Verification of Downscaling Framework for Interannual Variation of Tropical Cyclone in Western North Pacific
Verification of Downscaling Framework for Interannual Variation of Tropical Cyclone in Western North Pacific
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DOI：
10.2151/sola.2011-043
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发表时间：
2011-11
期刊：
影响因子：
1.9
通讯作者：
Tomonori Sato;Akira Juri;Kei Masuyama;Eiji Imakita;M. Kimoto
中科院分区：
文献类型：
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作者：
Tomonori Sato;Akira Juri;Kei Masuyama;Eiji Imakita;M. Kimoto
对Emanuel et al.（2008）提出的降尺度框架进行了改进，以改善西北太平洋热带气旋特征的年际变化。原来的框架，它利用轴对称模式驱动的月平均大气和海洋变量，以及再现的年际变化的热带气旋指数在北大西洋，而有进一步改进的空间WNP。相对涡度的修正处理对改善WNP生成数和功率耗散指数的年际变化有重要作用。在这次更新中，我们引入了WNP特有的气旋生成概率，它是使用月平均850-hPa相对涡度和最佳路径先验计算的。结果表明，月平均相对涡度代表了西北太平洋特征扰动的启动潜势，如季风槽和季节内变化。对流层中层垂直风切变的增加改善了西北太平洋热带气旋生成数的分布，但对生成数的年际变化影响不大。
The downscaling framework, which is originally proposed by Emanuel et al. (2008), is modified to improve the interannual variation of the tropical cyclone features in Western North Pacific (WNP). The original framework, which utilizes axisymmetric model driven using monthly mean atmosphere and ocean variables, well reproduced interannual variation of tropical cyclone indices over North Atlantic while there is room for further improvement over WNP. The modified treatment of relative vorticity plays an essential role for improving interannual variation of genesis counts and power dissipation index in WNP. In this update, we introduced probability of cyclogenesis special to WNP which is a priori calculated using monthly mean 850-hPa level relative vorticity and best track. The result suggests that the monthly mean relative vorticity represents a potential of characteristic initiating disturbance in WNP such as monsoon trough and intraseasonal variation. Another experiment shows increased influence of vertical wind shear in middle troposphere improves the distribution of tropical cyclogenesis in WNP while it slightly deteriorates the interannual variation of genesis count.