An effort is made to evaluate the performance of an atmosphere–ocean coupled regional model in simulating the Indian summer monsoon rainfall during the years 1995–2015. The RegCM and MITgcm models are taken as the atmospheric and oceanic components of the coupled model, respectively. It is found that the coupling helps to improve the SST of the Arabian Sea and Bay of Bengal regions of the model domain. The air–sea coupling also improves the wind speed simulation. The RegCM-MITgcm coupled model correctly represents the intraseasonal variability of the Indian summer monsoon rainfall as compared to the RegCM stand-alone model. It is shown that the very high and extreme rainfall intensity events are correctly simulated by the RegCM-MITgcm coupled model, whereas the RegCM stand-alone model underestimates the precipitation intensities. It is argued that the atmosphere–ocean coupling helps to increase the predictability skill of the Indian monsoon rainfall. For example, the limit of predictability of the Indian monsoon rainfall obtained from the coupled model (22 days) is closer to that obtained from the IMD observation (24 days). The corresponding limit of predictability from the stand-alone model is 20 days.

中文翻译：

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RegCM-MITgcm耦合区域模型在模拟印度夏季风降雨中的性能

努力评估大气-海洋耦合区域模型在模拟 1995-2015 年印度夏季风降雨量方面的性能。RegCM 和 MITgcm 模型分别作为耦合模型的大气和海洋成分。发现耦合有助于提高模型域阿拉伯海和孟加拉湾地区的海温。海气耦合还改进了风速模拟。与 RegCM 独立模型相比，RegCM-MITgcm 耦合模型正确地表示了印度夏季风降雨的季节内变化。结果表明，RegCM-MITgcm耦合模型正确模拟了极高和极端降雨强度事件，而RegCM独立模型低估了降水强度。有人认为，大气-海洋耦合有助于提高印度季风降雨的可预测性。例如，耦合模型获得的印度季风降雨的可预测性极限（22 天）更接近于 IMD 观测（24 天）获得的预测极限。独立模型的相应可预测性限制为 20 天。