Geoscience Reference
In-Depth Information
Plate 3.3
Average snow cover and sea ice extent in the Northern Hemisphere for the months of February, April,
June, August, October and December derived from weekly data for the period 1978-2007.
Source: National Snow and Ice Data Center (NSIDC), Boulder, Colorado (courtesy Mary Jo Brodzik, NSIDC).
Percentage of energy
234568 0
15
20
30 40
60 80 100
10
400
20
Visible part
Total
energy
30
40
300
Infrared
Visible
part
only
50
60
200
70
80
0.1m
90
1m
100
10m
100m
100
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
Wavelength
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5 ยต
Figure 3.14
Schematic representation of the energy spectrum of the sun's radiation (in arbitrary units) that
penetrates the sea surface to depths of 0.1, 1, 10 and 100m. This illustrates the absorption of infrared radiation by
water, and also shows the depths to which visible (light) radiation penetrates.
Source: From Sverdrup (1945). Courtesy of Allen & Unwin.
