shellig_module – radbelt

IGRF model

History

SHELLIG.FOR, Version 2.0, January 1992
11/01/91-DKB- SHELLG: lowest starting point for B0 search is 2
1/27/92-DKB- Adopted to IGRF-91 coefficients model
2/05/92-DKB- Reduce variable-names: INTER(P)SHC,EXTRA(P)SHC,INITI(ALI)ZE
8/08/95-DKB- Updated to IGRF-45-95; new coeff. DGRF90, IGRF95, IGRF95S
5/31/00-DKB- Updated to IGRF-45-00; new coeff.: IGRF00, IGRF00s
3/24/05-DKB- Updated to IGRF-45-10; new coeff.: IGRF05, IGRF05s

Uses

- radbelt_kinds_module
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Used by

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Variables

Type	Visibility	Attributes		Name		Initial
integer,	private,	parameter	::	filename_len	=	14	length of the model data file names
real(kind=wp),	private,	parameter	::	Era	=	6371.2_wp	earth radius for normalization of cartesian coordinates (6371.2 km)
real(kind=wp),	private,	parameter	::	erequ	=	6378.16_wp
real(kind=wp),	private,	parameter	::	erpol	=	6356.775_wp
real(kind=wp),	private,	parameter	::	Aquad	=	erequ*erequ	square of major half axis for earth ellipsoid as recommended by international astronomical union
real(kind=wp),	private,	parameter	::	Bquad	=	erpol*erpol	square of minor half axis for earth ellipsoid as recommended by international astronomical union
real(kind=wp),	private,	parameter	::	Umr	=	atan(1.0_wp)*4.0_wp/180.0_wp	atan(1.0)4./180. umr=
real(kind=wp),	private,	parameter, dimension(3, 3)	::	u	=	reshape([+0.3511737_wp, -0.9148385_wp, -0.1993679_wp, +0.9335804_wp, +0.3583680_wp, +0.0000000_wp, +0.0714471_wp, -0.1861260_wp, +0.9799247_wp], [3, 3])
integer,	private,	parameter	::	max_loop_index	=	3333	used in shellg for the field line integration loop

Derived Types

type, public :: shellig_type

Components

Type	Visibility	Attributes		Name		Initial
character(len=:),	private,	allocatable	::	igrf_dir			directory containing the data files
real(kind=wp),	private,	dimension(3)	::	sp	=	0.0_wp
real(kind=wp),	private,	dimension(3)	::	xi	=	0.0_wp
real(kind=wp),	private,	dimension(144)	::	h	=	0.0_wp	Field model coefficients adjusted for shellg
integer,	private		::	iyea	=	0	the int year corresponding to the file `name` that has been read
character(len=:),	private,	allocatable	::	name			file name
integer,	private		::	nmax	=	0	maximum order of spherical harmonics
real(kind=wp),	private		::	Time	=	0.0_wp	year (decimal: 1973.5) for which magnetic field is to be calculated
real(kind=wp),	private,	dimension(144)	::	g	=	0.0_wp	`g(m)` -- normalized field coefficients (see feldcof) m=nmax*(nmax+2)
integer,	private		::	nmax1	=	0	saved variables from the file
integer,	private		::	nmax2	=	0	saved variables from the file
real(kind=wp),	private,	dimension(144)	::	g_cache	=	0.0_wp	saved `g` from the file
real(kind=wp),	private		::	step	=	0.20_wp	step size for field line tracing
real(kind=wp),	private		::	steq	=	0.03_wp	step size for integration
real(kind=wp),	private,	dimension(120)	::	gh2	=	0.0_wp
real(kind=wp),	private,	dimension(:, :), allocatable	::	p			this was `p(8,100)` in the original code. used for the field line integration loop. changed it to be allocatable since it was changed to be p(8,3334).

