60 likes | 280 Views
THE RADIATION BUDGET (Exercise). Exercise: Monitor radiation budget at 2 sites (urban rural) using instruments. RADIATION BUDGET: Balance between incoming energy from the sun (SWR) and the outgoing long-wave (LWR) and reflected shortwave energy from the Earth. R = INPUT – OUTPUT
E N D
THE RADIATION BUDGET (Exercise) Exercise: Monitor radiation budget at 2 sites (urban rural) using instruments
RADIATION BUDGET: Balance between incoming energy from the sun (SWR) and the outgoing long-wave (LWR) and reflected shortwave energy from the Earth. R = INPUT – OUTPUT R = SWR + LWR - SWR - LWR
R (Net Radiation) in W m-2 Energy available for us, vegetation, environmental processes (ex: heat the air) • (Q+q): total solar radiation in W m-2 • a : albedo (no dimension) • I : outgoing LWR (W m-2) • I : atmospheric counter radiation (absorbed by the surface)
MEASUREMENT OF SOLAR RADIATION AND ALBEDO Instrument: Pyranometer (Q+q) total solar radiation: direct measurement with pyranometer right side up Albedo: a = [(Q+q) a] / (Q+q) Reflected solar radiation (pyranometer upside down)
MEASUREMENT OF OUTGOING LONG WAVE RADIATION Instrument: Infrared thermometer (“gun”) I = T4 Boltzmann constant T in °K Ts: Target temperature associated with the surface Te: Target temperature associated with sky and sorrounding environment