2019年夏季江南降水偏多的原因分析
Analysis on the Reasons of More Precipitation in the South of the Yangtze River in Summer of 2019

DOI: 10.12677/CCRL.2021.103025, PP. 217-227

Keywords: 夏季降水，锋面抬升，中亚高压脊，西太平洋副热带高压
Summer Precipitation, Frontal Lifting, Central Asian Ridge, Western Pacific Subtropical High

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Abstract:

本文利用NECP/NCAR提供的1981~2019年月平均位势高度场、风场、垂直速度场等再分析资料，对2019年夏季中国雨带位置异常偏南的原因进行了分析。研究发现，雨带位置偏南和行星锋区位置异常偏南、强度偏强有很大的关系。造成行星锋区位置异常偏南主要有两个原因：一是位于贝加尔湖附近的高压脊异常偏强，高压脊前的西北气流偏强，冷气团势力偏强将行星锋区推进到江南地区；二是行星锋区南侧西太平洋副热带高压位置的偏南，造成夏季风异常偏弱，暖气团势力相对较弱。副高位置偏南的原因与太平洋发生El Ni？o事件的次年及印度洋偶极子正位相有关。分别以850 hPa上的垂直速度异常考察行星锋区强迫抬升造成的上升运动异常，以500 hPa上垂直速度异常考察根据热成风原理，行星锋区对应高空西风急流南侧强辐散造成的对流上升运动，发现2019年夏季江南降水主要是由锋面抬升作用引起的。夏季风偏弱导致高空急流南侧对流层中、下层暖湿空气输送偏弱可能是对流性降水作用相对偏弱的原因。
Based on the NECP/NCAR reanalysis data of monthly mean geopotential height field, wind field and vertical velocity field from 1981 to 2019, this paper analyzes the reasons for the anomalous southward location of rain belts in China in the summer of 2019. It is found that the southward location of the rain belt is closely related to the anomalous southward location and strong planetary front. There are two main reasons for the anomalous southward position of the planetary front zone. First, the anomalous strong high pressure ridge near Lake Baikal, the strong northwest air flow in front of the high pressure ridge, and the strong cold air mass force pushed the planetary front zone to the south of the Yangtze River. Second, the position of the western Pacific subtropical high on the south side of the planetary front zone is southward, which results in the abnormally weak summer monsoon and relatively weak warm air. The southward location of the subtropical high is related to the next year of El Ni？o event in the Pacific Ocean and the positive phase of Indian Ocean Dipole. According to the thermal wind principle, the planetary front corresponds to the convective upward movement caused by the strong divergence on the south side of the high-altitude westerly jet. It is found that the summer precipitation over the south of the Yangtze River in 2019 is mainly caused by the frontal uplift. The weak transport of warm and moist air in the middle and lower troposphere on the south side of the upper jet due to the weak summer wind may be the reason why the convective precipitation is relatively weak.