Type-Bound Procedures

procedure, public :: igrfc
procedure, public :: igrf
procedure, public :: feldcof
procedure, public :: feldc
procedure, public :: feldg
procedure, public :: shellc
procedure, public :: shellg
procedure, public :: findb0
procedure, private :: feldi
procedure, private :: stoer
procedure, public :: get_data_file_dir
procedure, public :: set_data_file_dir
procedure, public :: destroy => destroy_shellig_type

Functions

private function get_data_file_dir(me) result(dir)

Get the directory containing the data files.

Arguments

Type	Intent	Optional	Attributes		Name
class(shellig_type),	intent(in)			::	me

Return Value character(len=:), allocatable

private pure function geo_to_cart(glat, glon, alt) result(x)

geodetic to scaled cartesian coordinates

Arguments

Type	Intent		Name
real(kind=wp),	intent(in)	::	glat	geodetic latitude in degrees (north)
real(kind=wp),	intent(in)	::	glon	geodetic longitude in degrees (east)
real(kind=wp),	intent(in)	::	alt	altitude in km above sea level

Return Value real(kind=wp), dimension(3)

cartesian coordinates in earth radii (6371.2 km)

x-axis pointing to equator at 0 longitude
y-axis pointing to equator at 90 long.
z-axis pointing to north pole

Subroutines

private subroutine destroy_shellig_type(me)

Destroy a shellig_type.

Arguments

Type	Intent	Optional	Attributes		Name
class(shellig_type),	intent(out)			::	me

private subroutine set_data_file_dir(me, dir)

Set the directory containing the data files.

Arguments

Type	Intent	Optional	Attributes		Name
class(shellig_type),	intent(inout)			::	me
character(len=*),	intent(in)			::	dir

private subroutine igrf(me, lon, lat, height, year, xl, bbx)

Wrapper for IGRF functions.

Arguments

Type	Intent		Name
class(shellig_type),	intent(inout)	::	me
real(kind=wp),	intent(in)	::	lon	geodetic longitude in degrees (east)
real(kind=wp),	intent(in)	::	lat	geodetic latitude in degrees (north)
real(kind=wp),	intent(in)	::	height	altitude in km above sea level
real(kind=wp),	intent(in)	::	year	decimal year for which geomagnetic field is to be calculated (e.g.:1995.5 for day 185 of 1995)
real(kind=wp),	intent(out)	::	xl	l-value
real(kind=wp),	intent(out)	::	bbx	b_total / b_equatorial ratio

private subroutine igrfc(me, v, year, xl, bbx)

Alternate version of igrf for cartesian coordinates.

Arguments

Type	Intent	Attributes		Name
class(shellig_type),	intent(inout)		::	me
real(kind=wp),	intent(in),	dimension(3)	::	v	cartesian coordinates in earth radii (6371.2 km) x-axis pointing to equator at 0 longitude y-axis pointing to equator at 90 long. z-axis pointing to north pole
real(kind=wp),	intent(in)		::	year	decimal year for which geomagnetic field is to be calculated (e.g.:1995.5 for day 185 of 1995)
real(kind=wp),	intent(out)		::	xl	l-value
real(kind=wp),	intent(out)		::	bbx	b_total / b_equatorial ratio

private subroutine findb0(me, stps, bdel, value, bequ, rr0)

Arguments

Type	Intent		Name
class(shellig_type),	intent(inout)	::	me
real(kind=wp),	intent(in)	::	stps
real(kind=wp),	intent(inout)	::	bdel
logical,	intent(out)	::	value
real(kind=wp),	intent(out)	::	bequ
real(kind=wp),	intent(out)	::	rr0

private subroutine shellc(me, v, dimo, fl, icode, b0)

Wrapper to shellg to be used with cartesian coordinates.

Arguments

Type	Intent	Attributes		Name
class(shellig_type),	intent(inout)		::	me
real(kind=wp),	intent(in),	dimension(3)	::	v	cartesian coordinates in earth radii (6371.2 km) * x-axis pointing to equator at 0 longitude * y-axis pointing to equator at 90 long. * z-axis pointing to north pole
real(kind=wp),	intent(in)		::	dimo	dipol moment in gauss (normalized to earth radius)
real(kind=wp),	intent(out)		::	fl	l-value
integer,	intent(out)		::	icode	Read more…
real(kind=wp),	intent(out)		::	b0	magnetic field strength in gauss

private subroutine shellg(me, glat, glon, alt, dimo, fl, icode, b0, v)

calculates l-value for specified geodaetic coordinates, altitude and gemagnetic field model.

