Problem Session 5 [11/4/96]

For the next 3 Problem Sets you will need some 1-D profiles of trace gases that are relatively long-lived in the atmosphere. They are given below.

       z    CH4    N2O     H2O    NOy
      (km) (ppmv) (ppbv)  (ppmv) (ppbv)
      
       50   0.2      7      5.5    11
       45   0.2     11      5.4    13
       40   0.3     21      5.2    15
       35   0.5     44      4.8    17
       30   0.7     90      4.4    17
       25   0.9    150      3.9    14
       20   1.3    230      3.3     7
       15   1.6    300      2.9     1.6
       10   1.7    315     36       ?
        5   1.7    315   1000       ?
        0   1.7    315  14000       ?

        ? - to be determined during class
       CH4-B&S,Appendix D
       N2O-B&S,Appendix D
       H2O-B&S,Appendix D
       NOy-B&S,Appendix D

For PS5 , you include the HxOy reactions [R8 - R15 from the Reaction Table on the Class Webpage] in your numerical solution for Stratospheric O3 and O. Use the family approximations [Ox, HOx, and H2O2] for this problem and solve for the steady-state concentrations of O3, O, OH, HO2 and H2O2 for the stratospheric levels, 50km - 20km.

Based on your solutions, answer the following questions:

1. First, show your O3 vertical profile and compare it to the profile from PS4.
2. What is the impact of the added HxOy reactions on Stratospheric O3?
3. Where do the added reactions have the biggest impact?
4. Which of the new reactions has the biggest impact on stratospheric O3?

PS5 will be due in 1 week [11/11/96]. It is important that you keep up with the assignments, since they are going to start rapidly building on each other. Next week we will add NOy chemistry in PS6 and CH4 chemistry will be added the following week in PS7. The model will be solved for both the stratosphere and troposphere in PS7.

It is our intention that everyone have a working stratosphere-troposphere chemical box model before Thanksgiving!