Lightning optical pulse statistics from storm overflights during the Altus Cumulus Electrification Study

Mach, Douglas M.; Blakeslee, Richard J.; Bailey, Jeff; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, Jeff

doi:10.1016/j.atmosres.2004.11.039

Cited by 29 publications

(27 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 850 overflights of electrified clouds were obtained from both the NASA ER‐2 aircraft [ Heymsfield et al , 2001; Hood et al , 2006] and the Altus unmanned aerial vehicle [ Blakeslee et al , 2002; Mach et al , 2005; Farrell et al , 2006]. The ER‐2 operates at a nominal altitude of 20 km with a cruise speed of about 210 m s −1 .…”

Section: Instrumentationmentioning

confidence: 99%

Global electric circuit implications of combined aircraft storm electric current measurements and satellite-based diurnal lightning statistics

Mach¹,

Blakeslee²,

Bateman³

2011

J. Geophys. Res.

150

View full text Add to dashboard Cite

[1] We have combined analyses of high-altitude aircraft observations of electrified clouds with diurnal lightning statistics from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) that are carried aboard low-Earth-orbiting satellites to reproduce the diurnal variation in the global electric circuit. Using basic assumptions about the mean storm currents as a function of flash rate and location (i.e., land or ocean) and the global electric circuit, our estimate of the current in the global electric circuit matches the Carnegie curve diurnal variation to within 4% for all but two short periods of time, in which the difference was 11% in one time period (0430 UTC) and 6% in the second period (1830 UTC). This excellent agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. We assume that (1) the mean values for current and flash rates in the aircraft storm overflight data set (1.7 A and 0.8 flashes min −1 for oceanic thunderstorms, 1.0 A and 2.2 flashes min −1 for land thunderstorms, 0.41 A for oceanic electrified shower clouds (i.e., electrified but no lightning detected), and 0.13 A for land electrified shower clouds) and (2) the diurnal variations in lightning rates over land and ocean found in the satellite data set are universally applicable. Mean contributions to the global electric circuit from land and ocean thunderstorms are 1.1 kA (land) and 0.7 kA (ocean). Contributions to the global electric circuit from electrified shower clouds are 0.22 kA for ocean storms and 0.04 kA for land storms. The mean total conduction current for the global electric circuit is 2.0 kA. The means that for the number of storms contributing to the global electric circuit, 1100 are land storms with lightning, 530 are ocean storms without lightning, 390 are ocean storms with lightning, and 330 are land storms without lightning. A closer fit to the Carnegie curve is possible if the contributions from electrified shower clouds are increased by a factor of 3 or 4.Citation: Mach, D. M., R. J. Blakeslee, and M. G. Bateman (2011), Global electric circuit implications of combined aircraft storm electric current measurements and satellite-based diurnal lightning statistics,

show abstract

Section: Instrumentationmentioning

confidence: 99%

Global electric circuit implications of combined aircraft storm electric current measurements and satellite-based diurnal lightning statistics

Mach¹,

Blakeslee²,

Bateman³

2011

J. Geophys. Res.

150

View full text Add to dashboard Cite

show abstract

“…In an integrating sensor, such as LIS/OTD, the frame time specifies how long a particular pixel accumulates charge between readouts. The median optical lightning pulse width when viewed from above is around 400 μ s [ Christian and Goodman , 1987; Christian et al , 1989; Goodman et al , 1989; Mach et al , 2005], which would indicate that a frame time of 1 ms would be most appropriate to minimize pulse splitting and maximize lightning detectability. Technological limitations, however, only allowed a 1.9‐ms integration time with a readout time of 0.1 ms (for a net frame‐to‐frame time of 2.0 ms).…”

Section: Introductionmentioning

confidence: 99%

Performance assessment of the Optical Transient Detector and Lightning Imaging Sensor

et al. 2007

View full text Add to dashboard Cite

[1] We describe the clustering algorithm used by the Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD) for combining the space-based observations of lightning pulse data into events, groups, flashes, and areas. Events are single pixels that exceed the LIS/OTD background level during a single frame (2 ms). Groups are clusters of events that occur within the same frame and in adjacent pixels. Flashes are clusters of groups that occur within 330 ms and either 5.5 km (for LIS) or 16.5 km (for OTD) of each other. Areas are clusters of flashes that occur within 16.5 km of each other. The flash data from LIS/OTD are currently being used for lightning and thunderstorm processes and climatological studies; therefore we test how variations in the algorithms for the event-group and group-flash clustering affect the flash count for a subset of the LIS and OTD data. We divided the subset into areas with low (1-3), medium (4-15), high (16-63), and very high (64+) flash counts to see how changes in the clustering parameters affect the flash rates in these different sizes of areas. We found that as long as the cluster parameters are within about a factor of two of the current values, the overall flash counts do not change by more than about 20%. Therefore the flash clustering algorithm used by the LIS and OTD sensors are robust and create flash rates that are relatively insensitive to reasonable variations in the clustering algorithms.

show abstract

“…The NASA Earth Science Enterprise Science Demonstration Project funded studies to use both of these aircraft. The first mission, the Altus Cumulus Electrification Study (ACES) mission, (Blakeslee et al 2002), used Altus to provide measurement of electrical fields within storm clouds (Mach et al 2005), while the Coffee Harvest mission demonstrated the capability of loitering for imaging between clouds, and the ability to provide precision agriculture information in near real-time. The science requirements for large UAV are largely to provide high-altitude measurements over long periods of time, and to carry multiple instruments with large mass and volume.…”

mentioning

confidence: 99%

The NASA SIERRA science demonstration programme and the role of small–medium unmanned aircraft for earth science investigations

Fladeland

Sumich

Lobitz

et al. 2011

Geocarto International

View full text Add to dashboard Cite

Lightning optical pulse statistics from storm overflights during the Altus Cumulus Electrification Study

Cited by 29 publications

References 14 publications

Global electric circuit implications of combined aircraft storm electric current measurements and satellite-based diurnal lightning statistics

Global electric circuit implications of combined aircraft storm electric current measurements and satellite-based diurnal lightning statistics

Performance assessment of the Optical Transient Detector and Lightning Imaging Sensor

The NASA SIERRA science demonstration programme and the role of small–medium unmanned aircraft for earth science investigations

Contact Info

Product

Resources

About