Study Guide (lecture #5)
Book pages: 63-72, skim 228-230 in §6.1, 91-92 in §4.1
Review:
(lecture #4)
- meridional heat transport
- zonal average T distribution
- radiative balance model of vertical T structure
Today's topics:
- radiative balance model improvements: e.g. radiative convective model
- zonal mean zonal wind [u]
- zonal mean meridional wind [v]
- meridional-vertical plane stream function and meridional cells
Jargon:
pseudo-adiabatic profile, radiative-convective model, subtropical jet,
polar night jet, ageostrophic, moist static energy
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Radiative balance model improvements:
Problems solved by:
- - include heat fluxes explicitly (not specified in this course,
see fig 6.5)
- - eliminate superadiabatic lapse rates by convection
- - eliminate T discontinuities at bottom of atmosphere using a heat
flux
- - lapse rate always non-negative (lapse rate = - dT/dz)
- need solar radiation absorbed to get a negative lapse rate (upper
stratosphere) (fig 6.3)
- can add other embellishments: clouds, horizontal heat fluxes
(figs. 6.4, 6.5)
Zonal average zonal wind ([u]):
- "[ ]" means zonal average -- see Appendix
- -jets
- -westerlies & easterlies
- -relate to [T] and ["theta"]
- -no net torque
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zonal average meridional wind [v]:
- -[v] much smaller than v, [v] = [v a] ageostrophic wind
- -Hadley cell
zonal average cells ["psi"]:
- - -streamfunction how to find & use for [v] & ["omega"]
- definition of angular momentum "rho" * M
- - 3-cell circulation
- - Hadley, Ferrel, polar cells
- - 3 cells seen in P coordinates, but "one" seen in "theta" coordinates
- - Ferrel cell rising motion from frontal systems in middle latitudes
- first strong evidence that Ferrel cell is related to midlatitude eddies