Introduction to Lightning Imaging Sensor (LIS)

GROUPS
structure name: group
  Status Parameter Structure Element Name Type Size Description
A   group time TAI93_time float64 1 TAI93 time of all events in group
B   length of observation observe_time int16 1 length of observation of the region where the group occurred (viewtime approximation at group centroid)
C   geolocated position location float32 2 latitude & longitude centroid (radiance weighted average?)
C   calibrated radiance radiance float32 1 radiance for 2ms sample period
D   footprint size footprint float32 1 areal extent of group in sq km
E   group record number address int32 1 group address
F   parent record number parent_address int32 1 pointer to parent's address
G   child record number child_address int32 1 address of first event in a sequential list
H   number of children child_count int32 1 number of events
I   8-bit threshold value approx_threshold byte 1 estimated value of threshold (8-bit digital count) for the group determined from the background level of illumination
             
J   alert flag alert_flag byte 1 reflects status of instrument, platform, external factors, and processing algorithms
K   clustering probability tag cluster_index byte 1 ranges from 0 to 99 (a high number indicates that group is not likely to be random noise) -- value computed from the average of event values
L   lightning activity index density_index byte 1 a spatial metric that indicates whether the group was geolocated in a region of high lightning activity -- value computed from the average of event values
M   noise index noise_index byte 1 a metric that indicates whether the group was detected during a period of high noise (100- percent signal) -- value computed from the average of event values
N   solar glint cosine glint_index float32 1 cosine of angle -- value computed from the average of event values
O   eccentricity oblong_index float32 1 a metric indicating how oblong the group footprint is
P   time order grouping_sequence int32 1 time sequence of group
T   grouping status grouping_status byte 1 0 = group grouped normally
1 = group split between orbits - other half in next orbit
2 = group split between orbits - other half in previous orbit
3 = grouping algorithm failed due to an overflow of the buffer size that was implemented