Validation
Ø  Requirements & Further Development
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
EUMETSAT LSA SAF
The Satellite Applications Facility on Land Surface Analysis, is a
consortium
dedicated to algorithm development, validation and operational
production of land surface related products based (primarily)
on European meteorological satellites (MSG and METOP)
Ø  Real time
Ø  Off-line distribution
Ø  Reviewed (~annually) by technical and scientific review panels
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
Land Surface Temperature
LST Algorithm Requirements:
ü  Maximize the use of available channels, in order to ...
ü  Minimize the incertainty of the retrievals, and ...
ü  being Computacionally Efficient.
SEVIRI - MSG
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Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
SEVIRI/Meteosat channels
& LST
Solar
contamination
Response
function of
channels 3-11
High emissivity
uncertainty
3.9
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
8.7
Tel.: (351) 21 844 7000
10.8 12.0
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST from SEVIRI/Meteosat
Generalised Split-Window → 10.8µm and 12.0µm (Wan & Dozier, 1996)
Trained using CLEAR SKY synthetic SEVIRI/MSG data
Ts = ( A1 + A2
1− ε
ε
+ A3
Δε T10.8 + T12.0
1− ε
Δε T10.8 − T12.0
)
+
(
B
+
B
+
B
)
+C
1
2
3
2
2
ε
2
ε
ε
2
GSW parameters depend on:
1.  total column water vapour
2.  viewing angle
ECMWF fc
Channel Emissivity → Land Type + Fraction Vegetation Cover
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST from SEVIRI/Meteosat
Generalised Split-Window
•  Trained using CLEAR SKY TOA Tb’s - MODTRAN
•  Verified against independent dataset ( ~ 15 700 profiles).
Algorithm uncertainty increases with view angle & water vapour, i.e., with
LST_Errors (K)
optical path.
Zenith Ang ~ 40º
Zenith Ang ~ 75º
4
4
4
2
2
2
0
0
0
-2
-2
-2
-4
-4
-4
~ NADIR
0
1.5
3
4.5 (cm)
0
1.5
3
4.5 (cm)
0
1.5
3
4.5 (cm)
TCWV
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Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
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URL: http://www.meteo.pt
LST from SEVIRI/Meteosat
Emissivty
VEGETATION COVER METHOD
Pixel MSG
ε = εveg FVC+ εground (1-FVC) + δε
LSA SAF Product
↑
Sfc Reflectances VIS
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•  Non-­‐accounted effects (mul2ple reflec2ons at sfc) •  Variability of bare ground/ vega within pixel Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST Uncertainty
Generalized Split-Windows - LST Errors
2
S
2
LST
⎛ ∂ f ⎞ 2
⎟⎟ σ X i
= ∑ ⎜⎜
i ⎝ ∂ X i ⎠
2
⎛ ∂ f ⎞ 2
⎟ σ θ + ΔLST 2
+ ∑ ⎜
⎜
⎟ j
j ⎝ ∂θ j ⎠
Algorithm uncertainty
↓
Input errors
↓
Retrieval conditions
Sensor noise; emissivity
Model parameters/ Implicit input variables
↓
TCWV (ECMWF); view angle
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
Land Surface Temperature - SEVIRI
LSA SAF LST Product
ü Genera2on Frequency -­‐ 15 min ü clear sky pixels ... ü  over land ... ü  where es2mated errors < 4K ü  Available since Ø  Europe – Feb 2005 Ø  Full disk – Jul 2005 http://landsaf.meteo.pt
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
Land Surface Temperature - SEVIRI
LST Error Bars
And error bars es2mated taking into account: ü  Uncertainty of the GSW regressions ü  Propaga2on of input uncertain2es: §  Emissivity §  Sensor noise §  TCWV ECMWF forecasts 0.0 0.8 1.6 2.4 3.2 4.0 ºC Masked out δLST > 4K
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
• Trigo et al (2008) in J. Geophys. Res. • Freitas et al (2010) in IEEE Trans. Remote Sens. Geosc. Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
Towards Global Coverage
GOES12
GOES12
GOES12
GOES-E
MSG2 MSG2
MSG2
MSG
MTSAT1-R
MTSAT1-R
MTSAT1-R
Met7
MTSAT
Dual-Channel
Dual-Channel
Generalized
Split-Window
Dual-Channel
Dual-Channel
Dual-Channel
Dual-Channel Generalized
Split-Window
Generalized
Split-Window
Algorithm
AlgorithmAlgorithm
AlgorithmAlgorithm
Algorithm
Algorithm
Algorithm
Algorithm
(LSA
SAF)
(LSA SAF)
(LSA SAF)
Geostationary data
ü  High temporal sampling – capable of describing LST diurnal cycle
