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Lightning Optical Pulse Statistics from Storm Overflights During the Altus Cumulus Electrification StudyThe Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect time resolved optical pulse data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses. Most of these observations were made while close to the top of the storms. We divided our data into two amplitude groups based on prior NASA U2 aircraft optical data and our pulse characteristics. The group of large pulses with radiance greater than 2.1 mW /sq m sr had mean and median 10 - 10% optical pulse widths of 765 and 735 microns respectively, the 50-50% pulse widths of 396 and 355 microns respectively, and 10-90% rise times of 290 and 260 microns. These values are very similar to the previous U2 based optical results The other group of pulses consisting of slightly more than a quarter of the total pulses observed had radiances less than the minimum values detected in the U2 study. The small pulses were narrower than the large pulses with 5040% mean and median values of 198 and 160 ps respectively. Only 12 % of the flashes contained only small pulses, minimizing the impact of this data on the estimates of detection efficiencies of the orbital instruments, the Lightning Imaging Sensor and Optical Transient Detector.
Document ID
20040082387
Document Type
Preprint (Draft being sent to journal)
Authors
Mach, D. M. (Alabama Univ. Huntsville, AL, United States)
Blakeslee, R. J. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Bailey, J. C. (Raytheon Information Technology and Scientific Services Huntsville, AL, United States)
Farrell, W. M. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Goldberg, R. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Desch, M. D. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Houser, J. G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Meteorology and Climatology
Distribution Limits
Public
Copyright
Other