Accession Number : AD0008042


Title :   THUNDERCLOUD ELECTRIFICATION STUDIES, II


Corporate Author : CORNELL AERONAUTICAL LAB INC BUFFALO NY


Personal Author(s) : Chapman, Seville


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/008042.pdf


Report Date : 20 Jun 1952


Pagination or Media Count : 158


Abstract : The investigation of the generation of electric charges in thunderclouds included experiments to determine the electrification generated by the disruption of rain drops, corona-point strengths on the ground during blizzards, and the earth's upper-air electric field during blizzards. Both positive and negative charges averaging from less than 10 to the -13 power to more than 10 to the -10th power coulombs/drop were generated by 4-mm drops of distilled water disrupted in a 4- x 8-in. vertical wind tunnel. These magnitudes were sufficient to account for either a negligible fraction or all of thundercloud electrification. Drop-breaking experiments on 3-mm water drops supercooled to -6 deg and 14 deg C yielded average charges of 6.8 x 10 to the -12 power coulombs/drop,respectively. The magnitudes of electrification varied fromdrop to drop by a factor of 100 or more in all cases. Corona-point records for 22 months showed currents of about 10 microamp and up to 20 microamp at points 32 and 54 ft above ground. The earth's field fluctuated markedly in magnitude and polarity over intervals of a few seconds in disturbed weather even in the absence of lightning. During a snow-storm, a variation from -10 to + or - 10 times normal was noted within a minute with no observable change in the storm. Corona-point records for lightning, rain, and snowstorms showed marked asymmetry in time and indicated horizontal inhomogeneties in storm-cloud structures. Radiosondes modified to measure the vertical component of the earth's electric field showed polarity reversals with altitude up to 10,000 ft. In one case the polarity was opposite to that of the fair weather fields as high as 10,000 ft.


Descriptors :   *ATMOSPHERIC ELECTRICITY , ELECTRIC CHARGE , ELECTRIC FIELDS , RAIN , LIGHTNING , ASYMMETRY , VERTICAL ORIENTATION , RAINDROPS , STORMS , RADIOSONDES , MEAN , EARTH(PLANET) , POLARITY , WIND TUNNELS , UPPER ATMOSPHERE , INTERVALS , MEASUREMENT , WEATHER


Subject Categories : Meteorology


Distribution Statement : APPROVED FOR PUBLIC RELEASE