斜压切变基流中横波型扰动的特征波动──Ⅰ:谱点分析  

CHARACTERISTIC WAVE OF TRANSVERSAL DISTURBANCE AT BAROCLINIC SHEAR FLOW Ⅰ:SPECTRUM ANALYSIS

作　　者：张立凤[1] 张铭[1] 

机构地区：[1]LASG中国科学院大气物理研究所,北京100080

出　　处：《气象学报》1999年第5期571-580,共10页Acta Meteorologica Sinica

基　　金：国家基础性研究项目!"气候动力学与气候预测课题"

摘　　要：文中对谱点的分布作了定性分析和数值计算。结果发现：当基流存在切变时，无论是重力惯性波还是涡旋波都存在连续谱。在通常的环境下，对天气尺度的扰动，3支波动的连续谱不重叠，3支波动明显可分；当扰动尺度小于临界波长l0时，可出现涡旋波和一支重力惯性波的两波连续谱区的重叠，当扰动尺度小于l0／2时，可出现涡旋波和一对重力惯性波的三波连续谱区的重叠，此时两种波动不可分。当出现重叠谱时，若出现不稳定扰动，其频率的实部落在重叠谱区。This paper is the first part of characteristic wave of transversal disturbance at baroclinicshear basic flow- The distribution of spectrum point is studied. The results show that,when the wind shear of basic flow is not zero, there exists continuous spectrum of gravitational inertial wave and vortex wave. Under usual circumstances, to synoptic scale, the continuous spectrum area of this three waves (that is distinct separated) are not overlap. Whenthe disturbance scale is smaller than the critical sca1e I0, there exists a overlap of the continuous spectrum area of two waves (vortex wave and a gravitational inertial wave), and whenit is smaller than I0/2, there exists a 0verlap of the continuous spectrum area of three wave(vortex wave and b0th gravitational inertial waves). This two kind of waves can not be separated at this moment, if the disturbance is instable, the real part of this frequency is in theoverlap spectrum area while there appears overlap spectrum.

关 键 词：特征波动 离散谱 斜压切变基流 横波型扰动 

分 类 号：P433.2[天文地球—大气科学及气象学]