Reducing HMB lower limit to 30 degrees

[ksterne]

As discussed in #617 and then more recently within the Data Analysis Working Group meetings, theres a need to reduce the minimum latitude of the HMB to 30 degrees from the 40 degrees it is at now.

I'm not as familiar with this code, so possibly double check that I got the edit correct as I'm going off of what was provided in #617.

I don't have great way to test this beyond a simple compilation test at the moment, but I can generate some data and/or plots if it needs it.

[pasha-ponomarenko]

@ksterne, this is not as simple. :-)
To change the minimum latitude for HMB, one needs to edit following three files:
/data/rst/rst-release-rst-5.1/codebase/superdarn/src.lib/tk/hmb.1.0/src/hmb.c

/data/rst/rst-release-rst-5.1/codebase/superdarn/src.lib/tk/hmb.1.0/include/map_addhmb.h

/data/rst/rst-release-rst-5.1/codebase/superdarn/src.bin/tk/tool/map_addhmb.1.17/map_addhmb.c

In each file, all 36s need to be replaced with 46s and 40s need to be replaced with 30s.

[pasha-ponomarenko]

@ksterne, I have done the necessary modifications. The ultimate test would be to generate maps for an active period like 10-11 May 2024 and see if the minimum HMB MLAT goes below 40 deg. Here is an excerpt from my presentation at the last workshop. Pay attention to black dots as they are obtained with the conventional HMB algorithm.

[egthomas]

I tested this for 10-11 May 2024 when the HMB was observed to saturate at 40 degrees magnetic latitude (#617). Here is the 48-hour output from hmb_plot with the current 40 degree limit:

and here is the output for the same interval using the new 30 degree limit:

so things look good to me. Note I made one more change to hmb_plot to support this new lower latitude limit.

[mtwalach]

Looks good to me. :)