Update to AACGM-v2 model now available from Dartmouth College

By: miker on: Wed., Jan. 22, 2020 03:58 PM EST (6593 Reads)

Simon Shepherd has announced that the Altitude Adjusted Corrected Geomagnetic Coordinates (AACGM-v2) model, originally developed to compare conjugacy of data from SuperDARN radars in the northern and southern hemispheres Baker and Wing, 1989, has been updated. In his words:

'With the recent release of the 13th generation International Geomagnetic Reference Field (IGRF-13) (https://www.ngdc.noaa.gov/IAGA/vmod/igrf.html) an update to AACGM-v2 is now available at http://superdarn.thayer.dartmouth.edu/aacgm.html

The update includes new AACGM-v2 coefficients that extend the date range to 2025 and small changes to the software to accommodate the new date range and coefficient files.

Note that small differences in the IGRF-13 coefficients will cause corresponding small changes in AACGM-v2 coordinates derived using the new model for dates beginning in 2010.'

A follow-on note from Emma Bland (Data Analysis Working Group):

'To add to Simon's email: if you would like to start using the new IGRF/AACGM-v2 coefficients inside RST immediately, you can download and install the "develop" branch of the RST from Github: https://github.com/SuperDARN/rst/tree/develop

Many thanks to Simon and to Evan Thomas for adding these new coefficients into RST so quickly. We are working on a new minor release of RST which should be available in early March.'

Simon's follow-on to Emma's follow-on:

If you are talking about your VT codes then fine, but keep in mind that the original AACGM (not called v1) is based on a different philosophy and I would strongly discourage you from deleting it.
The v2 code takes a hardline position on reproducing the field-line tracing results, which causes there to be a region where the coordinates are undefined. The original AACGM code did not and as a result, coefficients are defined everywhere (including where they should not be.) I suspect there are still people using the original code because they need things to be defined everywhere.

And earlier from Kevin: 'the DAWG to get a new minor release out (https://github.com/SuperDARN/rst/projects/4) that includes the AACGM update'

Update to AACGM-v2 model now available from Dartmouth College

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