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

RADIATION BUDGET

• 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 constantT in °K

Ts: Target temperature associated with the surfaceTe: Target temperature associated with sky and sorrounding environment