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