资源环境科技发展态势分析平台

All types of applications of stable water isotopes, for example, for the reconstruction of paleotemperatures or for climate model validation, rely on a proper understanding of the mechanisms determining the isotopic composition of water vapor and precipitation. In this study, we use the isotope-enabled limited-area model COSMOiso to characterize the impacts of continental evapotranspiration, rainout, and subcloud processes on D of European water vapor and precipitation. To this end, we first confirm a reliable implementation of the most important isotope fractionation processes in COSMOiso by comparing 5years of modeled D values with multiplatform D observations from Europe (remote sensing observations of the D of water vapor around 2.6km above ground level, in situ D measurements in near-surface water vapor, and D precipitation data from the Global Network of Isotopes in Precipitation). Based on six 15year sensitivity simulations, we then quantify the climatological impacts of the different fractionation processes on the D values. We find D of European water vapor and precipitation to be most strongly controlled by rainout. Superimposed to this are the effect of subcloud processes, which especially affects D in precipitation under warm conditions, and the effect of continental evapotranspiration, which exerts an important control over the D of near-surface water vapor. In future studies, the validated COSMOiso model can be employed in a similar way for a comprehensive interpretation of European isotope records from climatologically different time periods.