过去1500 a亚洲夏季风降水的强迫特征

基于通用地球系统模式(CESM)进行了 4组长达1500 a的模拟试验(全强迫试验,控制试验,自然外强迫试验和人类活动外强迫试验).在评估模式模拟亚洲夏季风降水可靠性的基础上,对模拟结果进行10～100 a的带通滤波以获取年代—百年际亚洲夏季风降水信号.主要结论为:①过去1500 a亚洲夏季风降水强度存在显著的约15 ...

The forced response of Asian summer monsoon precipitation during the past 1500 years based on the CESM

Asian summer monsoon(ASM), one of the key elements of the global climate system, strongly affects food production and security of most people over Asia. However, the characteristics and the forcing drivers of the ASM system at decadal to centennial time scales remain unclear. To address these issues, we report four 1500-a long climate model simulations based on the Community Earth System Model(CESM), including full-forced run(ALLR),control run(CTRL), natural run(NAT), and anthropogenic run(ANTH). After evaluating the performances of the CESM in simulating ASM precipitation, a 10-100 bandpass filter is applied to obtain the decadal-centennial signals in ASM precipitation. The main conclusions are as follows:(1) the variation of ASM intensity shows significant decadal to centennial periodicities in the ALLR, such as ~15, ~25, ~40 and ~70 years.(2) The major spatial-temporal distributions of ASM precipitation in the ALLR show an external forced mode and a climate internal variability mode.(3) The leading forced mode of ASM precipitation is mainly affected by natural forcing over the past 1500 years and characterizes a meridional spatial ’triple’ mode.In the NAT(solar irradiation and volcanic eruptions), the substantial warming(cooling) over the western tropical Pacific enhances(or reduces) the SST gradient change in the tropical Pacific and modifies the ASM rainfall distribution. Our findings contribute to a better understanding of the ASM in the past and provide implications for future projections of the ASM under global warming.