LTGLIST

Lists GOES-R Series Geostationary Lightning Mapper (GLM) and MTG Lightning Imager (LI) point data.

Format

LTGLIST map [keywords]

Parameters

map

name of the map that is used to set the lat/lon bounds for the LTG data that are listed in the output; use any predefined map in the MAP command, e.g., NA, USA, MID, EUR (default=WORL); to use an image frame's bounds rather than a map, omit this parameter and specify TIME=IMA or NAV=

Keywords

DATaset=	ADDE dataset name and position; specify as group/descriptor.position or alias.position where position is a positive integer (absolute position), or ALL (default=dataset determined by the values specified for the DEFTYPE, GROUP, DESCRIPTOR and POSITION keywords in the MCLTG.USER/.SITE/.CORE text file)
DAY=	bday eday	beginning and ending dates (bday default=current date, eday default=bday)
	IMA	uses the day and time of the current image frame
ECHo=	YES	shows the PTLIST commands that are run by LTGLIST (default=NO)
INCrement=	time increment, in minutes, that is used with the TIMe= and DAY= keywords to determine the time range of LTG data to list; see the Remarks for additional details and examples (default=value specified for the INCREMENT keyword in the MCLTG.USER/.SITE/.CORE text file; the increment is set to 5 [minutes] in MCLTG.CORE)
NAV=	frame to use for navigation; specify a frame number or C for current frame (default=C); no map is drawn; you can use this keyword only if nothing or X is specified in the map parameter
PARam=	parm1...parmN		list of parameters to list in the output (default=values in the LIST- definition for each type in the DEFPARAM section of the MCLTG.USER/.SITE/.CORE text file
POSition=	position to list the lightning strikes; valid options are GROUND or CLOUDTOP, where:
	GROUND	lists the lightning strikes at the ground positions (default) NOTE: GLM data is disseminated with parallax correction, i.e. POS=GROUND
	CLOUDTOP	lists the lightning strikes at the cloudtop positions NOTE: MTG LI data is disseminated without parallax correction, i.e. POS=CLOUDTOP
SATs=	ALL	lists data from all datasets matching the lat/lon extents of the image frame (default)
	DEF	lists data from the default dataset specified in the context file
	name	lists data from the satellite name in the context file. Current options are EAST, WEST, and MTG
TIMe=	sets the time or times that are used with the INCrement= keyword to determine the time range of data to list; the three formats are listed below; see the Remarks for additional details and examples
	etime	ending time of data to list (default=current time); beginning time is calculated from INCrement= keyword
	btime etime	time range of data to list; if using this option you must specify both btime and etime
	IMA	uses the day and time of the current image frame as the ending time of the data to list (the beginning time is calculated from the INCrement= keyword); also uses the image frame's domain for the lat/lon bounds if nothing or X is specified in the map parameter
TYPe=	data type; the valid options are EVEnt, GROup, FLAsh, AF, AFA, AFR (default=value specified for DEFTYPE keyword in MCLTG.USER/.SITE/.CORE text file; the value is set to GROUP in MCLTG.CORE)

Remarks

The LTGLIST command lists GOES-R Series Geostationary Lightning Mapper (GLM) and MTG Lightning Imager (MTG LI) point data. GOES data processing in the Ground System groups lightning flashes from the smallest increments (Events), to aggregates of Events (Groups) to aggregates of Groups (Flashes). Thus, Events are on a rectangular grid wherein each gridpoint is a GLM Field of View. Groups are located at the centroid of the Events that comprise the Group, and Flashes are located at the centroid of the Groups that comprise the Flash. Typically, the number of Events is greater than the number of Groups, which is greater than the number of Flashes.

MTG Lightning Imager data is arranged in a similar fashion to GOES GLM. The LI-L2-LGR Lightning GRoup product represents the Lightning Groups. The LI-L2-LFL Lightning FLash product represents the Lightning Flashes. The LI-L2-AFA Accumulated Flash Area product represents the area touched by multiple flashes, and the number of flashes per pixel. The LI-L2-AF Accumulated Flash product represents the normalised density of events per pixel from multiple flashes. The LI-L2-AFR Accumulated Flash Radiance product represents the total radiance per pixel from multiple events.

