Aerospace Toolbox

atmoscira - Use COSPAR International Reference Atmosphere 1986 model

Syntax

[T alt zwind] = atmoscira(lat, ctype, coord, mtype, month, action)

Description

[T alt zwind] = atmoscira(lat, ctype, coord, mtype, month, action) implements the mathematical representation of the Committee on Space Research (COSPAR) International Reference Atmosphere (CIRA) from 1986 model. The CIRA 1986 model provides a mean climatology of temperature, zonal wind, and geopotential height or pressure with nearly pole-to-pole coverage (80 degrees S to 80 degrees N) for 0 to 120 kilometers, encompassing the troposphere, middle atmosphere, and lower thermosphere. You can use this mathematical representation as a function of pressure or geopotential height.

Inputs for atmoscira are:

`lat`	An array of `m` geopotential heights, in meters.
`ctype`	A string to determine representation of coordinate type. Specify: `'Pressure'` Uses pressure in pascal. `'GPHeight'` Uses geopotential height in meters.
`coord`	Depending on the value of `ctype`, this argument specifies one of the following arrays: `m` pressures in pascal `m` geopotential height in meters
`mtype`	A string that selects one of the following mean value types: `'Monthly'` Monthly values. This is the default. `'Annual'` Annual values. Valid when `ctype` has a value of `'Pressure'`.
`month`	A scalar value that selects the month in which the mean values are taken. This argument applies only when `mtype` has a value of `'Monthly'`. Valid are `1` (January) through `12` (December). The default value is `1`.
`action`	A string to determine action for out-of-range input. Specify if out-of-range input invokes a `'Warning'`, `'Error'`, or no action (`'None'`). The default is `'Warning'`.

Outputs calculated for the CIRA 1986 model are:

T

An array of temperatures.

If m is 'Monthly', an array of m temperatures, in kelvin.
If mtype is 'Annual', an array of m-by-7 values. See T Array if mtype is Annual for a description of the values in this array.

alt

If mtype is 'Monthly', an array of m geopotential heights or m air pressures.

If ctype is 'Pressure'
This is an array m geopotential heights.
If ctype is 'GPHeight'
This is an array m air pressure.

If mtype is 'Annual', an array of m-by-7 values for geopotential heights . This array is defined only for the northern hemisphere (lat is greater than 0). See alt Array if mtype is Annual for a description of the values in this array.

zwind

An array of zonal winds:

If mtype is 'Monthly'
This is an array in meters per second
If mtype is 'Annual', an array of m-by-7 values. See zwind if mtype is Annual for a description of the values in this array.

T Array if mtype is Annual

If mtype is 'Annual'
This is an array of m-by-7 values. These values are:
- Annual mean temperature in kelvin
- Annual temperature cycle amplitude in kelvin
- Annual temperature cycle phase in month of maximum
- Semiannual temperature cycle amplitude in kelvin
- Semiannual temperature cycle phase in month of maximum
- Terannual temperature cycle amplitude in kelvin
- Terannual temperature cycle phase in month of maximum

alt Array if mtype is Annual

If mtype is 'Annual', alt is array of m-by-7 with the following values:

Annual mean geopotential heights in meters
Annual geopotential heights cycle amplitude in meters
Annual geopotential heights cycle phase in month of maximum
Semiannual geopotential heights cycle amplitude in meters
Semiannual geopotential heights cycle phase in month of maximum
Terannual geopotential heights cycle amplitude in meters
Terannual geopotential heights cycle phase in month of maximum

zwind if mtype is Annual

If mtype is 'Annual', zwind is an array of m-by-7 with the following values:

Annual mean zonal winds in meters per second
Annual zonal winds cycle amplitude in meters per second
Annual zonal winds cycle phase in month of maximum
Semiannual zonal winds cycle amplitude in meters per second
Semiannual zonal winds cycle phase in month of maximum
Terannual zonal winds cycle amplitude in meters per second
Terannual zonal winds cycle phase in month of maximum

Examples

Calculate the mean monthly values for temperature (T), geopotential height (alt), and zonal wind (zwind) using the CIRA 1986 model at 45 degrees latitude and 101,300 pascal for January with out-of-range actions generating warnings:

[T alt zwind] = atmoscira( 45, 'Pressure', 101300 )
T =
  280.6000
alt =
   -18
zwind =
    3.3000

Calculate the mean monthly values for temperature (T), pressure (pres), and zonal wind (zwind) using the CIRA 1986 model at 45 degrees latitude and 20,000 meters for October with out-of-range actions generating warnings:

[T pres zwind] = atmoscira( 45, 'GPHeight', 20000, 'Monthly', 10)
T =
  215.8500
pres =
  5.5227e+003
zwind =
    9.5000

Calculate the mean monthly values for temperature (T), pressure (pres), and zonal wind (zwind) using the CIRA 1986 model at 45 and -30 degrees latitude and 20,000 meters for October with out-of-range actions generating errors:

[T pres zwind] = atmoscira( [45 -30], 'GPHeight', 20000, 10, 'error')
T =
  215.8500  213.9000
pres =
  1.0e+003 *
    5.5227    5.6550
zwind =
    9.5000    4.3000

Calculate the mean monthly values for temperature (T) , geopotential height (alt) , and zonal wind (zwind) using the CIRA 1986 model at 45 degrees latitude and 2000 pascal and at -30 degrees latitude and 101,300 pascal for September with out-of-range actions generating warnings:

[T alt zwind] = atmoscira( [45 -30], 'Pressure', [2000 101300], 9)
T =
  223.5395  290.9000
alt =
  1.0e+004 *
    2.6692    0.0058
zwind =
    0.6300   -1.1000

Calculate the annual values for temperature (T) , geopotential height (alt) , and zonal wind (zwind) using the CIRA 1986 model at 45 degrees latitude and 2000 pascal with out-of-range actions generating warnings:

[T alt zwind] = atmoscira( 45, 'Pressure', 2000, 'Annual' )
T =
  221.9596    5.0998    6.5300    1.9499    1.3000    1.0499    1.3000
alt =
  1.0e+004 *
    2.6465    0.0417    0.0007    0.0087    0.0001    0.0015    0.0002
zwind =
    4.6099   14.7496    0.6000    1.6499    4.6000    0.5300    1.4000

Assumptions and Limitations

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

This function has the limitations of the CIRA 1986 model. The values for the CIRA 1986 model are limited to the regions of 80 degrees S to 80 degrees N on the Earth and geopotential heights of 0 to 120 kilometers. In each monthly mean data set, values at 80 degrees S for 101,300 pascal or 0 meters were omitted because these levels are within the Antarctic land mass. Zonal mean pressure in constant altitude coordinates: pressure data was not available below 20 kilometers. Therefore, this is the bottom level of the CIRA climatology.

References

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

http://modelweb.gsfc.nasa.gov/atmos/cospar1.html