Аннотация:A modeling approach to reconstruct the annual evapotranspiration of the ground surface covered by vegetation from palaeoecological data is suggested. It is based on assumption that the actual annual evapotranspiration is proportional to potential surface evaporation and some decoupling factor characterizing the surface moisture conditions. It is described in our study as a function of the climate moisture index (CMI). The potential evapotranspiration rate is derived using palaeoecological data about past land use structure, forest coverage, plant species compositions and annual temperature. The value of unknown decoupling factor is approximated using results of evapotranspiration measurements at selected FLUXNET experimental sites located in the areas with diverse (ranged from extremely wet to moderately dry) moisture conditions. Comparisons of modeled evapotranspiration rates with results of the field flux measurements showed their good agreement for various forest, shrubland and grassland ecosystems in different geographical regions.