The Characteristic Feature of Medium Scale Distubances in the Atmosphere (II)

[摘要] The stability of medium scale disturbances is discussed taking into account the latitudinal variation of the perturbations. In connection with this problem, we introduce three parameters, i.e., the Richardson number Ri and the Rossby numbers Rx and Ry in the longitudinal and latitudinal directions respectively. Theoretical consideration shows that according to RiRx2_??_Ry2 (1- Ri) the baroclinic or shearing instability predominates and it is also shown that the growth rate of disturbances in the latter case is larger than that in the former case. Numerical experiments are also performed in two cases where Ri≈2 and Ri≈1/2 in the lower atmosphere. The case where Ri≈1/2 presents the similar situation with the rapid cyclogenesis of medium scale disturbances along the surface front.

[学科分类] 大气科学