New Automated Survey... (Part 4) ... and the seasonal variations in the appearance of atmospheric holes in the Polar images in the 1990s (top chart)... ...are similar to those observed in the 1980s with Dynamic Explorer 1 (middle chart)... ..and by ground-based forward-scatter radar in the 1950s (bottom chart). "These variations," notes Frank, "can only be accounted for by the existence of a genuine geophysical phenomenon. Instrument noise cannot--and will not--produce such results." Go to Parts [1] [2] [3]