This paper reveals the temporal and spatial variations of stable isotope in precipitation of the Yarlung Zangbo River Basin based on the variations of δ^18O in precipitation at four stations （Lhaze, Nugesha, Yangcu...This paper reveals the temporal and spatial variations of stable isotope in precipitation of the Yarlung Zangbo River Basin based on the variations of δ^18O in precipitation at four stations （Lhaze, Nugesha, Yangcun and Nuxia） in 2005. The results show that δ^18O of precipitation has distinct seasonal changes in the Yarlung Zangbo River Basin. The higher value of δ^18O occurs in spring prior to monsoon precipitation, and the lower value occurs during monsoon precipitation. From the spatial variations, with the altitude-effect and rainout process during moisture transport along the Yarlung Zangbo River Valley, δ^18O of precipitation is gradually depleted. Thus, δ^18O of precipitation decreases gradually from the downstream to the upstream, and the lapse rate of δ^18O in precipitation is approximately 0.34‰/100m and 0.7%J‰/100km for the two reasons. During monsoon precipitation, spatial variation of δ^18O in precipitation is dominated by the amount effect in the large scale synoptic condition.展开更多
Precipitation δ 18O at Yushu, eastern Tibetan Plateau, shows strong fluctuation and lack of clear seasonality. The seasonal pattern of precipitation stable isotope at Yushu is apparently different from either that of...Precipitation δ 18O at Yushu, eastern Tibetan Plateau, shows strong fluctuation and lack of clear seasonality. The seasonal pattern of precipitation stable isotope at Yushu is apparently different from either that of the southwest monsoon region to the south or that of the inland region to the north. This different seasonal pattern probably reflects the shift of different moisture sources. In this paper, we present the spatial comparison of the seasonal patterns of precipitation δ 18O, and calculate the moisture transport flux by using the NCAR/NCEP reanalysis data. This allows us to discuss the relation between moisture transport flux and precipitation δ 18O. This study shows that both the southwest monsoon from south and inland air mass transport from north affected the seasonal precipitation δ 18O at Yushu, eastern Tibetan Plateau. Southwest monsoon brings the main part of the moisture, but southwest transport flux is weaker than in the southern part of the Tibetan Plateau. However, contribution of the inland moisture from north or local evaporation moisture is enhanced. The combined effect is the strong fluctuation of summer precipitation δ 18O at Yushu and comparatively poor seasonality.展开更多
Glaciers in the Yarlung Zangbo River witness severe glacial retreat nowadays,which gives important influence on lake processes in the region.We have studied glacial distribution,glacial mass balance and found large de...Glaciers in the Yarlung Zangbo River witness severe glacial retreat nowadays,which gives important influence on lake processes in the region.We have studied glacial distribution,glacial mass balance and found large deficit in glacial mass and its impact in the region.Our study also integrated the variation in glacial-fed lakes of the Nam Co and Ranwu Lake,and presented an initial assessment of the impact of glacial mass balance on lakes.The study has shown a significant contribution of glacial melting to recent lake expansion and lake level rising.展开更多
Atmospheric water vapor samples were col-lected in the Nagqu River Basin in the middle of Tibetan Plateau between August and October in 2004. Results show that there exist some fluctuations of the δ 18O of atmospheri...Atmospheric water vapor samples were col-lected in the Nagqu River Basin in the middle of Tibetan Plateau between August and October in 2004. Results show that there exist some fluctuations of the δ 18O of atmospheric water vapor, especially before and after the monsoon’s end. Moreover, the variety trend of the δ 18O of atmospheric water vapor inverse correlates with that of dew point. Precipitation events make an important effect upon the variation of δ 18O of atmospheric water vapor. During the whole sampling pe-riod, the δ 18O values of atmospheric water vapor are low while precipitation events occurred. The moisture origins also contribute to the variation of δ 18O of atmospheric water vapor. The oceanic moisture transported by the southwest monsoon results in lower δ18O of atmospheric water vapor in the Nagqu River Basin. Compared with the influence of the oceanic moisture, the δ 18O values, however, appear high re-sulting from the effect of the continental air mass in this re-gion.展开更多
Analysis of daily precipitation samples for stable oxygen isotopes (δ18O) collected at the Shiquanhe and Gêrzê (Gaize, Gertse) stations in the Ngari (Ali) region on the western Tibetan Plateau indicates tha...Analysis of daily precipitation samples for stable oxygen isotopes (δ18O) collected at the Shiquanhe and Gêrzê (Gaize, Gertse) stations in the Ngari (Ali) region on the western Tibetan Plateau indicates that air temperature affects the δ18O variations in precipitation at these stations. In summer, Shiquanhe and Gêrzê show strongly similar trends in precipitation δ18O, especially in simultaneous precipitation events. Moreover, both stations experienced low δ18O values in precipitation during the active monsoon period, resulting from the southwest monsoon (the summer phase of the Indian monsoon). However, during the break monsoon period (during the summer rainy season, when the monsoon circulation is disrupted), δ18O values in summer precipitation remain relatively high and local moisture recycling generally controls the moisture sources. Air temperature correlations with δ18O strengthen during the non-monsoon period (January―June, and October―December) due to continental air masses and the westerlies. In addition, evaporation also influences the δ18O variations in precipitation. The observed temporal and spatial variations of δ18O in precipitation on the western Tibetan Plateau and adjacent regions show that the late May and early June-the late August and early September time frame provides an important period for the transportation of moisture from various sources on the Tibetan Plateau, and that the region of the West Kunlun-Tanggula Ranges acts as a significant climatic divide on the Plateau, perhaps for all of western China.展开更多
基金National Natural Science Foundation of China, No.40121101 No.40671043+2 种基金 No.40571039 National Basic Research Program of China, No.2005CB422002 Knowledge Innovation Program of the Chinese Academy of Sciences, No.KZCX3- SW-339
文摘This paper reveals the temporal and spatial variations of stable isotope in precipitation of the Yarlung Zangbo River Basin based on the variations of δ^18O in precipitation at four stations （Lhaze, Nugesha, Yangcun and Nuxia） in 2005. The results show that δ^18O of precipitation has distinct seasonal changes in the Yarlung Zangbo River Basin. The higher value of δ^18O occurs in spring prior to monsoon precipitation, and the lower value occurs during monsoon precipitation. From the spatial variations, with the altitude-effect and rainout process during moisture transport along the Yarlung Zangbo River Valley, δ^18O of precipitation is gradually depleted. Thus, δ^18O of precipitation decreases gradually from the downstream to the upstream, and the lapse rate of δ^18O in precipitation is approximately 0.34‰/100m and 0.7%J‰/100km for the two reasons. During monsoon precipitation, spatial variation of δ^18O in precipitation is dominated by the amount effect in the large scale synoptic condition.
