Satellite-measured water vapor isotopologues across the Tianshan Mountains, central Asia

The satellite-based water vapor stable isotope measurements have been widely used in modern hydrological and atmospheric studies. Their use is important for arid areas where the precipitation events are limited, and below-cloud evaporation is strong. This study presents the spatial and temporal characteristics of water vapor isotopologue across the Tianshan Mountains in arid central Asia using the NASAAura Tropospheric Emission Spectrometer (TES). The near-surface water vapor stable isotopes are enriched in summer and depleted in winter, consistent with the seasonality of precipitation isotopes. From the surface to 200 hPa, the isotope values in water vapor show a decreasing trend as the atmospheric pressure decreases and elevation rises. The vapor isotope values in the lower atmosphere in the southern basin of the Tianshan Mountains are usually higher than that in the northern basin, and the seasonal difference in vapor isotopes is slightly more significant in the southern basin. In addition, bottom vapor isotopologue in summer shows a depletion trend from west to east, consistent with the rainout effect of the westerly moisture path in central Asia. The isotopic signature provided by the TES is helpful to understand the moisture transport and below-cloud processes influencing stable water isotopes in meteoric water.