物理海洋学 风生流动

u ( Az ) D Ru z v ( Az ) D Rv z
Stommel
Munk
1 p u 2u 2u fv ( Az ) AH 2 AH 2 x z z x y
1 p v 2v 2v fu ( Az ) AH 2 AH 2 y z z x y
Sverdrup Theory
Txz p fv x z Tyz p fu y z
Sverdrup Theory
P p dz x D x
Mx
0
P p dz y D y
My
0
D
udz
0
D
vdz
0
Txz Biblioteka Baidu0) Tx Tyz (0) Ty
Important Notes
• Stommel showed that western boundary currents are required for flow to circulate around an ocean basin when the Coriolis parameter varies with latitude. • Munk showed how to combine the two solutions to calculate the wind-driven geostrophic circulation in an ocean basin. In all cases, the current is driven by the curl of the wind stress. • The observed circulation in the ocean is very turbulent. Many years of observations may need to be averaged together to obtain a stable map of the mean flow.
Munk
AH curl zT x
4 Friction Sverdrup Balance
Sketch
Observed
Observed
Observed
Important Notes
• The theory for wind-driven, geostrophic currents was first outlined in a series of papers by Sverdrup, Stommel, and Munk. • They showed that realistic currents can be calculated only if the Coriolis parameter varies with latitude. • Sverdrup showed that the curl of the wind stress drives a northward mass transport, and that this can be used to calculate currents in the ocean away from western boundary currents.
Txz ( D) 0 Tyz ( D) 0
Sverdrup Theory
P fM y Tx x P fM x Ty y
M y curlz (T )
Stommel
• Stommel (1948) used essentially the same equations used by Sverdrup but he added a bottom stress proportional to velocity.
Wind Driven Ocean Circulation
Chapter 11
1947-1951
• A series of three remarkable papers published from 1947 to 1951.
– Harald Sverdrup (1947) – Henry Stommel (1948) – Walter Munk (1950)