On the asymmetric distribution of shear-relative typhoon rainfall
On the asymmetric distribution of shear-relative typhoon rainfall
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台风剪切相关降雨的不对称分布
DOI：
10.1007/s00703-016-0499-0
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发表时间：
2018
影响因子：
2
通讯作者：
Chen Zhifan
中科院分区：
文献类型：
--
作者：
Gao Si;Zhai Shunan;Li Tim;Chen Zhifan
利用2000-2015年热带降雨测量任务（TRMM） 3B42降水、国家环境预报中心（NCEP）最终分析和区域专业气象中心（RSMC）东京最佳轨迹资料，比较了不同垂直风切变方向下西北太平洋热带气旋（TCs）的空间降水分布，并探讨了可能的机制。结果表明：无论切变方向如何，最大TC降水均位于下切变左象限，且偏东切变TC的降水量级大于西风切变TC，与前人研究结果一致；热带气旋的降雨量与其相对位置、与副热带高压的接近程度以及水汽输送强度有关，低层急流有利于水汽输送。无论切变方向如何，垂直积分水汽通量辐合的最大值都位于下切变侧，风辐合对总水汽通量辐合的贡献远大于水汽平流。最大降雨量相对于最大MFC的气旋位移可能是由于低层和中层TCs气旋环流对水成物的平流。通过水汽输送和垂直风切变，TC降雨与西太平洋高压之间的关系表明，由于西太平洋高压的高可预测性，TC降雨可能具有很高的可预测性。
The Tropical Rainfall Measuring Mission (TRMM) 3B42 precipitation, the National Centers for Environmental Prediction (NCEP) Final analysis and the Regional Specialized Meteorological Center (RSMC) Tokyo best-track data during 2000–2015 are used to compare spatial rainfall distribution associated with Northwest Pacific tropical cyclones (TCs) with different vertical wind shear directions and investigate possible mechanisms. Results show that the maximum TC rainfall are all located in the downshear left quadrant regardless of shear direction, and TCs with easterly shear have greater magnitudes of rainfall than those with westerly shear, consistent with previous studies. Rainfall amount of a TC is related to its relative position and proximity from the western Pacific subtropical high (WPSH) and the intensity of water vapor transport, and low-level jet is favorable for water vapor transport. The maximum of vertically integrated moisture flux convergence (MFC) are located on the downshear side regardless of shear direction, and the contribution of wind convergence to the total MFC is far larger than that of moisture advection. The cyclonic displacement of the maximum rainfall relative to the maximum MFC is possibly due to advection of hydrometeors by low- and middle-level cyclonic circulation of TCs. The relationship between TC rainfall and the WPSH through water vapor transport and vertical wind shear implies that TC rainfall may be highly predictable given the high predictability of the WPSH.