大连春季首场透雨特征与环流背景分析及可能影响因子探讨

Analysis of Characteristics and Circulation Background of First Spring Soaking Rain and Discussion on Its Influence Factors in Dalian

选用1957—2012年大连3个代表站的降水量分析春季首场透雨出现日期的气候特征,得出其年(代)际特征明显:偏早9年,偏晚20年;20世纪50年代末至60年代末偏早,20世纪70年代初至90年代末明显偏晚,2000年后以偏早为主。另外,分析首场透雨出现日期与春季降水的关系后得出典型年份,对典型年份的环流场进行合成分析:透雨偏早降水偏多年大连地区受500hPa高度距平场正距平和水汽通量距平场反气旋环流控制,有异常偏多的偏南气流影响,水汽输送异常偏多,春季降水易偏早偏多;透雨偏晚降水偏少年,大连地区受500 hPa高度距平场负距平和水汽通量距平场气旋性环流控制,有异常偏多的西北气流影响,水汽输送异常偏少,春季降水易偏晚偏少。春季首场透雨出现日期和前冬日本海域海温异常存在很好的负相关;前冬日本海偏冷则透雨出现日期偏晚,前冬日本海偏暖则透雨出现日期偏早。

According to the precipitation data of the representative stations in Dalian during the period from 1957 to 2012, the authors characteristics of first spring analyzed the characteristics of first spring soaking soaking rain are obvious. There are 9 years＇ earlier later soaking rain. During the period from the late 1950s to the spring soaking rain is earlier, while it is obviously later during rain. It is found that the soaking rain and 20 years＇ late 1960s and after 2000, the date of first the period from the early 1970s to the late 1990s. Analysis of the relation between the date of first spring soaking rain and spring out to find the typical years, and then composition analysis of the circulation backgroun conducted. When there is earlier first spring soaking precipitation is carried d of the typical years is rain and more spring precipitation, influenced by positive 500 hPa height anomaly field and anticyclonic circulation of the vapor flux anomaly field, there are more south airflow and vapor transportation over Dalian. In contrast, when there is later first spring soaking rain and less spring precipitation, influenced by negative 500 hPa height anomaly field and cyclonic circulation of the vapor flux anomaly field, there are more northwest airflow and less vapor transportation over Dalian. There is a negative correlation between the date of first spring soaking Cooler earlier winter SST of Japan Sea could result in rain and SST anomaly of Japan Sea in early winter. later first spring soaking rain, and vice versa.