&鲁 Hadley Cell Discussion: UNN Asymmetry about the eguator* Review Lindzen-Hou (1988) Quasi-steady assumption,however the seasonal cycle is temporally progressing; The lack of angular momentum conservation in reality,especially when the angular momentum transport by eddies are significant. The moisture effect is still neglected; 授课教师：张洋7
授课教师：张洋 7 Hadley Cell - Discussion: Asymmetry about the equator* ! Lindzen-Hou (1988) ! Quasi-steady assumption, however the seasonal cycle is temporally progressing; ! The lack of angular momentum conservation in reality, especially when the angular momentum transport by eddies are significant. ! The moisture effect is still neglected; Review
设雾 Hadley Cell Role of eddies* Qualitative considerations 易M=-,C+where品-品+ D∂ 0 acosΦa入a0b In an axisymmetric flow ([M]=M): 2l-aosiA In a 3-D(with eddies)flow,the zonally averaged angular momentum: ade品adso+是o 0m+1 O arde品(m-是mo+aasB 1 1 vjos2到-品uror1es+as9B acosΦ0Φ Neglecting vertical advection,vertical eddy fluxes and friction: m]+回am=-1} O a 8o acos(a cos) 授课教师：张洋8
授课教师：张洋 @[m] @t + [v] a @[m] @ = 1 a cos @ @([u⇤v⇤]a cos2 ) 8 Hadley Cell : Role of eddies* ! Qualitative considerations In a 3-D (with eddies) flow, the zonally averaged angular momentum: D Dt M = 1 ⇢ @p @ + a cos F In an axisymmetric flow ([M]=M): D Dt[M] = a cos [F] D Dt = @ @t + u a cos @ @ + v a @ @ + w @ @z , where Neglecting vertical advection, vertical eddy fluxes and friction: @[m] @t + 1 a cos @ @ ([v][m] cos ) + @ @z ([w][m]) = 1 a cos @ @([m⇤v⇤] cos ) @ @z ([m⇤w⇤]) + a cos [F] = 1 a cos @ @([u⇤v⇤]a cos2 ) @ @z ([u⇤w⇤]a cos ) + a cos [F]
设雾 Hadley Cell Role of eddies* Qualitative considerations D 8 Di-at acosΦaλaab In an axisymmetric flow ([M]=M): -cmi In a 3-D(with eddies)flow,the zonally averaged angular momentum: Neglecting vertical advection,vertical eddy fluxes and friction: olm]lolm] acaei2erhoms2 1 20 [w] b Eddy momentum flux always 10 acts to decrease the angular momentum of the zonal flow, and the zonal velocity is lower than UM. Observations -20 10 授课教师：张洋9
授课教师：张洋 @[m] @t + [v] a @[m] @ = 1 a cos @ @([u⇤v⇤]a cos2 ) 9 Hadley Cell : Role of eddies* ! Qualitative considerations D Dt M = 1 ⇢ @p @ + a cos F In an axisymmetric flow ([M]=M): D Dt[M] = a cos [F] In a 3-D (with eddies) flow, the zonally averaged angular momentum: D Dt = @ @t + u a cos @ @ + v a @ @ + w @ @z , where Neglecting vertical advection, vertical eddy fluxes and friction: http://www.adultpdf.com Created by Image To PDF trial version, to remove this mark, please register this software. Observations Eddy momentum flux always acts to decrease the angular momentum of the zonal flow, and the zonal velocity is lower than UM
设雾 Hadley Cell Role of eddies* Numerical solutions: Vallis,2006, axisymmetric numerical results from idealized GCM 0.0 40 um n uo 0.5 20 us 0 1.0 Narrower but stronger 0.0 Hadley cell 3-D flow.with eddies 40 1化m E Upper jet shifts with weakeruo 0.5 20 maximum leuoz Stronger surface winds 0 Us 1.0 60 -30 0 30 60 -60 -30 0 30 60 Latitude Latitude
授课教师：张洋 10 Hadley Cell : Role of eddies* ! Numerical solutions: axisymmetric 3-D flow, with eddies Vallis, 2006, numerical results from idealized GCM Narrower but stronger Hadley cell Upper jet shifts with weaker maximum Stronger surface winds