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The use of airborne and space observations to map surface heat fluxes and soil water content at heterogeneous land surfaces was studied. Algorithms to estimate evaporation fluxes with satellite observations were evaluated against measurements. Spatialcorrelation lengths were studied with estimated maps of latent heat flux. Soil water content was estimated with microwaves; effects of soil mineral composition and solute concentration were studied in the laboratory. The significance of observed spatial variability was evaluated with probability distribution functions of errors of estimated latent heat flux and soil water content. Roughness properties were studied with laser measurements. Spatial fields of heat fluxes were obtained from a meteorologicalmodel.

The multispectral and multitemporal classification approach of AVHRR data on specific dates was studied for land cover mapping on a continental scale. Major conclusions are: decision keys must be developed that exploit both the use of multitemporal composites and multispectral data; the current classification distinguishes only main land cover types; due to mixed pixels the content of an AVHRR-derived land cover class can differ substantially over Europe. The main advantage of remote sensing over statistical surveys is its high spatial detail and consistent quality in land cover; the main disadvantage is the absence of specific classes.