| 2011年7月12—20日华北冷涡阶段性特征 |
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| 引用本文： | 郜彦娜,何立富.2011年7月12—20日华北冷涡阶段性特征[J].应用气象学报,2013,24(6):704-713. |
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| 作者姓名： | 郜彦娜 何立富 |
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| 作者单位： | 1.南京信息工程大学，南京 210044 |
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| 基金项目： | 资助项目：公益性行业(气象)科研专项(GYHY200906003) |
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| 摘 要： | 利用常规天气、地面危险天气报、自动站加密、NCEP/NCAR再分析资料等，对2011年7月12—20日持续9 d的华北冷涡过程阶段性特征进行分析。结果表明:冷涡过程降水主要分布在内蒙古东北部、华北和东北南部，发展阶段对流性强，多雷暴大风和冰雹，水汽来源于西南和东南气流，850 hPa上有强暖温度脊，高空急流较完整；减弱阶段以短时强降水为主，水汽来源于偏东气流；两阶段700 hPa以下为斜压，上升运动区主要位于东侧；发展阶段500 hPa为干区，南侧存在干空气侵入和θe梯度；减弱阶段整层相对湿度较大，θe锋区及不稳定度减弱。中层冷平流及中高层正涡度平流随高度增强是冷涡发展的主要因子，冷涡减弱是由低层冷平流进入冷涡中心、中层冷平流及中高层正涡度平流减弱共同影响所致。
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| 关 键 词： | 华北冷涡 位势高度距平 斜压结构 |
| 收稿时间： | 2013-03-20 |
The Phase Features of a Cold Vortex over North China |
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| Gao Yanna and He Lifu.The Phase Features of a Cold Vortex over North China[J].Quarterly Journal of Applied Meteorology,2013,24(6):704-713. |
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| Authors: | Gao Yanna and He Lifu |
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| Affiliation: | 1.Nanjing University of Information Science & Technology, Nanjing 2100442.National Meteorological Center, Beijing 100081 |
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| Abstract: | Using the conventional weather data, disastrous weather data, hourly precipitation data observed by automatic weather station and NCEP/NCAR reanalysis data, the phase features over North China during 12—20 July in 2011 are analyzed. The result indicates that the precipitation of the vortex is located in the northeast of Mongolia, North China and the south of Northeast China. Thunderstorm, gale and hail occur in the development stage, while short-time strong rainfall occurs in the weakening stage. Strong warm ridge is located at 850 hPa, a full jet stream exists at 200 hPa, and cold-core structure is presented on the whole troposphere in the development stage. The strong warm ridge isn't obvious in the weakening stage, the east wind is enhanced at the lower layers, and the cold-core also increases. The vortex is baroclinic at 700 hPa, the ascending motion is located in the east area and becomes stronger in the weakening stage, and the southeast wind is also speeded up. The relative humidity is larger at 300 hPa and 700 hPa, but it's dry at 500 hPa, and the south of cold vortex is invaded by dry and cold air in the development stage. The relative humidity is large at the whole layer in the weakening stage, as the vapor is brought by east wind. A northeast—southwest θe frontal zone exists in both stages of the cold vortex. The gradient of θe becomes significantly strong in the development stage, and the structure is unstable with dry and cold at the upper layer while warm and wet at the lower layer in the vertical direction. The θe frontal zone and the unstable structure weakens in the weakening stage. The cold advection which is located at the low and middle layers and the vorticity advection which is located at the middle and high layers play main roles for the cold vortex in the development stage. As the cold advection at the low layer enters the cold vortex center, the cold advection becomes weak at the middle layer, the positive vorticity advection recedes at the medium-to-high level, and the cold vortex weakens. |
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| Keywords: | cold vortex over North China geopotential height anomaly baroclinic structure |
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