Space indices

The SatelliteToolbox.jl can automatically fetch some space indices that are used in some computations, notably in the earth atmospheric models. First, it is necessary to initialize the related files, which is done by the function:

function init_space_indices(...)

When called without arguments, it will download all the supported files, if necessary. For more information about the many configuration options, please, see the function documentation.

The supported files are:

File	Download frequency	Information
`DTCFILE.TXT`	Daily	This file contains the exospheric temperature variation caused by the Dst index. This is used for the JB2008 atmospheric model.
`fluxtable.txt`	Daily	This file contains the F10.7 flux data in different formats.
`SOLFSMY.TXT`	Daily	This files contains the indices necessary for the JB2008 atmospheric model.
WDC Files	Once / Daily*	This set of files contain the Kp and Ap indices.

*: The WDC files are separated by year. The file related to the current year is downloaded on a daily-basis and the files related to the previous years are downloaded only once.

After the initialization of the files, the space indices can be obtained by the following function:

function get_space_index(IND, JD::Number, ...)

in which JD is the Julian Day in which the index will be computed, and IND is the desired space index as described in the following table.

`IND`	Space index
`F10()`	10.7-cm adjusted solar flux
`F10adj()`	10.7-cm adjusted solar flux
`F10obs()`	10.7-cm observed solar flux
`F10M()`	Average of 10.7-cm adjusted solar flux
`F10Madj()`	Average of 10.7-cm adjusted solar flux
`F10Mobs()`	Average of 10.7-cm observed solar flux
`Kp()`	Kp index (daily mean)
`Kp_vect()`	A vector containing the Kp index for the following hours of the day: 0-3h, 3-6h, 6-9h, 9-12h, 12-15h, 15-18h, 18-20h, 20-23h
`Ap()`	Ap index (daily mean)
`Ap_vect()`	A vector containing the Ap index for the following hours of the day: 0-3h, 3-6h, 6-9h, 9-12h, 12-15h, 15-18h, 18-20h, 20-23h
`S10()`	EUV index (26-34 nm) scaled to F10.7
`M10()`	MG2 index scaled to F10.7
`Y10()`	Solar X-ray & Lya index scaled to F10.7
`S81a()`	EUV 81-day averaged centered index
`M81a()`	MG2 81-day averaged centered index
`Y81a()`	Solar X-ray & Lya 81-day averaged centered index
`DstΔTc()`	Exospheric temperature variation due to `Dst`

Note

The index DstΔTc() is interpolated to the selected instant of the Julian Day, whereas all the other indices are constants within the seleteced day.

Note

For the indices F10M(), F10Madj(), and F10Mobs(), one can use an optional keyword window::Int that defines the size in days of the moving average window. If it is not specified, then it defaults to 81 days.

julia> init_space_indices()
[ Info: Downloading file 'DTCFILE.TXT' from 'http://sol.spacenvironment.net/jb2008/indices/DTCFILE.TXT'.
[ Info: Downloading file 'fluxtable.txt' from 'ftp://ftp.geolab.nrcan.gc.ca/data/solar_flux/daily_flux_values/fluxtable.txt'.
[ Info: Downloading file 'SOLFSMY.TXT' from 'http://sol.spacenvironment.net/jb2008/indices/SOLFSMY.TXT'.
[ Info: Downloading file 'kp2017.wdc' from 'ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/wdc/kp2017.wdc'.
[ Info: Downloading file 'kp2015.wdc' from 'ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/wdc/kp2015.wdc'.
[ Info: Downloading file 'kp2016.wdc' from 'ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/wdc/kp2016.wdc'.
[ Info: Downloading file 'kp2018.wdc' from 'ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/wdc/kp2018.wdc'.

julia> get_space_index(F10(), DatetoJD(2018, 6, 19, 18, 35, 00))
79.0

julia> get_space_index(F10M(), DatetoJD(2018, 6, 19, 18, 35, 00))
73.47037037037039

julia> get_space_index(F10M(), DatetoJD(2018, 6, 19, 18, 35, 00); window = 51)
74.60196078431372

julia> get_space_index(Ap(), DatetoJD(2018, 6, 19, 18, 35, 00))
5.125