庞轶舒,周长艳,王顺久,罗玉. 2024. 西南地区冬季异常冷湿/暖干的气候背景分析. 气象学报,82(X):1-17. DOI: 10.11676/qxxb2024.20230131
引用本文: 庞轶舒,周长艳,王顺久,罗玉. 2024. 西南地区冬季异常冷湿/暖干的气候背景分析. 气象学报,82(X):1-17. DOI: 10.11676/qxxb2024.20230131
Pang Yishu, Zhou Changyan, Wang Shunjiu, Luo Yu. 2024. Analysis on climate background of abnormal cold and wet/warm and dry winters in Southwest China. Acta Meteorologica Sinica, 82(X):1-17. DOI: 10.11676/qxxb2024.20230131
Citation: Pang Yishu, Zhou Changyan, Wang Shunjiu, Luo Yu. 2024. Analysis on climate background of abnormal cold and wet/warm and dry winters in Southwest China. Acta Meteorologica Sinica, 82(X):1-17. DOI: 10.11676/qxxb2024.20230131

西南地区冬季异常冷湿/暖干的气候背景分析

Analysis on climate background of abnormal cold and wet/warm and dry winters in Southwest China

  • 摘要: 利用1981—2022年西南地区409个地面气象站观测资料、NCEP/NCAR和NOAA再分析资料等,研究分析了西南冬季异常冷湿/暖干配置的气候变化特征及形成机制。结果表明,全区大部冷湿/暖干是西南地区冬季频繁出现的异常气候配置。20世纪80年代以来,全区暖干趋势显著。对流层中高层的贝加尔湖高压强(弱)和青藏高原高压弱(强),及中低层西伯利亚高压强(弱),协同构成的准正压“北正南负”(“南正北负”)环流型,是西南冬季冷湿(暖干)配置的关键环流背景。秋季阿留申群岛南侧,赤道东太平洋南侧和北侧,以及澳大利亚西南侧4个关键区的海温是上述异常环流型的关键前兆信号。阿留申群岛南侧海温偏高(低)可使秋、冬季亚速尔高压持续增强扩大(减弱缩小),然后通过罗斯贝波东传增强(减弱)下游贝加尔湖高压和西伯利亚高压。赤道东太平洋南侧和北侧的海温偏低(高),可共同促使东北太平洋和北大西洋低纬度地区位势高度场偏低(高),激发正(负)异常罗斯贝波源并东传减弱(增强)青藏高原高压;澳大利亚西南侧海温偏高(低),有利于高空越赤道偏南(北)风加强,进而增强(减弱)中东急流,导致青藏高原高压偏弱(强)。

     

    Abstract: Based on data collected at 409 surface meteorological observation stations in Southwest China (SWC) and reanalysis data from NCEP/NCAR and NOAA from 1981 to 2022, this study analyzes climate change characteristics and formation mechanisms of abnormal cold-wet/warm-dry winter climate patterns in SWC. The results show that cold-wet and warm-dry are the most common climate configurations in SWC during winter. Since the 1980s, the entire region shows a significant increase trend of warm-dry winters. A stronger (weaker) Baikal Lake High and a weaker (stronger) Qinghai-Xizang plateau high in the upper and middle troposphere as well as a stronger (weaker) Siberian high in the middle and lower troposphere synergistically form a quasi-barotropic "north positive south negative" ("south positive north negative") circulation pattern, which is the key atmospheric circulation background for the cold-wet (warm-dry) winter in SWC. Sea surface temperatures (SSTs) over the area to the south of Aleutian Islands, regions in the southern and northern sides of the eastern equatorial Pacific and the region to the southwest of Australia during autumn are key precursor signals of the circulation background. Warmer (colder) SSTs over the area to the south of Aleutian Islands can enhance (weaken) the Azores high continuously from autumn to winter and then strengthen (weaken) the Baikal lake high and the Siberian high with eastward propagation of Rossby waves from the enhanced (reduced) Azores high. Colder (warmer) SSTs over the regions in the southern and northern sides of the eastern equatorial Pacific can weaken (strengthen) geopotential height over the low latitudes of the Northeast Pacific and the North Atlantic in winter, which will then trigger positive (negative) abnormal Rossby waves sources that spread eastward by Rossby waves, resulting in lower (higher) Qinghai-Xizang plateau high. Moreover, warmer (colder) SSTs in the region to the southwest of Australia can enhance cross-equatorial southerlies (northerlies) in upper levels and subsequently strengthen (weaken) the Middle East jet, leading to lower (higher) Qinghai-Xizang plateau high.

     

/

返回文章
返回