Physical Oceanography Laboratory/CIMST, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266100, China.
CSIRO Oceans and Atmosphere, Aspendale, VIC 3195, Australia.
Sci Rep. 2017 Jul 10;7(1):4929. doi: 10.1038/s41598-017-05225-z.
El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) tend to exert an offsetting impact on Indian summer monsoon rainfall (ISMR), with an El Niño event tending to lower, whereas a positive IOD tending to increase ISMR. Simulation of these relationships in Phase Five of the Coupled Model Intercomparison Project has not been fully assessed, nor is their impact on the response of ISMR to greenhouse warming. Here we show that the majority of models simulate an unrealistic present-day IOD-ISMR correlation due to an overly strong control by ENSO. As such, a positive IOD is associated with an ISMR reduction in the simulated present-day climate. This unrealistic present-day correlation is relevant to future ISMR projection, inducing an underestimation in the projected ISMR increase. Thus uncertainties in ISMR projection can be in part induced by present-day simulation of ENSO, the IOD, their relationship and their rainfall correlations.
厄尔尼诺-南方涛动（ENSO）和印度洋偶极子（IOD）往往对印度夏季季风降雨量（ISMR）产生抵消影响，厄尔尼诺事件往往会降低 ISMR，而正印度洋偶极子往往会增加 ISMR。耦合模式比较计划第五阶段对这些关系的模拟尚未得到充分评估，它们对 ISMR 对温室变暖响应的影响也尚未得到评估。在这里，我们表明，由于 ENSO 的过度控制，大多数模型模拟的是一种不切实际的当前IOD-ISMR 相关性。因此，正印度洋偶极子与当前模拟气候中的 ISMR 减少有关。这种不切实际的当前相关性与未来的 ISMR 预测有关，导致对未来 ISMR 增加的低估。因此，ISMR 预测的不确定性部分可以由 ENSO、IOD、它们之间的关系及其降雨相关性的当前模拟引起。
