The variable H2OSTR overwrites the predefined H2O total column concentration from the selected atmospheric model in
MODEL by the user input H2OSTR value in [g·cm-2].
Typical worldwide and annual H2O concentrations range from 1 g·cm-2 to 6 g·cm-2, with typical mean values
around 3 g·cm-2.
Alternatively, negative values of H2OSTR are used as a scale-factor over the selected atmospheric MODEL.
As such, H2OSTR=-1 (default value) uses the predefined atmospheric model H2O
concentration.
In MODTRAN5, the water number density at each profile altitude will not be increased above 100% relative humidity (RH) or by more than 5 times the original value. When the 100% RH limit is reached, the water is distributed to other levels to the extent possible to achieve the input water column.
Atmospheric transmission curve calculated using MODTRAN v4.2
for a 1976 US Standard atmosphere.