û  Limited area coverage
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
Towards Global Coverage
Most relevant Channels for LST retrieval
Channels /
Resolution
SEVIRI
GOES Imager
MTSAT
Middle IR
3.5 – 4.4 µm
3.8 – 4.0 µm
3.5 – 4.0 µm
Thermal IR 1
10.0 – 11.5 µm
10.2 – 11.2 µm
10.3 – 11.3 µm
Thermal IR 2
11.2 – 12.8 µm
-
11.5 - 12.5 µm(*)
(**)
Spatial
sampling
Total
Temporal sampling
3 km
12 channels
5 km
5 channels
15 min
1h
5 km
1h
Significantly impact the quality of
the cloud screening
Night-time retrievals – Regression based on MIR & TIR
Daytime retrievals – Regression based on TIR
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
Towards Global Coverage
GOES-E
MSG
MTSAT
Met7
ü  Hourly projected onto 0.05 x 0.05º
ü  Available with uncertainty …
ü  since 2010
→ Freely Distributed within GMES
project
http://www.gmes-geoland.info/
[email protected]
Caveats
- not global – processing of Meteosat7 under preparation
- quality of retrieval varies with sensor
- observation times do not match exactly in overlapping areas
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST - Validation
Valida1on ü  con2nuous ac2vity ü  main source of info on product compliance with requiremets Comparison with similar products derived from other satellites : §  MODIS Useful to assess product consistency
§  AATSR Comparison against in situ observa1ons: §  Within MSG disk -­‐ LSA SAF team: Portugal (Evora, since 2005) Namibia (Gobabeb + Kalahari farm) §  Field Campaigns; SURFRAD; BSRN; Sites must be representative of pixel measurements
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST - Validation
Senegal
Rasmussen et al (2011), TGRS, doi 10.1109/TGRS.2011.2144604
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST - Validation
Evora (Portugal)
2005
(ºC)
Daytime
SEVIRI
MODIS
(ºC)
Night-time
SEVIRI
MODIS
BIAS
+1.9
-1.8
BIAS
-1.7
-2.6
RMSD
2.2
2.6
RMSD
2.1
2.7
Morning – green; afternoon – red; night - blue
•  Correction in level 1.5 processing at
EUMETSAT (May 2008): conversion of
digital counts to effective radiances (impact
small, but reaching significant values for
high brightness temperatures); ...
Evora – Aug 2009
(F. Goettsche)
•  Generalized Split-Windows – wider
calibration dataset; treatment of input
unceratainties and impact on LST errors.
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST - Validation
Namibia
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
LST - Validation
60
May 2008
Obs In Situ (ºC)
Obs In Situ (ºC)
LST MSG/SEVIRI (Land-SAF) versus in situ
40
20
0
0
Bias: -0.31ºC
RMS: 1.16ºC
20
40
60
40
20
40
20
0
0
Bias: +0.24ºC
RMS: 1. 44ºC
20
40
60
40
60
Mar 2009
40
20
0
0
60
LST SEVIRI/MSG (ºC)
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
20
LST SEVIRI/MSG (ºC)
Obs In Situ (ºC)
Obs In Situ (ºC)
Nov 2008
Bias: -0.91ºC
RMS: 1.67ºC
0
0
60
LST SEVIRI/MSG (ºC)
60
Jul 2008
Bias: -1.20ºC
RMS: 1.74ºC
20
40
60
LST SEVIRI/MSG (ºC)
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LST - Validation
GOES-E
SURFRAD
Crops
Grass
In situ LST (ºC)
In situ LST (ºC)
MTSAT
BSRN
Urban
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt
http://landsaf.meteo.pt
http://www.gmes-geoland.info
Publications
Download Data
Documentation (User Manuals, Validation Reports)
Helpdesk
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Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
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Further Development
Ø  Merging satellite products – GEO + LEO
ü  Cover poles
ü  Spatial down-scaling: keep high temporal sampling (hourly or higher)
& LEO spatial resolution (≤ 1km) for regions of interest
ü  Decrease dependence of retrievals on viewing geometry
Ø  Improvement of product accuracy
ü  Better characterization of emissivity maps
Ø  LST – All Weather
ü  Explore micro-wave
ü  Modelling cloudy areas (using radiation & vegetation parameters from
remote sensing)
Ø  REPROCESSING
Ministério da Educação e Ciência
Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal
Tel.: (351) 21 844 7000
Fax: (351) 21 840 2370
e-mail: [email protected]
URL: http://www.meteo.pt