Observation of evaporation at a non uniform surface using micro meteorological methods

Evaporation from land surface is a dominant process of heat and water exchange between atmosphere and land surface. The exchanged process in a wide area is an important element of a climate model because it affects a climate system. It is important to observe exact evaporation in order to not only improvement of the climate model but also utilization and management of water resources. Following the development of an automatic instrument for meteorological variables, a micro-meteorological method has become to a main method of evaporation measurement. The Bowen-ratio method and the aero-dynamical method are widely used. In order to apply both methods, some conditions must be satisfied, such as the horizontal homogeneity and the adequate fetch to upwind direction. However, evaporation measurement is often required at places where the conditions do not satisfy. In this study, the author verified the applicability of two micro-meteorological methods to the site with non-uniform surface condition near the Lake Kitagta, Awara City, Fukui Prefecture. As a results, the measurement error of both methods for daytime and hourly evaporation were within ±1mm and ±0.3mm respectively