Problem Session 2 [9/24/96]

1. I hope platform differences have now been overcome. You can pick up the problem and data from our class webpage for this assignment. I will also hang the data on anonymous ftp. Instructions for its use follow below.
2. Generic instructions for picking up files at GFDL:

   ftp to ftp.gfdl.gov

   lgn: anonymous

   psswd: your e-mail address

   cd geo537/outgoing

3. Capture the O3 [Ozone] data file BaSO3.dat, a formatted [2E10.3] set of O3(ilev) mixing ratios and z(ilev) heights [cm] from B&S.

4. The next step is to get the flux and cross-section data for O2 and O3. This is found in PS2_rad.dat, which is a formatted array of #of data [n]; wave length [wv in nm]; solar flux [flux in photons/cm2sec]; O2 cross-section [sigmaO2 in cm+2]; O3 cross-section [sigmaO3 in cm+2]. The format for the array is format(i4,f7.2,3e14.7). You can either take the radiation data array from the website or pick it up on GFDL's anonymous ftp site. Note that the first line in the data file contains the heading and is not data. You can either remove this line or read around it outside of the DO loop you will set up to read the 132 lines of data. A sample code to read the data is given below:

   -------open(unit=3, file='PS2_rad.dat', status='old')

   -------read(3) *

   -------do 1 = 1, 132

   -------read(3,15) i,wv(i),flux(i),so2(i),so3(i)

   ---15 --format(i4,f7.2,3e14.7)

   -------endo

5. The final step, a big one, is to calculate I(Z,wv), the direct beam solar flux that has been attenuated by O2 and O3 absorption as it travels down to Z, for the 11 heights and all 132 wavelength intervals [wv]. We would like to see a reduced table of your results for all 11 values of Z and for these 6 values of wv [ 200nm, 250nm, 350nm, 450nm, 550nm, 650nm]. We would prefer a plot of I(Z,wv)/flux(wv), but a table is OK, if you have trouble with the plot.

Good luck and CU at 4.

Lori Perliski and Chip Levy