European Space Agency

Royal Belgian Institute for Aeronomy

um539 - evaluate the magnetic field

subroutine  um539(mpos, amjd, mb, ifail)

Parameters:

• mpos [zgeo,in] :: geocentric location in GEO coordinates

• amjd [real8,in] :: modified Julian day

• mb [zvec,out] :: magnetic field vector

• ifail [integer4,out] :: error flag from Dependencies

Description

The subroutine UM539 evaluates the magnetic field vector at a given time and geographic location. The subroutine differs from subroutine UM530 by its argument amjd from which the time is specified. Note that the magnetic field models have to be firstly initialized, e.g. by a call to the subroutine UM510 and UM520. The time (argument amjd) passed to the subroutine is used to re-evaluate the position of the Sun and the GSM or SM coordinate transformation. Note that only the external magnetic field model is affected by the re-evaluation.

Diagnostics

those from Dependencies

Common Blocks

• uc140 - magnetic field

Dependencies

Called by

None

Calls

• um522 - position of the Sun

• um523 - GEO to GSM transformation

• um524 - GEO to SM transformation

• um530 - evaluate the magnetic field vector

See also

• um510 - select an internal field model

• um520 - select an external magnetic field model

• um530 - evaluate the magnetic field vector

• G.05 - What are the coordinates and units used ?

Reported Bugs

None

Examples

None

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UNILIB/tags/v3.02