摘要
Due to complex atmospheric circulations and topography,warm season moisture variability demonstrates significant regional variations in China.Studies based on the various proxy data suggested that there existed an anti-phase relationship in terms of moisture changes between the westerly-dominated arid central Asia(including Central Asia and Xinjiang in China)and monsoonal northern China during the last millennium[1,2].Besides the West-East anti-phase mode,the moisture variations in monsoonal eastern China exhibit a North-South anti-phase spatial structure,with a boundary roughly along the Huai River[2].In fact,the proxy data used in previous studies primarily reflect the moisture variability in the warm season.Generally,the North-South mode coupled with the West-East mode represents a warm season tripolar hydroclimatic pattern in China with three centers located respectively in the arid region(Xinjiang),semiarid region(North China),and humid region(South China)during the last millennium.Specifically,the warm season moisture variations in the semiarid region are out-of-phase with those in the arid and humid regions in the past when the anthropogenic effects are relatively weak[3].The pattern of moisture variability has a significant effect on water resources,food production and ecosystem[4-8].In future,the climate variations are largely drived by the anthropogenic factors[9,10].Therefore,investigating the spatiotemporal variation of this tripolar pattern and their mechanisms in the context of anthropogenic changes is important for agriculture,ecology,and economy in China.
过去千年我国暖季的干湿变化呈现出三极子模态,即新疆地区和华南地区的干湿变化趋势与华北地区相反.本文利用中国的台站观测资料及CMIP5的模拟数据构建干燥度指数(AI),对目前和未来中国水文气候三级子模态的变化特征及归因进行了分析.结果表明,1993~2015年期间,长期存在的三极子模态已经消失.在未来RCP8.5排放情景下,21世纪中期当全球升温低于2℃时,该模态可以恢复;但是在21世纪末,三级子模态将再次消失.归因分析表明,未来气温升高将导致新疆和华南地区变干.除温度外,相对湿度的变化也是造成未来华南地区变干的重要因子.而华北地区AI对全球变暖的响应则取决于升温程度.当未来升温低于2℃时,降水的增加使得华北地区变湿,而在21世纪末,升温高于2℃时,温度的升高将导致华北地区变干.
作者
Wei Huang
Chang Liu
Jinqiu Cao
Jianhui Chen
Song Feng
黄伟;刘畅;曹金秋;陈建徽;冯松(Key Laboratory of Western China’s Environmental Systems(Ministry of Education),College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China;Department of Geosciences,University of Arkansas,Fayetteville,AR 72701,USA)
基金
supported by the National Natural Science Foundation of China(41790421 and 41877446)
Maps in this article were reviewed by Ministry of Natural Resources of the People’s Republic of China(GS(2020)909).