基金the National Basic Research Program of China (Grant No.2005CB422002)National Natural Science Foundation of China (Grand Nos.40671043,40571039 and 40121101)
文摘Precipitation δ 18O at Yushu, eastern Tibetan Plateau, shows strong fluctuation and lack of clear seasonality. The seasonal pattern of precipitation stable isotope at Yushu is apparently different from either that of the southwest monsoon region to the south or that of the inland region to the north. This different seasonal pattern probably reflects the shift of different moisture sources. In this paper, we present the spatial comparison of the seasonal patterns of precipitation δ 18O, and calculate the moisture transport flux by using the NCAR/NCEP reanalysis data. This allows us to discuss the relation between moisture transport flux and precipitation δ 18O. This study shows that both the southwest monsoon from south and inland air mass transport from north affected the seasonal precipitation δ 18O at Yushu, eastern Tibetan Plateau. Southwest monsoon brings the main part of the moisture, but southwest transport flux is weaker than in the southern part of the Tibetan Plateau. However, contribution of the inland moisture from north or local evaporation moisture is enhanced. The combined effect is the strong fluctuation of summer precipitation δ 18O at Yushu and comparatively poor seasonality.
基金supported by the Ministry of Science and Technology of the People's Republic of China(2005CB422004)the National Natural Science Foundation of China(40810019001)+1 种基金BRAHMATWINN (FP6-036952)the Program of Tibet Science and Technology Agency
文摘Glaciers in the Yarlung Zangbo River witness severe glacial retreat nowadays,which gives important influence on lake processes in the region.We have studied glacial distribution,glacial mass balance and found large deficit in glacial mass and its impact in the region.Our study also integrated the variation in glacial-fed lakes of the Nam Co and Ranwu Lake,and presented an initial assessment of the impact of glacial mass balance on lakes.The study has shown a significant contribution of glacial melting to recent lake expansion and lake level rising.
基金This work was supported by the National Natural Science Foundation of China(Grant No.40271025)the Collective Innovation of the National Natural Science Foundation of China(Grant No.40121101)+1 种基金the Innovation Program of Chinese Academy of Sciences(Grant No.KZCX3-SW-339)Ministry of Science and Technology of China(Grant No.2001CCB711001).
文摘Atmospheric water vapor samples were col-lected in the Nagqu River Basin in the middle of Tibetan Plateau between August and October in 2004. Results show that there exist some fluctuations of the δ 18O of atmospheric water vapor, especially before and after the monsoon’s end. Moreover, the variety trend of the δ 18O of atmospheric water vapor inverse correlates with that of dew point. Precipitation events make an important effect upon the variation of δ 18O of atmospheric water vapor. During the whole sampling pe-riod, the δ 18O values of atmospheric water vapor are low while precipitation events occurred. The moisture origins also contribute to the variation of δ 18O of atmospheric water vapor. The oceanic moisture transported by the southwest monsoon results in lower δ18O of atmospheric water vapor in the Nagqu River Basin. Compared with the influence of the oceanic moisture, the δ 18O values, however, appear high re-sulting from the effect of the continental air mass in this re-gion.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 40830638, 40701037 and 40771048)Ministry of Science and Technology of the People’s Republic of China (Grant No. 2005CB422004)support of the State Key Laboratory of Cryospheric Sciences (Grant No. SKLCS 08-09) and Knowledge Innovation Program of the Chinese Academy of Sciences
文摘Analysis of daily precipitation samples for stable oxygen isotopes (δ18O) collected at the Shiquanhe and Gêrzê (Gaize, Gertse) stations in the Ngari (Ali) region on the western Tibetan Plateau indicates that air temperature affects the δ18O variations in precipitation at these stations. In summer, Shiquanhe and Gêrzê show strongly similar trends in precipitation δ18O, especially in simultaneous precipitation events. Moreover, both stations experienced low δ18O values in precipitation during the active monsoon period, resulting from the southwest monsoon (the summer phase of the Indian monsoon). However, during the break monsoon period (during the summer rainy season, when the monsoon circulation is disrupted), δ18O values in summer precipitation remain relatively high and local moisture recycling generally controls the moisture sources. Air temperature correlations with δ18O strengthen during the non-monsoon period (January―June, and October―December) due to continental air masses and the westerlies. In addition, evaporation also influences the δ18O variations in precipitation. The observed temporal and spatial variations of δ18O in precipitation on the western Tibetan Plateau and adjacent regions show that the late May and early June-the late August and early September time frame provides an important period for the transportation of moisture from various sources on the Tibetan Plateau, and that the region of the West Kunlun-Tanggula Ranges acts as a significant climatic divide on the Plateau, perhaps for all of western China.
