DEVELOPMENT OF AN ISOTOPIC LAND SURFACE MODEL AND RIVER FLOW SCHEME WITH EVAPOTRANSPIRATIVE FRACTIONATION

Abstract

Stable water isotopes (D and ¹⁸O) in river water, which have integrated information of land surface processes, have been firstly reproduced by an isotopic land surface model (IsoLSM) and an isotopic river flow scheme (IsoTRIP) in this paper. Isotopic fractionation by three types of evaporation fromland, i. e. evaporation, transpiration, and evaporation from intercepted water, are incorporated in IsoLSM. Further, a bucket model is assumed for runoff and fractionation calculation.
Authors suggest the use of river water isotopes for validation of LSMs output related with water transport from an aspect of water quality. Moreover, this study enables us to reasonably estimate variability of isotopic values of evapotranspirated water from land surface. That probably leads better reproduction of spatial and temporal distribution of precipitation isotopes with an atmospheric isotope circulation model.