Spatial and temporal distribution characteristics of the δD in the atmospheric vapor as retrieved from the TES data

Transport of water vapor in the atmosphere has the continuity in space and time. Using the isotope in water vapor, one can more comprehensively analyze the origins and transport paths of water vapor, and the re distribution and recharge forms of every component in the water cycle, and more in-depth understand the continuous variational characteristics and history of water vapor on the various spatial and temporal scales in the water cycle. This paper analyzes the spatial and temporal distribution of the δD in atmospheric water vapor and the relationship of the δD in water vapor with atmospheric humidity and with temperature at the different levels in the troposphere, and explores the relationship between the stable isotopes in water vapor and in precipitation and the possible impact of the large-scale hydrological cycle on the isotopes in water vapor, using the HDO and H2O data retrieved by Tropospheric Emission Spectrometer (TES), at 7 pressure levels from 825 hPa to 100 hPa. The results show that, in spatial variation, the δD in water vapor has a very obvious zonal distribution in the troposphere and a good correspondence with the precipitable water; the δD in water vapor decreases with vertical pressure as logarithmic type and shows a decreasing tendency in the average decline rate from the equator to high latitudes and from lands to oceans. In temporal variation, the seasonality of the δD in water vapor shows a regional difference. In the low-latitude lands, distinct seasonal variation of the δD in water vapor is corresponding to that of the precipitable water, but the δD in water vapor during summer is lower than that during winter in many parts of the middle and high latitudes. The consistent spatial distribution and the seasonal variation characterize the δD in the troposphere, but an opposite situation appears in the interlayer from the upper troposphere to the lower stratosphere. The correlations of the mean δD in water vapor versus the mean temperature and versus the mean precipitable water in interlayer have a similar distribution in the troposphere. The stable isotope in water vapor, compared with that in precipitation, is of some differences in the spatial distribution, the seasonal variation as well as the relationship with temperature and humidity, showing that the impacts of stable isotopic fractionation and atmospheric circulation types in the water cycle on two types of stable water isotopes have obvious differences.