2006~2015年昆明准静止锋变化趋势及春季不同类型静止锋环流特征

Variation Trend of Kunming Quasi-Stationary Front and Circulation Variation of Different Types Front in Spring from 2006 to 2015

摘要: 采用中国气象局国家气象信息中心整编的中国地面逐日观测资料和欧洲中长期天气预报中心ERA-interim逐日再分析资料，对2006~2015年云贵高原地区昆明准静止锋的时间变化特征进行分析，并探讨了春季不同类型昆明准静止锋的环流差异。结果表明：1) 近十年昆明准静止锋日数呈减少趋势，静止锋活动日数在117 (2010年)~164 (2012年)天之间。2) 昆明准静止锋全年均可出现，但其活动有明显的季节特征，其中1月和12月出现天数最多，7月最少。3) 昆明准静止锋以b类为主，月平均活动日数最多的是12月；其次是c类，活动日数最多的是1月和2月；出现天数最少的是a类。4) 当春季亚洲上空中高纬度为一槽一脊型，东亚大槽较强，副高强度较弱时，易形成a类静止锋。b类静止锋时，亚洲中高纬呈多波动分布，亚洲地区多低槽活动，冷空气活动频率高，副高强度较强，冷暖空气势力相当导致静止锋能够长时间维持。c类静止锋时的冷空气活动势力则明显弱于西南暖湿气流，导致准静止锋偏弱偏东。5) a类静止锋的纬向环流中，与云贵高原东部存在明显的异常环流圈下沉支相对应，中高层的深厚冷空气覆盖了云贵高原大部地区。b类和c类静止锋的则不存在明显的异常纬向环流圈，在各层大气中受到与暖湿气流相对应的异常上升气流所影响，另外c类静止锋的近地面存在1 m/s左右的西风异常区，表明其受暖湿气流影响强度明显高于其他两种类型。

Abstract: Based on the daily observation data of China compiled by Meteorological Information Center of China Meteorological Administration and the daily reanalysis data of ERA-interim from the European Centre for medium and long range weather forecasting, the temporal variation characteristics of Kunming quasi-stationary front in YunGui Plateau from 2006 to 2015, and the circulation differences of different types of Kunming quasi-stationary front in spring were discussed. Studies indicate, firstly, days of Kunming quasi-stationary front is decreasing, it is between 117 (2010) and 164 (2012) every year. Secondly, Kunming quasi-stationary front can appear all the year, and it has obvious seasonal characteristics, among which the days in January and December are the most, and the least in July. Thirdly, Kunming quasi-stationary front is dominated by b-type, with the most active is December, followed by type c, the most active is January and February, and the least active days in type a. Fourthly, in spring, when there appears one trough and one ridge in the middle and high latitudes over Asia, the East Asian trough is stronger and the subtropical high is weaker, it is easy to form the a-type stationary front. In the case of b-type stationary front, the middle and high latitudes of Asia are characterized by multi wave distribution, low trough activity, high frequency of cold air activity, strong intensity of subtropical high, and equal cold and warm air forces, which lead to the stationary front to maintain for a long time. The cold air of c-type stationary front is obviously weaker than the southwest warm and humid air flow, which leads the quasi stationary front to be weakening and locating to the East. Fifthly, in the zonal circulation of a-type stationary front, there is an obvious sinking branch of abnormal circulation circle in the east of YunGui Plateau, and the deep cold air in the middle and upper layers covers most of YunGui Plateau. There is no obvious abnormal zonal circulation circle for b-type and c-type stationary front, which is affected by the abnormal updraft corresponding to the warm and humid air flow in each layer of the atmosphere. In addition, there is a westerly anomaly area of about 1 m/s near the surface of c-type stationary front, which indicates that the influence intensity of warm and humid air flow is significantly higher than other two types.