(The solar constant is the amount of sunlight hitting the Earth per square meter
ID: 109775 • Letter: #
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(The solar constant is the amount of sunlight hitting the Earth per square meter. You can define the square meter to be of the Earth’s surface (which is a sphere), or of a flat disk with the same radius of the Earth facing directly towards the sun. Since I specified (Q0/4) in the question, the solar constant here is per square meter of the Earth’s surface, which is the value used in the diagram.)
2.) What is the longwave radiation emitted by the surface (in Wm-2)?
(This is the value given by “thermal up surface”)
3.) What is the "greenhouse forcing" - the difference between the radiation that would be emitted to space if there were no atmosphere (but the same surface temperature), and the terrestrial radiation emitted by the planet currently? Units are Wm-2, and the number should be positive, rounded to the nearest whole number.
(Here I asked you for the “greenhouse forcing” but told you exactly what to do. The radiation that would be emitted to space if there were no atmosphere but the same surface temperature is the emission from two steps ago. The current emitted radiation is given on the figure (thermal outgoing TOA). The answer is the difference between these two. This is effectively the amount of radiation the atmosphere prevents from getting to space.)
4.) What is the current energy imbalance at the top of the atmosphere? Units are Wm-2; use a positive number if the imbalance is currently warming the planet, use a negative number if cooling the planet.
(The “source” of energy to the Earth is the incoming solar TOA. The “sinks” are solar reflected TOA and thermal (terrestrial) outgoing TOA. The current imbalance is the difference between the two.
This extra energy is due to anthropogenic greenhouse gases. It is warming that has not yet increased the Earth’s temperature. It is warming in the “pipeline”, so to speak. Because the Earth has not had time to adjust to the increased greenhouse gases, the Earth must warm enough to offset this pipeline warming, even if greenhouse gas concentrations were held constant.)
solar reflected TOA thermal outgoing TOA incoming Units (Wm2) solar TO 340 (340, 341) 100 (96, 100 239 (236, 242) atmospheric indow 79 4,9 greenhouse gases latent heat solar absorbed atmosphere solar down surface 185 solar reflected surface (179, 189) (22 :: 161 (154, 166) 84 20 (70, 85) (15, 25) 398 (394, 400) 342 (338, 348) imbalance 0.6 thermal up surface thermal down surface solar absorbed evapo- sensible surface ration heatExplanation / Answer
Answer- The solar constant defined the rate at which solar energy reaches the surface of the earth. the value of solar constant is 1388 watt per meter square. it is mean of solar electromagnetic radiation per unit area.
Answer- the value of outgoing longwave radiation from the earth surface is 398 W-m2. this is amout of solar energy that is emitted from the earth surface in the form of outgoing longwave radiation.
Answer- greenhouse forcing may be defined is influence of presence of greenhouse gases in the atmosphere that can shift or change the climate. these gases are transparent to incoming short wave solar radiation and opaque to outgoing longwave radiation. if there is no atmosphere then radiation that would be emitted from earth surface will be 398 watt-m2. but there is presence of atmosphere also there is presence of greenhouse gases like carbon dioxide, methane, water vapour, etc. so the amount of radiation that will emitted from the atmosphere to outer space is 239 watt-m2. the difference between 398-239 = 159watt-m2
Answer- Climate change due to presence of greehouse gases present at the top of atmosphere ( in the layer of stratosphere) create the energy imbalance at the top of the atmosphere.that is 56 watt-m2
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