1. South North East West Sunrise Sunset Azimuth Angle (From South) Altitude altitude angle horizontal surface perpendicular to surface zenith angle Sun Figure 4.1 Ecological Climatology © 2008 G. Bonan

2. Winter Solstice North East West South 26.5 o Sunrise Sunset Summer Solstice South North East West Sunrise Sunset 73.5 o Figure 4.2 Ecological Climatology © 2008 G. Bonan

3. Winter Solstice December 21-22 66.5 o 23.5 o Equator South Pole North Pole Autumnal Equinox September 22-23 NH: Summer SH: Spring NH: Autumn Vernal Equinox March 21-22 Summer Solstice June 21-22 NH: Winter SH: Summer NH: Spring SH: Autumn SH: Winter 146 million km 151 million km 149 million km 148 million km Tropic of Capricorn (23.5 o S) Tropic of Cancer (23.5 o N) Declination Earth Sun Figure 4.3 Ecological Climatology © 2008 G. Bonan

4. -30 -20 -10 0 10 20 30 Declination Angle Vernal Equinox Autumnal Equinox Summer Solstice Winter Solstice JanFebMarAprMayJunJulAugSepOctNovDec Figure 4.4 Ecological Climatology © 2008 G. Bonan

5. 1.00 2.00 30 o Zenith Angle = 0 o Zenith Angle = 60 o North Pole South Pole Equator 0 10 20 30 40 50 60 70 80 90 100 0102030405060708090 Zenith Angle (degrees) Percent 0102030405060708090 Altitude Angle (degrees) Figure 4.5 Ecological Climatology © 2008 G. Bonan

6. 0 200 400 600 800 1000 1200 1400 03691215182124 Time of Day (hours) Solar Radiation (W m -2 ) 15  30  00 45  03691215182124 Time of Day (hours) 75  60  75  60  Figure 4.6 Ecological Climatology © 2008 G. Bonan

7. Figure 4.7 Ecological Climatology © 2008 G. Bonan

8. Figure 4.8 Ecological Climatology © 2008 G. Bonan

9. Absorbed By Atmosphere 350 W m -2 Incoming Solar Radiation 342 W m -2 Reflected Solar Radiation 107 W m -2 Reflected By Atmosphere 77 W m -2 Reflected By Surface 30 W m -2 Absorbed By Atmosphere 67 W m -2 Outgoing Longwave Radiation 235 W m -2 Emitted By Atmosphere 195 W m -2 Emitted By Surface 390 W m -2 Back Radiation 324 W m -2 Atmospheric Window 40 W m -2 Latent Heat 78 W m -2 Sensible Heat 24 W m -2 Absorbed By Surface 168 W m -2 Figure 4.9 Ecological Climatology © 2008 G. Bonan

10. Figure 4.10 Ecological Climatology © 2008 G. Bonan