Formulation of the Homogeneous Model
31
~·~~~~~~~~JTI]:][ITJJG~~~][~~~~:JIJJJ~;;~~--~~~~fMI"~
60"
30"
o•
30"
60"
60"
120"£
110"
120"W
60"
o•
Fig. 2.2.3. Estimate of the Ekman pumping by Hellerman and Rosenstein (1983) for average January
conditions (upper panel) and average July conditions (lower panel) . The Cross-hatching areas of
downward Ekman pumping stronger than 2x 10- 4 cmfs, slant-hatching downwelling weaker than
that; stippling, areas of Ekman upwelling
zero Ekman pumping line is often considered. The Ekman pumping is negative
in this idealization of the subtropical gyre. If the latitudinal extent of the basin
is 0 ~ y ~ L , the Ekman pumping is frequently idealized in the calculations
that we consider in the form:
WE= -Wosin( 7').
(2.2.12)