MODEL

Atmospheric profile model

Attributes

integer | discrete | dynamic | unit-less | basic

Description

The variable MODEL selects among one of the six geographical-seasonal model atmospheres, a gas-free atmosphere or specified atmosphere model from radiosonde data, thus defining the vertical structure of the atmosphere in terms of pressure, temperature and gas concentration (specifically H2O and O3). The available options are shown in the Table below:

Value(s)Description

1

Tropical *
Default H2O content: 4.12 g·cm-2. Default O3 content: 0.247 cm-atm. Default wind speed: 4.1 m·s-1

2

Mid-Latitude Summer * Default value
Default H2O content: 2.93 g·cm-2. Default O3 content: 0.319 cm-atm. Default wind speed: 4.1 m·s-1

3

Mid-Latitude Winter *
Default H2O content: 0.853 g·cm-2. Default O3 content: 0.395 cm-atm. Default wind speed: 10.29 m·s-1

4

Sub-Arctic Summer *
Default H2O content: 2.1 g·cm-2. Default O3 content: 0.48 cm-atm. Default wind speed: 6.69 m·s-1

5

Sub-Arctic Winter *
Default H2O content: 0.419 g·cm-2. Default O3 content: 0.48 cm-atm. Default wind speed: 12.35 m·s-1

6

1976 US Standard *
Default H2O content: 1.42 g·cm-2. Default O3 content: 0.344 cm-atm. Default wind speed: 7.2 m·s-1

0

No Gas Absorption
A synthetic atmosphere where all gas concentrations are reduced to 0. In this atmosphere, absorption is only due to suspended particles. Default wind speed: 6.9 m·s-1

<0

User-input model(s)
User-defined profiles described by the altitude (in km), ressure (in mbar), temperature (in K), and gas concentrations (e.g., H2O, O3, in ppmv) at 50 layers. Default wind speed: 6.9 m·s-1

See here for further information.

* Same model atmospheres from (McClatchey et al., 1972) as implemented in 6SV code.


Altitude vs temperature profiles for the default MODTRAN atmospheric models. Source: MODTRAN site


Altitude vs H2O and O3 concentration (left and right respectively) profiles for the default MODTRAN atmospheric models. Source: MODTRAN site

This variable, therefore, has an impact on the simulation of the absorption-scattering processes at various altitudes in the sun-target-sensor optical path.

The predefined columnar content of CO2, O3 and H2O in each model can be overwritten respectively by the key input variables CO2MX, O3STR and H2OSTR.

References

  • McClatchey, R.A., Fenn, R.W., Shelby, J.E.A., Volz, F.E., & Garing, J.S., (1972), "Optical properties of the atmosphere." 3rd Ed., Tech. Rep. AFCRL72-0497, 108 pp. Air Force Geophysics Laboratory, Hanscom AFB, Mass.