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The accurate representation of subgrid scale effects in climate models has been an issue of great controversy. In attempt to resolve this controversy, a model-independent technique was developed in this study to upscale land surface parameters through inverse-SVAT modeling. Upscaling laws are derived, that map the distributed land surface parameters of a heterogeneous land surface to their corresponding effective parameter. Simpler averaging methods of comparable performance are derived from the inverse modeling results, which drastically reduce the computational effort. The proposed method shows better performance than most well known methods. More importantly, the method is applicable in many fields.

This study concerns evapotranspiration, which accounts for 90% of the water balance in West Africa. At field level, crop and bare-soil albedo measurements were used to build simple models based on phenology, zenith angle and soil surface conditions. Interactions between tree water flux and environmental variables were examined. The complementarity Advection-Aridity (AA) relationship model adequately simulates the spatio-temporal distribution of regional ET rates. The monsoon clouds, harmattan and seasonal changes in surface albedo influence evapotranspiration processes in the Volta Basin. The good performance of the improved AA model indicates its utility for providing independent estimates of ET. These results are valuable input to eco?hydrology and climate models.

Slash-and-burn agriculture has characterized Eastern Amazonian land use for over 130 years. Documented consequences of this traditional land-use system have sparked a search for changes in field preparation and crop management techniques. The use of mulch technology in combination with alternative cropping cycles was proposed as a viable alternative. To make recommendations regarding the ecological effects of such innovations in land use, a detailed study of water and nutrient dynamics at a series of small agricultural watersheds in the eastern Amazon region was performed resulting in a complete water and nutrient balance for these watersheds.