UM530

[ Name | Synopsis | Arguments | Description | Diagnostics | Common Blocks | Dependencies | See Also | Reported Bugs | Examples ]

Name

Subroutine UM530 - evaluate the magnetic field vector

Synopsis

      RECORD /zgeo/ mpos
      RECORD /zvec/ mb
      INTEGER*4     ifail
        
      CALL UM530 (mpos, mb, ifail) 

Arguments

mpos

Geographic position in geocentric coordinates (GEO) [in]

mb

Magnetic field vector [out]

ifail

Error flag (see diagnostics) [out]

Description

The subroutine UM530 evaluates the magnetic field vector at a geographic location. Before the first call to subroutine UM530, the magnetic field parameters have to be initialized. These parameters are stored in the common block UC140 but they can be modified with the help of the subroutines UM510 and UM520. The subroutines UM510 and UM520 allow to select an internal geomagnetic field model (e.g. IGRF) and an external magnetic field (e.g. Tsyganenko), respectively.

The geographic location mpos has to be provided in geocentric spherical coordinates. The subroutine UM530 returns the spherical component and the intensity of the magnetic field vector. Note that the magnetic field vector is evaluated by the subroutine even when the error flag ifail is returned with the negative values -53002, -53003 and -53004. The diagnostics provided by the subroutine UM530 are controlled by the parameters xrmin, xbmin, xtmin and xbmax stored in the common block UC192.

Diagnostics

-53001, position too deep inside the Earth
-53002, too small value of the magnetic field intensity
-53003, too large value of the geomagnetic latitude
-53004, too large value of the magnetic field intensity
-53005, incorrect value of the co-latitude

Common Blocks

UC140, magnetic field description
UC160, general constants
UC192, control parameters, set 2

Dependencies

Called by

UL220, get information on a magnetic field line segment
UD328, evaluate the second derivative of B
UD329, interpolate between two or three points
UD332, evaluate the magnetic flux through a spherical pie
UF411, search a local magnetic equator
UF421, initialize and close a field line segment
UF423, Runge Kutta step
UF425, evaluate the curvature of the field lines
UM539, evaluate the magnetic field
UT998, evaluate the magnetic field vector and the normal to the field line

Calls

UM531, geomagnetic field
UM532, external magnetic field
UM533, distance to the magnetopause
UM535, geocentric to geodetic transformation
UM537, Kluge evaluation of the geomagnetic field

See also

UM510, select a geomagnetic field model
UM520, select an external magnetic field model
FAQ G.05 Which are the coordinates and units used ?

Reported Bugs

None

Examples

#1, evaluation of the magnetic field vector