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Solar Flux and Geomagnetic Index

Return solar flux and geomagnetic index

Since R2023a

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  • Flux Solar and Geomagnetic Index block icon

Libraries:
Aerospace Blockset / Environment / Celestial Phenomena

Description

The Solar Flux and Geomagnetic Index block extracts the solar flux and geomagnetic index from the MAT file that is generated as aeroSpaceWeatherData.mat by the aeroReadSpaceWeatherData function.

Limitations

When specifying Magnetic index extrapolation value as IGRF, the Solar Flux and Geomagnetic Index block predicts the elements of the magnetic index information outside the MAT file data range using the International Geomagnetic Reference Field. Because this model is defined for times between January 1, 1900, 12:00 AM UTC and January 1, 2025, 12:00 AM UTC, the predictions for times outside this range are clipped to values at these time limits.

Ports

Input

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Year, specified as a scalar. The aeroReadSpaceWeatherData function ignores the value of year.

Dependencies

To enable this port, set the Input time specification parameter to Year, day, sec.

Data Types: double

Day of year, specified as a scalar.

Dependencies

To enable this port, set the Input time specification parameter to Year, day, sec.

Data Types: double

Universal time (UT), specified as a scalar in seconds. This value is the number of seconds relative to midnight of DOY.

Dependencies

To enable this port, set the Input time specification parameter to Year, day, sec.

Data Types: double

Universal time (UT), specified as a scalar Julian date.

Dependencies

To enable this port, set the Input time specification parameter to Julian date.

Data Types: double

Output

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81-day average of F10.7 flux, centered on day of year (dayOfYear), specified as a scalar. This value corresponds to the 10.7 cm radio flux at the actual distance of the Earth from the Sun. The value does not correspond to the radio flux at 1 AU.

Data Types: double

Daily F10.7 flux for previous day, specified as a scalar. This value corresponds to the 10.7 cm radio flux at the actual distance of the Earth from the Sun. The value does not correspond to the radio flux at 1 AU.

Data Types: double

Magnetic index information, specified as an 1-by-7 array. This information consists of:

  • Daily magnetic index (AP)

  • 3-hour AP for current time

  • 3-hour AP for 3 hours before current time

  • 3-hour AP for 6 hours before current time

  • 3-hour AP for 9 hours before current time

  • Average of eight 3-hour AP indices from 12 to 33 hours before current time

  • Average of eight 3-hour AP indices from 36 to 57 hours before current time

    For more information, see Limitations.

Data Types: double

Parameters

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MAT file of space weather data. This file is the output from the aeroReadSpaceWeatherData function.

Aerospace Blockset™ includes a default space weather data file, aeroSpaceWeatherData.mat. To use the most recent data available, use aeroReadSpaceWeatherData to generate a new MAT file, and specify the file name for this parameter. For more information, see aeroReadSpaceWeatherData.

If the file is not on the MATLAB® path, specify the full pathname. The MAT file must contain these variables from the space weather data file:

  • YEAR

  • MONTH

  • DAY

  • AP1

  • AP2

  • AP3

  • AP4

  • AP5

  • AP6

  • AP7

  • AP8

  • AP_AVG

  • F107_OBS

  • F107_DATA_TYPE

  • F107_OBS_CENTER81

Dependencies

To enable this parameter:

  • Set the Propagation method parameter to Numerical (high precision).

  • Set the Central Body parameter to Earth.

  • Select the Include atmospheric drag check box.

  • Set the Atmospheric density source parameter to Dialog.

  • Set Atmospheric model to NRLMSISE-00.

Programmatic Use

Block Parameter: SpaceWeatherDataFile
Type: character vector
Values: 'aeroSpaceWeatherData.mat' | MAT file name
Default: 'aeroSpaceWeatherData.mat'

Input time format, specified as:

  • Year, day, sec — Enter the year, day, and seconds through the Year, DOY, and UT (sec) input ports.

  • Julian date — Enter the Julian date through the TJD input port.

Programmatic Use

Block Parameter: InputSpec
Type: character vector
Values: 'Year, day, sec.' | 'Julian date'
Default: 'Year, day, sec.'

Extrapolation method for f107Average and f107Daily for times outside the range of the MAT file data, specified as one of these values.

MethodDescription
None - clip

Set f107Average and f107Daily to the nearest data point available in the MAT file.

Constant

Set f107Average and f107Daily to a constant value specified by the Magnetic index extrapolation method parameter value.

