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