A tentative study of the relationship between annual δ~(18)O & 5D variations of precipitation and atmospheric circulations-A case from Southwest China

摘要

In this study, we present the 6-year delta O-18 and delta D records of precipitation from Chongqing, southwest China. Based on these data, the local meteoric water line (LMWL) has been set up as: delta D = 8.33 delta O-18+19.42. It is demonstrated that in El Nino scenarios, more vapor from closer moisture source (Western Pacific) was transported to south China, resulted in heavier stable isotopes of precipitation in southwest China, while in La Ninna scenarios, the situations were just on the contrary. In addition, there is a positive correlation between the delta O-18 of precipitation in southwest China and the Northern Atlantic Oscillation Index (NAOI) when the NAO is in the positive phase (typically in boreal winter-half year). At the interannual timescale, the delta O-18 of precipitation in southwest China is more negative in strong NAO years than that in weak NAO years. We speculate that the north-south position migration of the westerlies and the route changes of vapor transport are correlated with the delta O-18 changes of precipitation in southwest China under the climate change scenario around the North Atlantic. (C) 2017 Elsevier Ltd and INQUA. All rights reserved.