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赵晓琳, 牛若芸. 2019: 2016年和1998年夏季长江中下游持续性强降雨及大气环流特征异同. 暴雨灾害, 38(6): 615-623. DOI: 10.3969/j.issn.1004-9045.2019.06.006
引用本文: 赵晓琳, 牛若芸. 2019: 2016年和1998年夏季长江中下游持续性强降雨及大气环流特征异同. 暴雨灾害, 38(6): 615-623. DOI: 10.3969/j.issn.1004-9045.2019.06.006
ZHAO Xiaolin, NIU Ruoyun. 2019: Similarities and differences of summer persistent heavy rainfall and atmospheric circulation characteristics in the middle and lower reaches of the Yangtze River between 2016 and 1998. Torrential Rain and Disasters, 38(6): 615-623. DOI: 10.3969/j.issn.1004-9045.2019.06.006
Citation: ZHAO Xiaolin, NIU Ruoyun. 2019: Similarities and differences of summer persistent heavy rainfall and atmospheric circulation characteristics in the middle and lower reaches of the Yangtze River between 2016 and 1998. Torrential Rain and Disasters, 38(6): 615-623. DOI: 10.3969/j.issn.1004-9045.2019.06.006

2016年和1998年夏季长江中下游持续性强降雨及大气环流特征异同

Similarities and differences of summer persistent heavy rainfall and atmospheric circulation characteristics in the middle and lower reaches of the Yangtze River between 2016 and 1998

  • 摘要: 超强厄尔尼诺事件衰减年背景下的2016年和1998年夏季,长江中下游地区出现阶段性持续性强降雨,分别为2016年6月19日—7月7日(简称2016年段)与1998年6月12—27日(简称1998年第Ⅰ段)、7月17日—8月2日(简称1998年第Ⅱ段),给国家防汛工作带来很大挑战。基于中国大陆2 407个气象台站逐日降水量、NCEP/NCAR逐日大气再分析等资料,对比分析了2016年和1998年夏季长江中下游持续性强降雨及其大气环流特征异同。结果表明:(1)上述三段持续性强降雨的雨带位置,2016年段最北,1998年第Ⅰ段最南;降雨强度,2016年段与1998年第Ⅰ段大体相当,强于1998年第Ⅱ段。(2)三段持续性强降雨期间大气环流特征相似之处表现为我国东部沿海附近均有低槽,西北太平洋副热带高压(简称副高)和南亚高压相较常年同期其范围偏大、强度偏强,高空西风急流和低空西南急流的强度以及副高南侧偏东气流的水汽输送也均较常年同期偏强。(3)三段持续性强降雨期间大气环流特征的差异是,2016年(1998年)持续性强降雨期间我国东部沿海附近低槽较浅(深),同时副高、南亚高压脊线北侧与西风急流带南侧之间的高空辐散区、低空急流带及辐合切变线的位置、南半球澳大利亚高压位置等也偏北(南),形成的强降雨带位置亦偏北(南);2016年段和1998年第Ⅰ段持续性强降雨期间副高、南亚高压、高空西风急流的强度明显强于1998年第Ⅱ段,形成的降雨强度也更强。

     

    Abstract: During the summer of 2016 and 1998 in the context of the decaying phase of the super El Niño event,the three persistent heavy rainfall events occurred in the middle and lower reaches of the Yangtze River from June 19 to July 7 in 2016 (hereinafter referred to as during the period of 2016),from June 12 to 27 (hereinafter referred to as during the period Ⅰ of 1998) in 1998, and from July 17 to August 2 (hereinafter referred to as during the period Ⅱ of 1998) in 1998, which brought great challenges to the national flood control business. Based on daily precipitation at 2407 meteorological observation stations in mainland China,daily reanalysis atmospheric data from NCEP/NCAR and other data,we have conducted a comparative analysis of the similarities and differences of summer persistent heavy rainfall and associated atmospheric circulation characteristics in the middle and lower reaches of the Yangtze River between 2016 and 1998. Results are as follows. (1) The persistent heavy rainfall belt is the northernmost during the period of 2016 and the southernmost during the period Ⅰ of 1998 among the three events,while the rainfall intensity during the period of 2016 is roughly the same as that during the period Ⅰ of 1998, and it for both periods is stronger than that for the period Ⅱ of 1998. (2) There are many similarities in the atmospheric circulation characteristics during the three periods of persistent heavy rainfall. For example,there exist low troughs near the eastern coast of China,the Northwest Pacific Subtropical High (NWPSH) and South Asia High (SAH) are larger in range and stronger in intensity than normal,and the intensity of the upper westerly jet (UWJ) and low southwest jet and the easterly water vapor transport along the south side of the NWPSH are also stronger than normal. (3) The significant differences in the atmospheric circulation during the three periods of persistent heavy rainfall events are that the low trough near the coastal of eastern China during the persistent heavy rainfall of 2006 (1998) is shallow (deep). When upper-level divergence zone between the north sides of NWPSH and SAH ridge lines and the south sides of westerly jet belt,low-level jet belt and shear line with convergence,and Australian High in the southern hemisphere are northerly (southerly) in position,the persistent heavy rainfall zones are also northerly (southerly). NWPSH,SAH,and upper-level westerly jet during the period of 2016 and the period Ⅰ of 1998 are significantly stronger than those during the period Ⅱ of 1998. The rainfall intensity in the former two periods is also greater than that in the later period.

     

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