Surface Energy Budget

R = - (G + H + L )

R = net solar and terrestrial radiation at the earth’s surface (+ into surface)

Absorbed solar radiation (incoming – reflected)

Incoming longwave radiation emitted by gases and clouds in the atmosphere

Outgoing longwave radiation emitted by the earth’s surface

G- storage of energy into the deep soil (- into soil)

H – heat flux into atmosphere(- into atm)

L – Latent heat flux into atmosphere ( - into atm)

Heat Storage

Soil Temperature

high intensity of solar radiation at high altitudes can result in high surface temperature

Austria- 80C humus at 2070 m; air temp at 2 m 30C

New Guinea 60C at 3480 m air temp 15C

Net Radiation

Surface Energy Budget

Solar Radiation

Slide 8

Solar Radiation- Ideal Atmosphere

Slide 10

Absorbed Solar Radiation

Absorbed solar radiation depends strongly on albedo: Abs Solar = Solar (1 – a)

Snow cover reflects solar radiation and diminishes absorbed solar radiation

Annually, snow cover at high elevation later in season than in valleys tends to cause absorbed solar radiation to diminish with elevation

Incoming Longwave Radiation

Outgoing Infrared Radiation

Stefan-Boltzmann Law: IR = esT⁴

As elevation increases:

temperature decreases, IR radiation decreases

Optical thickness of atmosphere decreases (less greenhouse gases, including water vapor), atmospheric transparency to outgoing radiation increases, more IR escapes

Emissivity (e) of snow and ice is high

Infrared Radiation: December, Austrian Alps

Net Radiation

Net Radiation = Absorbed solar radiation + downwelling IR – IR

Effect of altitude on net radiation is variable and depends most strongly on decrease with height of absorbed solar radiation

Peter Sinks

Radiation Budget on Slope

Variations in sunrise time

Influence of aspect (orientation)

Influence of slope angle

Inclination angle, valley orientation, season

Microclimates

Small topographic irregularities

Differences in slope angle and aspect

Types (Turner 1980)

Sunny windward slope (high radiation; high wind)

Sunny lee slope (high radiation; low wind)

Shaded windward

Shaded lee

Microclimates


	R = - (G + H + L )
	R = net solar and terrestrial radiation at the earth’s surface (+ into surface)
		Absorbed solar radiation (incoming – reflected)
		Incoming longwave radiation emitted by gases and clouds in the atmosphere
		Outgoing longwave radiation emitted by the earth’s surface
	G- storage of energy into the deep soil (- into soil)
	H – heat flux into atmosphere(- into atm)
	L – Latent heat flux into atmosphere ( - into atm)


	high intensity of solar radiation at high altitudes can result in high surface temperature
	Austria- 80C humus at 2070 m; air temp at 2 m 30C
	New Guinea 60C at 3480 m air temp 15C


	Absorbed solar radiation depends strongly on albedo: Abs Solar = Solar (1 – a)
			Snow cover reflects solar radiation and diminishes absorbed solar radiation
			Annually, snow cover at high elevation later in season than in valleys tends to cause absorbed solar radiation to diminish with elevation


	Stefan-Boltzmann Law: IR = esT⁴
	As elevation increases:
		temperature decreases, IR radiation decreases
		Optical thickness of atmosphere decreases (less greenhouse gases, including water vapor), atmospheric transparency to outgoing radiation increases, more IR escapes
	Emissivity (e) of snow and ice is high


	Net Radiation = Absorbed solar radiation + downwelling IR – IR
	Effect of altitude on net radiation is variable and depends most strongly on decrease with height of absorbed solar radiation


	Small topographic irregularities
	Differences in slope angle and aspect
	Types (Turner 1980)
			Sunny windward slope (high radiation; high wind)
			Sunny lee slope (high radiation; low wind)
			Shaded windward
			Shaded lee