The TIMe=, DAY= and INCrement= keywords work together to determine the time range of LTG data to list. If TIMe= is not specified the time range is from the current time minus the INC= value to the current time (e.g., if the current time is 12:15 and INC=60 then data from 11:15 to 12:15 are listed). If you specify a single time or IMA in TIMe= the time range is from that time minus the INC= value to that time. The examples below assume that the INC= value has not been changed from its default setting of 5 in MCLTG.CORE.
      TIME=IMA - lists data from 5 minutes before the image time to the image time
      TIME=18:15 - lists data from 18:10 to 18:15
      TIME=18:15 INC=30 - lists data from 17:45 to 18:15
      TIME=18:15 19:15 - lists data from 18:15 to 19:15

The LTGDISP and LTGLIST commands use the MCLTG.* context files (where * = .CORE, .SITE and .USER) to set the defaults for many of the commands' parameter and keyword settings. The dataset names in MCLTG.CORE may not be appropriate for users who access their data from somewhere other than SSEC Satellite Data Services. Those users may need to specify the datasets they use in the DATaset= keyword, or create a MCLTG.USER or .SITE file (see instructions below) and add them there.

The .CORE files are supplied with McIDAS-X and should not be modified. You can, however, change their settings to your preferences. To do so, copy the .CORE file from ~mcidas/data to your $HOME/mcidas/data or another MCPATH directory, change its extension from .CORE to .USER or .SITE, then edit the settings as needed. The .USER file overrides the .SITE file, which overrides the .CORE file. This order of precedence ensures that your local settings (in the .USER and/or .SITE file) override the settings in the .CORE file.

Examples:

LTGLIST

This entry lists all the lightning data in last 5 minutes in the WORL domain. The type (Group, Event or Flash) and dataset are determined by the settings in the MCLTG.CORE/USER/SITE text files. The default listing will list 10 data points each from the WEST, EAST, and MTG datasets.

LTGLIST NY TYPE=GROUP TIME=11 12 NUM=ALL

This entry lists all of the GLM data of type GROUP from 11:00 to 12:00 UTC for the current day in the domain that the command "MAP NY" displays. Note that the listing of GLM data is not limited to points in the state of New York; it includes all portions of all states that are shown in the map. If you want to limit the data to a smaller region, or a region that is not in one of the predefined maps, add the SELect= keyword from the PTDISP command, as shown in the following example.

LTGLIST TYPE=EVENT TIME=12:28 12:30 SELECT='LAT 10 30; LON 60 100' NUM=ALL

This entry lists all of the GLM data of type EVENT from 12:28 to 12:30 UTC for the current day in the region from 10 to 30 degrees North latitude and 60 to 100 degrees West longitude.

LTGLIST TX TYPE=EVENT DAY=26/AUG/2017 TIME=18:00 INC=60 DATASET=HARVEY/GLM

This entry lists the default of ten observations of the GLM data of type EVENT in dataset HARVEY/GLM from 17:00 to 18:00 UTC on 26 August 2017 in the domain that the command "MAP TX" displays.

LTGLIST NV TYPE=FLASH TIME=20:30 21:00 POS=GROUND
LTGLIST NV TYPE=FLASH TIME=20:30 21:00 POS=CLOUD

The commands above show the difference between GLM lightning locations that are corrected for parallax versus those with the correction removed. Both commands list the GLM data of type FLASH from 20:30 to 21:00 UTC in the domain that the command "MAP NV" displays. The first command with POS=GROUND lists the latitudes and longitudes in the default locations, which are parallax-corrected ground positions in the GLM files. The second command with POS=CLOUD removes the parallax correction so that the latitudes and longitudes match the approximate cloudtop positions as viewed from the GOES-R series satellite.

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