Geoscience Reference
In-Depth Information
200
160
120
80
40
0
1700
1710
1720
1730
1740
1750
1760
1770
1780
1790
1800
200
160
120
80
40
0
1800
1810
1820
1830
1840
1850
1860
1870
1880
1890
1900
200
160
120
80
40
0
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
Figure 3.2
Yearly sunspot numbers for the sun's visible surface for the period 1700-2005.
Sources: Reproduced by courtesy of the National Geophysical Data Center, NOAA, Boulder, Colorado.
