夏季西北太平洋台风生成数的敏感性因子

比较了台风生成参数中各因子与西北太平洋7-9月台风生成数(WNPSTYN)的相关关系,也比较各因子在北半球台风主要源区的纬向距平分布特征,发现涡度因子与WNPSTYN的关系最好,在台风生成条件中相对富有但不特别富足的特性决定了其是WNPSTYN年际变化的敏感性因子.同时还分析了西北太平洋关键区涡度因子年际变化的来源和表征台风生成数的优越性,发现关键区涡度因子年际变化与南方涛动、南极涛动和澳洲东部高度场的年际变化有关,体现了南半球两大系统和ENSO对WNPSTYN的影响；涡度因子与WNPSTYN的显著相关区与台风生成源地集中区一致,表征台风年际变化有明显的优越性.这些特性对关于WNPSTYN的影响机制研究和气候模式模拟有非常重要的意义.

SENSITIVITY FACTORS FOR TYPHOON GENESIS OVER THE WESTERN NORTH PACIFIC DURING JULY-SEPTEMBER

The paper compares the correlations between each factor of Typhoon Genesis Index and the number of typhoons over the Northwest Pacific that occurred from July to September. It also compares the characters of zonal departure distribution of each factor in primary typhoon source areas in the Northern Hemisphere. Results show that the vorticity factor is a key that mainly determines the typhoon number over the Western North Pacific. The annual variability and the advantages of vorticity factors are also analyzed for key areas representing the change in the number of these typhoons. Results show that the annual variability of the vorticity in key areas is significantly correlated with ENSO, AAO and cold air activity over Australia, which reflects that the number of these typhoons is affected by the Antartica oscillation and Southern Oscillations in the Southern Hemisphere and ENSO. Vorticity factors have much advantages in representing the yearly variability of the number of these typhoons, because their significant correlations with the number of these typhoons and typhoon genesis are clear in physical meaning and regional consistency. Those characters are important for researches on impacting mechanisms of the number of these typhoons and simulation of climate models.