西太平洋副热带高压不同特征指数与贵州夏季降水的关系

摘要

利用贵州85个气象观测站1979—2015年6—8月逐月降水资料、2011—2015逐日降水资料、国家气候中心副高指数及NCEP第二套再分析资料对西太平洋副热带高压与贵州夏季降水的关系进行了分析,并对副高位置发生变化时贵州暴雨带的变化进行了对比,结果表明:(1)贵州夏季大部分区域的降水与副高面积指数、强度指数为正相关,与脊线位置、西伸脊点为负相关;当副高面积增大或强度增强时,对应贵州夏季降水偏多;降水偏多时,6—8月副高的位置偏西或接近平均年份;降水偏少年,副高位置偏东或接近平均年份,且无论偏多(少)年均具有逐步北推东退的趋势.(2)面积指数、强度指数与降水在2～4a较为显著的凝聚共振关系,二者基本为同位相变化;副高脊线位置、西伸脊点与降水具有2a的凝聚共振关系,二者与降水均呈反位相变化,脊线位置(西伸脊点)的变化明显超前于降水的变化.(3)贵州6—8月出现暴雨天气时,副高脊线的平均位置具有逐步北推的趋势,且贵州暴雨日数先增加后减少,西伸脊点具有逐步西进的趋势,且贵州暴雨日数逐步增加;当脊线位置位于25°—29°N或西伸脊点位于90°—100°E时贵州暴雨日数最多.%Based on the summer daily and monthly precipitation data in Guizhou province from 1979 to 2015, the subtropical high index provided by National Climate Center and the re-analysis data from NCEP/NCAR,the relationship between the summer precipitation and the western Pacific subtropical high was analyzed,and the rain storms'position was analyzed when the subtropical high position changed. The re-sults are as follows:(1) The summer precipitation and the subtropical high intensity/area index are positively correlated,and the summer pre-cipitation and ridge line/west ridge point are negatively correlated. When the size and strength of the subtropical high are enhanced, rainfall is increased. In positive precipitation anomaly years,the position of subtropical high is either to the west or closed to the average. In negative precipitation anomaly years,the position of subtropical high is either to east or closed to the average. In either cases, it tends to gradually be pushed back to northeast. (2) Area index, intensity index and precipitation have condensed resonance relations in 2-4 years, and the change of the subtropical high area (intensity) is behind the change of precipitation. The subtropical high ridge line and west ridge point with precipi-tation have 2 years of coherence resonance,and the ridge line stretch (west ridge point) of changes is significantly ahead of the change of pre-cipitation. (3) The average location of subtropical high ridge line is gradually pushed to the north,and so is the Guizhou rain belt. Heavy rain days first increases then decreases. West ridge point is pushed to the west gradually. Guizhou storm days is reduced gradually,when the ridge line is located in 25°-29°N. When the west ridge point is located in 90°-100°E, Guizhou heavy rain days are the most.