Evaluation of evapotranspiration variations as a function of relief and terrain exposure through multivariate statistical analysis

Abstract

Knowing the variation of the water consumption of a crop or vegetation can help to avoid damages caused by the lack of water, besides allowing a better knowledge of the environment around. Thus, variations in evapotranspiration in sugarcane, planted forest, and native forest were examined as a function of relief variations and terrain exposure in the northeast sector of the State of São Paulo, Brazil (20°43′55.2″S–22°36′28.8″S, 46°37′48.0″W–48°50′16.8″W). These areas, covering a total of 2232km2, were studied using monthly Landsat 8 satellite data (Path 220 and Row 75) collected over 24 months from April 2013 to March 2015. Thus, this study aimed to use a hybrid Two Source Energy Balance (TSEB), adjusted to convert hourly ET to monthly and annually data, in obtaining ET for two years to areas with sugarcane, planted and native forests and evaluate how this evapotranspiration behaves spatially for some parameters, as altitude, slope, exposure faces of the terrain and biomes, using multivariate analysis. The results identified three evapotranspiration groups: highest evapotranspiration in the highest altitudes and topographic slope; medium evapotranspiration in medium altitudes and slopes; and low evapotranspiration at low altitudes and slopes. The highest rates of evaporation occurred in summer and fall, when temperatures were highest.