摘要
利用NCEP/NCAR再分析资料对1991年5月18日—7月13日江淮地区梅雨期的湿位涡、正压湿位涡、斜压湿位涡以及它们的扰动量进行了诊断分析,并讨论了经向风场及温度、湿度场和大气对称不稳定度的演变特征及其与降水的关系。结果表明:对流层低层的对称不稳定度与降水的发生发展有较好的对应关系,较强对称不稳定对应较强降水的发生,当对称不稳定度减弱,降水也随之减弱或渐止。对称不稳定度的大小与对流不稳定、惯性不稳定以及大气湿斜压性和风的垂直切变紧密相关。西南风活跃、冷暖空气交汇,形成对称不稳定倾斜上升气流区,是导致在梅雨锋上暖湿空气一侧发生强降水的重要原因。
By using NCEP/NCAR reanalysis data,the moist potential vorticity（MPV） and its barotropic and baroclinic terms（MPV1 and MPV2 respectively） and their perturbations during the Meiyu period over the Yangtze-huaihe Rivers basin in 1991 are diagnostically studied.The relationship between the precipitation and the features of longitudinal wind,temperature and relative humidity fields,and symmetric instability are discussed.Results showed that the symmetric instability in the lower troposphere are closely related with the precipitation.Higher symmetric instability corresponds to heavy rain,while the precipitation may weaken or cease when the symmetric instability decreases.Symmetric instability is related with convective instability,inertial instability,moist baroclinicity and vertical wind shear.The active southwest wind,the collision of warm and cold air and the slantwise unstable flows are the basic factors to cause the heavy precipitation on the Meiyu front.
出处
《热带气象学报》
CSCD
北大核心
2010年第6期781-789,共9页
Journal of Tropical Meteorology
基金
国家自然科学基金项目(41005027、40875025、40875030、40775033)
气象灾害省部共建教育部重点实验室开放课题KLME0905共同资助
关键词
天气学
对称不稳定
诊断分析
湿位涡
西南风
diagnostic analysis
symmetric instability
moist potential vorticity
southwest wind
