1.7), the martian system would be comparatively wetter than at present. In contrast, during periods of lower eccentricity (e.g., ∼1.2 Ma ago, Fig. The martian system of the recent past thus becomes “less wet” under higher eccentricity conditions. Given today’s polar distribution of water ice, having even cooler summer months would result in less heating of the northern water ice cap and would reduce the rate of summertime sublimation. Increasing the eccentricity would exacerbate this seasonal dichotomy-the northern spring and summer would become even longer and cooler. Icarus 170, 343–364.Īt the present day, aphelion occurs during late northern spring/southern autumn, while perihelion occurs during late northern autumn/southern spring, and so the northern spring and summer months are cooler than their southern counterparts (this difference is believed to be a contributing factor to the seasonality in the martian dust cycle and formation of the aphelion cloud belt, both discussed in Section 1.1). Long term evolution and chaotic diffusion of the insolation quantities of Mars. A long-term numerical solution for the insolation quantities of the Earth. Data from Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A.C.M., Levrard, B., 2004a. Present-day values are found at the right edge of the figure. Eccentricity history of Mars (black) and Earth (red) over the past 21 Ma.
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