SYNTHESIS OF ATMOSPHERIC ELECTRICITY OBSERVATIONS: A THUNDERSTORM ON JULY 22, 1977, IN FLORIDA; DAY 77203 TRIP 77, KENNEDY SPACE CENTER (ATMOSPHERIC ELECTRICITY, LIGHTNING)
CONRAD, ARVIN CLARENCE, JR.
Doctor of Philosophy
Observations of an air-mass thunderstorm occurring July 22, 1977, during the Thunderstorm Research International Program (TRIP-77) at Kennedy Space Center (KSC), Florida are interpreted. These observations yield insight into storm dynamical and eletrical mechanisms and their interrelationships. The dynamics of this storm are markedly different from that of the classical picture of an isolated convective system. The observed air-mass cells exhibit dynamic and electric changes on time and spatial scales that are significantly smaller than described in text book examples: time scales on the order of 10 rather than 30-90 minutes and areal extents on the order of < 4 km rather than 6-10 km. Fast scanning radar (NMIMT-REDBALL) images indicate that dynamic periodicity is produced by rapid buoyant-bubble growth. Comparison of acoustic and radio frequency (RF) derived source locations suggest that these techniques depict entirely different scale phenomena. The RF (KSC-REAL TIME LDAR) consistently located sources higher in the cloud than the concurrent thunder locations. These thunderstorms produce copious quantities of RF radiation from small discharge processes that are not classically considered lightning (i.e., a flash of light followed by thunder). There is temporal complementarity (anticorrelation) in the activity profiles of the small upper-cloud discharges and lightnings; i.e., RF "sizzle" precedes lightning that produces an acoustic "bang". When acoustic source locations of sequential events are overlaid, the volumes depicted by these loci seek or fill disjoint jet contiguous regions rather than repeatedly discharging the same volume. This is important to considerations of thunderstorm charging rates because the lightnings are not discharging the same volume, hence, cloud volume recharging between events is not necessary. The inherent temporal and spatial "granularity" in the data acquisition makes data comparisons difficult which inhibits the ability of such experiments to resolve questions of cloud electrification. The testing of these hypotheses requires highly resolved ground based observations and in situ microphysical and electrical measurements. Attention to simultaneity in data acquisition is paramount in the design of cooperative thunderstorm electrification studies.