Temporal and Spatial Variation Characteristics of Actual Evapotranspiration in the Yiluo River Basin Based on the Priestley–Taylor Jet Propulsion Laboratory Model

Abstract

Evapotranspiration is an important part of the hydrological cycle, affecting the terrestrial hydrological process and the relationship between water resource transformation. Analyzing and mastering the temporal and spatial variations in evapotranspiration are of great significance for the rational development, utilization, and protection of water resources in the basin. Based on MODIS remote sensing data and combined with meteorological and hydrological data, the PT-JPL model was used to estimate the actual evapotranspiration of the Yiluo River Basin, and the applicability of the PT-JPL model for estimating actual evapotranspiration in the basin was analyzed. The spatial and temporal characteristics of actual evapotranspiration in the Yiluo River Basin were analyzed, and the correlation between actual evapotranspiration in the basin and influencing factors such as precipitation, temperature, and vegetation was explored. The main conclusions are as follows: the PT-JPL model has good applicability in the Yiluo River Basin; the total actual evapotranspiration in the basin showed a decreasing trend, which was consistent with the trend of precipitation, indicating that the actual evapotranspiration may be limited by water conditions in the study area. The evapotranspiration of the basin was higher in the upstream and lower in the downstream, which may be related to the better vegetation coverage in the upper basin than in the downstream. As an important indicator of vegetation change, NDVI showed a good correlation with evapotranspiration, which also verified this. In addition, the correlation between evapotranspiration and temperature was also good.