Ozone problem Calculate the dependence of O 3 and O with altitude. In class I only showed qualitatively Use an O 2 density of n 2 (z) = n 2 (0)exp[-z/H]. Use H = 6.5 km as an average H, which of course depends on T and is different in the troposphere where there is mixing and the upper region where there is diffusion. Also use n 2 (0) = (0.21 n M ) = 0.21x (2.5x10 19 molecules/cc). Use J 2 (z) =J 2 o exp[ - 2 (z)] with J 2 o ~ 2x10 -9 /s,  2 =   2 n 2 dz with  2 = ~0.5 x cm 2. Use J 3 =J 3 o exp[-  3 (z)] with J 3 o ~10 -2 /sec and  3 =  3 n 3 dz with  3 = ~0.5x cm 2 (as in the Fig in the lecture notes). Use J 2 o and J 3 o as starting at 100km From the lecture notes: n 1 (z) =[J 2 J 3 /k 13 k 12 n M ] 1/2 n 3 = n 2 [(J 2 /J 3 ) (k 12 n M / k 13 )] 1/2 Use k 13 = 8.0 x cm 3 /s and k 12 = 6x (cm 6 /s) First calculate and plot J 2 (z). Start at 100km Then calculate and plot the product n 1 x n 3, which as you can see, and as in the notes, is independent of J 3. (Note since n 1 and n 3 are <<n 2 and J 2 <<J 3 one has to be a little careful numerically--also change km to cm, not vice versa.) Then calculate and plot n 3 and J 3 (this is more difficult because J 3 depends on the amount of n 3 above each z). At top J 3 is constant, so calculate n 3 (100km) first using J 2 o /J 3 o and then use that to calculate the reduction in J 3 due to absorption of UV photons. Go to a slightly lower z and repeat calculating the n 3 using the new J 3. Gradually integrate downwards until n 3 goes through a peak and then decreases.

Problems: Radio Waves 1. If the night time F region is at ~ 200km, what is the furthest away I can pick – up the Chicago Cubs on WGN. (Note: the earth is curved) 2. Describe how a spacecraft’s transmission at radio frequencies can be used to measure the ionosphere density vs. altitude when is passes behind a planet.

Greenhouse Use the result for the ground temperature,Tg /Te vs.  g * to get the CO2 content of the atmosphere of Venus compared to the CO2 content of the earth’s atmosphere assuming CO2 is the only greenhouse gas on each planet. Use Te and Tg from tables and assume the fraction of CO2 (and othe principal greenhouse gases) is ~1% at earth but ~100% at Venus