热带气旋台风阶段强度突变的角动量收支

ON ANGULAR MOMENTUM BUDGETS FOR TYPHOONS WITH SUDDEN INTENSITY CHANGE

摘要:

本文利用探空和热带网格资料的合成方法,对西北太平洋热带气旋台风阶段的强度突然变化各时段进行了角动量收支分析。主要结论是:角动量输送可以作为热带气旋台风阶段强度变化的诊断工具;台风中层850—300hPa大的角动量输送对台风强度变化起着重大作用;台风的海面摩擦耗散非常巨大,以致于流入层的角动量输送不足以抵消摩擦汇项,台风的突然增强需要中层大的角动量输送补尝,以及中高层之间明显的反气旋性风切变加速。

Abstract:

Using composite rawinsonde and tropical grid data, angular momentum budgets are analysed for periods covering sudden intensity change at the stage of typhoon for tropical cyclones in the western North Pacific. Main conclusions; angular momentum transfer can be used to diagnose the intensity change for the periods; the transfer at 850-300 hPa of the typhoon is important for the change in intensity; sea surface frictional dissipation is too great to be compensated by the angular momentum transfer in the typhoon inflow layer; any sudden intensification of typhoon must be supplemented by large mid-layer transfer of angular momentum in combination with significant anticyclonic wind shear acceleration between the middle and outflow layers.