Evapotranspiration Dynamics in Monsoon-dominated Region in the Korean Peninsula

Abstract. This study investigates the dynamics of evapotranspiration in a monsoon-dominated region of the Korean Peninsula, with a particular focus on the challenges associated with measurement, identification, and prediction of the potential and actual evapotranspiration. The research delves into various models and theories, notably the Complementary Relationship of Evapotranspiration (CRE) hypothesis widely used for estimating AET indirectly when direct measurements are difficult to obtain. The study area encompasses the Yongdam dam basin, utilizing data from flux towers, evaporimeters, and meteorological stations to estimate both actual evapotranspiration (AET) and potential evapotranspiration (PET). The Penman-Monteith equation is employed for PET estimation, with reference evapotranspiration calculations conducted using the FAO Penman-Monteith equation. This research confirms the existence of complementary relationship behaviour in regions where strong correlations between soil moisture and air humidity are observed, such as deserts and tropical areas. In these regions, the influence of annual climate fluctuations and seasonal winds is comparatively minor. Nevertheless, it is important to note that the correlation between soil moisture and air humidity diminishes in areas affected by external factors, such as the dominant influence of the monsoon climate zone. In such instances, potential evaporation and actual evaporation often deviate from the expected complementary relationship, adopting a more erratic pattern of distribution.