Unit_3_blackbody+albedo
91d265f4-cc1b-4beb-9671-d37e575249cc
isee systems, inc.
Stella Professional
0
50
4
m
meter
kg
kilogram
yr
year
degk
degree k
j
joule
s
second
This model is a "swamp model", which assumes that the whole of the Earth's surface is covered by a layer of water of a certain depth (in this case 1 meter). This is done to simplify the model, as the Earth's surface can then be considered to have uniform conditions.
The Earth Energy reservoir contains the number of joules stored in the 1 m swamp layer.
All reservoirs are in units of joules (J).
0.0
Solar_to_Earth
Surface_heat_to_Space
j
All flows are in units of joules per year (J/yr).
The total energy striking the Earth's surface every year is determined by multiplying the value of the solar constant by the area of a disk with the same diameter as the Earth and by the fraction of energy that is not reflected back to outer space (1-albedo).
Solar_Constant*(1-Earth_Albedo)*Earth_Cross_Section
j/yr
All flows are in units of joules per year (J/yr).
Earth_Surface_Area*Stefan_Boltzmann*Temperature^4
j/yr
Temperature = Earth_Energy (J) / Heat_Capacity (J/K)
Temperature is in units of degrees Kelvin (K).
Earth_Energy/Heat_Capacity
degK
The heat capacity = Water_Depth (m) * Earth_Surface_Area (m^2) * Water_Density (Kg/m^3) * Specific_Heat_Water (J/Kg*K)
Heat_Capacity is in units of joules per degrees Kelvin (J/K).
Water_Depth*Earth_Surface_Area*Water_Density*Specific_Heat_Water
joules/degrees K
This model is a "swamp model", which assumes that the whole of the Earth's surface is covered by a layer of water of a certain depth (in this case 1 meter). This is done to simplify the model, as the Earth's surface can then be considered to have uniform conditions.
The specific heat of water = 4218.0 joules per kilograms degrees Kelvin (J/Kg*K).
4218.0
joules/(kilograms-degrees K)
The percentage of incoming solar radiation that is reflected back into space (dimensionless).
One minus this fraction is multiplied by the solar constant and the cross section of the Earth to determine the amount of energy actually absorbed by Earth's surface.
For the Earth, the albedo = 30%, however this number can be changed to represent increases or decreases in cloud and ice cover.
0.3
This model is a "swamp model", which assumes that the whole of the Earth's surface is covered by a layer of water of a certain depth (in this case 1 meter). This is done to simplify the model, as the Earth's surface can then be considered to have uniform conditions.
The density of water = 1000.0 kilograms per meters cubed (Kg/m^3).
1000.0
kilograms/meters^3
This model is a "swamp model", which assumes that the whole of the Earth's surface is covered by a layer of water of a certain depth (in this case 1 meter). This is done to simplify the model, as the Earth's surface can then be considered to have uniform conditions.
The initial assumption of depth of the layer of water ("swamp") covering the Earth is 1.0 meter. This may be changed for experimentation.
100
m
Earth_Surface_Area is in units of meters squared (m^2).
Area of a sphere = 4*PI*r^2
Earth_Surface_Area = 4*PI*(Earth_Radius^2)
4*PI*(Earth_Radius^2)
meters^2
The radius of the earth is 6371.0e3 meters (m).
6371.0e3
m
Earth_Cross_Section is in units of meters squared (m^2).
Area of a circle = PI * r^2
Earth_Cross_Section = PI*(Earth_Radius^2)
PI*(Earth_Radius^2)
meters^2
3.15576e7 seconds per year (s/yr).
3.15576e7
seconds/years
The amount of solar radiation received each year by a square meter of Earth at the Earth's average distance from the Sun.
The solar constant is in units of Watts per meters squared (W/m^2), or joules per meters squared seconds (J/m^2s). Here we multiply by the number of seconds in a year to determine the number of joules per square meter received annually.
1368.0*Seconds_per_Year
joules/(meters^2-seconds)
Stefan_Boltzmann = The Stefan Boltzmann constant {5.67e-8 (J/m^2*s*K^4)} * Seconds_per_Year (s/yr). The S-B constant relates the energy contained in a black body to its temperature.
Stefan_Boltzmann is in units of (J/m^2*yr*K^4)
5.67e-8*Seconds_per_Year
joules/(meters^2secondsdegrees K^4)
Earth_Albedo
Solar_to_Earth
Water_Depth
Heat_Capacity
Water_Density
Heat_Capacity
Specific_Heat_Water
Heat_Capacity
Earth_Surface_Area
Heat_Capacity
Earth_Radius
Earth_Surface_Area
Earth_Radius
Earth_Cross_Section
Earth_Energy
Temperature
Temperature
Surface_heat_to_Space
Seconds_per_Year
Stefan_Boltzmann
Seconds_per_Year
Solar_Constant
Temperature
Surface_heat_to_Space
Surface_heat_to_Space
Solar_to_Earth
Solar_to_Earth
Blackbody + Albedo Model (Earth Energy Model 2)
Here the blackbody model has been modified through the addition of the surface albedo to account for the fact that the Earth is not a perfect absorber of energy. Instead, a sizable portion of the incoming solar radiation is reflected back to space.
Heat_Capacity
Earth_Surface_Area
Stefan_Boltzmann
Solar_Constant
Earth_Cross_Section