摘要
介绍了"扰动热力切变平流参数"的概念,并基于此概念及波流相互作用的理论,对登陆台风"凤凰"2008年7月27日00:00—31日00:00(世界时)的暴雨过程进行了诊断分析。通过采用ARPS模式的资料,对波作用密度M和波作用通量散度▽·F进行计算,分析其与6h累积地面降水的关系。结果表明,波作用密度的异常值区始终覆盖观测雨区,二者在水平分布和时间演变趋势上比较相似,该波作用密度能够比较准确地综合表征强降水系统典型的动力场和热力场扰动的垂直结构,因而与降水系统的发生演变密切相关,其正高值区与观测的6h累积地面降水具有良好的对应关系。同时对波作用通量散度▽·F的分析表明,在登陆台风引发的暴雨过程中,非地转风位涡扰动和一阶扰动平流与动力场和热力场扰动梯度耦合项是影响扰动热力切变平流异常变化的主要强迫项。进一步分析表明扰动与基本态的交换主要是扰动热量平流交换,而扰动动量平流交换非常弱。
A new concept of thermodynamic shear advection parameter is introduced in this paper. Based on the parameter and the theory of wave-flow interaction, we conducted the diagnostic analysis on the heavy-rainfall event caused by landfall typhoon ＂Fung-wong＂. With the assimilation data of the ARPS mode, M and V F were calculated to analyze the relationship between them and the observed 6 h accumulated surface rainfall. The result showed that the abnormal values of wave action density M （disturbance thermodynamic shear advection parameter） always covered the observed precipitation re- gions and both their horizontal distribution and their temporal evolution were quite similar. The positive high-value area of the parameter corresponded well with the observed 6 h accumulated surface rainfall. The analysis of 7 ~ F showed that in the process of rainfall which was caused by the landfall typhoon, the potential vorticity disturbance of ageostrophic wind was the main forcing term affecting the variation of disturbance thermodynamic shear advection parameter. Further analysis showed that the major exchange between the disturbance and basic states was the advection exchange of disturbance heat, whilethe advection exchange of disturbance momentum was very weak.
出处
《大气科学学报》
CSCD
北大核心
2013年第1期7-19,共13页
Transactions of Atmospheric Sciences
基金
国家自然科学基金资助项目(41175060
41075098
41005005)
公益性行业(气象)科研专项(GYHY(QX)200906001
GYHY(QX)200906004)
国家重点基础研究发展计划项目(2009CB421505)
中国气象科学研究院灾害天气国家重点实验室开放课题(2011LASW-B15)
关键词
扰动热力切变平流参数
波作用密度
对流涡度矢量
广义位温
台风降水
disturbance thermodynamic shear advection parameter
wave action density
convective vorticity vector
generalized potential temperature
typhoon precipitation
