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.

2

Mid-Latitude Summer * Default value
Default H2O content: 2.93 g·cm-2. Default O3 content: 0.319 cm-atm.

3

Mid-Latitude Winter *
Default H2O content: 0.853 g·cm-2. Default O3 content: 0.395 cm-atm.

4

Sub-Arctic Summer *
Default H2O content: 2.1 g·cm-2. Default O3 content: 0.48 cm-atm.

5

Sub-Arctic Winter *
Default H2O content: 0.419 g·cm-2. Default O3 content: 0.48 cm-atm.

6

1976 US Standard *
Default H2O content: 1.42 g·cm-2. Default O3 content: 0.344 cm-atm.

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.

<0

User-input model(s)
User-defined profiles described by the altitude (in km), pressure (in mbar), temperature (in K), and gas concentrations (e.g., H2O, O3, in cm-3).

See here for further information.
Note yet implemented

* Same model atmospheres from (McClatchey et al., 1972 and Anderson et al., 1986) 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 CO2, O3 and H2O. Additional trace gas concentrations can also be overwritten through the remaining Trace Gases variables.

References