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STATUS OF DEVELOPMENT OF THE LSA-SAF EVAPOTRANSPIRATION PRODUCT
2nd LSA-SAF Training Workshop Lisbon, 8-10 March 2006 STATUS OF DEVELOPMENT OF THE LSA-SAF EVAPOTRANSPIRATION PRODUCT by Françoise Gellens-Meulenberghs Alirio Arboleda Nicolas Ghilain Royal Meteorological Institute Avenue Circulaire, 3 B-1180 Brussels, Belgium
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LAND-SAF 2nd User Training Workshop, Lisbon
OVERVIEW: Introduction Methodology Validation Developments planned for 2006 Future work (CDOP) Conclusions 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
OVERVIEW: Introduction Methodology Validation Developments planned for 2006 Future work (CDOP) Conclusions 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
introduction Evapotranspiration = evaporation + transpiration 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Link to the energy balance:
introduction Link to the energy balance: E: evapotranspiration (ET) [kg m-2 s-1] LE: latent heat flux [W m-2] LE = Lv E Lv : latent heat of vaporisation Lv ~ 2,5 106 J kg-1 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
introduction Objective: Conceive and develop an algorithm for the estimation of evapotranspiration (ET) taking advantage of the improved capabilities of the new MSG and EPS sensors. 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
OVERVIEW: Introduction Methodology Validation Developments planned for 2006 Future work (CDOP) Conclusions 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
methodology Pixels and tiles: Each pixel is composed by several tiles - grassland - crops - forest - bare soil - … 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
methodology At pixel level: Agregation of fluxes on each tile Sensible heat flux: Latent heat flux: Méthodology based on Tessel-SVAT Van den Hurk et al. (2000) 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Equations at tile level:
methodology Equations at tile level: Surface energy budget: Sensible heat flux: Latent heat flux: Canopy resistance: S = DSSFSAF = ALSAF L = DSLFSAF = SAF LAI = LAISAF ) ( 3 2 1 min , a s c D f LAI r q = 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Equations at tile level:
methodology Equations at tile level: Aerodynamic resistance: Friction velocity: Obukhov length: iterative procedure used until convergence 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
methodology * to be added in the future 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Current status of the algorithm
methodology Current status of the algorithm First version implemented in the IM system since February 2005 Second version developed in 2005 presented here 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Differences between 1st and 2nd versions:
methodology Differences between 1st and 2nd versions: All variables computed at tile level G computed from LAI (Chehbouni, 1996) ECOCLIMAP can replace IGBP land cover 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Characteristics of ET product following URD
methodology Characteristics of ET product following URD full spatial resolution full temporal resolution Europe 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Results: hourly ET for 22 – 24 /6/2005
methodology Results: hourly ET for 22 – 24 /6/2005 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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New products can be envisaged
methodology New products can be envisaged depending on users’requests 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Exemple 1: daily ET product
methodology Exemple 1: daily ET product 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Exemple 1: daily ET product
methodology Exemple 1: daily ET product 22/6/2005 23/6/2005 24/6/2005 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Exemple 2: fraction of evaporation
methodology Exemple 2: fraction of evaporation 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
OVERVIEW: Introduction Methodology Validation Developments planned for 2006 Future work (CDOP) Conclusions 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Comparison with in-situ observations at Melle (B) grassland
validation Comparison with in-situ observations at Melle (B) grassland +++ obs, ---- LSA-SAF (IGBP), ---- LSA-SAF (ECOCLIMAP), ---- ECMWF 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Comparison with in-situ observations at Humain (B) grassland
validation Comparison with in-situ observations at Humain (B) grassland +++ obs, ---- LSA-SAF (IGBP), ---- LSA-SAF (ECOCLIMAP), ---- ECMWF 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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validation Comparison with in-situ observations at Puechabon (F) mediterranean forest +++ obs, ---- LSA-SAF (IGBP), ---- LSA-SAF (ECOCLIMAP), ---- ECMWF 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
validation Sensitivity studies Assumptions: Gaussian distribution of errors 5000 runs for each time step Comparison to the control run 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
validation Sensitivity studies: Ex: DSSF: = 15 W m-2 DSLF: = 10% of actual value AL: = 10% of actual value Absolute error on ET higher during daytime 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
validation Sensitivity studies: Relative error on ET lower during daytime 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Comparison with other ET results at large scale
validation Comparison with other ET results at large scale 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Comparison with other ET results at large scale
validation Comparison with other ET results at large scale 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Other validation approaches
Scintillometry measurements of H * Cabauw: Kohsiek et al. (2002) * Lindenberg: Beyrich et al. (2002) Airborne observations (ex: CarboEurope) Feasibility / availability to be investigated 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
OVERVIEW: Introduction Methodology Validation Developments planned for 2006 Future work (CDOP) Conclusions 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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developments planned for 2006
Second set of LSA-SAF variables to be included as input into ET algorithm EM SC FVC LAI Tests at station level; If conclusive, implementation to the grid version 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Towards an improved use of LST ?
