王欢^1,,
李栋梁^2,,
1. 四川师范大学地理与资源科学学院, 成都 610101
2. 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/气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室, 南京 210044

基金项目: 国家重点基础研究发展计划(973计划)项目(2013CB430202), 公益性行业(气象)科研专项(GYHY201506001-1), 江苏省普通高校学术学位研究生科研创新计划项目(1354051501003), 国家自然科学基金项目(91337109、41305080), 江苏高校优势学科建设工程资助项目(PAPD)


详细信息

作者简介: 王欢, 女, 1989年生, 博士研究生, 主要从事气候动力学与气候变化研究.E-mail:wangh.11s@igsnrr.ac.cn

通讯作者: 李栋梁, 男, 1957年生, 教授, 主要从事气候动力学研究.E-mail:lidl@nuist.edu.cn

中图分类号: P402

收稿日期:2018-11-09
修回日期:2019-11-08
上线日期:2020-02-05

Impacts of decadal variability in sensible heat over the Tibetan Plateau on decadal transition of summer precipitation over dominant regions of monsoon rainfall band in eastern China since the early 2000s

WANG Huan^1,,
LI DongLiang^2,,
1. The faculty Geography Resources, Sichuan Normal University, Chengdu 610101, China
2. Nanjing University of Information Science & Technology/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster, Ministry of Education/International Joint Research Laboratory on Climate and Environment Change(ILCEC), Nanjing 210044, China


More Information

Corresponding author: LI DongLiang,E-mail:lidl@nuist.edu.cn

MSC: P402

--> Received Date: 09 November 2018
Revised Date: 08 November 2019
Available Online: 05 February 2020


摘要
摘要:基于中国气象局提供的气象站点月值资料，NOAA、CMAP降水格点月值资料，NDVI卫星资料及再分析资料，利用统计方法分析了1961-2014年青藏高原感热与中国东部季风雨带关键区夏季降水的年代际变化，并根据热动力平衡方程结合CESM模式试验解释了21世纪初高原感热异常对关键区夏季降水的影响机理.结果表明：21世纪初，黄淮、江淮地区降水增加，而长江以南地区降水减少.同时，高原感热也发生年代际增强，当春季感热增强后，大气热能上传导致夏季高原近地面产生气旋性环流异常，大气辐合；高层产生反气旋性环流异常，大气辐散.黄淮、江淮地区在对流层中低层受异常偏南风控制，高层受高原上空的大尺度反气旋环流影响产生异常偏北风.此外，高原感热增强通过影响黄淮、江淮地区产生暖平流输送和非绝热加热正异常，该区域产生异常的上升运动，降水量增加.长江以南地区在对流层中低层存在一个异常的反气性环流，有来自海洋的冷平流输送，同时大气非绝热加热在该地区为负异常，产生异常的下沉运动，降水量减少.模式敏感性试验的结果证实了当高原感热发生年代际增强，黄淮、江淮地区水平温度平流及非绝热加热为正异常，而在华南地区为负异常，从而导致黄淮、江淮地区大气上升运动增强，降水增加；而华南地区下沉运动增强，降水减少.
关键词: 季风雨带关键区/
夏季降水/
青藏高原感热/
21世纪初年代际变化/
环流/
热动力平衡/
CESM模式试验

Abstract:This study utilizes monthly records of meteorological stations provided by China Meteorological Administration, NOAA and CMAP gridded monthly precipitation datasets, NDVI and reanalysis datasets to investigate decadal variations in summer precipitation over dominant regions of monsoon rainfall band in eastern China (SPEC) and sensible heat flux over the Tibetan Plateau (TPSH) during 1961-2014 using statistical methods, and illuminates the mechanism of how the abnormal TPSH influences the SPEC at the beginning of the 21st century based on thermodynamic energy equation combing CESM model simulation. Results show that the SPEC experienced a significant decadal change around 2003 demonstrating positive rainfall anomalies over the Yellow-Huai River valley (YHV) and the Yangtze-Huai River valley (CHV), and negative rainfall anomalies over south of the Yangtze River (SYR). Meanwhile, a conspicuous strengthening in the TPSH occured in the early 2000s on a decadal time scale. When the spring TPSH was abnormally strong, there was a stronger atmospheric heat source transferring to the upper layer, inducing an abnormal cyclonic circulation and airflow convergence at the TP surface and an anticyclonic circulation and airflow divergence in the upper layer in the forthcoming summer. It was controlled by mid-to lower-layer southerly and upper-layer northerly wind attributed to the large-scale anticyclonic circulation above the TP over the YHV and CHV. In addition, when the spring TPSH was enhanced, there was a stronger upward air motion due to the positive variations in the diabatic heating and the horizontal temperature advection over the YHV and CHV, which gave rise to positive rainfall amounts over these areas. On the contrary, accompanied by the negative diabatic heating, there was a mid-to lower-layer anticyclonic circulation and cold advection from the neighboring ocean over the SYR. As a result, a stronger downward air motion led to less rainfall in the corresponding area. The results of the CESM sensitivity simulation confirm that when the TPSH was enhanced, the variations in the diabatic heating and the horizontal temperature advection were positive over the YHV and CHV and negative over the SYR, leading to the stronger upward and downward air motions in the corresponding areas, respectively. As a consequence, the SPEC variations show positive rainfall anomalies over the YHV and CHV, and negative anomalies over the SYR.
Key words:Dominant regions of monsoon rainfall band in eastern China/
Summer precipitation/
Sensible heat over the Tibetan Plateau/
Decadal variations in the early 2000s/
Circulation/
Thermodynamic equilibrium/
CESM simulation



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