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| 山西夏季不同等级降水时空演变特征及其影响要素研究 | |
| 引用本文： | 刘焕才,许芃,李曼.山西夏季不同等级降水时空演变特征及其影响要素研究[J].地理科学,2021,41(3):544-552. |
| 作者姓名： | 刘焕才 许芃 李曼 |
| 作者单位： | 1. 山西师范大学地理科学学院，山西 临汾 041000 2. 陕西师范大学地理与旅游学院，陕西 西安 710062 3. 中国科学院西北生态环境资源研究院，甘肃 兰州 730000 |
| 基金项目： | 国家自然科学基金项目（41901071，41701062，41807518）资助 |
| 摘 要： | 基于1961—2018年降水观测资料，应用经验正交函数分解（EOF）、大气诊断等方法对山西夏季不同等级降水时空演变特征及其影响要素进行分析。结果表明：① 山西夏季降水量主要由大雨贡献（51.9%），但在降水频次上以小雨为主。山西大雨与小雨事件存在显著差异。小雨多年平均雨量由南至北递增，而大雨却由南至北递减。此外，EOF表明全区一致型均是不同等级降水中的主空间模态，但在小雨和大雨中高载荷区存在明显差异。② ENSO在影响山西降水特别是大雨中占据主导，而NAO在小雨中作用更为突出。对大气环流异常结构的诊断分析表明，冷（暖）ENSO位相时，源于热带西太平洋并经由南海北上的季风水汽输送增强（减弱），同时在ENSO和中高纬度大气活动联动调控下，在东亚地区建立的异常反气旋（气旋）可通过其西支南（北）风气流引导（抑制）季风水汽向山西进一步纵深推进，两者共同调配使得山西大雨事件增多（减少）；NAO主要通过一条沿西欧?东欧?乌拉尔山?蒙古高原的高纬度路径对降水施加影响，NAO正（负）位相时，在蒙古高原甚至山西建立的深厚异常（反）气旋通过其南支西（东）风一方面阻挡低纬度季风水汽进入山西，另一方面增强（减弱）山西有限的内陆水汽供应，从而引起山西小雨事件的增多（减少）。 |
| 关 键 词： | 降水等级 ENSO NAO 山西省 |
| 收稿时间： | 2020-05-09 |
Spatio-temporal Characteristics of Summer Graded Precipitation and Its Influencing Factors in Shanxi |
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| Liu Huancai,Xu Peng,Li Man.Spatio-temporal Characteristics of Summer Graded Precipitation and Its Influencing Factors in Shanxi[J].Scientia Geographica Sinica,2021,41(3):544-552. | |
| Authors: | Liu Huancai Xu Peng Li Man |
| Institution: | 1. College of Geographical Sciences, Shanxi Normal University, Linfen 041000, Shanxi, China 2. School of Geography and Tourism, Shaanxi Normal University, Xi’an 710062, Shaanxi, China 3. Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou 730000, Gansu, China |
| Abstract: | Based on situ observational daily precipitation data from 1961 to 2018, the spatio-temporal characteristics of Shanxi summer graded precipitation and its influencing factors are analyzed by applying empirical orthogonal function (EOF) and atmospheric diagnosis methods. The results show that: 1) The total summer precipitation is mainly dominated by Heavy Rain (51.9%), however Light Rain occupies a leading position in precipitation frequency. There is a significant difference between Heavy Rain and Light Rain. The long-term mean Light Rain in summer increases from south to north, while Heavy Rain decreases from south to north. In addition, EOF analysis indicates that Uniformly Signed Mode is the dominant mode in all summer graded precipitation, but its distribution of eigenvector field is different among them, especially between Light Rain and Heavy Rain. 2) ENSO plays a leading role in influencing precipitation of Shanxi, especially in Heavy Rain. Relatively, NAO plays more prominent role in Light Rain. In cold (warm) ENSO phase, the monsoon water vapor originated from the tropical western Pacific and transported northward via South China Sea strengthens (weakens). Meanwhile, under the joint control of ENSO and middle- and high-latitude atmospheric activities, an anomalous anticyclone (cyclone) is established over East Asia and guides (restrains) monsoon water vapor to move further to Shanxi through the south (north) wind of its western flank. Finally, the Heavy Rain events in Shanxi increase (decrease); NAO exerts influence on precipitation mainly through a high-latitude path along the Western Europe-Eastern Europe-Ural-Mongolia Plateau. During the positive (negative) phase of NAO, the deep anomalous (anti)cyclone established in the Mongolian Plateau and even in Shanxi blocks the monsoon water vapor into Shanxi through the west (east) wind of its southern flank, and on the other hand, this anomalous wind enhances (weakens) the limited inland moisture supply. Consequently, the Light Rain events in Shanxi increase (decrease). |
| Keywords: | graded precipitation ENSO NAO Shanxi Province |
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