| 摘要: |
| 选用中国气象局提供的华南地区（共48个站）1960—2011年共52年的逐日降水资料，通过EOF分解、回归分析等方法分析了华南地区秋季无降水日的变化特征及其与海温的联系。研究结果表明，在华南各个区域的无降水日数年均分布基本保持一致，但秋季的发生频次最多，且线性上升趋势最强。因此，侧重分析华南地区秋季无降水日数特征，EOF分解的主要模态在空间上表现为无降水日数呈现全区域一致变化，时间序列上包含年际和年代际变率。进一步寻找前期典型海区的影响，表明显著影响的海域为前期（7—8月）西北太平洋。该地区的海温将通过影响整层水汽通量散度和局地的下沉运动，不利于秋季降水的发生。 |
| 关键词: 华南地区 无降水日频数 海温 秋季 |
| DOI：10.16032/j.issn.1004-4965.2020.011 |
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| FEATURES OF THE AUTUMN NON-RAINFALL FREQUENCY OVER SOUTH CHINA AND THE ASSOCIATED OCEAN CONDITIONS |
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WUFUER Waili1, YAN Pei-wen2, HUANG Dan-qing3
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1.Akto County Meteorological Bureau, Kezhou, Xinjiang 845550, China;2.Shaoxing Meteorological Bureau, Shaoxing 312000, China;3.School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
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| Abstract: |
| Based on the daily precipitation station data over South China from National Weather Service during 1960—2011, the features of non-rainfall days and possible factors are analyzed. The result shows that the frequency of non-rainfall days over south China is the largest in autumn and shows a significant increasing trend. Thus, we focus on the frequency of non-rainfall days in autumn. Based on the EOF analysis, the spatial variation of frequency of non-rainfall days over south China in autumn shows a homogenous variation. The corresponding time serials contain decadal and interannual variations. We further discuss the possible factors by analyzing the previous SST conditions. The results indicate that the warming over northwestern Pacific in previous July-August may result in the increase of the frequency of non-rainfall days, via the divergence of moisture flux and local descending motion. |
| Key words: south China frequency of non-rainfall SST autumn |
