Please see http://modtran.spectral.com/modtran_home . Use the following parameters to generate spectral radiance values in the range 0.9um to 2.7um in 0.004um increments.
| Parameter | Value | Comment |
|---|---|---|
| Mode | Radiance | |
| Atmosphere Model | Mid-Lattitude Summer | |
| Water Column (atm-cm | 3635.9 | set automatically by choice of Atmospheric Model |
| Ozone Column (atm-cm | set automatically by choice of Atmospheric Model | |
| CO2 (ppmv) | 400 | up from 280 ppm since the start of the industrial revolution [2] |
| CO (ppmv) | 0.15 | (default) |
| CH4 (ppmv) | 1.8 | (default) |
| Ground Temperature (K) | 300 | |
| Ground Albedo | 0.15, 0.2, 0.3 | [1]. [3]. Try multiple values |
| 0.27 on average. | ||
| Aerosol Model | Rural | |
| Visibility (km) | 23km | [1] |
| Sensor Altitude | 1km, 100km, 500km | |
| Sensor Zenith | 150deg, 180deg | see note below |
Sensor Zenith = 180 degree means the satellite takes pictures at solar zenith. MODTRAN uses the figure below left to define Sensor Zenith) In general, the viewing situation is described by two angles (see right).
After pressing “RUN”, MODTRAN will generate two plots. The plot showing spectral radiance is of interest to us.
To access the numerical values for this plot (which is what we need to do actual calculations), run “Inspect Element” (right click on webpage > Inspect)
Once you have that docs_json variable copied over, find the properties under the names “x” and “y” with a list of numbers following them- this corresponds to the wavelength and radiance values, respectively.
Plot it and save the numerical data in such a way that preserves the parameters with which the data was obtained. (E.g., a simplified JSON file without all the extraneous formatting details used by MODTRAN).
I would like you to try different values of albedo (0.15, 0.2, 0.3), different satellite altitudes (1km, 100km, 500km), and different solar zenith angles (180 deg, 150deg). Please compile the results of this numerical investigation below.