孟加拉湾对流对广西秋季暴雨影响分析
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摘要
利用综合观测数据1°×1°FNL和2.5°×2.5°NCEP再分析资料、以及卫星云顶黑体辐射温度资料(TBB),对2015年11月广西出现的三次暴雨过程(8日、11—12日和20日)的850 h Pa水汽通量散度及水汽输送特征进行了对比分析。8日和20日暴雨的低层水汽主要来自南海,11—12日连续暴雨的水汽来自南海和孟加拉湾。暴雨前后TBB的分析表明,在暴雨发生前2～3 d,孟加拉湾对流发展到最强,孟加拉湾对流对广西秋季暴雨具有前兆信号特征。暴雨前后TBB时空剖面表明,暴雨发生前孟加拉湾对流有向广西波动传播的特征。模式敏感性实验显示,当关闭孟加拉湾对流2～3 d后,广西48 h累计雨量减小。
Based on conventional observation data, the 1 °×1 ° FNL and 2.5 °×2.5 ° NCEP reanalysis data and the black body temperature data at the top of the cloud(TBB), a comparative analysis was conducted of the 850 hPa water vapor divergence and vapor fluxes of three heavy rainfall events(on 8, 11—12 and 20 November) in Guangxi in 2015. On 8 and 20 November low-level water vapor was transported from the South China Sea, while water vapor was not only transported from the South China Sea but also from the Bay of Bengal during 11—12 November 2015. The analysis of the TBB data before and after the occurrence of heavy rains showed that 2 ～3 d before the heavy rainfall, the convection over the Bay of Bengal developed vigorously. The convection over the Bay of Bengal is a precursory signal to the autumn heavy rain in Guangxi. TBB time-space profiles before and after the heavy rainfall showed that the convection of the Bay of Bengal spread in the form of waves from the Bay of Bengal to Guangxi before the autumn heavy rainfall. Model sensitivity experiments showed that 2～3 d after the heat source over the Bay of Bengal was shut off, 24-hour cumulative precipitation was reduced.
Based on conventional observation data, the 1 °×1 ° FNL and 2.5 °×2.5 ° NCEP reanalysis data and the black body temperature data at the top of the cloud(TBB), a comparative analysis was conducted of the 850 hPa water vapor divergence and vapor fluxes of three heavy rainfall events(on 8, 11—12 and 20 November) in Guangxi in 2015. On 8 and 20 November low-level water vapor was transported from the South China Sea, while water vapor was not only transported from the South China Sea but also from the Bay of Bengal during 11—12 November 2015. The analysis of the TBB data before and after the occurrence of heavy rains showed that 2 ～3 d before the heavy rainfall, the convection over the Bay of Bengal developed vigorously. The convection over the Bay of Bengal is a precursory signal to the autumn heavy rain in Guangxi. TBB time-space profiles before and after the heavy rainfall showed that the convection of the Bay of Bengal spread in the form of waves from the Bay of Bengal to Guangxi before the autumn heavy rainfall. Model sensitivity experiments showed that 2～3 d after the heat source over the Bay of Bengal was shut off, 24-hour cumulative precipitation was reduced.
引文
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[3]许晓林,徐海明,司东.华南6月持续性致洪暴雨与孟加拉湾对流异常活跃的关系[J].南京气象学院学报,2007,30(4):463-471
[4]张艳焕,郭品文,周惠.孟加拉湾热源对亚洲夏季风环流系统的影响[J].南京气象学院学报,2005,28(1):l-8.
[5]周兵,吴国雄,梁潇云,等.孟加拉湾深对流加热对东亚季风环流系统的影响[J].气象学报,2006,64(1):48-55.
[6]林志强,边巴扎西,文胜军,等.孟加拉湾热带风暴活动路径的客观分类[J].热带气象学报,2013,29(6):973-981.
[7]朱志伟,何金海.孟加拉湾低涡与南海季风爆发关系及其可能机理[J].热带气象学报,2013,29(6):915-924.
[8]吕爱民,文永仁,李英.一次孟加拉湾风暴Akash(0701)对我国西南地区强降水过程的影响分析[J].大气科学,2013,37(1):160-170.
[9]段旭,段玮.孟加拉湾风暴对高原地区降水的影响[J].高原气象,2015,34(1):1-10.
[10]李英,张腾飞,索渺清.孟加拉湾云团影响下云南强降水分析[J].气象科学,2003,23(2):185-191.
[11]段旭,张瑾文.“双峰”期孟加拉湾风暴对西南水汽输送的贡献[J].大气科学,2015, 39(3):526-534.
[12]柳龙生,李英,王蕾.初夏孟加拉湾风暴活动期间青藏高原大气环流的异常特征[J].热带气象学报,2016,32(3):368-376.
[13]艾永智,金少华,郑建萌,等.南海、孟加拉湾不对称环流变化对2009年西南特大秋旱的影响[J].热带气象学报,2012,28(4):594-602.
[14]李向红,庞传伟,梁维亮,等.孟加拉湾旺盛对流作为广西连续暴雨的前兆信号特征分析[J].气象,2015,41(11):1 383-1 389
[15]许美玲,梁红丽,段旭,等.秋季孟加拉湾风暴影响云南降水差异的对比分析[J].高原气象,2014,33(5):1 229-1 238