| 摘要: |
| 根据近50年(1971—2020年)广东省86个气象站的观测数据、NCEP/NCAR再分析数据和NOAA海温数据，采用线性趋势分析、合成分析等统计方法，研究了广东春运期间气温和降水的时空分布特征，从气温降水协同变化的角度切入划分了气候异常类型，并对比分析了其异常成因。结果表明：近50年来，广东省春运期间平均气温呈现显著上升趋势，珠江三角洲和粤东地区最明显。而降水日数则表现出显著减少趋势，粤西北、粤东和粤西沿海最明显。气温和降水协同变化的异常年(冷湿(4年)、冷干(6年)和暖干(11年))共有21年，占全部年份的42%。冷湿年和冷干年，欧亚大陆中高纬度都表现出经向环流特征，西伯利亚高压偏强，有利于冷空气活跃南下。不同的是冷湿年东亚西部地区“北高南低”，低纬度地区“东高西低”，对应的冷空气路径为中、西路，有利于水汽输送；而冷干年东亚东部地区“北高南低”，低纬度地区一致偏低，对应的冷空气路径偏东，不利于水汽输送。另外，冷湿年前期赤道中东太平洋偏暖，呈现El Ni?o状态，受其影响西太平洋副热带高压偏大偏强，西太暖池偏冷，在菲律宾海区域激发出一个反气旋性环流，有利于西南水汽输送到广东地区，降水偏多；而冷干年则相反。暖干年，东亚中高纬表现出“北低南高”的纬向环流分布，东亚大槽和西伯利亚高压偏弱，不利于冷空气的生成和南下，广东上空受反气旋式环流控制，辐散下沉，温高雨少。 |
| 关键词: 广东 春运 协同变化 气候特征 冷湿 冷干 暖干 |
| DOI：10.16032/j.issn.1004-4965.2023.022 |
| 分类号: |
| 基金项目: |
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| CLIMATIC CHARACTERISTICS OF CONCURRENT TEMPERATURE AND PRECIPITATION VARIATION IN GUANGDONG FESTIVAL TRAVEL RUSH OVER RECENT 50 YEARSDURING SPRING |
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WANG Mingsheng1, HU Yamin1, HU Ting2, DONG Shaorou1, ZHAO Liang3
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1. Guangdong Climate Center, Guangzhou 510641, China;2. Guangzhou Meteorological Observatory, Guangzhou 511430, China;3. State Key Laboratory of Numerical Modeling for Atmosphere Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
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| Abstract: |
| Based on the data from observational stations in Guangdong, the NCEP/NCAR reanalysis data, and the NOAA sea surface temperature (SST) data for the last 50 years from 1971 to 2020, this paper has analyzed the temporal and spatial distribution characteristics of temperature and precipitation during the Spring Festival travel rush in Guangdong. Possible causes of three types of climate anomalies are also investigated through comparison. The results are as follow: Over these five decades, the average temperature in Guangdong, especially in the Pearl River Delta and eastern Guangdong, showed a significant upward trend during the Spring Festival travel rush. Meanwhile, the number of rainy days in Guangdong, especially in northwestern Guangdong and the coastal regions of eastern/ western Guangdong, showed a significant decreasing trend. There were totally 21 abnormal years with different concurrent variation between temperature and precipitation, including four cold and wet years, six cold and dry years, and eleven warm and dry years. In cold and wet years and cold and dry years, the meridional circulation prevailed over the mid‐high latitudes of Eurasia and the Siberian high pressure was relatively strong, which were favorable for the southward invasion of cold air. In particular, the pattern with northward higher and southward lower geopotential height was found over the western part of East Asia during cold and wet years while over the eastern part of East Asia during cold and dry years, respectively. Moreover, cold air invaded through the middle and the west paths when the geopotential height was higher eastward and lower westward over the low latitudes in cold and wet years. By contrast, in cold and dry years, cold air invaded through the east path when coincidently negative anomaly of geopotential height occupied the low latitudes. In short, transport of water vapor was favored during cold and wet years while depressed during cold and dry years. Furthermore, the equatorial central and eastern Pacific was warmer (colder) earlier in the cold and wet (cold and dry) years, which resulted in larger (smaller) and stronger (weaker) subtropical high over the western Pacific and colder (warmer) western Pacific warm pool. Thus, obvious anti-cyclonic (cyclonic) circulation was stimulated over the Philippine Sea area, which promoted (depressed) the southwestward water vapor transport and generated more (less) precipitation in Guangdong. In warm and dry years, zonal circulation prevailed and the pattern with northward lower and southward higher geopotential height was found over the mid-high latitudes of East Asia. Moreover, both East Asian trough and Siberian high were weak, which were not favorable for the southward invasion of cold air. Guangdong was under the control of anticyclonic circulation, and thus divergence and sinking brought high temperature and less rainfall to Guangdong. |
| Key words: Guangdong Spring Festival travel rush concurrent variation climatic characteristics cold and wet cold and dry warm and dry |