Arguments

Type	Intent	Optional	Attributes		Name
class(shellig_type),	intent(inout)			::	me
real(kind=wp),	intent(in)			::	glat	geodetic latitude in degrees (north)
real(kind=wp),	intent(in)			::	glon	geodetic longitude in degrees (east)
real(kind=wp),	intent(in)			::	alt	altitude in km above sea level
real(kind=wp),	intent(in)			::	dimo	dipol moment in gauss (normalized to earth radius)
real(kind=wp),	intent(out)			::	fl	l-value
integer,	intent(out)			::	icode	Read more…
real(kind=wp),	intent(out)			::	b0	magnetic field strength in gauss
real(kind=wp),	intent(in),	optional,	dimension(3)	::	v	cartesian coordinates in earth radii (6371.2 km) Read more…

private subroutine stoer(me, p, bq, r)

subroutine used for field line tracing in shellg. calls entry point feldi in geomagnetic field subroutine feldg

Arguments

Type	Intent	Attributes		Name
class(shellig_type),	intent(inout)		::	me
real(kind=wp),	intent(inout),	dimension(7)	::	p
real(kind=wp),	intent(out)		::	bq
real(kind=wp),	intent(out)		::	r

private subroutine feldg(me, glat, glon, alt, bnorth, beast, bdown, Babs)

Calculates earth magnetic field from spherical harmonics model

Arguments

Type	Intent		Name
class(shellig_type),	intent(inout)	::	me
real(kind=wp),	intent(in)	::	glat	geodetic latitude in degrees (north)
real(kind=wp),	intent(in)	::	glon	geodetic longitude in degrees (east)
real(kind=wp),	intent(in)	::	alt	altitude in km above sea level
real(kind=wp),	intent(out)	::	bnorth	components of the field with respect to the local geodetic coordinate system, with axis pointing in the tangential plane to the north, east and downward.
real(kind=wp),	intent(out)	::	beast	components of the field with respect to the local geodetic coordinate system, with axis pointing in the tangential plane to the north, east and downward.
real(kind=wp),	intent(out)	::	bdown	components of the field with respect to the local geodetic coordinate system, with axis pointing in the tangential plane to the north, east and downward.
real(kind=wp),	intent(out)	::	Babs	magnetic field strength in gauss

private subroutine feldc(me, v, b)

Alternate version of feldg to be used with cartesian coordinates

Arguments

Type	Intent	Attributes		Name
class(shellig_type),	intent(inout)		::	me
real(kind=wp),	intent(in),	dimension(3)	::	v	cartesian coordinates in earth radii (6371.2 km) x-axis pointing to equator at 0 longitude y-axis pointing to equator at 90 long. z-axis pointing to north pole
real(kind=wp),	intent(out)		::	b(3)	field components

private subroutine feldi(me)

Used for l computation.

Arguments

Type	Intent	Optional	Attributes		Name
class(shellig_type),	intent(inout)			::	me

private subroutine feldcof(me, year, dimo)

Determines coefficients and dipol moment from IGRF models

Arguments

Type	Intent		Name
class(shellig_type),	intent(inout)	::	me
real(kind=wp),	intent(in)	::	year	decimal year for which geomagnetic field is to be calculated (e.g.:1995.5 for day 185 of 1995)
real(kind=wp),	intent(out)	::	dimo	geomagnetic dipol moment in gauss (normalized to earth's radius) at the time (year)

private subroutine getshc(Fspec, Nmax, Erad, Gh, Ier)

Reads spherical harmonic coefficients from the specified file into an array.

