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  • Author or Editor: Frank W. Gallagher III x
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Frank W. Gallagher III

Abstract

It has been suggested that green light often observed in association with severe thunderstorms is caused by sunlight being reflected onto the cloud by green vegetation. Colorimetric observations were recorded of green-colored and blue-colored thunderstorms in conjunction with spectral measurements of the light reflected by the ground beneath the storms. Simple numerical models were used to evaluate the likelihood of ground-reflected light causing the green color in storms. Both the observations and calculations indicate that the green light seen in severe thunderstorms is not caused by light reflected from green foliage.

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Frank W. Gallagher III

Abstract

The theoretical development presented by Fraser can produce a spectrum of light that would be perceived as a faint green. The theory assumed a perfectly black background thunderstorm. Severe thunderstorms are certainly not black when observed from a distance of 30–40 km. Thus it is useful to compare the theory with some observed examples of severe thunderstorms that should have been green by the Fraser theory but were not. Therefore, some elementary modifications of the Fraser model such as using a nonblack background are suggested. The use of a nonblack cloud background tends to shift the resulting dominant wavelengths away from the green portion of the spectrum, suggesting a better match with observations.

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