|
|
|
|
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 |
|
|
|
|