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composed of 165 pluviométrie stations. The details of this work can be found in Lopez-Baeza et al., (1993b 
and c). 
4 - FLUX ESTIMATES FROM REMOTE SENSING 
Four contributions are presented in this section dealing with the estimation and mapping of surface fluxes at 
a regional scale from remote sensing data. The team of the University of Valencia focussed on the 
improvement of semi-empirical models relating actual évapotranspiration to surface temperature, and 
proposed adaptions to the case of barley and maize. The INRA team describe a methodology to study the 
signification of coefficients to be introduced in such relationships in order to derive surface fluxes directly 
at regional scale from NOAA-AVHRR data. To avoid the arbitrary character linked to the use of semi- 
empirical relationships, the Winand Staring Center propose a new algorithm based on the use of NDV1 to 
take into account vegetation parameters in a better way. They give two examples of application over the 
Tomelloso and Barrax areas. Finally a joint work made by the JPL and DLR present a method based on the 
combination of a SVAT model with SAR data. The authors refer to Chapter 7.4 of the EFEDA Final Report 
edited by Lagouarde (1993) to get a detailed account of these works. 
5 - ACKNOWLEDGEMENTS 
The work was performed under CEC contract EPOC-CT-90-030. There are also many additional national 
contributions which are greatfully acknowledged here. 
This presentation tries to summarize the work of the EFEDA sub-group on Remote Sensing and 
Radiometric Properties of the Surface developed under the Phase I of the experiment. The authors would 
like to refer to the other centers which compose this sub-group and whose principal investigators are: H.-J. 
Bolle (F.U. Berlin, FRG), A.M. Jochum (D.L.R., Oberpfaffenhofen, FRG), P. Rabat and W. Bastiaanssen 
(Winand Staring Center, Wageningen, The Netherlands), J.-P. Lagouarde (I.N.R.A., Villenave d’Omon, 
France), F. Nerry (Univ. Louis Pasteur, Strasbourg, France), S.S. Saatchi (J.P.L., Pasadena, USA), and J. 
Thornes (Univ. of London, UK). The important contribution from US American groups are pleasantly 
mentioned here as well and everyone in EFEDA acknowledges the support of NASA (D. Wickland, NASA 
Headquarters, Washington, USA). 
6 - REFERENCES 
/ersity of 
ATREM 
la, pixels 
analysis 
tbles the 
3 data. In 
tn NDVI 
from the 
-omising, 
from the 
istilla-La 
91) from 
aitute of 
whether 
Dnce this 
id NDVI 
eloped in 
me hand, 
value of 
the other 
'ed from 
ark, now 
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Billing H., Bolle H.-J., Eckardt M„ Fell F., Koslowsky D., Langer I. and Tonn W„ 1993b. 
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and B. Streckenbach. August 1993, Berlin. 
Bolle H.-J. et al., 1993. EFEDA: European field experiment in a desertification-threatened area. Ann. 
Geophysicae 11,173-189. 
Bolle H.-J. and Streckenbach B. (Editors), 1993. Land-surface radiation properties. Ch 7 in EFEDA 
Final Report, August 1993, Berlin. 
CSES, 1992. Atmospheric Removal Programme (ATREM) Users Guide V 1.1. Center for the Study 
of Earth from Space, University of Boulder, Boulder, Colorado. 
Fortea, J.C., Lopez-Baeza, E., Melia, J., and Moreno, J„ 1993a. Corrección atmosférica de los datos 
del sensor multiespectral AVIRIS utilizando LOWTRAN-7 y radiosondeos de EFEDA. XXIV 
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radiometría de campo en la zona experimental EFEDA. El NDVI como indicador del crecimiento. V 
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1993 
Gilabert M.A., Lopez-Baeza E., Younis M.T., Lopez A., Melia J. and Campos J., 1993b. 
Contribution of the Remote Sensing Group of the University of Valencia. Ch. 7.1.2 in EFEDA Final 
Report. Ed. by H.-J. Bolle and B. Streckenbach. August 1993, Berlin. 
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at EFEDA site (Spain). 6 th Int. Symp. on Physical Measurements and Signatures in Remote Sensing, 
Vail d’Isere, January 17 -21,1994. 
Harrison A.R., Hurcom S.J. and Tabcrncr M„ 1993a. Contribution of the University of Bristol. Ch. 
7.1.1 in EFEDA Final Report. Ed. by H.-J. Bolle and B. Streckenbach. August 1993, Berlin.