Proccess Module _ Test 1 Flashcards
2 types of radiation
Shortwave (K) and Longwave (L)
Longwave radiation
Low frequency, low energy
Earth emits, 5-25 um
Shortwave Radiation
High frequency, high energy
Emitted by sun , <2 um
visible light makes up 45%
Stefan Boltzman Equation
E=oT^4
Weins Law
max wavelength
Spectral Plot
shows how much energy is being produced at each wavelength.
- can calculate total energy by adding area under the curve.
2 controls on shortwave radiation
- Large-scale : lattitude, axial tilt, seasons
- Local scale : time of day, slope, albedo
Clouds affect on planetary warming
Low Clouds: cooling
- reflect large amounts of solar radiation back but do little to change L up b/c their tops are relatively warm (low)
High Clouds: warming
- reflect some K, reduce L up b/c tops are cold(high) thus trap energy in earths system.
Pressure
force per unit area
Force
mass x acceleration
where does atm pressure come from ?
F(column air) = m (column air) x g
- must consider the mass of column of air above a pt, does not have to be the surface
Density
increases toward surfaces
surface air pressure
weight of air in the column above unit area
Distribution of Pressure with elevation
very strong vertical gradient
P drops 500 hPa(mb) in less than 10 km
What is the atm made of
O2 - 21%
N2 - 78%
Ar - small
Water vapour - variable gas (GHG)
- relative proportions are very consistent w/in the atm
What is avg. sea level pressure?
101326 Pa
1013.26 hPa
1013.26 mb
Or
101326 N/m2
Horizontal distribution of Pressure?
Pressure varies over horizontal space
P is a function of T (PV=T)
- variations in T result in changes in P
“static relationship”
Horizontal pressure gradients are much smaller than vertical
Isobars
black lines on a chart
connects points of equal mean sea level Pressure
Gradient
an amount of change over an amount of distance
(series of lines on a chart)
gradient = rate of change = delta P/delta T
Pressure Gradient Force
force that pushes air into motion
if delta P is large, PGF large
= gradient
occurs over equator - air moves from H to L
Coriolis Force
deflects winds to the right in the N.hem, to the left in the S. Hem
0 at equator
1 at N pole, -1 at S pole
balance results in winds flowing parallel to isobars
Geostropic Flow
winds flowing parallel to isobars due to the balance btw the Coriolis and PGF
Equation for Coriolis
CF= V2 *U * sin0
Friction Force
- not a true force
acts to reduce velocity near the surface - weakens Coriolis causing cross isobaric flow
