Pan Evaporation for Estimating Evapotranspiration

Role of pan evaporation in the study on evapotranspiration (I)

Abstract

During the progress in the study on evapotranspiration (ET), pan evaporation (Epan) has played an important role as reference evaporation to derive various formulae for estimating ET and to study the ET mechanism. While more physical methods that fit the computerized work have recently been developed, the pan evaporation method is more practical, cost the least, more convenient, and reflects the meteorological environment more clearly than the other methods.
In this series of papers, the purposes of the studies on ET with pan evaporation are grouped into the following four: to scrutinize (1) ET formula, (2) reference evaporation for estimating ET, (3) characteristics of pan, and (4) advection effect. In the present paper, in relation to the standardization of the observation of Epan and the progress of the concept of potential evaporation, studies on purposes (1) and (2), and the results and problems brought by Epan are summarized. Then, the role of Epan as reference evaporation, that has been completed is summarized. Finally, reconsidering the significance of Epan, we review its role in the future.