第六届青年地学论坛

1377 / 2019-08-09 22:01:50

Effect of precipitation seasonality on annual oxygen isotopic composition in the area of spring persistent rain in southeastern China and its palaeoclimatic implication

15、冰冻圈科学 > 专题7：高低纬相互作用及水汽循环过程

This study examines the seasonality of precipitation amount and δ18O over the monsoon region of China (MRC). We find that the precipitation amount associated with the East Asian summer monsoon (EASM) in the spring persistent rain (SPR) region is equivalent to that of the non-summer monsoon (NSM), with the latter contributing ~50% to the amount-weighted annual δ18O values in contrast with other areas of the monsoon region of China (MRC) where the δ18O of annual precipitation is dominated by the EASM precipitation. The interannal relationships between ENSO index, simulated δ18O data from IsoGSM and seasonal precipitation amount in the SPR region were also analyzed. We find that on interannual timescales, less (more) EASM and more (less) NSM precipitation leading to lower (higher) EASM/NSM precipitation amount ratios result in higher (lower) amount-weighted annual precipitation δ18O and consequently, in speleothems δ18O during El Niño (La Niña) phases, although moisture sources and pathways may also impact this relationship. Characterizing the spatial differences in seasonal precipitation is therefore, key in correctly interpreting the speleothem δ18O records from the MRC.