GIS-aided evaluation of evapotranspiration at multiple spatial and temporal climate patterns using geoindicators

The procedure was applied to a cropland test site at Mediterranean sub-regional basin scale (Tammaro, South Italy) to develop a climatological baseline estimation of AET refined at slope scale. After the upscaling, the most frequent estimated AET values were about 550 mm yr−1 (with quasi-normal distribution), while underestimations were observed in the preliminary, smoothed map (positively skewed distribution with mean 460 mm yr−1). The upscaling allowed the influence of the topographic factor to emerge, with a wider range of values (about 300-900 mm yr−1) being estimated and substantially not visible in the smoothed pattern. A temporal climate pattern of soil water depletion in the growing season was also shown as reflected in the increase of AET flux in the period 1991-2008 in comparison to the precedent climate (1961-1990).