Application of the surface layer energy balance model for calculating of the evaporation from water objects

Abstract

Formulation of the problem. When solving hydrological problems associated with the water balance of water bodies and the possibility of economic use of their water resources, an important problem is the accurate determination of evaporation from the water surface, which is the main component of water losses. Review of previous publications and studies.Currently, many indirect and empirical methods for calculating evaporation from the surface of soil, water and vegetation, developed by domestic and foreign scientists: M.I. Budyko, V.S. Mezentsev, A.R. Konstantinov, N.N. Ivanov, Penman-Monteith and others, are used. Most empirical methods do not have universal applicability, since, in most cases, they cannot take into account the features of various underlying surfaces and hydrometeorological conditions that affect evaporation processes. The only acceptable methods for estimating actual or potential evaporation can only be parametric models based on a numerical solution of the surface heat balance equation. One of such models is the atmospheric surface layer model – model SLEB, created at Odessa State Ecological Environmental University. Purpose. The purpose of this study is to obtain quantitative estimates of changes with evaporation of water surfaces with SLEB model and compare them with the measured and model data of analogous methods obtained by other authors (Ivanova, Penman), for example, a freshwater lake Yalpug. Methods. For research, a parametric energy balance model of the atmospheric surface layer SLEB, which is used standard meteorological information, was used. The main advantage of this model is the high accuracy of determining the heat expenditure for evaporation in the calculation of mass-heat transfer between the underlying surface and the atmosphere at the micro- and mesoscales. The SLEB model is applicable for all types of underlying surfaces characteristic of the territory of Ukraine. Results. The value of evaporation from unit area of the water surface of Lake Yalpug calculating by model SLEB was obtained for the first time taking into account the development of wave formation on the surface of the lake, which changes the hydrodynamic properties of the water surface and the aerodynamics of the air flow. Accounting for the effect of wind waves on the vast lake surface allowed us to obtain results almost equal to the measured evaporation from the pool surface. The results showed that the calculated values of evaporation from the water surface by the methods of Penman and Ivanov overestimate the amount of evaporated moisture compared with the values measured and calculated by the SLEB model. Conclusions. Application of the SLEB model allows to increase the quantitative estimation accuracy of the water balance main component – water losses due to evaporation from the water bodies water surface, which, in turn, can increase the water resources management efficiency of natural water bodies for purpose of their rational use for drinking water supply and land irrigation.