关键词: 药效, 药效

Abstract: According to the precipitation data of the representative stations in Dalian during the period from 1957 to 2012, the authors analyzed the characteristics of first spring soaking rain. It is found that the characteristics of first spring soaking rain are obvious. There are 9 years’earlier soaking rain and 20 years’ later soaking rain. During the period from the late 1950s to the late 1960s and after 2000, the date of first spring soaking rain is earlier, while it is obviously later during the period from the early 1970s to the late 1990s. Analysis of the relation between the date of first spring soaking rain and spring precipitation is carried out to find the typical years, and then composition analysis of the circulation background of the typical years is conducted. When there is earlier first spring soaking 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 rain and SST anomaly of Japan Sea in early winter. Cooler earlier winter SST of Japan Sea could result in later first spring soaking rain, and vice versa.