Stable isotopic compositions of precipitation events from Kathmandu, southern slope of the Himalayas  

作　　者：Tek Bahadur Chhetri Tandong Yao Wusheng Yu Li Ding Daniel Joswiak Lide Tian Lochan Prasad Devkota Dongmei Qu 

机构地区：[1]Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Central Department of Hydrology and Meteorology, Tribhuvan University, Kathmandu, Nepal [4]Yinchuan Meteorological Administration

出　　处：《Chinese Science Bulletin》2014年第34期4838-4846,共9页

基　　金：supported by the Major Program of National Natural Science Foundation of China(41190081);the National Basic Research Program of China(2010CB951702);the Strategic Priority Research Program of Chinese Academy of Sciences(XDB03030207 and XDA05080600);the National Natural Science Foundation of China(41025002,41125003,41371086,and40971049)

摘　　要：Investigation of temporal variations in the stable d18 O and d D isotopes from Kathmandu's precipitation events shows that the relatively enriched d18 O and d D values in the winter(the dry season, dominated by the westerlies) were positively correlated with temperature,indicating a temperature effect controlling the changes of d18 O and d D. However, the d18 O and d D values were depleted in the summer(the wet season, dominated by the Indian monsoon), which were negatively correlated with precipitation amount, indicating an amount effect. In addition, the comparison of stable isotopes in precipitation from Kathmandu and Mawlong(near the Bay of Bengal)shows that the overall trends of d18 O and d D values at Kathmandu generally approximate those at Mawlong.However, there remain many differences between the details of the isotopic changes at Kathmandu versus those at Mawlong. Compared with those at Mawlong, the further rainout effect and the more intense lift effect of the oceanic moisture by the high mountains resulted in the moredepleted d18 O and d D values in summer precipitation at Kathmandu. A deuterium excess and the local meteoric water lines reveal that evaporation at Kathmandu exceeds that at Mawlong. The data also show that the Indian monsoon activities at Mawlong are more intense than those at Kathmandu.Investigation of temporal variations in the stable δ^18O and δD isotopes from Kathmandu＇s precipitation events shows that the relatively enriched δ^18O and δD values in the winter （the dry season, dominated by the westerlies） were positively correlated with temperature, indicating a temperature effect controlling the changes of δ^18O and δD. However, the δ^18O and δD values were depleted in the summer （the wet season, dominated by the Indian monsoon）, which were negatively correlated with precipitation amount, indicating an amount effect. In addition, the comparison of stable isotopes in precipitation from Kathmandu and Mawlong （near the Bay of Bengal） shows that the overall trends of δ^18O and δD values at Kathmandu generally approximate those at Mawlong. However, there remain many differences between the details of the isotopic changes at Kathmandu versus those at Mawlong. Compared with those at Mawlong, the further rainout effect and the more intense lift effect of the oceanic moisture by the high mountains resulted in the more depleted δ^18O and δD values in summer precipitation at Kathmandu. A deuterium excess and the local meteoric water lines reveal that evaporation at Kathmandu exceeds that at Mawlong. The data also show that the Indian monsoon activities at Mawlong are more intense than those at Kathmandu.

关 键 词：同位素组成 稳定同位素 降水事件 喜马拉雅山 南坡 温度效应 印度季风 夏季降水 

分 类 号：P426.6[天文地球—大气科学及气象学]