Description of the data columns included in the FEGS Pulse Data Version 2
2018/08/02
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List of Column Parameters

1. Pulse ID
2. Data Channel Number
3. Year
4. Month
5. Day
6. Hour
7. Minute
8. Second.subsecond
9. GPS second
10. Latitude
11. Longitude
12. Altitude
13. Roll Angle
14. Pulse Start Index
15. Pulse Stop Index
16. Pulse Peak Radiance [W/m2 Sr]
17. Pulse Duration [ms]
18. Pulse 10-90 % Rise Time [ms]
19. Pulse 10-10 % Width [ms]
20. Pulse 50-50 % Width [ms]
21. Pulse Radiant Energy [J/m2 Sr]
22. Pulse Complexity
23. Signal-to-Noise Ratio
24. Mean Background Radiance [W/m2 Sr]
25. Maximum Pixel Number illuminated by the pulse
26. FOV Latitude 1
27. FOV Longitude 1
28. FOV Latitude 2
29. FOV Longitude 2
30. FOV Latitude 3
31. FOV Longitude 3
32. FOV Latitude 4
33. FOV Longitude 4

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Description

Summary:
FEGS Pulse Level Data provides timing, location, measured power, energy and temporal characteristics of the optical pulses identified in the FEGS data set.  To create this dataset the background radiance was estimated and subtracted from the optical time series and statistically large pulses were identified.

Column 1 lists the Pulse ID tag.  PulseID =1 is the first pulse detected during the flight.

Column 2 lists the Data Channel Number for the radiometer that detected the pulse.

Columns 3-8 list the microsecond precision UTC timestamp for the beginning of the 1 second data period that contains the identified optical pulse.

Column 9 lists the GPS timestamp of the 1 second data period that contains the identified optical pulse.  The subsecond information from column 6 should be added to this for subsecond accuracy.

Column 10-13 list the 3D GPS location and Roll angle of the ER2 at the time of the pulse.  Roll angles greater than about 5 degrees indicate that the ER2 was in a turn, and the foot print of the FEGS FOV at cloud top will be highly skewed.  Pulses observed during a turn should be analyzed with caution.

Columns 14 and 15 list the start and stop index of the pulse within the 1 second data period.  The index identifies the sample number of the digital signal that a pulse begins and ends on.  FEGS sample rate is 100 kHz, and sample period is 10 us.  Thus the beginning time of each pulse is found by adding the time stamp listed in columns 3-9 to the start index multiplied by 10 us.

Pulse Peak Radiance [W/m2 Sr] is the calibrated peak radiance measured for the detected pulse for the specified radiometer

Pulse Duration is the duration of time that the lightning signal was identified above the background level.

10-90% Rise Time indicates the time period for the optical pulse to increase from 10% of the peak value to 90% of the peak value on the initial rise to peak.

10-10% Width indicates the duration of time the pulse radiance was larger than 10% of the peak value.

50-50% Width is the Full Width at Half Maximum of the pulse, and indicates the duration of time that the pulse radiance was larger than 50% of the peak value.

Pulse Radiant Energy [J/m2 Sr] is the radiant energy measured by integrating the radiance over the duration of the pulse for the specified radiometer.

Pulse Complexity is a parameter included to quantify the number of radiance peaks superimposed upon one another during the identified pulse.  For low S/N ratios, this parameter greatly overestimates the actual number of peaks.  Currently this parameter is not trust worthy.

Signal-to-Noise Ratio is the ratio of the Pulse Peak Radiance to the Standard Deviation of the Background Radiance.

Mean Background Radiance is an estimate of the background radiance at the time of the identified pulse.

Columns 26-33 list GPS coordinates of a 4 point polygon that roughly outlines the FEGS FOV at the time of the pulse.  This spatial footprint assumes a cloud top height of 13 km which was typical for storms observed during the GOES-R Validation ER2 flight campaign.