Generation and Development of Cyclone in Thermal Wind

Abstract

The flow in the planetary atmosphere and ocean is influenced by both the effects of Coriolis force and the buoyancy. The effect of vertical and horizontal temperature gradients is also important in a global weather phenomenon, such as thermal wind, i.e., a jet generated on upper atmospheric stratum. In this study, the effect of the horizontal temperature gradient on the sense of the rotation in the vertical vortices is investigated by using direct numerical simulation in the homogeneous shear flow under the effects of rotation and stable stratification. As a result, it is found that in the thermal wind with the horizontal temperature gradient, the cyclons with the same sense of the rotation as the earth, become dominant. On the other hand, in the case without horizontal temperature gradient, the anticyclonic vortices are enhanced.