&会 Hadley Cell Theories Held-Hou model (1980) MARCI 1980 ISAAC M.HELD AND 515 Nonlinear Axially Symmetric Circulations in a Nearly Inviscid Atmosphere IsAAC M.HELD ARTHUR Y.Hou Center for Earth and Plaxetary Physics.Harvard University,Cambridge,MA 02138 (Manuscript received 23 July 1979,in final form 16 October 1979) ABSTRACT on a sphere is the polew rving.The cory predicts the lotal po et in the zonal wir nd,and 1.Introduction atmospheres (e.g..Dickinson,1971:Leovy,1964) The importance of mixing induced by large-scale the meridional is determined baroclinic or barotropic instabilities for the general by the parameterized small-scale frictional stresses circulation of the atmosphere can best be a ppreciated in the zonal momentum equation.Detailed analyses by artificially suppressing these instabilities and of such models do not promise to be very fruitful examining the circulation which develops in their as long as theories for small-scale momentum mixing absence.This is most easily accomplished in the are themselves not very well developed. idealized case for which radiative foreing and the Schneider and Lindzen have recently computed lower boundary condition are both axially symmetric some axisymmetric flows forced by small-scale (independent of longitude).The flow of interest in fluxes of heat and momentum that do bear some this case is the large-scale axisymmetric flow resemblance to the observed cireulation (Schneider consistent with radiative forcing and whatever small- and Lindzen,1977;Schneider,1977).Using simple scale mixing is still present in the atmosphere theories for moist convective as well as boundary after the large-scale instabilitics have been suppressed. and radiative fluxes,Schneider obtains a Hadley Such axisymmetric circulations have not received cell which terminates abruptly at more or less the as much attention in the meteorological literature right latitude.a very strong subtropical jet at the as one might expect,given what would appear to be poleward boundary of the Hadley cell,strong trade their natural position as first approximations to the winds in the tropics,and a shallow Ferrel cell and general circulation.Reasons for this neglect are not surface westerlies poleward ofthe trades.Nakamura Isaac M.Held hard to find.It is the accepted wisdom that large (1978)describes an effectively axisymmetric calcula- scale zonally asymmetric baroclinic instabilities are tion (with heating and frictional formulations differ- 0z 8z J义个作寸大PJ八/十 3n Held-Hou model (1980) 授课教师：张洋 3 Hadley Cell - Theories Isaac M. Held Review