Please help! I need to double check my work to make sure I have answered the que
ID: 285675 • Letter: P
Question
Please help! I need to double check my work to make sure I have answered the questions correctly. thank you!!!!
1. Earth's Radiation Balance The energy balance for a planet can be determined by the following equations: Energy emitted by planet Energy absorbed by planet Energy emitted by planet Energy intercepted - Energy reflected For the planet Earth, the following values are known: S (average solar flux)- 1368 W/m2, A (average albedo)-30% or 0.30, and (Stefan-Bolzman constant) = 5.67x 108 w m3K4 The planet Venus is closer to the sun than Earth (0.72 AU) and therefore receives more solar energy (2614 W/mr) and also has a higher albedo, with A-75% or 0.75. Venus therefore absorbs less solar energy than Earth, so Venus ought to be colder than Earth, right? But we all know Venus is MUCH hotter than Earth... a) Based on the given values and equation above, determine TE (the average surface air temperature of Earth) in units of K? Hint: It is actually unnecessary to know R since it cancels out of both sides of the equation (b) Based on the given values and equation above, determine Tv (the average surface air temperature of Venus) in units of K. (c) What you calculated in (a) and (b) are the so-called "blackbody" temperatures of Earth and Venus blackbody being something that emits or absorbs radiation with 100% efficiency at all wavelengths that Earth has an average temperature of 288 K (or 15°C) and Venus has an average temperature of 737 K (464°C). What is the difference between these value and the values you calculated in (a) and (b)? (d) Are the blackbody temperatures you calculated in (a) and (b) larger or smaller than the average actual surface air temperatures of Earth and Venus given in (c)? What explain why the actual temperatures of Earth and Venus are different than their blackbody temperatures? Is there a relationship between the hotter surface temperatures a natural mechanism exists that would d the higher albedo of Venus?Explanation / Answer
Ans a) 4×sigma×T^4=S(1-A)
T= (S(1-A)÷(4×sigma))^(1/4)
T= (1368(1-0.3)÷(4×5.67×10^(-8)))^(1/4)
T= 254.9090 K
Ans b)
T=(2614(1-0.75)÷(4×5.67×10^(-8)))^(1/4)
T= 231.6865 K
Ans c) The difference between the actual value and calculated value for Earth is 33.091 K.
The difference in case of venus is 505.3135 K.
Ans d) The presence of green house gases causes the higher actual temperatures. The atmosphere of Venus is primarily composed of CO2 which is a strong green house gas.
Yes, higher temperature causes higher outgoing radiations, as explained by stefan boltzmann law,
Energy= sigma × T^(4)
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