| 摘要: |
| 利用观测数据、FNL数据以及雷达产品等资料对2020年6月8日夜间湘北一次西南涡北侧强降水过程预报误差进行分析研究。结果表明：中低层河套高压与副高形成了一个高压坝，偏东气流加强，西南涡北侧出现了强降水。湖南境内强降水落区与≥95%相对湿度高值区的对应关系较好。虽湘南850 hPa以下为不稳定层结，但850—600 hPa为稳定层结，不利于强降水发生。锋区低层以下沉气流为主，700 hPa及以上才有上升运动发展，而地面辐合线附近上升运动从近地面伸展至300 hPa附近，其最大强度仅约锋区中心强度一半，湘北强降水正好位于中层锋区与地面辐合线之间。受冷空气及山地地形影响，石门县上空形成辐合区，并有局地涡旋系统，对应强回波中心达到45 dBZ以上。模式预报低涡切变线在湘中一线，并预计西南涡东出，但在偏东气流影响下，湘北北部出现了倒槽，西南涡向东北方向移动。 |
| 关键词: 强降水；漏报；西南涡；偏东气流 |
| DOI： |
| 投稿时间：2022-01-25修订日期：2022-07-05 |
| 基金项目: |
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| Prediction error analysis of a heavy precipitation process on the north side of Southwest Vortex in Northern Hunan |
| tian ze yun |
| (Changde Meteorological Bureau) |
| Abstract: |
| Using the observation data, FNL data and radar products, the prediction error of a heavy precipitation process on the north side of the southwest vortex in Northern Hunan on the night of June 8, 2020 is analyzed and studied. The results show that a high-pressure dam is formed by the middle and low-level Hetao High and the subtropical high, the easterly airflow is strengthened, and there is heavy precipitation on the north side of the southwest vortex.The relationship between heavy precipitation area and the value of high relative humidity ≥95% is the best.Although the stratification below 850 hPa in southern Hunan is unstable, 850-600 hPa is stable.The downdraft is dominant in the lower layer of the frontal area, and the upward movement developes only at 700 hPa and above. The upward movement near the surface convergence line extends from near the surface to around 300 hPa, but its maximum intensity is only about half of the intensity of the center of the frontal area. The heavy precipitation in northern Hunan is exactly located between the middle frontal area and the surface convergence line.Due to the influence of cold air and mountain terrain, the northerly wind and easterly wind forms a convergence area in Shimen County and generates a local vortex system, of which the corresponding strong echo center reaches more than 45 dBZ.The model predictes that the vortex shear line is in the middle of Hunan, and the southwest vortex expectes to move eastward. However, under the influence of easterly flow, the inverted trough appears in the north of Northern Hunan, and the southwest vortex moves toward northeast. |
| Key words: Heavy precipitation; Omission; The southwest vortex; By east airflow |
