途经鲁西地区两类台风的多尺度环流对比分析

The comparison analysis on multi-scale circulations of two types of typhoons passing through western Shandong

利用中国气象局上海台风研究所、联合台风警报中心和东京区域专业气象中心提供的台风最佳路径集以及NCEP/NCAR提供的再分析资料,将途经鲁西地区的台风分为穿越型和溜边型,运用动态合成方法分析不同尺度环流场对两类台风的影响。结果表明:穿越型台风强度整体偏强,β效应作用明显,有利于台风北抬,台风西移北上过程中途经鲁西,不需要西风槽的配合;溜边型台风强度相对偏弱,β效应使得台风两侧地转偏向力的差异减小,台风趋向于沿低频引导气流移动,必须有西风槽配合,在转向东移过程中途经鲁西。此外,偏高的表面温度、偏强的季风涌、稍强的低层扰动和高层辐散以及适中的环境垂直风切变均有利于穿越型台风强度强于溜边型台风;而高低频环流的相互作用使两类台风的β效应和副热带高压的形态存在差异。

Based on the best track datasets provided by Shanghai Typhoon Institute,Joint Typhoon Warning Center,Tokyo Regional Typhoon Center and the reanalysis data provided by NCEP/NCAR during 1950-2017,the typhoons that passing through western Shandong are divided into two types,namely crossing TCs and edging TCs.The effects of different-scale circulations on two types of typhoons are analyzed by using dynamic synthesis.The result shows that crossing TCs are stronger on the whole,theβeffect is significant and tend to make typhoons move northward.The northwest-moving typhoons affect western Shandong without the cooperation of westerly trough.The edging TCs are relatively weak,theβeffect reduces the difference of geostrophic deflection force between two sides of typhoons,the typhoons tend to move along the low frequency flows and influence western Shandong when they move northeastward with the cooperation of westerly trough.In addition,the higher surface temperature,the stronger monsoon surge,low level disturbance and high level divergence and the moderate environmental vertical wind shear are all favorable to make crossing TCs stronger than edging TCs.The interaction between high and low frequency flows causes the difference of theβeffect and the pattern of the west pacific subtropical high between two types of typhoons.