The Green Flash Observed October 16, 1929, at Little America by Members of the Byrd Antarctic Expedition

35 minute green flash observed at Little America on 16 October 1929: a retrospective study

“…In either event, both types of subcritical Novaya Zemlya mirages are capable of producing large color dispersion when only the top edge of the Sun is present [9]. The photographed appearance of the horizontally-wide and vertically-narrow top of the top of the Sun during the last stage of other examples of these mirages [11] is also consistent with the fact that "occasionally green, orange, and red flares could be seen simultaneously at different points" [13].…”

“…The published account of the 16 October 1929 green flash by Haines states that "Between the Sun and the camp lay a depression in the barrier within which the air was often much colder and less disturbed than the overall surrounding area. Conditions seemed favorable for marked refraction, as a very shallow layer of surface air from the South underran a northerly wind all evening, which condition should have caused a marked temperature inversion" [13]. A temperature inversion in the "depression in the barrier" suggests that, although the observers were standing at ground level at the start of the observation, the green flash might have been associated with a mock mirage or subcritical inferior Novaya Zemlya mirage, for which the observer is at a higher elevation than the temperature inversion.…”

“…Numerous times while on the barrier the writer looked for the green flash under quite similar conditions but failed to observe it. This fact would seem to indicate that a favorable condition of the air is necessary for its occurrence at a time when a very small part of the Sun's disk is visible" [13].…”

“…In contrast to these observations, on 16 October 1929, five members of the Byrd Expedition 1, including two meteorologists and one physicist who were experienced observers, saw a green flash at the Little America station in Antarctica that is reported to have occurred intermittently for 35 min as the top of the Sun skimmed along the horizon while it was setting. The published account of the observation [13] states that "the length of time during which the green flare was visible varied from a fraction of a second to several seconds." Since the effect was seen looking over the Ross Ice Shelf to the south of the Little America station, the intermittance was in part due to "… the unevenness of the Barrier surface which formed the line of the horizon.…”

“…These points or flashes of light would sometimes have a general greenish color on their appearance or disappearance. Occasionally, green, orange, and red flares could be seen simultaneously at different points, giving one the impression of traffic lights" [13].…”