Modeling of evaporation and its influence on surface temperature

Juliana Arbelaez Gaviria

Master's thesis

Abstract:

Evaporation (E) and evapotranspiration (ET) are dynamic and non-linear processes that incorporate various internal transport mechanisms, which are essential in the unsaturated zone in arid regions under low soil moisture conditions. The evaluation of ET from soils and water bodies is necessary for planning and operating water resource projects such as water supply (surface and underground), multipurpose water projects as irrigation, power, waste transportation, and storage, flood control, and many others. FAO Penman-Monteith (PM) equation is the most widespread method to estimate the evaporation rate in saturated soils. This approach can be implemented as a boundary condition for the Richards' equation and related to the evaporation rate with the soil's water content. However, the PM equation is not valid when the soil moisture is low, and the vapor flux is an essential component of the total water flux. In this case, the governing equations are formed out of the coupled Richards' equation with the heat transport, where the boundary conditions originate from the surface energy balance and the evaporation rate. In this contribution, the numerical implementation of the Penman-Monteith method as the boundary condition of the classical Richards equation is presented. Additionally, the application of the coupled model of heat and water flow was included in the free software Dual Richards Unsaturated Equation Solver. Two scenarios were designed to test the performance of both models under a controlled meteorological environment and the impact of the evaporation rate on the pressure head and water content, including the energy surface balance.

Keywords

Richards' equation, surface energy balance, vapor flow, energy flux

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 30. 6. 2020

Obhajoba závěrečné práce

• Vedúci: doc. Ing. Michal Kuráž, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / odbor:
Landscape Engineering / Environmental Modelling