| 我国中部地区夏季干旱的多时间尺度特征及其环流、海温异常 |
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| 引用本文： | 赵昶昱,陈海山,孙善磊.我国中部地区夏季干旱的多时间尺度特征及其环流、海温异常[J].气象科学,2019,39(3):386-395. |
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| 作者姓名： | 赵昶昱 陈海山 孙善磊 |
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| 作者单位： | 南京信息工程大学 气象灾害预报预警与评估协同创新中心/气候与环境变化国际合作联合实验室/气象灾害教育部重点实验室, 南京 210044;南京信息工程大学 大气科学学院, 南京 210044;宁波市气象站, 浙江 宁波 315012,南京信息工程大学 气象灾害预报预警与评估协同创新中心/气候与环境变化国际合作联合实验室/气象灾害教育部重点实验室, 南京 210044;南京信息工程大学 大气科学学院, 南京 210044,南京信息工程大学 气象灾害预报预警与评估协同创新中心/气候与环境变化国际合作联合实验室/气象灾害教育部重点实验室, 南京 210044 |
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| 基金项目： | 国家自然科学基金资助项目（41625019） |
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| 摘 要： | 基于CRU逐月降水和NCEP/NCAR再分析等资料,利用集合经验模态分解(Ensemble Empirical Mode Decomposition,EEMD)方法,分析1948—2016年中国中部地区夏季降水变化的多时间尺度特征及其对应的环流、海温异常,进而解释不同时期影响干旱发生的背景场有何不同。结果表明,中部地区夏季降水以年际变化为主,周期长度为3.8 a和6.9 a,年代际和多年代际变化的方差贡献不足20%。然而,各时间尺度降水变化对不同时期干旱事件的贡献存在较大差异,1960s、1970s,降水年际变化偏弱,相反地,多年代际变化正处于负位相的极小值期;1980s、1990s,多年代际变化位相转正;2000s初,年际变化明显增强。此外,通过分析不同时间尺度降水变化对应的环流、海温背景场,发现热带印度洋海温异常及其引起的西北太平洋副热带高压的变化、大西洋北部海温异常激发的纬向波列以及贝加尔湖地区的阻塞活动、1970s末PDO位相转变伴随的东亚夏季风突变是分别解释降水年际、年代际和多年代际变化的主要原因,进而揭示影响中部地区夏季干旱发生的关键因子及其相对重要性。
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| 关 键 词： | 中部地区干旱 夏季降水 环流和海温异常 多时间尺度 EEMD方法 |
| 收稿时间： | 2017/11/29 0:00:00 |
| 修稿时间： | 2018/3/29 0:00:00 |
Multipletime-scale characteristics of summer droughts over central China and relevant atmospheric circulation and sea surface temperature anomalies |
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| ZHAO Changyu,CHEN Haishan and SUN Shanlei.Multipletime-scale characteristics of summer droughts over central China and relevant atmospheric circulation and sea surface temperature anomalies[J].Scientia Meteorologica Sinica,2019,39(3):386-395. |
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| Authors: | ZHAO Changyu CHEN Haishan and SUN Shanlei |
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| Institution: | Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/International Joint Research Laboratory of Climate and Environment Change/Key Laboratory of Meteorological Disaster, Ministry of Education, Nanjing University of Information Science & Technology, Nanjing 210044, China;School of Atmospheric Science, Nanjing University of Information Science & Technology, Nanjing 210044, China;Ningbo Meteorological Observation, Zhejiang Ningbo 315012, China,Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/International Joint Research Laboratory of Climate and Environment Change/Key Laboratory of Meteorological Disaster, Ministry of Education, Nanjing University of Information Science & Technology, Nanjing 210044, China;School of Atmospheric Science, Nanjing University of Information Science & Technology, Nanjing 210044, China and Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/International Joint Research Laboratory of Climate and Environment Change/Key Laboratory of Meteorological Disaster, Ministry of Education, Nanjing University of Information Science & Technology, Nanjing 210044, China |
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| Abstract: | Based on Climatic Research Unit (CRU) monthly precipitation and NCEP/NCAR reanalysis datasets, different time-scale characteristics of precipitation variation in summer over central China and relevant atmospheric circulation and Sea Surface Temperature (SST) anomalies were analyzed using the Ensemble Empirical Mode Decomposition (EEMD) method, and the different ambient fields affecting the drought in different period were further explained. The results indicate that the Interannual Variation (IAV) of summer precipitation over central China has cycle lengths of 3.8 and 6.9 years, and the Interdecadal and Multidecadal Variations (IDV and MDV) account for less than 20% of the total variance. However, different time scales have varying contributions to drought events in different periods:IAV is relatively weaker during 1960s and 1970s while MDV reaches the negative peak, but MDV turns into positive phase during 1980s and 1990s, and IAV has significantly increased at the beginning of the 21st century. Moreover, through analyzing the atmospheric circulation and SST ambient field associated with different time-scale precipitation variations over central China, it is found that the SST anomalies in the tropical Indian Ocean and the resulting changes in the Northwest Pacific subtropical high, the zonal wave train excited by SST anomalies in northern Atlantic and the Lake Baikal blocks, and the abrupt change of East Asian summer monsoon accompanied with the PDO phase shift in the late 1970s account for interannual, interdecadal and multidecadal changes in precipitation, respectively, which also reveal the main factors that affect the summer drought over central China during different periods. |
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| Keywords: | drought over central China summer precipitation atmospheric circulation and SST anomalies multiple time-scale EEMD method |
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