Regression of Martian North polar cap 1994-1995

Abstract

The regression of the Martian north polar cap during the 1994-1995 apparition is examined with the measurements of the CCD (Charge Coupled Device) images and of the photographs of Mars obtained at the Hida Observatory, at the Vainu Bappu Observatory, and at the Bosscha Observatory. The retreat of the cap stopped until Mars reached about Ls = 54 deg (Ls is the areocentric longitude of the sun) when the cap started to shrink. The regression of the north polar cap in 1994-1995 appears to have been a little faster than the mean regression or the regression in 1979-1980, but to have been similar to those in 1946, in 1948, in 1950, in 1972, and in 1977-1978. Like the case of the south polar cap, the behavior of the north polar cap seems to be different from year to year.