湿C矢量及其应用  

The moist C-vector and its applications

作　　者：黄逸飞 姚秀萍[1,2] HUANG Yifei;YAO Xiuping(Chinese Academy of Meteorological Sciences,Beijing 100081,China;China Meteorological Administration Training Centre,Beijing 100081,China)

机构地区：[1]中国气象科学研究院,北京100081 [2]中国气象局气象干部培训学院,北京100081

出　　处：《气象学报》2023年第6期985-997,共13页Acta Meteorologica Sinica

基　　金：国家自然科学基金项目(42275013、42030611、42175008);第二次青藏高原科学考察研究项目(2019QZKK0105)

摘　　要：C矢量(C)是Q矢量(Q)在三维空间中的延伸,表征了三维非地转运动。然而,C是基于地转风近似和绝热条件得到的,不包含大气运动的非绝热加热信息。大气中的降水及其影响天气系统往往与大气凝结潜热释放所产生的非绝热效应有关。从β平面下的p坐标系大气原始方程组出发,考虑大气非绝热效应,推导湿C矢量(C*),揭示C*的物理意义。利用ERA5再分析资料和高原低涡数据集,通过C*诊断青藏高原低涡(简称“高原涡”)个例形成、发展和移动过程,并与C的诊断结果进行对比以证实C*的应用价值。结果表明,相较于Q和C,C*包含更全面的非地转运动信息,在诊断中具有优势。C*的水平分量(Chor*)表征了热成风非平衡和非绝热加热作用产生的次级环流,能更好地解释高原涡移动方向改变的原因;C*的垂直分量(Cp*)恢复了被Q丢失的非地转运动信息,描述了地转非平衡产生的水平非地转运动,其负值中心表征高原涡中心的位置,且对高原涡发展具有一定的预示作用。此外,Chor*和Cp*的相对大小还表明高原涡存在显著的斜压性。The C-vector(C)is an extension of the Q-vector(Q)in the three-dimensional space,characterizing three-dimensional ageostrophic motion.However,C is derived from the geostrophic wind and adiabatic approximations,and the diabatic effect is excluded.Precipitation and its impact on weather systems in the atmosphere are frequently related to the diabatic effect produced by the release of latent heat.Based on the primitive equations in p-coordinate with theβ-plane approximation and the diabatic effect,the moist C-vector(C*)is proposed,and its physical interpretations are revealed.A Qingzang plateau vortex case is diagnosed by C*using the fifth-generation European Center for Medium-Range Weather Forecasts atmospheric reanalysis data(ERA5)and the database of the Qingzang plateau vortex.Results are compared with the diagnostic results of C to prove the application value of C*.It is found that compared with Q and C,C*contains more comprehensive information of the ageostrophic motion and thus has more C∗horadvantages in diagnosis.The horizontal component of C*()depicts the secondary circulation caused by thermal wind imbalance and diabatic effect,better explaining the reason for the direction change of the Qingzang plateau vortex movement than that C.The C∗pvertical component of C*()restores the information of ageostrophic motion which is lost by Q,and depicts horizontal ageostrophic C∗pmotion caused by geostrophic imbalance.The negative center represents the Qingzang plateau vortex center,and has a certain C∗hor C∗ppredictive effect on the development of the Qingzang plateau vortex.Besides,the relative sizes of and indicate that the Qingzang plateau vortex has a significant baroclinic property.

关 键 词：湿C矢量 C矢量 非地转运动 非绝热效应 高原涡 

分 类 号：P433[天文地球—大气科学及气象学]