This study examines the shear-relative rainfall spatial distribution of tropical cyclones (TCs) during landfall based on the 19-year (1998–2016) TRMM satellite 3B42 rainfall estimate dataset and investigates the role of upper-tropospheric troughs on the rainfall intensity and distribution after TCs make a landfall over the six basins of Atlantic (ATL), eastern and central Pacific (EPA), northwestern Pacific (NWP), northern Indian Ocean (NIO), southern Indian Ocean (SIO), and South Pacific (SPA). The results show that the wavenumber 1 perturbation can contribute ∼ 50% of the total perturbation energy of total TC rainfall. Wavenumber 1 rainfall asymmetry presents the downshear-left maxima in the deep-layer vertical wind shear between 200 and 850 hPa for all the six basins prior to making a landfall. In general, wavenumber 1 rainfall tends to decrease less if there is an interaction between TCs and upper-level troughs located at the upstream of TCs over land. The maximum TC rain rate distributions tend to be located at the downshear-left (downshear) quadrant under the high (low)-potential vorticity conditions.

中文翻译：

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观测到的与登陆热带气旋有关的剪切相关降雨不对称

这项研究基于19年（1998-2016）TRMM卫星3B42降雨估算数据集，研究了登陆期间热带气旋（TCs）的相对剪切降雨空间分布，并研究了对流层低谷对降雨强度和分布的作用TC在大西洋（ATL），东部和中部太平洋（EPA），西北太平洋（NWP），北印度洋（NIO），南印度洋（SIO）和南太平洋（SPA）的六个盆地登陆之后。结果表明，波数1的扰动可贡献总TC降雨的总扰动能量的约50％。1号波的降雨不对称性表明，在登陆之前，所有六个盆地的深层垂直风切变在200至850 hPa之间均具有左剪切左最大值。一般来说，如果TCs和位于陆地上TCs上游的高层槽之间存在相互作用，则1号波的降雨趋于减少。在高（低）势涡度条件下，最大TC降雨率分布倾向于位于左下剪切（下剪切）象限。