A comparative study of radiation balance above forest and grassland

✍ Scribed by C. J. Moore

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 594 KB
• Volume: 102
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710243416

✦ Synopsis

Abstract

Daily net radiation above a Pinus radiata plantation was found to exceed that measured above nearby grassland by about 12% during the winter and 24% during the summer months. This difference was related to differences in the albedo and net longwave radiation associated with the surface temperature of each vegetation. Forest albedo was found to be 0.11 ± 0.001 throughout the winter and did not exhibit a significant diurnal variation. The grassland albedo was found to give the usual diurnal trend and a mean winter albedo of 0.27 ± 0.03 which decreased to 0.24 ± 0.01 in summer, consistent with increasing solar elevation.

Hourly values of net radiation R~n~ above the forest during daylight hours were found to exceed those for grassland by about 15% during the winter and about 25% during the summer. When the forest was wet and the change in canopy heat storage Q and ground heat flux G were small, such differences also applied to the energy (R~n~—G—Q) available for evaporation. However, when the canopy was dry, values of Q during the day were sufficiently large to reduce the forest available energy to about that of the grassland. This forest canopy energy was generally lost during the night.