西太副高第一次北跳与其后热带气旋的关系

Relationship between first northward-jump of northwest Pacific subtropical high and tropical cyclone thereafter

为了研究西太平洋副热带高压5-6月第一次季节性北跳和其之后的第一个热带气旋(TC)生成的关系,利用1980-2015年美国环境预报中心和美国大气研究中心500hPa高度场再分析资料和中国台风研究所发布的最佳路径台风数据,采用统计、气候检验、合成分析等方法进行分析。结果表明:在近2/3的年份里,副热带高压北跳后不到1周就有TC生成;其余年份在副热带高压北跳后,超过2周或更长的时间内无TC生成,而这些年份的气候背景相对比较复杂,但也有规律可循,即在强厄尔尼诺年,副热带高压北跳之后均无TC生成。副热带高压的合成指数显示:副热带高压北跳后无TC生成时,和副热带高压的强度偏强、位置偏南等因素有关;副热带高压北跳后有TC生成时,副热带高压的强度、位置与气候态平均值无明显差异,但脊线和南界5 880gpm等位势高度线在副热带高压北跳后均有明显北抬现象。

In order to study the relationship between the First Northward-Jump of the Northwest Pacific Subtropical High from May to June and the first tropical cyclone（TC）Formation thereafter,the best-track typhoon data and the NCEP/NCAR（National Centers Environmental Prediction/National Center for Atmospheric Research）reanalysis data during 1980-2015 were used,and the study was conducted by methods of statistical,synthetic and saliency detection.It is found that in nearly 2/3years,there is TC formation after the First Northward-Jump in one week.Differently,in the rest of the years,there is no TC formation in two weeks or even longer,and the climatic background of these years appears more complicated,but there exist some physical characteristics.In strong El Ni1 o years,there is no TC formation.The Northwest Pacific Subtropical High indices imply that there is no TC occurring after the First NorthwardJump is closely related toits stronger intensity and the southward location.In the scenario that there is TC formation after the First Northward-Jump,compared with the mean climatic value,there is no significant difference in the intensity and position of the Northwest Pacific Subtropical High,but the ridge position of it and southern boundary of the 5 880 gpm usually transits significantly northward.