On Mars annual mean surface temperature near +/-60° latitude varies predominately with precession and is not closely related to annual mean insolation. Based on the last few million years of orbital history, the precession cycle dominates in a narrow latitude range 54°-65°, in which the margins of the two ice-rich permafrost layers in each hemisphere happen to lie, while mean annual temperature at other latitudes is controlled by the obliquity cycle. The phenomenon already exists on an airless uniform body in Mars orbit, where this latitude range shifts to 62°-74° on both hemispheres, and is closely related to temperature amplitude dependent reradiation into space.
Geophysical Research Letters
- Pub Date:
- September 2008
- Planetary Sciences: Solar System Objects: Mars;
- Planetary Sciences: Solid Surface Planets: Orbital and rotational dynamics (1221);
- Paleoceanography: Milankovitch theory