Main Content

# atmoshwm

Implement horizontal wind model

## Syntax

``wind = atmoshwm(latitude,longitude,altitude)``
``wind = atmoshwm(latitude,longitude,altitude,Name,Value)``

## Description

example

````wind = atmoshwm(latitude,longitude,altitude)` implements the U.S. Naval Research Laboratory Horizontal Wind Model (HWM™) routine to calculate the meridional and zonal components of the wind for one or more sets of geophysical data: `latitude`, `longitude`, and `altitude`. ```

example

````wind = atmoshwm(latitude,longitude,altitude,Name,Value)` uses additional options specified by one or more `Name,Value` pair arguments.```

## Examples

collapse all

Calculate the total horizontal wind model for a latitude of 45 degrees south, longitude of 85 degrees west, and altitude of 25,000 m above mean sea level (msl). The date is the 150th day of the year, at 11 am UTC, using an Ap index of 80. The horizontal model version is 14.

`w = atmoshwm(-45,-85,25000,'day',150,'seconds',39600,'apindex',80,'model','total', 'version', '14')`
```w = 3.2874 25.8735```

Calculate the quiet horizontal wind model for a latitude of 50 degrees north, two altitudes of 100,000 m and 150,000 m above msl, and a longitude of 20 degrees west. The date is midnight UTC of January 30. The default horizontal model version is 14.

`w = atmoshwm([50;50],[-20;-20],[100000;150000],'day',[30;30])`
```w = -42.9350 -40.3693 29.1106 0.6253```

Calculate the disturbed horizontal wind model for an altitude of 150,000 m above msl at latitude 70 degrees north, longitude 65 degrees west. The date is midnight UTC of June 15. The default horizontal model version is 14.

`dw = atmoshwm(70,-65,150000,'day',166,'model','disturbance')`
```dw = 1.7954 -1.7130```

## Input Arguments

collapse all

Geodetic latitudes, in degrees, specified as a scalar or M-by-1 array, where M is one or more sets of geophysical data.

Example: -45

Data Types: `double`

Geodetic longitudes, in degrees, specified as a scalar or M-by-1 array, where M is one or more sets of geophysical data.

Example: -85

Data Types: `double`

Geopotential heights, in meters, within the range of 0 to 500 km, specified as a scalar or M-by-1 array. M is one or more sets of geophysical data.

Example: 25000

Data Types: `double`

### Name-Value Pair Arguments

Specify optional comma-separated pairs of `Name,Value` arguments. `Name` is the argument name and `Value` is the corresponding value. `Name` must appear inside quotes. You can specify several name and value pair arguments in any order as `Name1,Value1,...,NameN,ValueN`.

Example: `'apindex',80,'model','total'` specifies that the total horizontal wind model be calculated for an Ap index of 80.

Ap index for the Universal Coordinated Time (UTC) at which `atmoshwm` evaluates the model, specified as an M-by-1 array of zeroes, a scalar, or an M-by-1 array. M is one or more sets of geophysical data. Select the index from the NOAA National Geophysical Data Center, which contains three-hour interval geomagnetic disturbance index values. If the Ap index value is greater than zero, the model evaluation accounts for magnetic effects.

Specify the Ap index as a value from 0 through 400. Specify an Ap index value for only the disturbance or total wind model type.

Data Types: `double`

Day of year in UTC. Specify the day as a value from 1 through 366 (for a leap year), specified as an M-by-1 array of zeroes, a scalar, or an M-by-1 array. M is one or more sets of geophysical data.

Data Types: `double`

Elapsed seconds since midnight for the selected day, in UTC, specified as specified as an M-by-1 array of zeroes, a scalar, or an M-by-1 array. M is one or more sets of geophysical data.

Specify the seconds as a value from 0 through 86,400.

Data Types: `double`

Horizontal wind model type for which to calculate the wind components. This setting applies to all the sets of geophysical data in M.

• `'quiet'`

Calculates the horizontal wind model without the magnetic disturbances. Quiet model types do not account for Ap index values. For this model type, do not specify an Ap index value when using this model type.

• `'disturbance'`

Calculates the effect of only magnetic disturbances in the wind. For this model type, specify Ap index values greater than or equal to zero.

• `'total'`

Calculates the combined effect of the quiet and magnetic disturbances. for this model type, specify Ap index values greater than or equal to zero.

Data Types: `char` | `string`

Function behavior when inputs are out of range, specified as one of these values. This type applies to all the sets of geophysical data in M.

ValueDescription
`'None'`No action.
`'Warning'`Warning in the MATLAB® Command Window, model simulation continues.
`'Error'`MATLAB returns an exception, model simulation stops.

Data Types: `char` | `string`

Implements specified horizontal wind model type.

• `'14'`

Horizontal Wind Model 14.

• `'07'`

Horizontal Wind Model 07.

Data Types: `char` | `string`

## Output Arguments

collapse all

Meridional and zonal wind components of the horizontal wind model, returned as an M-by-2 array, in m/s.

## See Also

Introduced in R2016b

## Support Get trial now