McIDAS User's Guide
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GLMLIST | GOES-R Series Geostationary Lightning Mapper (GLM) point data GLMLIST type
Parameters: type | source type; the valid options are EVEnt, GROup or FLAsh (def=value specified for DEFTYPE keyword in GLM.USER/.SITE/.CORE text file; the value is set to GROUP in GLM.CORE) Keywords: DATaset= | ADDE GLM dataset name and position; specify as group/descriptor.position or alias.position where position is a positive integer (absolute position), or ALL (def=dataset determined by the values specified for the DEFTYPE, GROUP, DESCRIPTOR and POSITION keywords in the GLM.USER/.SITE/.CORE text file; the values for them in GLM.CORE result in the default set to EAST/GLM-GROUP.ALL) DAY=bday eday | beginning and ending dates (bday def=current date, eday def=bday) =IMA | use the day and time of the current image frame INCrement= | time increment, in minutes, that is used with the TIME= and DAY= keywords to determine the time range of GLM data to list; see the Remarks for additional details and examples (def=value specified for the INCREMENT keyword in the GLM.USER/.SITE/.CORE text file; the increment is set to 5 [minutes] in GLM.CORE) MAP= | name of the map that is used to set the lat/lon bounds for the GLM data that are listed in the output; use any predefined map in the MAP command, e.g., WORL, NA, USA, TX (def=USA) PARam=parm1...parmN | list of parameters to list in the output (def=values in the LISTEVENTS, LISTGROUPS, LISTFLASHS keywords in the DEFPARAM section of the GLM.USER/.SITE/.CORE text file; the values are as follows in GLM.CORE: for 'type' EVENT: LISTEVENTS=DAY TIME LAT LON IDN ENGY GRUP for 'type' GROUP: LISTGROUPS=DAY TIME LAT LON IDN ENGY AREA FLSH for 'type' FLASH: LISTFLASHS=DAY TIME LAT LON IDN ENGY AREA) POSition= | position to list the lightning strikes; valid options are GROUND or CLOUDTOP, where: - GROUND lists the lightning strikes at the corrected ground positions, keeping the native parallax correction in the GLM file (def) - CLOUDTOP lists the lightning strikes at the approximate cloudtop positions as viewed from the GOES-R series satellite, removing the native parallax correction in the GLM file TIMe= | sets the time or times that are used with the INCrement= keyword to determine the time range of GLM data to list; the three formats are listed below; see the Remarks for additional details and examples =etime | ending time of GLM data to list (def=current time); the beginning time is calculated from the INCrement= keyword =btime etime | time range of GLM data to list; if using this option you must specify both btime and etime =IMA | use the day and time of the current image frame as the ending time of the GLM data to list; the beginning time is calculated from the INCrement= keyword Remarks: The GLMLIST command lists GOES-R Series Geostationary Lightning Mapper (GLM) point data. GLM 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. Real-time GLM datasets normally consist of netCDF files that each contain 20 seconds of data. For example, there are separate files at 21:25:00, 21:25:20, 21:25:40, 21:26:00, 21:26:20, etc., assuming the GLM detected lightning during each of the corresponding 20 second intervals. The TIMe=, DAY= and INCrement= keywords work together to determine the time range of GLM 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 GLM.CORE. TIME=IMA - lists GLM data from 5 minutes before the image time to the image time TIME=18:15 - lists GLM data from 18:10 to 18:15 TIME=18:15 INC=30 - lists GLM data from 17:45 to 18:15 TIME=18:15 19:15 - lists GLM data from 18:15 to 19:15 The POSition=GROUND/CLOUDTOP keyword lets you choose whether to list the lightning strikes with the parallax correction that is included in the GLM files. The default option, GROUND, lists the lightning strikes at the ground positions stored in the GLM files. These are approximate locations that are parallax corrected based on a latitude-varying seasonally-mean tropopause height, not the height where the GLM sensor detected the lightning. The CLOUDTOP option removes the parallax correction of the latitude/longitude values in the GLM file. This results the locations of the lightning as viewed from the satellite, often on the cloud top. The GLMDISP and GLMLIST commands use the GLM.* context files (where * = .CORE, .SITE and .USER) to set the defaults for many of the commands' parameter and keyword settings. The dataset names in GLM.CORE may not be appropriate for users who access their GLM 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 GEODATA.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: GLMLIST This enry lists all the GLM data in last 5 minutes in the MAP=USA domain. The type (Group, Event or Flash) and dataset are determined by the settings in the GLM.CORE, GLM.SITE and GLM.USER text files. GLMLIST FLASH MAP=WORL TIME=12 INC=1 This entry lists all the GLM data of type FLASH from 11:59 to 12:00 UTC. Although the GLM senses data only in the satellite's field of view (i.e., not globally), the keyword MAP=WORL was specified in this example to ensure that all of the data that the GLM sensed in that one minute time period is listed in the output. The keyword INC=1 was specified because the number of matches be can be extreme (i.e., thousands of lines of output) if an increment of 5 minutes (the default) or more is requested. GLMLIST GROUP MAP=NY TIME=11 12 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. GLMLIST EVENT TIME=12:28 12:30 SELECT='LAT 10 30; LON 60 100' 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. GLMLIST EVENT MAP=TX DAY=26/AUG/2017 TIME=18:00 INC=60 DATASET=HARVEY/GLM This entry lists all 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. GLMLIST FLASH MAP=NV TIME=20:30 21:00 GLMLIST FLASH MAP=NV 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 all of 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 (without POS=CLOUD) 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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