资源环境科技发展态势分析平台

Climatic significance of ice core stable isotope record in the Himalayas and southern Tibetan Plateau (TP), where the climate is alternately influenced by Indian summer monsoon and mid-latitude westerlies, is still debated. A newly drilled Zuoqiupu ice core from a temperate maritime glacier on the southeastern TP covering 1942-2011 is investigated in terms of the relationships between delta O-18 and climate parameters. Distinct seasonal variation of delta O-18 is observed due to high precipitation amount in this area. Thus the monsoon (June to September) and non-monsoon (October to May) delta O-18 records are reconstructed, respectively. The temperature effect is identified in the annual delta O-18 record, which is predominantly contributed by temperature control on the non-monsoon precipitation delta O-18 record. Conversely, the negative correlation between annual delta O-18 record and precipitation amount over part of Northeast India is mostly contributed by the monsoon precipitation delta O-18 record. The variation of monsoon delta O-18 record is greatly impacted by the Indian summer monsoon strength, while that of non-monsoon delta O-18 record is potentially associated with the mid-latitude westerly activity. The relationship between Zuoqiupu delta O-18 record and Sea Surface Temperature (SST) is found to be inconsistent before and after the climate shift of 1976/1977. In summer monsoon season, the role of SST in the monsoon delta O-18 record is more important in eastern equatorial Pacific Ocean and tropical Indian Ocean before and after the shift, respectively. In non-monsoon season, however, the Atlantic Multidecadal Oscillation has a negative impact before but positive impact after the climate shift on the non-monsoon delta O-18 record.