中文摘要：

利用常规的高空、地面观测、NCEP的1°×1°再分析资料和FY-2E水汽图像等资料,分析了一次北上的江南气旋降水分布、生成环境、结构特征及气旋发展和移动的成因。结果表明：（1）气压场形状和强降水落区的演变类似于Shapiro-Keyser气旋模型。（2）江南气旋发生并向北发展,表现为250 hPa高空辐散,500 hPa西北槽与高原东部槽东移合并、下游脊加强环流的背景。（3）这次气旋虽然没有出现Shapiro-Keyser气旋模型中明显的暖锋后弯现象,但在低压中心附近存在弱的暖核,该核主要位于850 hPa以下层次。（4）当正相对涡度区随高度向西倾斜、地面气旋中心西侧的冷锋锋区增强、高层相对涡度值增大时,气旋处于快速加深过程中;当高低层正相对涡度中心几乎垂直重合、且对流层低层冷锋锋区减弱,则气旋缓慢发展。（5）暖湿气流向北发展和垂直于暖锋的次级环流加强使得暖锋附近的降水增强。（6）用准地转ω运动方程诊断得到,在气旋的初生阶段,地面气旋上空垂直上升速度几乎为0,气旋基本不发展;但其下游暖平流和高低层涡度平流差值大,有利于气旋快速向东北方向移动。在气旋发展阶段,地面气旋上空垂直上升速度加大,气旋快速发展,但其下游暖平流和高低层涡度平流差值减小使得气旋移速缓慢。在气旋发展停滞阶段,地面气旋上空垂直上升速度微弱,气旋发展趋于停止,且其下游暖平流和高低层涡度平流差值继续减小,气旋移速进一步变缓。

英文摘要：

The structure and mechanism of a Jiangnan cyclone with a northern track that occurred during 10--13 May 2014 was analyzed by using conventional observations, NCEP 1°×1°reanalysis data and water vapor images from FY-2E. The results are as follows： （1） The distribution of pressure and rainfall areas is similar to the output of Shapiro-Keyser conceptual model. （2） The Jiangnan cyclone occurred under the weather situation of the diver- gence at 250 hPa, and trough merger and ridge development downward at 500 hPa. （3） The weak warm core existed close to the low center under 850 hPa, but there was no back-bent warm front as Shapiro-Keyser conceptual model showed. （4） When the positive relativity vorti-city tilted westward with height, the cold frontal zone intensified in the western side of surface cyclone and the positive relativity vorticities in the upper troposphere strengthened, the cyclone was rapidly deepening; when the positive relative vorticities at different levels were nearly vertically overlapped and the cold frontal zone in the low troposphere weakened, the cyclone developed slowly. （5） Heavy rain was caused by warm and moisture air, strong upward vertical volecity with two secondary circulation crossing the warm front. （6） It was also found by equation that surface cyclone hardly developed without upward vertical velocity at the initial stage, but it moved rapidly toward northeast as the result of warmer advection and larger differential vaorticity advection between the upper-level and low-level troposphere downstream during cyclo- genesis. Then surface cyclone was intensified rapidly by srtong upward vertical velocity, but it moved slowly ciue to the less warm advection and differential vorticity advection. Surface cyclone was slowly deepening due to weakly upward vertical velocity, and it moved more slowly because of the weakly warm advection and differential vorticity advection.