初始扰动垂直结构对热带斜压大气半地转适应过程的影响

THE INFLUENCE OF INITIAL DISTURBANCE'S VERTICAL STRUCTURE ON SEMIGEOSTROPHIC ADAPTATION IN TROPICAL BAROCLINIC ATMOSPHERE

文中利用一个半位势涡度时间不变式对热带斜压大气地转适应过程中的尺度准则进行了研究。结果表明 :对深厚系统而言 ,只要初始扰动的纬圈特征尺度足够大 ,则不论其初始扰动的经圈特征尺度多大 ,适应后的压力场的变化都很大 ,而纬圈流几乎维持不变 ,压力场向纬圈流适应 ;至于浅薄系统 ,对纬圈和经圈特征尺度都很大的初始扰动而言 ,适应后的压力场易于维持 ,主要是纬圈流向压力场适应 ;但当初始扰动呈现出纬圈型扰动特征时 ,适应后的压力场变化也很大 。

Based on an invariant of semi-potential vorticity,the scale criterion of geostrophic adaptation in tropical baroclinic atmosphere is discussed.For a deep system,no matter how long the meridional characteristic scale of initial disturbance is,if the zonal characteristic scale of initial disturbance is bigger than the equatorial Rossby radius of deformation,the pressure field changes greatly and the zonal current is almost no any change.For a shallow system,when the zonal and meridional characteristic scales of initial disturbance are greater than the equatorial Rossby radius of deformation, the pressure field is easy to preserve, the zonal current changes to adapt the pressure field,but when the initial disturbance exhibits zonal-type character, the pressure field adapts to the zonal current.