References

[1]	黄荣辉, 蔡榕硕, 陈际龙, 周连童. 我国旱涝气候灾害的年代际变化及其与东亚气候系统变化的关系[J]. 大气科学, 2006, 30(5): 730-743.
[2]	孙林海, 陈兴芳. 南涝北旱的年代气候特点和形成条件[J]. 应用气象学报, 2003, 14(6): 641-647.
[3]	吴荷, 陈海山, 黄菱芳. 欧亚中高纬春季地表感热异常与长江中下游夏季降水的可能联系[J]. 气候与环境研究, 2015, 20(1): 119-128.
[4]	陶诗言, 赵煜佳, 陈晓敏. 东亚的梅雨期与亚洲上空大气环流季节变化的关系[J]. 气象学报, 1958, 29(2): 119-134.
[5]	李维京. 1998年大气环流异常及其对中国气候异常的影响[J]. 气象, 1999, 25(4): 20-25.
[6]	Nakazawa, T. (2001) Suppressed Tropical Cyclone Formation over the Western North Pacific in 1998. Journal of the Meteorological Society of Japan, 79, 173-183. https://doi.org/10.2151/jmsj.79.173
[7]	刘芸芸, 丁一汇. 西北太平洋夏季风对中国长江流域夏季降水的影响[J]. 大气科学, 2009, 33(6): 1225-1237.
[8]	况雪源, 张耀存. 东亚副热带西风急流位置异常对长江中下游夏季降水的影响[J]. 高原气象, 2006, 25(3): 382-389.
[9]	叶许春, 许崇育, 张丹, 李相虎. 长江中下游夏季降水变化与亚洲夏季风系统的关系[J]. 地理科学, 2018, 38(7): 1174-1182.
[10]	彭加毅, 孙照渤, 倪东鸿. 春季赤道东太平洋海温异常与东亚夏季风的关系[J]. 南京气象学院学报, 2000, 23(3): 385-390.
[11]	苗秋菊, 徐祥德, 张雪金. 长江中下游旱涝的环流型与赤道东太平洋海温遥相关波列特征[J]. 气象学报, 2002, 60(6): 687-697.
[12]	邓伟涛, 孙照渤, 曾刚, 倪东鸿. 中国东部夏季降水型的年代际变化及其与北太平洋海温的关系[J]. 大气科学, 2009, 33(4): 835-846.
[13]	黄荣辉, 陈文, 丁一汇, 李崇银. 关于季风动力学以及季风与ENSO循环相互作用的研究[J]. 大气科学, 2003, 27(4): 484-502.
[14]	闵锦忠, 孙照渤, 曾刚. 南海和印度洋海温异常对东亚大气环流及降水的影响[J]. 南京气象学院学报, 2000, 23(4): 532-548.
[15]	Karumuri, A., Zhao, Y.G. and Toshio, Y. (2001) Impact of the Indian Ocean Dipole on the Relationship between the Indian Monsoon Rainfall and ENSO. Geophysical Research Letters, 28, 4499-4502. https://doi.org/10.1029/2001GL013294
[16]	李崇银, 穆明权. 赤道印度洋海温偶极子型振荡及其气候影响[J]. 大气科学, 2001, 25(4): 433-443.
[17]	李崇银, 肖子牛. 大气对外强迫低频遥响应的数值模拟——II: 对欧亚中高纬“寒潮”异常的响应[J]. 大气科学, 1993, 17(5): 523-531.
[18]	Wu, B.Y., Yang, K. and Zhang, R.H. (2009) Eura-sian Snow Cover Variability and Its Association with Summer Rainfall in China. Advances in Atmospheric Sciences, 26, 31-44. https://doi.org/10.1007/s00376-009-0031-2
[19]	张庆云, 陶诗言, 陈烈庭. 东亚夏季风指数的年际变化与东亚大气环流[J]. 气象学报, 2003, 61(5): 559-568.
[20]	解晋, 周宁芳. 2019年7月大气环流和天气分析[J]. 气象, 2019, 45(10): 1494-1500.
[21]	丁婷, 高辉. 2019年夏季东亚大气环流异常及对我国气候的影响[J]. 气象, 2020, 46(1): 129-137.
[22]	Kalnaye, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., Gandin, L., et al. (1996) The NCEP/NCAR 40-Year Reanalysis Project. Bulletin of the American Meteorological Society, 77, 437-472. https://doi.org/10.1175/1520-0477(1996)077%3C0437:TNYRP%3E2.0.CO;2
[23]	刘芸芸, 李维京, 艾(子兑)秀, 李清泉. 月尺度西太平洋副热带高压指数的重建与应用[J]. 应用气象学报, 2012, 23(4): 414-423.
[24]	Liu, Y.Y., Liang, P. and Sun, Y. (2019) The Asian Summer Monsoon: Characteristics, Variability, Teleconnections and Projection. Candice Janco, Cambridge, 233-237.
[25]	孙林海, 赵振国, 许力, 陈国珍, 李维京, 王永光, 等. 中国东部季风区夏季雨型的划分及其环流成因分析[J]. 应用气象学报, 2005, 16(z1): 56-62.
[26]	林大伟, 布和朝鲁, 谢作威. 夏季中国华北降水、印度降水与太平洋海表面温度的耦合关系[J]. 大气科学, 2018, 42(6): 1175-1190.

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