We use an unprecedented ensemble of regional climate model (RCM) projections over seven regional CORDEX domains to provide, for the first time, an RCM-based global view of monsoon changes at various levels of increased greenhouse gas (GHG) forcing. All regional simulations are conducted using RegCM4 at a 25 km horizontal grid spacing using lateral and lower boundary forcing from three General Circulation Models (GCMs), which are part of the fifth phase of the Coupled Model Inter-comparison Project (CMIP5). Each simulation covers the period from 1970 through 2100 under two Representative Concentration Pathways (RCP2.6 and RCP8.5). Regional climate simulations exhibit high fidelity in capturing key characteristics of precipitation and atmospheric dynamics across monsoon regions in the historical period. In the future period, regional monsoons exhibit a spatially robust delay in the monsoon onset, an increase in seasonality, and a reduction in the rainy season length at higher levels of radiative forcing. All regions with substantial delays in the monsoon onset exhibit a decrease in pre-monsoon precipitation, indicating a strong connection between pre-monsoon drying and a shift in the monsoon onset. The weakening of latent heat driven atmospheric warming during the pre-monsoon period delays the overturning of atmospheric subsidence in the monsoon regions, which defers their transitioning into deep convective states. Monsoon changes under the RCP2.6 scenario are mostly within the baseline variability.

我们使用前所未有的对七个区域CORDEX区域的区域气候模型（RCM）预测集合，首次提供了基于RCM的全球季风变化在不同水平的温室气体（GHG）强迫作用下的全球视图。所有区域模拟都是使用RegCM4在25 km的水平网格间距上进行的，其中使用了三个通用环流模型（GCM）的横向和下边界强迫，这是耦合模型相互比较项目（CMIP5）第五阶段的一部分。每种模拟都涵盖两个代表性浓度途径（RCP2.6和RCP8.5）下从1970年到2100年的时间。区域气候模拟在捕获历史时期整个季风区域的降水和大气动力学的关键特征方面表现出很高的保真度。在未来的时期 区域性季风在较高的辐射强迫下表现出季风发作的空间稳健性延迟，季节性增加和雨季长度减少。季风爆发有明显延迟的所有区域都表现出季风前降水减少，表明季风前干燥与季风爆发之间有很强的联系。季风前期潜热驱动的大气变暖的减弱延迟了季风区大气沉降的翻转，这阻碍了它们向深对流状态的转变。RCP2.6情景下的季风变化大部分在基线变化范围内。季风爆发有明显延迟的所有区域都表现出季风前降水减少，表明季风前干燥与季风爆发之间有很强的联系。季风前期潜热驱动的大气变暖的减弱延迟了季风区大气沉降的翻转，这阻碍了它们向深对流状态的转变。RCP2.6情景下的季风变化大部分在基线变化范围内。季风爆发有明显延迟的所有区域都表现出季风前降水减少，表明季风前干燥与季风爆发之间有很强的联系。季风前期潜热驱动的大气变暖的减弱延迟了季风区大气沉降的翻转，这阻碍了它们向深对流状态的转变。RCP2.6情景下的季风变化大部分在基线变化范围内。阻止了它们过渡到深对流状态。RCP2.6情景下的季风变化大部分在基线变化范围内。阻止了它们过渡到深对流状态。RCP2.6情景下的季风变化大部分在基线变化范围内。