The aim of the project is to study the climatological and hydrological surface-atmospheric interactions in semi-arid environments, in order to provide significant improvements in global climate modelling.
This project is a preliminary test phase of the HAPEX-II-SAHEL programme scheduled for 1992 in Niger, which is a part of large scale land-surface field experiments to obtain quantitative understanding of the water and energy cycles over extended land areas.
The general strategy is to gather intensive measurements in 3 selected areas, hereafter called "supersites" and to extend the results to an area significant for climate studies (i.e. 100 km x 100 km area).
Soil moisture measurements, measurements of the ecophysiological functioning of the vegetation in conjunction with biometric ones, as well as measurements of the spectral characteristics of the vegetation and soil will be carried out in many locations in each "supersite". The resulting data will be used to calibrate local transfer models and to validate remote sensing inverse models which will be used for upscaling of soil hydraulic parameters and transport resistance.
Spatial extension of surface fluxes at the scale of the "supersites" will be performed using mostly aircraft remote sensing. In addition, onedimensional transfer models will be calibrated at this scale.
Satellite data, vegetation and soil maps and meteorological data gathered by ground station networks and radiosounding to describe the atmospheric forcing will finally be used to extend the surface fluxes to a climatologicaly significant area. The resulting fluxes will be checked using direct measurements from aircraft.
Part of the experimental concept and equipment will be tested in Spain, where the experimental phase of a complementary project (EFEDA: European Field Experiment in Desertification Threatened Area) will be held.
Funding SchemeCSC - Cost-sharing contracts
6709 PA Wageningen
1350 Koebenhavn K/copenhaegen
RG6 2AU Reading / Silchester
6700 AC Wageningen