How to make an atmospheric model in 47 easy steps.
Find MODTRAN and start it
The PcModwin 4.0 icon should be on the desktop, and you double
click on it to get1.psd
Configure model input data
Select Modtran Input-> Model Atmosphere (1)3.psd
Model atmosphere parameters
Select model Atmosphere->1976 U.S. StandardSelect Type of
Atmospheric Path -> Slant PathSelect Mode of Execution ->
Transmittance5.psd
Hit Next!
Atmospheric Column parameters hit Next!Aerosols (note that were
using Rural, with 23 km visibility) Hit Next6.psd7.psd
Geometry and Spectral Band (3)lots to do here
Many path types, use defaultObserver height 60 kmFinal Height 0
kmZenith Angle 180 degreesInitial Frequency 0.5 micronsFinal Freq
2.9 micronsNext!8.psd
Sanity check diagram
The model parameters are reproduced here to make sure that the
program is configured correctly.Model parameters at topNote diagram
showing viewing geometry9.psd
Run the model
Select Run Model-> Run ModtranWait.Hit any key to
continue10.psd11.psd
Plot that puppy.
Select Plot -> InteractiveSelect MODOUT2Change X-axis to
Micrometers, hit okay21.psd22.psd23.psd
Wait for it to plot twice
Now we have a plot of transmissivity in the VNIR, and you can
answer the questions in lab. Oh wait, perhaps a little more
direction would be helpful.First trick. Clicking on the plot will
show the X and Y location youve clicked on the upper left corner.
This is probably all you need to answer the first
question.26.psd
More Plotting Tricks
If youre one of those types who has to have the exact answer, you
can adjust the plotting parameters as you like.Select Plot->Edit
PlotFor example:
Autoscale: OFF
Min X=1, Max X=1.1
X Decimal = 2 (you might have to fiddle with X Divisions too) will
yield27.psd
A Beautiful Butterfly of a Plot
So that you can get ridiculously exact about answering the
questions in the lab.For example:
Autoscale: OFF
Min X=0.938,
Max X=0.946
X Decimal = 5 will yield the plot on the next page29.psd
Still more plotting tricks
There are also ways to plot one data set over another, and various
other things that you should mess around with, but first answer the
first question in the lab. Then go to the next page to do the
tropical model, and answer those questions.
Tropical Model
Click on Card1 InputWhich brings up the dialog box Model
Atmosphere(1)Select Model Atmosphere-> Tropical ModelHit okay,
and run the model again. Plot it and fill in the blanks on the
answer sheet for Tropical model.45.psd
