atmositu

Use ITU reference atmospheres

Since R2021a

Syntax

[T,P,wvden] = atmositu(h)

[T,P,wvden] = atmositu(___,Name,Value)

atmositu(___)

Description

[T,P,wvden] = atmositu(h) calculates the International Telecommunication Union (ITU) standard atmospheric model known as the Mean Annual Global Reference Atmosphere (MAGRA) and returns the atmospheric temperature T, total air pressure P, and water-vapor density wvden. MAGRA approximates the U.S. Standard Atmosphere 1976 with insignificant relative error.

[T,P,wvden] = atmositu(___,Name,Value) returns the atmospheric temperature, total pressure, and water-vapor density with additional options specified by one or more name-value pairs. For example, 'LatitudeModel','High' specifies a reference model for latitudes greater than 45°.

atmositu(___) with no output arguments plots:

• Atmospheric temperature T versus altitude in linear scale

• Atmospheric pressure P versus altitude in logarithmic x-scale

• Atmospheric water-vapor density wvden versus altitude in logarithmic x-scale

Examples

Find Temperature, Pressure, and Water Vapor Density

Compute the atmospheric temperature, pressure, and water vapor density at a height of 5 km at high latitudes in summer. Use default parameters.

h = 5e3;
[T,P,wvden] = atmositu(h)

T = 
255.6755

P = 
540.4828

wvden = 
0.6156

Compute and Visualize Atmospheric Profiles

Compute the atmospheric temperature, pressure, and water-vapor density for a mid-latitude area during winter. Specify an altitude range between 2 km and 88 km.

h = (2:88).*1e3;

[T,P,wvden] = atmositu(h,'LatitudeModel','Mid','Season','Winter');

Display the first 6 values of temperature, pressure, and water vapor density.

disp([T(1:6)',P(1:6)',wvden(1:6)'])

  264.7771  789.5947    1.7601
  260.2759  689.4528    1.1320
  255.4229  598.9723    0.6829
  250.2181  518.1532    0.3875
  244.6615  446.9955    0.2074
  238.7531  385.4992    0.1049

Plot the atmospheric temperature, pressure, and water-vapor density profiles for the same model.

atmositu(h,'Latitude','Mid','Season','Winter')

Input Arguments

h — Geometric heights

M-length row vector

Geometric heights corresponding to the altitude above mean sea level (MSL), specified as a row vector. The atmositu function returns NaN's for any input value outside of the interval [0,100000]. Units are in meters.

Data Types: double

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: atmositu(h,'LatitudeModel','Mid','Season','Winter') specifies the mid-latitude model during winter.

VaporDensity — Standard ground-level water-vapor density

7.5 (default) | scalar

Standard ground-level water-vapor density in g/m³, specified as a scalar. VaporDensity applies only when LatitudeModel is set to the default 'Standard' model.

Data Types: double

ScaleHeight — Scale height

2000 (default) | scalar

Scale height in meters, specified as a scalar. ScaleHeightapplies only when LatitudeModel is set to the default 'Standard' model. For a dry atmosphere, set ScaleHeight to 6000.

Data Types: double

LatitudeModel — Reference latitude model

'Standard' (default) | 'Low' | 'Mid' | 'High'

Reference latitude model, specified as:

• 'Standard' — This is the Mean Annual Global Reference Atmosphere (MAGRA) model that reflects the mean annual temperature and pressure averaged across the world.

• 'Low' — Use this model for latitudes lower than 22°, with little seasonal variation.

• 'Mid' — Use this model for latitudes between 22° and 45° that have seasonal profiles for summer and winter. You can specify a seasonal profile using the Season name-value pair.

• 'High' — Use this model for latitudes greater than 45° that have seasonal profiles for summer and winter. You can specify a seasonal profile using the Season name-value pair.

Season — Seasonal profile

'Summer' (default) | 'Winter'

Seasonal profile, specified as 'Summer' or 'Winter'. This argument is valid only when LatitudeModel is set to 'Mid' or 'High'.

Output Arguments

T — Temperature

M-length row vector

Atmospheric temperature in Kelvin, returned as an M-length row vector.

Note

The atmositu, gaspl, and tropopl functions use different units for pressure and temperature.

Pressure and Temperature Units

Function	Pressure Units	Temperature Units
atmositu	hectoPascals (hPa)	kelvin (K)
tropopl	hectoPascals (hPa)	kelvin (K)
gaspl	Pascals (Pa)	Celsius (C)

One hPa equals 100 Pa and K = C + 273.15. Use caution when combining the use of these three functions.

P — Total atmospheric pressure

M-length row vector

Total or barometric atmospheric pressure in hectoPascals, returned as an M-length row vector.

wvden — Water-vapor density

M-length row vector

Atmospheric water-vapor density in g/m³, returned as an M-length row vector.

References

[1] International Telecommunication Union (ITU). "Reference Atmospheres". Recommendation ITU-R P.835-7, P Series, Radiowave Propagation (Aug. 2024).

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2021a

R2025b: ITU Reference Atmosphere Updated

atmositu now uses the International Telecommunication Union (ITU) Recommendation ITU-R P.835-7 (2024) reference atmosphere.