Stratosphere‐Troposphere Exchange Corresponding to a Deep Convection in the Warm Sector and Abnormal Subtropical Front Induced by a Cutoff Low over East Asia
Stratosphere‐Troposphere Exchange Corresponding to a Deep Convection in the Warm Sector and Abnormal Subtropical Front Induced by a Cutoff Low over East Asia
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DOI：
10.1002/cjg2.20079
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
Shi Chun-hua;Guo Dong;L. Hui;Zheng Bin;Liu Renqiang
中科院分区：
文献类型：
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作者：
Shi Chun-hua;Guo Dong;L. Hui;Zheng Bin;Liu Renqiang
利用Cloudsat的云廓线雷达资料、FY 2C的黑体温度资料、Aura/MLS的大气成分资料、ECMWF的气象资料和HYSPLIT 4轨迹模式，对2009年6月东亚上空一次由截止低压引起的暖区深对流和副热带锋异常进行了研究。分析表明，由于南槽的存在，使得内锋降水减弱，暖区出现近1000 km尺度的深对流。在低压接近成熟阶段，由于西南暖湿气流沿副热带锋沿着汇聚，切断低压诱导的副热带锋在整个对流层异常发展。锋面快速东移进入暖区雨带后，穿越锋区的热力间接二次环流强上升分支加强了锋面下方较冷部位的深对流。但由于异常锋面阻挡了水汽的补充，使其难以持续。此外，由于对流注入平流层侵入物，在副热带锋区异常，平流层-对流层交换强烈。在臭氧和水汽的散点图上，这是两个特殊的聚集区，这两种物质的浓度都很高（低）。
We studied a deep convection in the warm sector and abnormal subtropical front caused by a cutoff low over East Asia in June 2009 by using cloud profile radar data from Cloudsat, temperature of black body from FY2C, atmospheric compositions from Aura/MLS, meteorological data from the ECMWF and HYSPLIT4 trajectory model. The analysis shows that for the sake of the background of southern trough, there is a weaker rainfall from the inner fronts, while nearly 1000km-scale deep convection occurs in the warm sector. At the nearly mature stage of the low, the subtropical front induced by the cutoff low is abnormally developing throughout the whole troposphere, which is due to the warm and humid air from southwest gathering along the subtropical front. After rapid eastward movement of the front into the rain belt of the warm sector, the strong ascending branch of thermal indirect secondary circulation across the frontal zone enhances deep convection at the colder part below the front. But it is difficult to sustain because the supplement of water vapor is blocked by the abnormal front. Furthermore, intense stratosphere-troposphere exchange occurs in the abnormal subtropical front zone due to the convective injection into stratospheric intrusions. On the scatter plot of ozone and water vapor these are two special gathering areas with both high (low) concentrations of the two species.