Seasonal prediction of Indian summer monsoon rainfall has been considered as one of the important factors to decide the social and economic aspect of India because of its multi-sectorial dependencies. This study evaluates the performance of seven state-of-the-art GCMs in simulating the summer monsoon rainfall on a seasonal scale over the period of 1982–2008 using the GCM reforecasts. The rainfall simulated by the models is compared with the IMD observed rainfall dataset at 0.25° × 0.25°. Preliminary analysis of spatial pattern and statistics shows that the models IITM-CFSv2, NCEP-CFSv2 and ECMWF are some of the prominent models that capture the seasonal rainfall pattern and possess good skill. ECMWF performs very well in simulating the rainfall pattern as well as the rainfall intensities. Comprehensive statistical analysis such as standard deviation ratio and skill scores concludes that the IITM-CFSv2 produces the rainfall pattern as well as the variability of the summer monsoon better than its counterparts. The multi-model simple mean also tends to improve with the addition of IITM-CFSv2. Though the rainfall trend and variance simulated by IITM-CFSv2 is quite in agreement with the observed, there lies a significant dry bias over the north-west India. The mean simulated rainfall is quite less with the CFSv2 models. Though the IITM-CFSv2 simulates lesser rainfall at all the four-lead times, it is quite capable in capturing the rainfall variability. The models ECMWF and GFDLA04 are well performers in terms of mean rainfall estimates whereas the models CFSv2 is better in terms of reproducing the rainfall variability.

印度夏季风降雨的季节性预测因其多部门依赖性而被认为是决定印度社会和经济方面的重要因素之一。本研究使用 GCM 重新预测评估了 7 个最先进的 GCM 在 1982-2008 年期间在季节性尺度上模拟夏季季风降雨的性能。模型模拟的降雨与IMD观测降雨数据集在0.25°×0.25°进行了比较。对空间格局和统计的初步分析表明，模型IITM-CFSv2、NCEP-CFSv2和ECMWF是一些捕捉季节性降雨模式并具有良好技能的突出模型。ECMWF 在模拟降雨模式和降雨强度方面表现非常出色。标准差比率和技能分数等综合统计分析得出的结论是，IITM-CFSv2 产生的降雨模式以及夏季风的可变性比其对应项更好。随着 IITM-CFSv2 的加入，多模型简单均值也趋于改善。尽管 IITM-CFSv2 模拟的降雨趋势和方差与观测结果非常一致，但印度西北部存在显着的干旱偏差。CFSv2 模型的平均模拟降雨量要少得多。尽管 IITM-CFSv2 在所有四个提前期都模拟了较小的降雨量，但它非常有能力捕捉降雨量的变化。ECMWF 和 GFDLA04 模型在平均降雨量估计方面表现良好，而模型 CFSv2 在再现降雨变异性方面表现更好。