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气象:2019,45(4):565-576
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2018年秋季我国气候异常及成因分析
赵俊虎,王永光
(国家气候中心,中国气象局气候研究开放实验室,北京 100081)
Features and Possible Causes of the Climatic Anomaly in China in Autumn 2018
ZHAO Junhu,WANG Yongguang
(Laboratory of Climate Studies, National Climate Centre, CMA, Beijing 100081)
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投稿时间:2018-12-26    修订日期:2019-03-21
中文摘要: 2018年秋季我国气候异常特征总体表现为:气温呈“东高西低”的分布;东部降水呈“南北多、中间少”的分布,其中内蒙古中东部、东北、江南南部和华南大部地区降水异常偏多,而华北至江南北部降水异常偏少,且江南和西南地区降水出现明显的季节内反向分布转变特征。异常成因分析表明,秋季欧亚中高纬度槽脊活动频繁,冷空气活跃,西太平洋副热带高压较常年同期偏强偏西,脊线季节内南北波动较大,西南水汽输送偏强,导致我国东部降水南北多、中间少。进一步研究表明,海温异常是影响2018年秋季我国气候异常的最主要外强迫因子,季节内El Ni〖AKn~D〗o由中部型向东部型发展,热带印度洋海温偶极子正位相持续,副热带南印度洋偶极子正位相发展。秋季后期El Ni〖AKn~D〗o影响增强,东亚副热带大气环流发生明显的季节内响应。因此,El Ni〖AKn~D〗o和印度洋海温的演变及其对东亚环流的影响,加上欧亚中高纬环流异常的季节内调整,二者共同导致了我国南方地区降水出现明显的东西反向的季节内变化。
Abstract:During the autumn of 2018, the surface air temperature was below normal in West China but above normal in East China. And the distribution of precipitation in eastern China was “more in the north and south, less in the middle”. The precipitation was above normal in the central and eastern part of Inner Mongolia, Northeast China, the southern part of the south of the Yangtze River and South China, but below normal in the region from North China to the northern part of the south of the Yangtze River. In addition, the precipitation in the south of the Yangtze River and Southwest China showed obvious seasonal reverse distribution characteristics. By analyzing the causes for the climatic anormaly, we found that in autumn, ridge and trough activities in middle and high latitudes of Eurasia were frequent, the cold air was active, the western Pacific subtropical high (WPSH) was stronger and more westward than normal, the ridges of WPSH fluctuated greatly from north to south, and the southwest water vapor transport was stronger, resulting in the abnormal distribution of precipitation in eastern China. Further studies have shown that the sea surface temperature anomaly (SSTA) was the major extermal forcing factor for the climatic anomalies in the autumn of 2018. The El Ni〖AKn~D〗o type developed from the central Pacific type (CP) El Ni〖AKn~D〗o to the eastern Pacific type (EP) El Ni〖AKn~D〗o. The positive phase of tropical Indian Ocean dipole (TIOD) turned to the positive phase of South Indian Ocean dipole (SIOD). And there was obvious response of the East Asian subtropical atmospheric circulation to the SSTA in the Pacific and Indian Ocean in autumn. Therefore, the evolution of El Ni〖AKn~D〗o and the SST in the Indian Ocean and their influence on the East Asia atmospheric circulation, together with the seasonal adjustment of the anomalous circulation in the middle and high latitudes in Eurasia, led to the obvious east west interseasonal changes of precipitation in sou thern China.
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基金项目:国家重点研发计划(2018YFC1506005)、国家自然科学基金项目(41875093、41705074和41505061)、中央引导地方科技发展专项(ZY18C12)及陕西省气象局气候监测与预测创新团队项目共同资助
引用文本:
赵俊虎,王永光,2019.2018年秋季我国气候异常及成因分析[J].气象,45(4):565-576.
ZHAO Junhu,WANG Yongguang,2019.Features and Possible Causes of the Climatic Anomaly in China in Autumn 2018[J].Meteor Mon,45(4):565-576.