| 季风湿润区夏季水汽收支的年代际变化特征 |
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| 引用本文： | 廖荣伟,赵平.季风湿润区夏季水汽收支的年代际变化特征[J].应用气象学报,2013,24(1):12-22. |
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| 作者姓名： | 廖荣伟 赵平 |
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| 作者单位： | 1.国家气象信息中心，北京 100081 |
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| 基金项目： | 国家重点基础研究发展计划项目（2009CB421404） |
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| 摘 要： | 采用1983—2002年NCEP/NCAR再分析资料和我国660站降水资料，对我国东部季风湿润区夏季水汽收支变化与大气环流和我国降水异常特征的关系进行研究。结果表明:20世纪80—90年代夏季水汽收支时间序列表现出明显的年代际变化增加趋势，与降水时间序列的相关系数为0.71；水汽收支高值、低值年代不仅能够指示季风湿润区经向风的异常变化，还能够指示东亚夏季风的强弱和降水异常变化。合成的水汽输送年代际异常在东亚—西太平洋区表现为4个异常环流，异常水汽通量辐合区位于长江流域及以南地区。水汽收支高值年代，亚洲大陆高纬度地区低压偏弱，大陆表面温度及西太平洋海温偏高，我国东部沿海盛行异常偏南风，低层气流辐合、高层气流辐散强，垂直上升运动强烈；低值年代则相反。合成的经向水汽收支占总收支的71.3%，合成的异常降水量最大达100 mm以上。
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| 关 键 词： | 水汽收支 降水 大气环流 年代际变化 |
| 收稿时间： | 2012-06-13 |
Inter decadal Variations of Summer Water Budgets in the Monsoon Wetness Region of Eastern China |
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| Liao Rongwei and Zhao Ping.Inter decadal Variations of Summer Water Budgets in the Monsoon Wetness Region of Eastern China[J].Quarterly Journal of Applied Meteorology,2013,24(1):12-22. |
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| Authors: | Liao Rongwei and Zhao Ping |
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| Institution: | 1.National Meteorological Information Center, Beijing 1000812.State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081 |
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| Abstract: | Using monthly means of NCAR/ NCEP reanalysis datasets and rainfall data from 660 surface stations in China, a water budgets time series over the monsoon wetness region in Eastern China is calculated by a water vapor transport method for the period from 1983 to 2002, referring to changes in inter decadal variability of water budgets associated with the anomalous atmospheric circulations and precipitation in the monsoon wetness region of Eastern China. Relationships between the water budget index and the variability of the atmospheric circulation and rainfall in China are examined. The results show that the summer water budget time series displays the variability on the inter decadal scale from the 1980s to the 1990s in the region. The correlation coefficient is 0.71 between the water budgets and regional average precipitation and decreases to 0.55 after removing the trends. The index reflects the variations of the meridional winds anomalies and indicates an intensity of summer monsoon and an anomaly of rainfall along the valleys in the monsoon wetness region of Eastern China. The anomalous water vapor transport is affected by four anomalous circulations: The anomalous cyclonic circulation between 20°N and 30°N over the Eastern China, and the anomalous anti cyclonic circulations between 40°N and 60°N over East Asian continent, between 18°N and 30°N over the west Pacific, and between 5°N and 20°N over the Bay of Bengal. Anomalous moisture flux convergence appears in the south of the Yangtze. Corresponding to the higher index value decades, the low pressure centering in Mongolia is weaker and the surface temperature, sea surface temperature, the convergence in lower troposphere and divergence in upper troposphere are generally stronger in East Asia and the western north Pacific. Meanwhile, the southerly wind anomalies are prevailing in the eastern coast of China. This anomaly intensifies upward motion over the south mainland of China and drives the water vapor transport from South China Sea, and increases the water budgets and precipitation, with the difference of rainfall above 100 mm in the southern China. The water budgets are net surplus though uneven from 1983 to 2002. Vapor income in the low value year is about 24.3% less than in the high value year, and the precipitation is less by 18%. The anomalous meridional water budget is larger than zonal one, accounting for 71.3% of net budget. The anomalous water budget of low index value decades accounts for 7% in latitude and 24% in longitude relative to the high index value decades. The variation of the meridional water budget is larger than zonal one and is greater in magnitude. Therefore, the net water budget is quite different between high and low value decades of water budget and the anomalous precipitation is also significantly different. |
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| Keywords: | water budget rainfall atmospheric circulation inter decadal variability |
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