1970-2009年冬季昆明准静止锋的变化特征及其影响分析

Variation of Kunming Quasi-Stationary Front and Its Effect Analysis in Winter during 1970-2009

利用1970-2009年冬季逐日地面常规观测资料和国家气候中心提供的74项环流指数资料,统计分析了1970-2009年冬季昆明准静止锋的移动变化特征,并分析了贵阳、昆明、沾益的阴天日数、降雨日数、干旱变化与准静止锋活动的联系。结果表明:1970-2009年,昆明准静止锋的活动总体呈减少趋势,准静止锋影响范围的变化明显,锋面位于沾益与贵阳之间最为频繁,影响贵阳最多,其次是锋面在沾益与昆明之间,而锋面影响昆明最少。昆明准静止锋对昆明的影响总体呈减少趋势,对滇东北沾益的影响总体上变化不明显,但从2000/2001年冬季至2008/2009年冬季影响次数则呈增加趋势,对贵阳的影响次数总体呈略减弱趋势。昆明准静止锋对贵阳的阴天日数均有影响。随着影响昆明的准静止锋减少,昆明的阴天日数呈减少趋势。准静止锋的影响时间与降雨日数呈正相关,而与干旱日数的变化呈反相关。昆明冬季降雨日减少以及干旱次数增加与准静止锋明显减少有关。不同的天气系统对静止锋位置变化的影响并不完全一致。准静止锋的活动范围与西太平洋副热带高压西伸脊点的相关最好,且与静止锋影响云南的日数呈正相关。当西太平洋副热带高压西伸且维持时影响云南的静止锋较少,东退时则影响云南的静止锋偏多;西太平洋副热带高压西伸脊点与影响贵州的静止锋持续时间呈反相关。另外,准静止锋位于云南的时间还与南支槽、副热带高压面积和强度、亚洲纬向环流指数、欧亚纬向环流呈负相关,与亚洲极涡面积的活动呈正相关;而准静止锋位于贵州的日数与西太平洋副热带高压面积、南支槽的影响有关,且均为正相关。

Using the daily ground routine observation data and 74 kinds of circulation index data provided by the China climate center from 1970 to 2009, the characteristics of the Kunming quasi-stationary front in winter and the relationships among the Kunming stationary front activities and cloudy days, precipitation days, and drought variation in Guiyang, Kunming and Zhanyi stations are analyzed. The results show that the Kunming stationary from activity number is decreasing, and the sphere of influence by it has marked change from 1970 to 2009. The numbers affected by the Kunming quasi-stationary front is the most in Guiyang, the second is in the area be- tween Zhanyi and Kunming, the last is in Kunming. The numbers of influence Kunming and Guiyang by the Kunming quasi-stationary front is a decreasing trend, and is unchanged in Zhanyi, but increased in winter of 2000 and 2008. With the decreasing of the Kunming stationary front in winter appearance in Kunming, the cloudy days are decreasing in Yunnan. The trend of cloudy days was consistent with the variation of Kunming quasi-stationary front. The time affected by the Kunming quasi-stationary front was positively correlated with pre- cipitation days, and negative correlated with drought days. Kunming precipitation in winter reduction and drought increase are related to the significant reduction of stationary front influence. The influences of the differ- ent weather system on the location of Kunming quasi-stationary front are not the same. The west ridge of the Western Pacific subtropical high was the best related to the range of stationary front activities, and it was posi- tively correlated with the numbers of influence Yunnan by the stationary front, but was negatively correlated with the consistent time of the stationary front influence on Guizhou. When the Western Pacific Subtropical High keeps in the west, the stationary front affected on Yunnan happen less. When the Western Pacific Subtropical High retreats in the east, the stationary front affected on Yurman happen more. In addition, the time of the sta- tionary front located in Yunnan was negatively correlated with the Southern Branch Trough （SBT）, the area and intensity of subtropical high, Asian zonal index and Eurasian zonal circulation, and was positively correlated with the activities of Asian polar vortex area. The time of the stationary front located in Guizhou was positively correlated with the area of the Western Pacific subtropical high and the SBT strength.