Seminar: Tejasvi Chauhan

Potential evaporation is critical for eco-hydrological modelling and its formulations based on Penman (1948) are often considered the most physically consistent estimates. These formulations consist of two components: a radiative component where evaporation is driven by net radiation at the surface, and a mass transfer component, which depends on the vapor pressure deficit (VPD). However, the aerodynamic component is known to overestimate potential evaporation in the presence of water limitation, exceeding the limits imposed by surface energy balance. In this talk, I will show that this inconsistency can be explained using the link between the diurnal variation of VPD and the diurnal temperature range (DTR), which in turn represents mostly the heat storage changes in the atmospheric boundary layer caused by solar heating. I will then show that this bias from Potential evaporation can be analytically removed using a physical description of the land-atmosphere system.