Response of the Tropical Atmosphere to the Initial Forcing on the Equator and the Middle Latitude Boundary

[摘要] The response of the tropical atmosphere for the large-scale (wavenumber 4) initial forcing is examined in terms of the vertical scale using a 10-layer primitive model. In case of the initial forcing over the equator, the induced distrurbance broadly spreads to the middle latitude when the forcing has a large vertical scale. As the vertical scale becomes small, the response is strongly confined to the equatorial region and the disturbance resembles the mixed Rossbygravity wave.The response is also examined for the initial forcing given at the middle latitude boundary. When the vertical scale of the forcing is large, the tropical atmosphere is affected intensely, but the influence does not propagate far into the equatorial region in case of the small vertical scale.It is also shown that the horizontal shear between the equatorial easterly and the mdilatitudinal westerly tends to prevent the above interaction. Under the shear of 10 m⋅s-1/10°, the influence of the mid-latitudinal initial forcing of wavenumber 4 does not penetrate into the tropics even for the large vertical scale. Some interpretation of recent works of tropical data assimilation is also mentined based on the results of this study.

[学科分类] 大气科学