Correct the tc_gen BEST track genesis event definition.

[JohnHalleyGotway]

Describe the Enhancement

Dan Halperin did more testing of the tc_gen tool with the met-9.1_beta3 development release and found a bug. tc_gen is not identifying genesis at the correct point for BEST tracks. Test this using bal022019.dat. The BEST track genesis is identified when the storm is a disturbance (category=DB) rather than the correct time when it is a tropical depression (category=TD), as requested in the TC-Gen configuration file:

best_genesis = {
   technique   = "BEST";
   category    = [ "TD", "TS" ];
   vmax_thresh = NA;
   mslp_thresh = NA;
}

Time Estimate

1 day.

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• Select engineer(s) or no engineer required: John Halley Gotway
• Select scientist(s) or no scientist required: Kathryn Newman

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[JohnHalleyGotway]

Input from Dan H showing examples of bug (1) where genesis is identified at the wrong time:

[JohnHalleyGotway]

I found the bug in tc_gen.cc on this line:

https://github.com/NCAR/MET/blob/10c4da8ba90c5f85416ae86a0e68c1ab29d1a0ce/met/src/tools/tc_utils/tc_gen/tc_gen.cc#L588

This adds the track to the list of Genesis events without specifying the track point at which genesis actually occurred. The library code just chooses the first track point. Instead, pass a second argument indicating the genesis track point.

Used this BEST track to test:
bal022019.txt

Prior to the fix, GenesisTime = "20190710_120000":

DEBUG 6: |    [1] GenesisInfo: IsSet = true, IsBest = true, IsOper = false, IsAnly = false, StormId = "AL022019", Basin = "AL", Cyclone = "02", StormName = "BARRY", TechniqueNumber = -9999, Technique = "BEST", Initials = "(nul)", GenesisTime = "20190710_120000", InitTime = "NA", LeadTime = "000000", Lat = 28.50000, Lon = -86.50000, DLand = 92.24668, NPoints = 25, MinValidTime = "20190710_120000", MaxValidTime = "20190716_060000", MinWarmCoreTime = "NA", MaxWarmCoreTime = "NA"

After the fix, GenesisTime = "20190711_000000":

DEBUG 6: |    [1] GenesisInfo: IsSet = true, IsBest = true, IsOper = false, IsAnly = false, StormId = "AL022019", Basin = "AL", Cyclone = "02", StormName = "BARRY", TechniqueNumber = -9999, Technique = "BEST", Initials = "(nul)", GenesisTime = "20190711_000000", InitTime = "NA", LeadTime = "000000", Lat = 27.80000, Lon = -87.60000, DLand = 118.85302, NPoints = 25, MinValidTime = "20190710_120000", MaxValidTime = "20190716_060000", MinWarmCoreTime = "NA", MaxWarmCoreTime = "NA"

And that matches the time and location of the first instance of category = TD in the ATCF input file:

AL, 02, 2019071100,   , BEST,   0, 278N,  876W,  30, 1008, TD,   0,    ,    0,    0,    0,    0, 1013,  180,  80,  35,   0,   L,   0,    ,   0,   0,        TWO, M,  0,    ,    0,    0,    0,    0, genesis-num, 005,