1. 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

2. 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

3. 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

4. LAND-SAF 2nd User Training Workshop, Lisbon
introduction
Evapotranspiration
= evaporation + transpiration
8 March 2006
LAND-SAF 2nd User Training Workshop, Lisbon

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. LAND-SAF 2nd User Training Workshop, Lisbon
methodology
* to be added in the future
8 March 2006
LAND-SAF 2nd User Training Workshop, Lisbon

13. 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

14. 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

15. 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

16. 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

17. 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

18. Exemple 1: daily ET product
methodology
Exemple 1: daily ET product
8 March 2006
LAND-SAF 2nd User Training Workshop, Lisbon

19. 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

20. Exemple 2: fraction of evaporation
methodology
Exemple 2: fraction of evaporation
8 March 2006
LAND-SAF 2nd User Training Workshop, Lisbon

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. 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

30. 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

31. 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

32. 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

33. 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

34. 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

35. 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

36. 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

37. 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

38. 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

39. 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

40. 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

41. 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

42. 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

43. 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

44. 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

45. Thank you for your attention !
8 March 2006
LAND-SAF 2nd User Training Workshop, Lisbon