Forthcoming 2007/2008 Mars

Watch the South Polar Region

CMO #341 (10 January 2008)

Masatsugu MINAMI


Japanese here


he movement of the tilt of the south pole this apparition is quite different than that of 15 years ago. In 1992/1993, the tilt was always away from the Earth during the early autumn, while this apparition it is toward us from 1 January (λ=011Ls) to 29 February (λ=039Ls). This implies this season is favoured in the sense we can observe the south circumpolar polar region at the season when the north polar cap remains large. In 1992/1993, the south autumnal equinox visited on 21 Nov 1992 when φ=12.9N and then down but the tilt was maximum with φ=3.8N at λ=039Ls. On the contrary this year the southern tilt is toward to us until λ=039Ls.

 We are now appreciating the hypothesis of W. H. PICKERING that the maximal polar caps cannot exist at the same time. Some numerical experiments based on the pure CO2 atmosphere theory predict a growing of the spc just before λ=025Ls (while maximum is retarded until after λ=090Ls, winter solstice), but before that the spr will be obscured by the nph. Unfortunately since DS gradually goes down to the north (intersection point of the dotted lines in the Figure (due to NISHITA)), the defect of illumination will affect near the area of the south pole soon. Nevertheless this is the best chance for us to watch the trend of the south circumpolar region in the southern early autumn. Any image should be accompanied by B ingredient and processed carefully paying attention to the southern terminator.


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