The Detailed Dynamics of the Hadley Cell. Part II: December–February

Abstract This paper complements an earlier on the June–August Hadley cell by giving a detailed analysis of December–February as seen in 30-yr climatology ERA-Interim data. The focus is dynamics upper branch cell. There are significant differences between cells two solsticial seasons. These particularly associated with ITCZs staying north equator and mean westerlies equatorial regions east Pacific Atlantic December–February. latter enables westward-moving mixed Rossby–gravity waves to be slow moving those therefore respond strongly upstream off-equatorial active convection. However, main result that both seasons it times convection predominantly lead upper-tropospheric outflows structures average give flow toward winter pole, steady transient fluxes momentum vorticity balance Coriolis terms. response preferred shown means regressions data from synoptic examples one season. Eddies tropical origin important their own right also interaction higher-latitude systems. support for relevance new conceptual model based sporadic nature time space.