NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Nighttime observations of thunderstorm electrical activity from a high altitude airplanePhotographs from a NASA U-2 airplane flying over nocturnal thunderstorms show frequent lightning activity in the upper part of the cloud. In some cases, unobscured segments of lightning channels 1 km or longer are visible in clear air around and above the cloud. Multiple images of lightning channels indicate multiple discharges in the same channel. Photographs taken through a diffraction grating show that the lightning has a spectrum similar to that observed in the lower troposphere. Lightning spectra obtained with a slitless line-scan spectrometer show strong singly ionized nitrogen emissions at 463.0 and 500.5 nm. Field changes measured with an electric field-change meter correlate with pulses measured with a photocell optical system. Optical signals corresponding to dart leader, return stroke, and continuing current events are readily distinguished in the scattered light emerging from the cloud surface. The variation of light intensity with time in lightning events is consistent with predicted modification of optical lightning signals by clouds. It appears that satellite based optical sensor measurements cannot provide reliable information on current rise times in return strokes. On the other hand, discrimination between cloud-to-ground and intracloud flashes and the counting of ground strokes is possible using the optical pulse pairs which have been identified with leader, return-stroke events in the cloud-to-ground flashes studied.
Document ID
19840023527
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Brook, M. (New Mexico Inst. of Mining and Technology Huntsville, AL, United States)
Rhodes, C. (New Mexico Inst. of Mining and Technology Albany, United States)
Vaughan, O. H., Jr. (NASA Marshall Space Flight Center Albany, United States)
Orville, R. E. (State Univ. of New York)
Vonnegut, B. (State Univ. of New York)
Date Acquired
September 4, 2013
Publication Date
September 1, 1984
Subject Category
Instrumentation And Photography
Report/Patent Number
NASA-TM-86455
NAS 1.15:86455
Accession Number
84N31597
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available