CIRA-86 Atmosphere Model

Implement mathematical representation of 1986 CIRA atmosphere

Libraries:
Aerospace Blockset / Environment / Atmosphere

Description

The CIRA-86 Atmosphere Model block implements the mathematical representation of the 1986 Committee on Space Research (COSPAR) International Reference Atmosphere (CIRA). The block provides values for mean temperature, pressure, and zonal wind speed for the input geopotential altitude.

The CIRA-86 Atmosphere Model block port labels change based on the input and output units selected from the Units list.

Limitations

• This block uses a corrected version of the CIRA data files provided by J. Barnett in July 1990 in ASCII format.

• This block has the limitations of the CIRA 1986 model.

• The CIRA 1986 model that CIRA-86 Atmosphere Model implements limits values to latitudes of 80 degrees S to 80 degrees N on Earth and geopotential heights of 0 to 120 kilometers. The CIRA-86 Atmosphere Model block clips output beyond these ranges.

The CIRA 1986 model data also has missing data points.

• In each monthly mean data set, the model omits values at 80 degrees S for 101,300 pascal or 0 meters, because these levels are within the Antarctic land mass.

• In the annual mean data set for latitudes 70, 75, and 80 degrees S, the model also omits these values:

• 101,300 and 78,895 pascal

• 0 and 2,500 meters

As a result of the missing data points, input for pressures above 61,441 pascal or geopotential heights below 5000 meters at these latitudes generate `NaN` output.

For zonal mean pressure in constant altitude coordinates, pressure data is not available below 20 km. This value is the bottom level of the CIRA climatology.

When the CIRA-86 Atmosphere Model block detects an out-of-range input, the block uses the Action for out-of-range input parameter to determine the block behavior.

Ports

Input

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Contains the latitude in degrees (limited to +/-80 degrees).

Data Types: `double`

Contains an `m` array of either:

• Geopotential heights in selected length units (Coordinate type is `GPHeight`)

• Pressures in selected pressure units (Coordinate type is `Pressure`)

Data Types: `double`

Output

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Mean temperature, specified as an array, in selected units.

Data Types: `double`

`m` array of either:

• Pressures in selected pressure units (Coordinate type is `GPHeight`)

• Geopotential heights in selected length units (Coordinate type is `Pressure`)

Data Types: `double`

Mean zonal winds, specified as an array, in selected units.

Data Types: `double`

Parameters

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Input and output units, specified as:

Units

Height

Temperature

Speed of Sound

Air Pressure

Air Density

`Metric (MKS)`

Meters

Kelvin

Meters per second

Pascal

Kilograms per cubic meter

```English (Velocity in ft/s)```

Feet

Degrees Rankine

Feet per second

Pound-force per square inch

Slug per cubic foot

```English (Velocity in kts)```

Feet

Degrees Rankine

Knots

Pound-force per square inch

Slug per cubic foot

Programmatic Use

 Block Parameter: `units` Type: character vector Values: ```'Metric (MKS)'``` | ```'English (Velocity in ft/s)'``` | ```'English (Velocity in kts)'``` Default: ```'Metric (MKS)'```

Coordinate type representation, specified as:

• `Pressure`

Indicates pressure in pascal.

• `GPHeight`

Indicates geopotential height in meters.

Programmatic Use

 Block Parameter: `ctype` Type: character vector Values: `'GPHeight'` | `'Pressure'` Default: `'GPHeight'`

Mean value types, specified as:

• `Monthly`

Indicates monthly values. If you select `Monthly`, you must also set the Month parameter.

• `Annual`

Indicates annual values. Valid when Coordinate type has a value of `Pressure`.

Dependencies

Setting this parameter to `Monthly` enables the Month parameter.

Programmatic Use

 Block Parameter: `mtype` Type: character vector Values: `'Monthly'` | `'Annual'` Default: `'Monthly'`

Month in which the mean values are taken.

Dependencies

This parameter is enabled when Mean value type is set to `Monthly`.

Programmatic Use

 Block Parameter: `month` Type: character vector Values: `'January'` | `'February'` | `'March'` | `'April'` | `'May'` | `'June'` | `'July'` | `'August'` | `'September'` | `'October'` | `'November'` | `'December'` Default: `'January'`

Out-of-range block behavior, specified as:

ActionDescription

`None`

No action.

`Warning`

Warning in the Diagnostic Viewer, model simulation continues.

`Error` (default)

Error in the Diagnostic Viewer, model simulation stops.

Programmatic Use

 Block Parameter: `action` Type: character vector Values: `'None'` | `'Warning'` | `'Error'` Default: `'Warning'`

References

[1] Fleming, E. L., Chandra, S., Shoeberl, M. R., Barnett, J. J., Monthly Mean Global Climatology of Temperature, Wind, Geopotential Height and Pressure for 0-120 km, NASA TM100697, February 1988.

Version History

Introduced in R2007b

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