| 海洋性大陆核心区域非绝热加热年代际变化及其与东亚夏季风变异的可能联系 |
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| 引用本文： | 许琪,管兆勇.海洋性大陆核心区域非绝热加热年代际变化及其与东亚夏季风变异的可能联系[J].热带气象学报,2017,33(1):21-29. |
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| 作者姓名： | 许琪 管兆勇 |
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| 作者单位： | 1.南京信息工程大学气象灾害省部共建教育部重点实验室，江苏 南京 210044 |
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| 基金项目： | 国家自然科学基金重点项目41330425 |
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| 摘 要： | 海洋性大陆区域是太平洋和印度洋通过“大气桥”发生相互作用的区域，也是亚洲季风和澳洲季风相互作用的重要地区。利用1979—2012年的NCEP/NCAR、CMAP月平均资料和合成分析等方法，研究了海洋性大陆核心区域非绝热加热年代际变化规律及其与东亚夏季风的可能联系。海洋性大陆地区气候变动在95~145 °E，10 °S~10 °N区域尤为显著，记此区域为海洋性大陆核心区域（即KMC区域）。不考虑大气中潜热释放时，KMC区域的非绝热加热率在1979—2012年之间存在显著的年代际变化，加热作用由弱增强，在1980年代末期达到峰值后，即转为减弱阶段。对非绝热加热异常各分量的分析发现，在KMC区域，表面潜热和净大气长波辐射起主要作用。当非绝热加热负异常时，KMC区域的陆地降水偏多，海洋上降水偏少，赤道上存在气流辐合。在115~120 °E区间平均的经圈剖面上，气流在赤道地区上升、南海下沉、30 °N处上升，构成了异常的垂直环流圈。水汽从孟加拉湾、南海地区向中国东部输送，利于产生降水正异常。东亚剖面上的经圈环流在联系KMC区域非绝热加热和东亚夏季风异常的年代际变化中起重要作用。
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| 关 键 词： | 海洋性大陆 非绝热加热 东亚夏季风 年代际变化 北半球夏季 |
| 收稿时间： | 2015-08-25 |
INTERDECADAL CHANGE OF DIABATIC FORCING OVER KEY REGION OF THE MARITIME CONTINENT AND ITS POSSIBLE RELATIONS WITH EAST ASIAN SUMMER MONSOON ANOMALIES |
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| Institution: | 1.Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of information science & technology, Nanjing 210044, China2.Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of information science & technology, Nanjing 210044, China |
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| Abstract: | Maritime continent is an important region where the tropical Pacific and Indian Ocean interact with each other via "the atmospheric bridge" and also a key region where the Asian monsoons interact with the Australian monsoons. Using the NCEP/NCAR and CMAP monthly mean reanalysis over the period of 1979—2012, the interdecadal variations of diabatic forcing over key region of the Maritime Continent and its possible relations with East Asian summer monsoon anomalies have been investigated in the present paper. Our results show that climate variations in the Maritime Continent are particularly strong in the area 95~145 °E, 10 °S~10 °N. This area is hence defined as the key area of the Maritime Continent (i.e., KMC area). Without the input of latent heat release in the atmosphere, distinct interdecadal change of diabatic heating are found to exist from 1979 to 2012 in the KMC area; it intensified before the 1980s and peaked in the late 1980s and weakened after this period. By analyzing different components of the diabatic heating in the KMC area, it is found that surface latent heat flux and net long-wave radiation in the atmosphere are the dominant components. When the anomalies of diabatic heating are negative, there will be more precipitation on land, less precipitation over sea, and more rainfall around the equator, which is in correspondence with a convergence center around the equator in the KMC area. In the meridional-vertical section averaged over 115~120 °E, well-defined vertical circulation anomalies are observed with its ascending branches over KMC and the area near 30 °N respectively and the descending branch over the South China Sea. Water vapor transports from the Bay of Bengal and South China Sea area to the east of China to benefit the positive precipitation anomalies. This vertical circulation plays a crucial role in linking the diabatic heating over the KMC region and East Asian summer monsoon variations on interdecadal time-scale. |
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