developments planned for 2006 Towards an improved use of LST ? Radiative (LST) – at pixel level - and aerodynamic (Tskin) – at tile level - temperatures are different concepts Research is needed to determine how LST can be used to improve Tskin 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Comparisons between LST and Tskin
developments planned for 2006 Comparisons between LST and Tskin +++ obs trees, +++ obs grass, …. LST, …. Tskin 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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A LSA-SAF SM input ? ET currently uses with ECMWF SM input
developments planned for 2006 A LSA-SAF SM input ? ET currently uses with ECMWF SM input good results can be run operationally as a first step More research is needed to develop coherent ET and future SM products RMI is willing to take an active role 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Comparisons between ECMWF and observed SM
developments planned for 2006 Comparisons between ECMWF and observed SM Evora (Portugal) El Saler (Spain) Superficial SM: ---- obs, ---- ECMWF We need a SM index able to produce good ET fluxes 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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First steps towards a METOP / EPS ET product
developments planned for 2006 First steps towards a METOP / EPS ET product Input format characteristics ? Handling of land cover data base ? Projection of ECMWF meteo input ? TO BE DECIDED AT THE CONSORTIUM LEVEL 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
OVERVIEW: Introduction Methodology Validation Developments planned for 2006 Future work (CDOP) Conclusions 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Continuous development
future work (CDOP) Continuous development Feedback between Algorithm improvement Validation With consolidation / new developments retated with Vegetation SM LST 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Extension outside Europe (MSG/METOP)
future work (CDOP) Extension outside Europe (MSG/METOP) With special attention to extreme climate condition Good quality validation datasets are needed for arid, semi-arid, tropical, … climates 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
OVERVIEW: Introduction Methodology Validation Developments planned for 2006 Future work (CDOP) Conclusions 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
conclusions 1st ET algorithm is running in real time since February 2005 2nd version could be implemented soon Large amount of validations done in 2005 Good results are obtained ET can be run operationally using ECMWF SM as a first step 1/2 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
conclusions Research is needed to develop coherent ET and future SM LSA-SAF products RMI is ready to participate actively into this process Additional ET based products can be foreseen to comply with users requests 2/2 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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LAND-SAF 2nd User Training Workshop, Lisbon
Acknowledgments Thanks to all data flux providers contacted: S. Rambal, A. Carrara, F. Bosveld, J.C. Calvet, M. Aubinet, A. Wolfgang, B. Longdoz, L. Montagnani, R. Ceulemans, A. Granier, H. Verbeeck, M. Marek and P. Cellier … and also R. Stockli, M. Rodell, H. Kato … and LSA-SAF colleagues Thanks to ESA and Belgian Science Policy for co-funding this project with EUMETSAT ESA/Contract Nr /01/NL/Sfe(IC) 8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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Thank you for your attention !
8 March 2006 LAND-SAF 2nd User Training Workshop, Lisbon
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