Climatic significance of δ18O records from precipitation on the western Tibetan Plateau

• Published in: Chinese science bulletin 2009-08, Vol.54 (16), p.2732-2741
• Main Authors: Yu, WuSheng, Ma, YaoMing, Sun, WeiZhen, Wang, Yu
• Format: Article
• Language: English
• Subjects: Chemistry/Food Science; Earth Sciences; Engineering; Humanities and Social Sciences; Life Sciences; multidisciplinary; Physics; Science; Science (multidisciplinary); Special Topic/Aricles/Geochemistry
• ISSN: 1001-6538; 2095-9273; 1861-9541; 2095-9281
• DOI: 10.1007/s11434-009-0495-6

Analysis of daily precipitation samples for stable oxygen isotopes (δ 18 O) 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 δ 18 O variations in precipitation at these stations. In summer, Shiquanhe and Gêrzê show strongly similar trends in precipitation δ 18 O, especially in simultaneous precipitation events. Moreover, both stations experienced low δ 18 O 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), δ 18 O values in summer precipitation remain relatively high and local moisture recycling generally controls the moisture sources. Air temperature correlations with δ 18 O 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 δ 18 O variations in precipitation. The observed temporal and spatial variations of δ 18 O 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.