2:25 p.m.
Hi,
If you are a user of the International Reference Ionosphere (IRI) and use the daily
updated index files provided by the University of New Brunswick and the IRI Working Group
(https://chain-new.chain-project.net/echaim_downloads/ig_rz.dat and
https://chain-new.chain-project.net/echaim_downloads/apf107.dat) please be aware that a
hardcoded limit in versions of the IRI from before December 2023 will result in the model
crashing if used with the provided updated index files after October 31st. We encourage
all users of the IRI to update to the latest version of the model to avoid interuption and
to ensure continued use of the model after October 2024.
If you use an older version of the IRI, a truncated index file is provided here:
https://chain-new.chain-project.net/echaim_downloads/capped/ig_rz.dat This file will not
include dates after October 2024, as such older versions of the IRI will not crash with
this file, but they will not be able to be used for dates beyond October 2024.
If you use an older version of IRI2020, IRI2016, or IRI2012 but cannot update to the
latest version and still need to run for dates after October 2024, a stopgap fix can be
enacted as follows:
In the read_ig_rz subroutine within your version of irifun.for, replace the real variable
declaration with the following:
real aig(1600),arz(1600)
and in the tcon subroutine within your version of irifun.for, replace the real variable
declaration with the following:
real ionoindx(1600),indrz(1600)
real ig(3),rz(3)
In versions of the IRI prior to December 2023, these variables are set to 806 elements
which needs to be increased, here to 1600 elements. You should also implement a fix to the
real(12,*) declarations in read_ig_rz subroutine within irifun.for with the following:
read(12,*) iupm,iupd,iupy
read(12,*) imst,iyst,imend,iyend
I do not guarantee that these changes will work for all older versions of the IRI and
still recommend that all users update to the latest version, but if you recompile with
these changes it should make it so that you can use those older versions of the model with
the new index files.
If you use IRI2007, the ig_rz.dat file for that version is formatted differently and the
new index files would not work regardless.
If you have any questions, please reach out to me or the IRI Working Group.
Cheers,
David Themens