Least squares fit

Approximate f107Average and f107Daily using a least-squares fit of the space weather data from October 1, 1957, to December 1, 2040. This method uses a trigonometric function of the form:

a + b*cos(c*t + d*sin(e*t)),

where:

  • a is 128.2351780622538

  • b is 54.3285872213434

  • c is 0.0015460708364

  • d is 0.2429462096495

  • e is 0.0015563188188

  • t is jdCurrent - jdReftime

  • jdCurrent is the current Julian date

  • jdRef is 2436112.5

Note

For f107Average values,if part of the 81-day period falls inside the MAT file range of space weather data, the Solar Flux and Geomagnetic Index block uses the actual daily values from the overlapping portion. To calculate the average for the nonoverlapping portion, the block uses the clipped, constant, or least squares daily value.

Dependencies

To enable this parameter:

  • Set the Propagation method parameter to Numerical (high precision).

  • Set the Central Body parameter to Earth.

  • Select the Include atmospheric drag check box.

  • Set the Atmospheric density source parameter to Dialog.

  • Set Atmospheric model to NRLMSISE-00.

Programmatic Use

Block Parameter: F107ExtrapMethod
Type: character vector
Values: 'None - clip' | 'Constant' | 'Least squares fit'
Default: 'None - clip'

Extrapolation value to assign to f107Average and to calculate f107Daily, specified as a scalar.

Tunable: Yes

Dependencies

This value is assigned when:

  • F10.7 extrapolation method is set to Constant.

  • Time specified by the Year, DOY, and UT (sec) ports is outside the range of the data in the MAT file.

Programmatic Use

Block Parameter: F107ExtrapValue
Type: character vector
Values: '150.0' | scalar
Default: '150.0'

Dependencies

To enable this parameter:

  • Set the Propagation method parameter to Numerical (high precision).

  • Set the Central Body parameter to Earth.

  • Select the Include atmospheric drag check box.

  • Set the Atmospheric density source parameter to Dialog.

  • Set Atmospheric model to NRLMSISE-00.

  • Set F10.7 extrapolation method to Constant.

Extrapolation method for magnetic index information values for times outside the range of the MAT file data, specified as one of these values.

MethodDescription
None - clip

Set elements of magnetic index information to the nearest data point available in the MAT file.

Constant

Set elements of magnetic index information to a constant value specified by the Magnetic index extrapolation method parameter.

The elements of magnetic index for times outside this range are based on clipped values of the horizontal magnetic field strength at these time limits.

IGRF

Calculate the elements of magnetic index information using the International Geomagnetic Reference Field. Because this model is defined for times between January 1, 1900, 12:00 AM UTC and January 1, 2025, 12:00 AM UTC, the predictions for times outside this range are clipped to values at these time limits.

Dependencies

To enable this parameter:

  • Set the Propagation method parameter to Numerical (high precision).

  • Set the Central Body parameter to Earth.

  • Select the Include atmospheric drag check box.

  • Set the Atmospheric density source parameter to Dialog.

  • Set Atmospheric model to NRLMSISE-00.

Programmatic Use

Block Parameter: MagneticIndexExtrapMethod
Type: character vector
Values: 'None - clip' | 'Constant' | 'IGRF'
Default: 'None - clip'

Extrapolation value used to calculate magnetic index elements, specified as a scalar.

Tunable: Yes

Dependencies

This parameter is enabled when Magnetic index extrapolation method is set to Constant.

Dependencies

To enable this parameter:

  • Set the Propagation method parameter to Numerical (high precision).

  • Set the Central Body parameter to Earth.

  • Select the Include atmospheric drag check box.

  • Set the Atmospheric density source parameter to Dialog.

  • Set Atmospheric model to NRLMSISE-00.

Programmatic Use

Block Parameter: MagneticIndexExtrapValue
Type: character vector
Values: '4.0' | scalar
Default: '4.0'

Algorithms

The default space weather data file aeroSpaceWeatherData.mat installed with the Aerospace Blockset was created using the aeroReadSpaceWeatherData function. aeroReadSpaceWeatherData reads space weather data from a CelesTrak® consolidated space weather data file into a MAT file.

  • Geomagnetic data - Provided by the Geomagnetic Observatory Niemegk, GFZ German Research Center for Geosciences, and licensed under the CC-BY-4.0 license. Matzka, J., Stolle, C., Yamazaki, Y., Bronkalla, O. and Morschhauser, A., 2021. The geomagnetic Kp index and derived indices of geomagnetic activity. Space Weather, https://doi.org/10.1029/2020SW002641.

  • Solar Radio Flux Data - Provided by Dominion Radio Astrophysical Observatory and Natural Resources Canada.

  • 45-Day and Monthly predictions - Provided by the Space Weather Prediction center of the National Oceanic and Atmospheric Administration (NOAA).

To generate an up-to-date space weather data MAT file to use with the Solar Flux and Geomagnetic Index block, use the aeroReadSpaceWeatherData function.

Extended Capabilities

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

Version History

Introduced in R2023a

See Also

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