Transcript images7

Single cell model: simple but not good enough, e.g., our surface winds do
not flow N-S.
We really do need to include Earth’s rotation and land masses in a more
complex model
convective cell
sun
Unequal heating of
surface by the Sun
(the beginning of
ALL weather).
Uneven energy
input is
redistributed by
atmosphere and
oceans
convective cell
Fig. 7-15, p.182
Three cell model: much better, but not perfect.
Here we “allow” rotation, but still have ocean-covered planet.
Land masses obscure this predicted three-cell pattern.
Predicted surface winds after PGF and
CF included
Must be an odd number of cells: what goes up at beginning of first cell must be “balanced”
by what comes down at end of last cell.
Could be 1, 3, 5, etc. Three on Earth dictated by rotation speed. On Venus, where rotation is
very slow, only one cell develops.
Fig. 7-16, p.183
Minot, N. Dakota (48 N)
westerlies
Tucson, Arizona (32 N)
easterlies
Fig. 7-15b, p.182
Subpolar low
Subtropical high
Equatorial low
Subtropical high
Subpolar low
(shows up as a
trough, as predicted)
Fig. 7-17a, p.184
Pacific H has moved N.
and W. allowing sinking,
warming air to subside
along Pacific coast
Bermuda H. has moved
S. and W. driving air to
thermal low over AZ and
setting up conditions for
monsoons
For more about the monsoon see
http://www.wrh.noaa.gov/twc/monsoon/monsoon.php
Fig. 7-17b, p.185
Fig. 7-18, p.186
Elevated inversion due to sinking air from Ferrel cell,
which warms as it compresses on the way down to
the surface (see Fig. 12.12).
Fig. 7-19, p.187
During summer, the eastern edge of the Pacific High
is well situated to force sinking warming air down
over Los Angeles causing a strong elevated
inversion that prevents convection and clouds/rain
(see Fig. 7.17b).
Fig. 7-20, p.187
Polar low
Fig. 7-21, p.187
Fig. 7-22, p.188
Fig. 7-23, p.189
For us, the following are the most important ocean currents:
1) Gulf Stream
2) North Atlantic Drift
3) Newfoundland Current
9) South Equatorial Current
16) California Current
17) Peru (Humbolt) Current
Fig. 7-24, p.190
Table 7-2, p.190
Cold CA current
If the CA current brings
cold water down from
Alaska then why is the
coldest water halfway
down the coast and
not further north?
Answer – upwelling.
Fig. 7-25, p.191
Coriolis “force” causes ocean
current to deflect to the right, i.e.,
offshore
Upwelling of very cold water from
the bottom of the Pacific is evident
off San Francisco
Fig. 7-26, p.191
ENSO = El Nino/Southern Oscillation (in atmospheric
pressure and wind direction)
Fig. 7-27, p.193
97/98 El Nino animation:
http://www.cdc.noaa.gov/map/clim/sst_olr/old_sst/sst_9798_anim.shtml
Current sea surface temperature animation:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstanim.html
“Temperature anomaly” scale
Fig. 7-28, p.194
Very weak ENSO this winter:
warmer/wetter conditions to SE
AZ
Fig. 7-29, p.195
Table 7-1, p.168