Baroclinic eddies linear baroclinic instability Charney's model JULE CHARNEY was one of the dominant figures in atmospheric science in the three decades following World War II.Much of the change in meteorology from an art to a science is due to his scientific vision and his thorough commitment to people and programs in this field." -by Norman Phillips Jule Gregory Charney 0年年卡0年9+年年年44。。4年0年004e4 1917-1981 授课教师：张洋
授课教师：张洋 7 Baroclinic eddies - linear baroclinic instability n Charney’s model “ JULE CHARNEY was one of the dominant figures in atmospheric science in the three decades following World War II. Much of the change in meteorology from an art to a science is due to his scientific vision and his thorough commitment to people and programs in this field.” -- by Norman Phillips
Baroclinic eddies Review From linear to nonlinear Linear Reduce the zonal flow Basic flow process temperature gradient; or stablize the lower level Pre-existing flow stratification;enhance the (without zonal variation westerly jet and baroclinic unstable) Small Nonlinear perturbation interactions Perturbations Equilibrated states between grow with time Eddy-mean interactions the adjusted zonal flow (finite amplitude pert.) (Adjust the zonal flow) and baroclinic eddies 授课教师：张洋 8
授课教师：张洋 8 Baroclinic eddies n From linear to nonlinear Basic flow or Pre-existing flow (without zonal variation and baroclinic unstable) Small perturbation Perturbations grow with time (finite amplitude pert.) Eddy-mean interactions (Adjust the zonal flow) Equilibrated states between the adjusted zonal flow and baroclinic eddies Linear process Nonlinear interactions Reduce the zonal flow temperature gradient; stablize the lower level stratification; enhance the westerly jet Review
Baroclinic eddies > Review From linear to nonlinear spinup of Numerical results from a QG model eddies, (Zhang,2009) 400 Basic flow E-P flux or Nonlinear Equilibrium Pre-existing flow adjustment (without zonal variation 20 and baroclinic unstable) 200 x)3d3 Small perturbation 0 100 200 300 400 500 600 day Perturbations Equilibrated states between grow with time Eddy-mean interactions the adjusted zonal flow (finite amplitude pert.) (Adjust the zonal flow) and baroclinic eddies 授课教师：张洋 9
0 100 200 300 400 500 600 40 50 60 70 80 90 100 Time series of KE for SD run MKE ( × 105 J/m2 ) 0 100 200 300 400 500 600 0 5 10 15 20 25 30 EKE ( × 105 J/m2 ) 0 100 200 300 400 500 600 200 400 day Time series of PE for SD run MPE ( × 105 J/m2 ) 0 100 200 300 400 500 600 0 20 40 EPE ( × 105 J/m2 ) Numerical results from a QG model (Zhang, 2009) 授课教师：张洋 9 Baroclinic eddies n From linear to nonlinear Basic flow or Pre-existing flow (without zonal variation and baroclinic unstable) Small perturbation Perturbations grow with time (finite amplitude pert.) Eddy-mean interactions (Adjust the zonal flow) Equilibrated states between the adjusted zonal flow and baroclinic eddies Equilibrium Nonlinear adjustment spinup of eddies E-P flux 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10
授课教师：张洋 10 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
The Ferrel Cell -Review< The balance equations [T] b Tropopause a([u*v*]) by +f+E到 a0。_a[0*v] ∂0s. y 20 wp by 00s l ap + ∂(e*v*]) Po R/Cp OY by Cp Boundary layer Ground Subtropics Latitude Subpolar 11
11 n The balance equations: The Ferrel Cell @[✓] @t + [!] @✓s @p = @([✓⇤v⇤]) @y + ✓po p ◆R/cp [Q] cp @[u] @t = @([u⇤v⇤]) @y + f[v]+[Fx] Observations - Eddy fields 15 \ 授教：洋 ! Heat flux: http://www.adultpdf.com Created by Image To PDF trial version, to remove this mark, please register this software. Transient components: strongest at 40-50 degree, with obvious seasonal variation in N.H.. Stationary components: strongest at mid-latitude in N.H., whose directions are reversed from winter to summer. Zonal mean flow: centered in the tropics, whose directions are reversed from winter to summer. Wednesday, October 30, 2013 ! @✓s @p ⇠ @[✓⇤v⇤] @y < 0 ! @✓s @p ⇠ @[✓⇤v⇤] @y > 0 Review