Arguments

Type	Intent	Attributes		Name
character(len=*),	intent(in)		::	Fspec	File specification
integer,	intent(out)		::	Nmax	Maximum degree and order of model
real(kind=wp),	intent(out)		::	Erad	Earth's radius associated with the spherical harmonic coefficients, in the same units as elevation
real(kind=wp),	intent(out),	dimension(*)	::	Gh	Schmidt quasi-normal internal spherical harmonic coefficients
integer,	intent(out)		::	Ier	Error number: Read more…

private subroutine intershc(date, dte1, nmax1, gh1, dte2, nmax2, gh2, nmax, gh)

Interpolates linearly, in time, between two spherical harmonic models.

Arguments

Type	Intent		Name
real(kind=wp),	intent(in)	::	date	Date of resulting model (in decimal year)
real(kind=wp),	intent(in)	::	dte1	Date of earlier model
integer,	intent(in)	::	nmax1	Maximum degree and order of earlier model
real(kind=wp),	intent(in)	::	gh1(*)	Schmidt quasi-normal internal spherical harmonic coefficients of earlier model
real(kind=wp),	intent(in)	::	dte2	Date of later model
integer,	intent(in)	::	nmax2	Maximum degree and order of later model
real(kind=wp),	intent(in)	::	gh2(*)	Schmidt quasi-normal internal spherical harmonic coefficients of later model
integer,	intent(out)	::	nmax	Maximum degree and order of resulting model
real(kind=wp),	intent(out)	::	gh(*)	Coefficients of resulting model

private subroutine extrashc(date, dte1, nmax1, gh1, nmax2, gh2, nmax, gh)

Extrapolates linearly a spherical harmonic model with a rate-of-change model.

Arguments

Type	Intent		Name
real(kind=wp),	intent(in)	::	date	Date of resulting model (in decimal year)
real(kind=wp),	intent(in)	::	dte1	Date of base model
integer,	intent(in)	::	nmax1	Maximum degree and order of base model
real(kind=wp),	intent(in)	::	gh1(*)	Schmidt quasi-normal internal spherical harmonic coefficients of base model
integer,	intent(in)	::	nmax2	Maximum degree and order of rate-of-change model
real(kind=wp),	intent(in)	::	gh2(*)	Schmidt quasi-normal internal spherical harmonic coefficients of rate-of-change model
integer,	intent(out)	::	nmax	Maximum degree and order of resulting model
real(kind=wp),	intent(out)	::	gh(*)	Coefficients of resulting model

shellig_module Module

Contents

Variables

Derived Types

Functions

Subroutines

History

Uses

Used by

Variables

Derived Types

type, public :: shellig_type

Components

Type-Bound Procedures

Functions

private function get_data_file_dir(me) result(dir)

Arguments

Return Value character(len=:), allocatable

private pure function geo_to_cart(glat, glon, alt) result(x)

Arguments

Return Value real(kind=wp), dimension(3)

Subroutines

private subroutine destroy_shellig_type(me)

Arguments

private subroutine set_data_file_dir(me, dir)

Arguments

private subroutine igrf(me, lon, lat, height, year, xl, bbx)

Arguments

private subroutine igrfc(me, v, year, xl, bbx)

Arguments

private subroutine findb0(me, stps, bdel, value, bequ, rr0)

Arguments

private subroutine shellc(me, v, dimo, fl, icode, b0)

Arguments

private subroutine shellg(me, glat, glon, alt, dimo, fl, icode, b0, v)

Arguments

private subroutine stoer(me, p, bq, r)

Arguments

private subroutine feldg(me, glat, glon, alt, bnorth, beast, bdown, Babs)

Arguments

private subroutine feldc(me, v, b)

Arguments

private subroutine feldi(me)

Arguments

private subroutine feldcof(me, year, dimo)

Arguments

private subroutine getshc(Fspec, Nmax, Erad, Gh, Ier)

Arguments

private subroutine intershc(date, dte1, nmax1, gh1, dte2, nmax2, gh2, nmax, gh)

Arguments

private subroutine extrashc(date, dte1, nmax1, gh1, nmax2, gh2, nmax, gh)

Arguments