南京大学：《大气环流》课程教学资源（课件讲稿）第四章 中纬度的经向环流系统（4/4）

E-P flux,TEM and Residual Circulation - E-P flux: F三-[u*v*]j+f Summary-Review u*θ1k 0s/∂p In a steady,adiabatic and frictionless flow: ow回= 1∂ =于a时 2[0*v1 ∂9s/ap V.F=0 Residual mean circulations: [回=网+ 闷=网- [u*θ*] 80s/8p, Op 80s/8p TEM equations: =f向+v.F+, ] Po RICp [Q] 8t 8t -0 Cp 授课教师：张洋2

授课教师：张洋 2 E-P flux, TEM and Residual Circulation - Summary n E-P flux: F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k n TEM equations: n Residual mean circulations: n In a steady, adiabatic and frictionless flow: @[✓] @t = ￾ ˜[!] @✓s @p + ✓po p ◆R/cp [Q] cp @[u] @t = f ˜[v] + r · F + [Fx] , ˜[!]=[!] + @ @y ✓ [v⇤✓⇤] @✓s/@p ◆ ˜[v]=[v] ￾ @ @p ✓ [v⇤✓⇤] @✓s/@p ◆ , [!] = ￾ r · F = 0 @ @y ✓ [✓⇤v⇤] @✓s/@p ◆ [v] = 1 f @ @y ([u⇤v⇤]) Review

E-P flux,TEM and Residual Circulation - E-P flux: F三-[*v*]j+f Summary-Review *1k 0s/∂p In a steady,adiabatic and frictionless flow: 1∂ 网=于∂ (u*o*]) = [0*v*1 ∂s/p V.F=0 +o而 ∂[w*9*] +F-0 Ot =.F 子=CgA 5A +7.(Acg)=0 Residual mean circulations: 回=网+ [u*1 闷=网- [u*0*] 80s/8p), Op a0s/ap TEM equations: =f脑+v.F+l, ] Po [Q] 8t 8t p Cp 授课教师：张洋3

@A @t + r · (Ac~g)=0 授课教师：张洋 3 E-P flux, TEM and Residual Circulation - Summary n E-P flux: F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k n TEM equations: #1[v⇤q⇤] = @ @y [u⇤v⇤] + fo @ @p [v⇤✓⇤] @✓s/@p = r · F #3 F ~ = c ~ gA n Residual mean circulations: #2 @A @t + r · F = 0 n In a steady, adiabatic and frictionless flow: @[✓] @t = ￾ ˜[!] @✓s @p + ✓po p ◆R/cp [Q] cp @[u] @t = f ˜[v] + r · F + [Fx] , ˜[!]=[!] + @ @y ✓ [v⇤✓⇤] @✓s/@p ◆ ˜[v]=[v] ￾ @ @p ✓ [v⇤✓⇤] @✓s/@p ◆ , [!] = ￾ r · F = 0 @ @y ✓ [✓⇤v⇤] @✓s/@p ◆ [v] = 1 f @ @y ([u⇤v⇤]) Review -

及图乐 Outline Observations The Ferrel Cell ■ Baroclinic eddies Review:baroclinic instability and baroclinic eddy life cycle Eddy-mean flow interaction,E-P flux Transformed Eulerian Mean equations Eddy-driven jet The energy cycle 授课教师：张洋4

授课教师：张洋 4 Outline n Observations n The Ferrel Cell n Baroclinic eddies n Review: baroclinic instability and baroclinic eddy life cycle n Eddy-mean flow interaction, E-P flux n Transformed Eulerian Mean equations n Eddy-driven jet n The energy cycle

Baroclinic eddy life cycle An E-P flux view W"0*]k 下=-[u**1j+fo9e/0n Review Simmond. Numerica 于=cgA Eddies:generate at lower level, 1978,JAS propagate upwards and away from the eddy source region 0 a b 200 200 200 NAAA入4 400 AAAAAA4 400 400 P (MB] LMB) (MB] 600 A不A 600 600 800 800 800 1000 00 300 600 1000 00 300 600 1000 00 300 TOTAL E-P FLUX DIVERGENCE TOTAL E-P FLUX OIVERGENCE TOTAL E-P FLUX DIVERGENCE 0AY.00 0AY5.00 0A￥8.00 授课教师：张洋 5

授课教师：张洋 5 F ~ = c ~ gA F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k Baroclinic eddy life cycle - An E-P flux view Numerical results from Simmons and Hoskins, 1978, JAS Eddies: generate at lower level, propagate upwards and away from the eddy source region Review

E-P flux t"0")k F=-u'v"li+f0p -The westerly jet-Review Wave energis: F=cgA propagate upwards and away from the center of the jet =f网+V.F+F 7 Ot 200 Convergence- In the vertical direction: 400 Accelerating the lower jet decelerating the upper jet 600 reduce the vertical shear of U 800 Divergence 岁 1000 10 30 50 0 90 Latitude 授课教师：张洋6

i i i i i i i i Latitude Latitude (a) (b) Fig. 12.17 The Eliassen–Palm flux in an idealized primitive equation of the atmo￾sphere. (a) The EP flux (arrows) and its divergence (contours, with intervals of 2ms￾1/day). The solid contours denote flux divergence, a positive PV flux, and eastward flow acceleration; the dashed contours denote flux convergence and de￾celeration. (b) The EP flux (arrows) and the time and zonally averaged zonal wind (contours). See the appendix for details of plotting EP fluxes. From Vallis (2006) From Vallis (2006) r · F 授课教师：张洋 6 F ~ = c ~ gA @[u] @t = f ˜[v] + r · F + [Fx] F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k E-P flux - The westerly jet Wave energies: propagate upwards and away from the center of the jet Divergence Convergence Accelerating the lower jet decelerating the upper jet reduce the vertical shear of U In the vertical direction: Review

