IQ reversal periods

An IQ reversal period for SyowaEast is
from 08:17:00 UT on Dec. 27, 1997 (year=1997, ysec=31133820, day=360)
......to 11:18:28 UT on Jul. 16, 1999 (year=1999. ysec=16975108, day=196)
And two periods
from 08:16:00 UT to 10:00:00 UT on Dec. 27, 1997
(which corresponds to data files '97122708nA' - '97122708nF')
and
from 11:17:00 UT to 11:25:00 UT on Jul. 16, 1999
(which corresponds to '99071611n' data)
are periods for replacing receiver, getting CAL data or tuning up etc... so please do NOT use these 2 periods as natural phenomena in your scientific analysis.

An IQ reversal period for SyowaSouth is
all days in 1995
and any time prior to 11:00:00 UT on Apr. 24, 1996 (year=1996, ysec=9889200, day=115)

All the velocity data were reversed in sign for each period for the correspoding radar.

To read proper and correct LOS Doppler velecity data from each FIT data for these period, you should use newest version of SuperDARN libfit and libmerge shared libraries.
(We will NOT change original fit files. We change the reading software, instead.)
A patch info for this can been seen HERE in this page.
I hope this will be included in official SuperDARN library source codes soon (by APL).

We do NOT change our original DAT files, either.
We have now no plan to modify libraw(readraw) library. You have to be careful enough to analyse them.

We do NOT change our SMR files, either. You have to be careful enough to analyse them.
We've added a small code to quick_look plot program so as to deal with this and to create proper RTI summary plots.
You should also have this modification for any smr reading software (or should convert the original smr files, or recreate smr files from original fit files using the newest libfit library.)

We've already replaced all the summary plots by correct ones(marked as 'VelRevOK' on each image) on our SuperDARN SENSU Web Page at NIPR(here to see) by the new QL program described above.

All the summary plots for these periods on SuperDARN southern hemisphere summary plots at BAS (here to see) are currently *NOT* correct (velocity sign reversed), so please be careful.

A patch for libfit/libmerge SuperDARN libraries

A patch for source codes for SuperDARN libfit/libmerge libraries.
i.e. a patch for /project/radar/radops/fitread/fitropen.c Revision 1.10 to create Revieion 1.11...
.......................................................................
Add...
Revision 1.11 1999/07/17 00:00:00 Sessai
fix for the velocity sign error that is present in Syowa East data
between December 27, 1997 and July 16, 1999.
.......................................................................
Change...
char fitropen_rev[] = {"$Revision: 1.10 $"};
to...
char fitropen_rev[] = {"$Revision: 1.11 $"};
(by RCS?...)
.......................................................................
Just after a define statement...
#define SYOWA 12
add the following line...
#define SYOWAEAST 13
.......................................................................
Just after a part in the Rev 1.10 original code...
/* the last step is to see if this is actually a Syowa radar file.
   If it is, then we have to check the date and time to see if
   this data is from the period when the velocity on the Syowa data
   was reversed in sign.

   The period of sign reversed data is any time prior to 11 UT, April 24, 1996

   */

if (fdata->p.ST_ID == SYOWA)
{
  if ((fdata->p.YEAR < 1996) ||
      ((fdata->p.YEAR == 1996) && (inx_stime < 9889200))) {

    fit_file->fit_read = read_fit386_syowa;
        /* added by Sessai just for checking... */
        //printf("Special read_fit386_syowa (Vel Reverse!!!) selected...\n");
  }
        /* added by Sessai just for checking... */
  //else printf("normal read_fit386_v130 (No Vel Reversal..) selected...\n");
}
Add the following code...
/* one more step! is to see if this is actually a Syowa East radar file.
   If it is, then we have to check the date and time to see if
   this data is from the period when the velocity on the Syowa East data
   was reversed in sign.

   The period of sign reversed data is
	from 08:17:00 UT, December 27, 1997
		(1997/12/27 (day 360) 08:17:00 UT (year=1997, ysec=31133820))
	to   11:18:28 UT, July     16, 1999
		(1999/07/16 (day 196) 11:18:28 UT (year=1999, ysec=16975108))
   */

if (fdata->p.ST_ID == SYOWAEAST)
{
  if ((fdata->p.YEAR == 1998) ||
      ((fdata->p.YEAR == 1997) && (inx_stime > 31133820)) ||
      ((fdata->p.YEAR == 1999) && (inx_stime < 16975108))) {

    fit_file->fit_read = read_fit386_syowa;
	/* added by Sessai just for checking... */
	//printf("Special read_fit386_syowa (Vel Reverse!!!) selected...\n");
  }
	/* added by Sessai just for checking... */
  //else printf("normal read_fit386_v130 (No Vel Reversal..) selected...\n");
}
.......................................................................
...and save it, confirm you also have
/project/radar/radops/fitread/read_fit386_syowa.c (Revision 1.1)
...and recompile all the shared libraries you need...
That's it!...
.......................................................................
Many thanks for your attention!!!

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