饱和湿大气中惯性重力内波不稳定判据的探讨  

Research on the Unstable Criterion about the Internal Inertial Gravity Wave with any Frequency in the Saturated Atmosphere

作　　者：吴洪[1] 张昕[1] 孙俊[2] WU Hong;ZHANG Xin;SUN Jun(China Meteorological Administration Training Center,Beijing 100081,China;Sichuan Sub-Center of China Meteorological Admin-istration Training Center,Chengdu 610071,China)

机构地区：[1]中国气象局气象干部培训学院,北京100081 [2]中国气象局气象干部培训学院四川分院,四川成都610071

出　　处：《成都信息工程大学学报》2024年第4期458-463,共6页Journal of Chengdu University of Information Technology

基　　金：国家自然科学基金资助项目(42030611)。

摘　　要：为分析饱和湿斜压大气中任意频率的惯性重力内波的稳定性,利用非静力平衡Boussinesq近似的方程组,在饱和湿斜压大气中考虑湿绝热过程,着重分析讨论任意频率的惯性重力内波不稳定的充分条件(即判据),主要得出:当饱和湿斜压大气的位温经向梯度与饱和相当位温经向梯度之和大于零时,波动不稳定的必要条件是波动向北倾斜;反之,波动不稳定的必要条件是波动向南倾斜。在基流、基本温度场分布不同的饱和湿斜压环境大气中,任意频率惯性重力内波的不稳定判据呈多种不同的表达式,变化复杂。一般情况下,波动不稳定的充分条件即不稳定判据是饱和湿斜压环境大气不仅满足动热力参数Δ大于零,且波动等位相面的倾斜度必须位于与Δ有关的两个参数值A_(1)、A_(2)之间。当位温经向梯度与饱和假相当位温经向梯度的方向相反,波动相对更稳定。如果惯性重力内波发生不稳定,饱和湿斜压环境大气的等饱和相当位温面的倾斜度可能超过等绝对动量面的倾斜度,也可能小于等绝对动量面的倾斜度。This study investigates the stability conditions for internal inertial gravity waves in a saturated baroclinic atmos-phere.The analysis focuses on the instability criteria,using equations based on the Boussinesq approximation,non-hy-drostatic balance,and moist adiabatic processes.The main results show that if the sum is greater than zero of the latitu-dinal gradient of the field about the potential temperature and the one of the field about the saturated potential pseudo-e-quivalent temperature,the necessary condition of the instability is that the slope of the constant phase line of wave is slant towards north.If the sum is less than zero,the necessary condition of the instability is that the slope of the constant phase line of the wave is a slant towards south.There are so many different and rather complicated formulas of the unsta-ble criterion about the wave in the saturated baroclinic atmosphere.In general,it must be the sufficient condition of the instability about the internal inertial gravity wave that not only the dynamical and thermal parameter Δ is greater than ze-ro about the saturated baroclinic atmosphere,but also the slope of the phase line about the wave must be greater the A_(1) and less than A_(2) which are relative to the Δ.While the direction of the gradient of the field of saturation equivalent poten-tial temperature is the opposite of the gradient of the field of potential temperature,there is stable more easily about the internal inertial gravity wave.If the wave is unstable,the slope of the isoline of saturation equivalent potential tempera-ture may be more vertical than or less vertical than one of the isolines of absolute momentum.

关 键 词：湿绝热过程 惯性重力内波 稳定性 斜压 

分 类 号：P433[天文地球—大气科学及气象学]