及图 t"0*)k 下=-u*o*1j+fa0e/0p we enero propagate upwards and away from the center of Rossby waves break dissipate Momentum the jet divergence Stirring Momentum 子=CgA convergence Rossby waves Momentum break dissipate divergence ∂ Ot =- [u'v*]>-r[usurf] <means vertical average 授课教师：张洋7

@ @t = ￾ @ @y ￾r[usurf] 授课教师：张洋 7 F ~ = c ~ gA F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k Wave energies: propagate upwards and away from the center of the jet means vertical average i i i i i i i i Fig. 12.3 Generation of zonal flow on a ￾-plane or on a rotating sphere. Stirring in mid-latitudes (by baroclinic eddies) generates Rossby waves that propagate away from the disturbance. Momentum converges in the region of stirring, producing eastward flow there and weaker westward flow on its flanks. From Vallis (2006) From Vallis (2006) Review

t"0*)k 下=-u**1j+fo9a/p Review Wave energis: propagate upwards and away from the center of Rossby waves break dissipate Momentum the jet divergence Stirring Momentum 子=cgA convergence In equilibrium: 、个 Rossby waves Momentum break dissipate divergence rlaund ∂ 8t =- [u'v*]>-r[usurf] <means vertical average 授课教师：张洋7

@ @t = ￾ @ @y ￾r[usurf] r[usurf] ⇠ ￾ @ @y 授课教师：张洋 7 F ~ = c ~ gA F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k Wave energies: propagate upwards and away from the center of the jet means vertical average i i i i i i i i Fig. 12.3 Generation of zonal flow on a ￾-plane or on a rotating sphere. Stirring in mid-latitudes (by baroclinic eddies) generates Rossby waves that propagate away from the disturbance. Momentum converges in the region of stirring, producing eastward flow there and weaker westward flow on its flanks. From Vallis (2006) From Vallis (2006) In equilibrium: Review

*01k 下=-u*v*1j+fo0e/0p Review Wave energis: propagate upwards and away from the center of Rossby waves break dissipate Momentum the jet divergence Stirring Momentum convergence In equilibrium: 子=cgA 、个 Rossby waves Momentum break dissipate divergence rluauei 8 =- [u'v*]>-r[usurf] There MUST be surface 8t westerlies at midlatitudes. <means vertical average 授课教师：张洋7

@ @t = ￾ @ @y ￾r[usurf] r[usurf] ⇠ ￾ @ @y 授课教师：张洋 7 F ~ = c ~ gA F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k Wave energies: propagate upwards and away from the center of the jet means vertical average i i i i i i i i Fig. 12.3 Generation of zonal flow on a ￾-plane or on a rotating sphere. Stirring in mid-latitudes (by baroclinic eddies) generates Rossby waves that propagate away from the disturbance. Momentum converges in the region of stirring, producing eastward flow there and weaker westward flow on its flanks. From Vallis (2006) From Vallis (2006) In equilibrium: There MUST be surface westerlies at midlatitudes. Review

Eddy-driven jet: w"0]k 下=-[u**]j+f0./m the momentum budget-Review Wave energis: propagate upwards and away from the center of Rossby waves break dissipate Momentum the jet divergence Stirring Momentum 子=cgA convergence In equilibrium: 个 Rossby waves Momentum lan ∂ break dissipate divergence a =- [u"v*]>-rlusurt] There MUST be surface 8t westerlies at midlatitudes. <means vertical average 授课教师：张洋7

@ @t = ￾ @ @y ￾r[usurf] r[usurf] ⇠ ￾ @ @y 授课教师：张洋 7 F ~ = c ~ gA F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k Wave energies: propagate upwards and away from the center of the jet means vertical average i i i i i i i i Fig. 12.3 Generation of zonal flow on a ￾-plane or on a rotating sphere. Stirring in mid-latitudes (by baroclinic eddies) generates Rossby waves that propagate away from the disturbance. Momentum converges in the region of stirring, producing eastward flow there and weaker westward flow on its flanks. From Vallis (2006) From Vallis (2006) Eddy-driven jet: - the momentum budget In equilibrium: There MUST be surface westerlies at midlatitudes. Review

t"0")k F≡-[u'v*1j+f0e/p F=cgA E-P FLUX TRANSIENT EDDIES (a) 5×1015 () -1.25×1015 DJF JJA 2 2 ×<11-1 3 1-4 6 1t111, 6 7 -2111H+, :11111 9 87 9 10 10 10 1020 30 40 5060 7080N 1020 30 4050 60 70 80N 授课教师：张洋8

http://www.adultpdf.com Created by Image To PDF trial version, to remove this mark, please register this software. 授课教师：张洋 8 F ⌘ ￾[u⇤v⇤] j + f [v⇤✓⇤] @✓s/@p k F ~ = c ~ gA