| 东亚降水格局:季风与瞬变涡动的竞争 |
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| 引用本文： | 张凯静,戴新刚,汪萍.东亚降水格局:季风与瞬变涡动的竞争[J].地球物理学报,2011,54(10):2477-2486. |
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| 作者姓名： | 张凯静 戴新刚 汪萍 |
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| 作者单位： | 1. 中国科学院东亚区域气候与环境重点实验室,中国科学院大气物理研究所,北京 100029;
2. 兰州大学大气科学学院,兰州 730000;
3. 中国气象科学研究院,北京 100081 |
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| 基金项目： | 国家自然科学基金项目，科技部科技支撑项目 |
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| 摘 要： | 利用再分析资料ERA-40计算了东亚气候平均对流层水汽输送(MT)、平均气流水汽输送(MMT)、瞬变涡动水汽输送(EMT)及其散度,并同降水场进行比较分析.结果表明,季节平均水汽散度场同东亚降水分布型存在一定的配置关系,水汽辐合区对应于降水大值区,辐散区降水较少.东亚大部分地区MMT散度大于EMT,但符号相反,即MMT...
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| 关 键 词： | 水汽输送 水汽散度 瞬变涡动 东亚夏季风 气候降水型 |
| 收稿时间： | 2010-11-11 |
East Asian precipitation pattern: competing monsoon and transient eddy activity |
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| ZHANG Kai-Jing,DAI Xin-Gang,WANG Ping.East Asian precipitation pattern: competing monsoon and transient eddy activity[J].Chinese Journal of Geophysics,2011,54(10):2477-2486. |
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| Authors: | ZHANG Kai-Jing DAI Xin-Gang WANG Ping |
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| Institution: | 1. RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,China;
2. College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000,China;
3. Chinese Academy of Meteorological Sciences, Beijing 100081,China |
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| Abstract: | This paper aims at investigating the climate-mean integrated moisture transport (MT) of troposphere for 1971~2000 and the relationship between moisture divergence and seasonal precipitation in East Asia. The results made from ERA-40 shows that the spatial pattern of the precipitation approximately coincides with large-scale moisture divergence. A further decomposition manifests that the monthly-wind moisture transport (MMT) plays the dominant role for seasonal divergence patterns. The MMT convergence areas approximately fit in the big precipitation areas, while the MMT divergence almost covers the arid and semi-arid zones in northern China and Mongolia. The transient eddy moisture transport (EMT) is about ten-time smaller than MMT's in magnitude and plays a key role in moisture transport northward for non-monsoon period. Usually, EMT divergence is of inverse phase to MMT's, suppressing the MMT impact on precipitation in summer monsoon zones, and it is the major one that supplies water vapor to the precipitation in arid and semi-arid zones. However, their divergences are compatible and overlapped in phase around the phase transition belt of the MMT divergence. It turns out that large-scale precipitation characteristics greatly rely on competence of MMT and EMT, being the physical cause that lead to specific pattern of the large-scale precipitation. Besides, the mechanism of regional climate formation also implies the mechanism of regional precipitation change. A case study shows that the severe floods in both Yangtz River and Songhua-Nen rivers basin in 1998 resulted from anomalous MMT convergence of monsoon moisture transport, while both MMT and EMT divergences led to anomalous dry climate in the north and the northwest of China. In addition, it is the strong EMT divergence resulting in significant rainfall reduction in the south part of North China and the southeast coast of China. One could also make a further investigation on the causes leading to the anomaly of MMT or EMT, or both. This is a new way for exploring the mechanism of regional climate change. |
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| Keywords: | Moisture transport Moisture divergence Transient eddy East Asian monsoon Precipitation pattern |
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