过去2000年东亚夏季风降水百年际变化特征及成因的模拟研究

利用地球系统模式CESM过去2 000年气候模拟试验结果,探讨了在百年尺度上东亚夏季风降水的时空变化特征及其成因,对于认识百年尺度气候变化规律、区分外强迫因子对东亚季风的影响有着重要的科学意义。研究表明:1东亚夏季风降水与温度基本同相变化,降水存在准100年、准150年和准200年周期。2降水标准化EOF第一模态为由北向南"负—正—负—正"的条带状空间分布,而EOF第二模态基本为全区一致的分布型态。3东亚夏季风降水准100年周期主要受太阳辐射、火山活动和气候系统内部变率的共同影响;准150年周期主要受太阳辐射的影响;准200年周期主要受太阳辐射和火山活动的影响。东亚夏季风降水在温带地区主要受温室气体和土地利用/覆盖的影响;在副热带地区主要受太阳辐射和火山活动的影响;在热带地区主要受太阳辐射、火山活动和气候系统内部变率的影响。

Modeling Study on the Characteristics and Causes of East Asian Summer Monsoon Precipitation on Centennial Time Scale over the Past 2000 Years

The characteristics and causes of the spatio-temporal variation of the EASM precipitation on centennial time scale were analyzed in this paper based on the climate simulation results over the past 2000 years using the Community Earth System Model (CESM). It has an important scientific significance to recognize the climate change on centennial time scale and to distinguish the influence of external forcing on the EASM. The results show: ①The East Asian Summer Monsoon (EASM) precipitation and temperature mainly reflect an in phase variability on centennial time scale. We found that there are three periodicities (100a, 150a and 200a) in the EASM precipitation. ②The spatial structures of the first mode of the standardization EOF of the EASM precipitation show the “minus-plus-minus-plus” zonal belts while the spatial structures of the second mode show almost an in phase variability in the East Asian region. ③The 100 year cycle of the EASM precipitation is caused by the total solar irradiation, the volcanic eruptions and the internal variability of climate system. The 150 year cycle is caused by the total solar irradiation and the 200 year cycle is caused by the total solar irradiation and the volcanic eruptions. The main cause of the spatial patterns of precipitation in the East Asian region is the total solar irradiation but forcings affect differently in different latitude. The factors affecting the spatial change of the extratropical EASM precipitation are the greenhouse gases and the land use and land cover change, while the factors affecting the spatial change of the subtropical EASM precipitation are the total solar irradiation and the volcanic eruptions. And the factors affecting the spatial change of the tropical EASM precipitation are the total solar irradiation, the volcanic eruptions and the internal variability of climate system.