Consider this graph of downwelling solar and downwelling/upwelling infrared radi
ID: 107741 • Letter: C
Question
Consider this graph of downwelling solar and downwelling/upwelling infrared radiation (Links to an external site.)Links to an external site. for a surface site. If the surface temperature trend was a function of only the surface radiation budget, characterize this trend during the period from 1700 to 1900 UTC. Note: For this problem, please assume that all downwelling radiation is absorbed by the surface (albedo=0).
A. surface temperatures are slowly increasing
B. surface temperatures are slowly decreasing
C. surface temperatures are holding steady
D. the surface temperature trend cannot be determined from this data
A. surface temperatures are slowly increasing
B. surface temperatures are slowly decreasing
450 T T T T T 400 Upwe ng infrared 350 300 Downwelling infrared E 250 200 50 100 50 Downwelling solar 50 0000 0200 0400 0500 0800 1000 1200 1400 1600 1800 2000 2200 0000 Hour (UTO) Downwelling solar Downwelling infrared Upwe ng infraredExplanation / Answer
ANS - b. surface temperatures are slowly decreasing
The upwelling longwave radiation and the reflected solar radiation, on the other hand, are under no such restrictions. This gives us the opportunity to see distinguish between the hypothesis that the system responds in such a way as to counteract changes in forcing, and the consensus view that the system responds to changes in forcing by changing the surface temperature. At equilibrium, what is emitted by the earth has to equal the incoming radiation, 340 watts per meter squared (W/m2). Of this, about 100 W/m2 are reflected solar shortwave radiation and 240 W/m2 of which are upwelling longwave (thermal infrared) radiation.