一次罕见黄渤海大风天气成因分析

Causal Analysis of a Strong Wind Process over Yellow and Bohai Seas

利用气象常规资料、风廓线资料和NCEP/NCAR 1°×1°再分析资料,对2015年10月1日黄渤海罕见大风天气成因进行分析。结果表明:较强冷空气与快速发展的入海气旋相互作用形成强气压梯度是导致此次海上强风的主要原因。对流层中低层强冷平流区与地面变压风大值区有较好的对应关系。上下相接的整层冷平流有利于地面形成强气压梯度和变压梯度。气压梯度在大风形成的初期起主导作用,变压梯度有利于强风的维持。本次过程出现明显动量下传现象,大风形成初期,500~1000m出现低空动量下传并影响地面风场,高空槽过境后,2000m以上的高空动量能够影响地面风场。风廓线观测到低层强风并伴有强的下沉运动,可以作为海上大风临近预警的指标之一。

Based on the conventional observational data,wind profile data and NCEP/NCAR1°×1°reanalysis data,a strong wind process happened over the Yellow and Bohai Seas on 1 October 2015 is analyzed.Results show that the large-scale baric gradient wind caused by the cold air and rapidly growing surface cyclone led to the gale.The strong cold advection area is corresponding to the ground allobaric wind.The whole layer cold advection caused the strong pressure gradient and allobaric gradient on the ground.Pressure gradient played a leading role in the early wind process,and allobaric gradient was conducive to the maintenance of strong winds and downward propagation of upper level momentum occurred in this process;the lower level winds at 500 to 1000 meters affected the surface wind,and the wind above 2000 meters affected the surface wind after the trough crossing.The wind profile observations of low-level strong winds accompanied by strong subsidence movement can be used as an indicator of high sea wind warning.