Documentation

Horizontal Wind Model 07

Implement Horizontal Wind Model 07

Library

Environment/Wind

Description

The Horizontal Wind Model 07 block implements the U.S. Naval Research Laboratory HWM™ routine to calculate the meridional and zonal components of the wind for a set of geophysical data: latitude, longitude, and altitude.

Parameters

Units

Specify the input and output units. The units you select determine the input and output wind speed and velocity, as shown in the table.

Units

Wind Speed

Wind Velocity

Metric (MKS)

Meters per second

Meters per second

English (Velocity in ft/s)

Feet per second

Feet per second

English (Velocity in kts)

Knots

Knots

Model

Select the horizontal wind model type for which to calculate the wind components.

  • Disturbance

    Calculate the effect of only magnetic disturbances in the wind. For this model type, input Ap index values greater than or equal to 0.

  • Quiet

    Calculate the horizontal wind model without the magnetic disturbances. For this model type, do not input an Ap index value.

  • Total

    Calculate the combined effect of the quiet and magnetic disturbances. For this model type, input Ap index values greater than or equal to 0.

Action for out-of-range input

Specify the block behavior when the block inputs are out of range.

ValueDescription

None

No action. The block imposes upper and lower limits on an input signal.

Warning

Warning in the Diagnostic Viewer, model simulation continues. For Accelerator and Rapid Accelerator modes, setting the action to Warning has no effect and the model behaves as though the action is set to None.

Error (default)

MATLAB® returns an exception, model simulation stops. For Accelerator and Rapid Accelerator modes, setting the action to Error has no effect and the model behaves as though the action is set to None.

Inputs and Outputs

InputDimension TypeDescription

First

Three-element vector of doubles

The input specifies the geodetic latitude (μ), longitude (l), and geopotential altitude (h) where the block implements the model.

Latitude and longitude values are in degrees.

The altitude value is in the units you selected in the Units parameter. Specify the altitude element as a value between 0 and 500 km.

Second

Scalar double

The input specifies the day of year in Universal Coordinated Time (UTC). The input specifies the day as a value between 1 and 366 (for a leap year).

Third

Scalar double

Contains elapsed seconds since midnight for the selected day, in UTC.

Fourth (Optional)

Scalar double

Contains the Ap index for the Universal Time (UT) when the block evaluates the model. Select the index from the NOAA National Geophysical Data Center, which contains 3 hour interval geomagnetic disturbance index values. If the Ap index value is greater than zero, the software takes into account magnetic effects during model evaluation.

This input appears when you select the total or disturbance wind model type. Specify the Ap index as a value between 0 and 400. This input disappears when you select the quiet model type in the Model parameter.

OutputDimension TypeDescription

First

1-by-2 vector of doubles

The wind velocity vector contains the meridional and zonal wind components in that order.

Limitation

For code generation, use this block only for targets whose type is int 32 or higher.

Introduced in R2014b

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