Geoscience Reference
In-Depth Information
(a)
90°N
200
200
200
60°N
240
240
240
280
280
280
320
320
320
360
360
360
30°N
400
400
400
Equator
400
360
320
280
240
200
400
400
360
320
280
240
200
30°S
360
320
280
60°S
240
200
90°S
30°E
60°E
90°E 120°E 150°E 180° 150°W 120°W 90°W 60°W 30°W 0°
(b)
90°N
80
80
80
120
120
60°N
120
160
160
160
200
200
240
240
240
30°N
280
240
320
280
280
280
280
320
280
320
320
320
320
Equator
320
280
280
320
280
30°S
280
280
240
240
240
200
200
200
160
160
160
60°S
120
120
80
120
80
80
90°S
30°E
60°E
90°E 120°E 150°E 180° 150°W 120°W 90°W 60°W 30°W 0°
Figure 5.5 Climatology of (a) incident solar radiation and (b) solar radiation
absorbed at the top of the atmosphere. Contour intervals are 20 W/m 2 .
0.08 which is accurate only for solar zenith angles of less than about 40°. At
higher zenith angles, the albedo of water drops significantly as illustrated in
Figure 5.7. In the late afternoon or early morning, many of us have experienced
a strong glare from water standing on a road, or from the open water of a
lake near sunrise or sunset. This albedo effect is most pronounced under clear-
sky conditions, when much of the solar radiation remains in the direct solar
beam. Since the annually averaged zenith angle is smaller close to the equator, a
higher fraction of the incident solar radiation is absorbed at low latitudes. This
effect causes the latitudinal gradients in the planetary albedo over the oceans
in middle latitudes (see Fig. 5.6 ).
 
Search WWH ::




Custom Search