Remote sensing inversion characteristic and driving factor analysis of wetland evapotranspiration in the Sanmenxia Reservoir area, China

Abstract

Evapotranspiration in the hydrologic cycle realizes the energy and water transport in the atmosphere. Evapotranspiration differences concerning land-use types provide data for studying the evapotranspiration of river basins. To investigate the evapotranspiration in the reservoir under artificial regulation, we selected the river basin in the Sanmenxia Reservoir as the study area. Data sources are two-period Landsat8 OIL_TIRS remote sensing images during the growing season of wetland plants. Based on meteorological data in this river basin, we investigated the evapotranspiration differences of different land-use types using the Surface Energy Balance Algorithm for Land model. The FAO Penman–Monteith formula verified the remote sensing inversion results. Analysis shows that significant differences were manifested between wetland and non-wetland landscapes in evapotranspiration among different land-use types. Non-wetland landscapes accounted for about 97.23% of the river basin’s total area, but their daily average evapotranspiration was only 7.26 mm/d. Those of wetland landscapes were 2.77% and 12.17 mm/d. In this river basin, the differences between the wetland and non-wetland landscapes in evapotran-spiration are mainly associated with plant diversity, vegetation coverage and surface temperature (beyond other driving factors like meteorological and hydrological solar radiation factors).