The contribution of evapotranspiration to the seasonal and intraseasonal variability of regional moisture transport along the eastern flanks of the Andes

The contribution of evapotranspiration (ET) to the regional moisture transport along the eastern flanks of the Andes was investigated using the Weather Research and Forecasting (WRF3.4) model. As the South American Low Level Jet (SALLJ) is a major component of the boundary layer water budget over this region and its moisture primarily originates from the Amazon, the contributions of low-land versus high-land ET were examined separately for characteristic hydrometeorological regimes during the monsoon and dry season. Both real-data cases and idealized simulations were conducted. The wet season real-data case simulations were carried out during the South American Low Level Jet Experiment (SALLJEX), for which a large number of observations (e.g., aircraft, radiosonde, stations based and etc.) are available. To examine the insights learned from the realistic simulations, two types of idealized simulations were implemented: high-resolution quasi-2D simulations with topography matching the NE-SW cross section going through Cusco, Peru to examine the contributions of ET from highland forest, and 3D idealized simulations at relatively coarser resolution, with topography representing the shape and geometry of the Andes, to examine the influence of Amazon ET on moisture fluxes.