Role of H2O and CO2 Ices in Martian Climate Changes

✍ Scribed by Tokuta Yokohata; Masatsugu Odaka; Kiyoshi Kuramoto

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 145 KB
• Volume: 159
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.2002.6944

✦ Synopsis

In order to study the stability of martian climate, we constructed a two-dimensional (horizontal-vertical) energy balance model. The long-term CO 2 mass exchange process between the atmosphere and CO 2 ice caps is investigated with particular attention to the effect of planetary ice distribution on the climate stability. Our model calculation suggests that high atmospheric pressure presumed for past Mars would be unstabilized if H 2 O ice widely prevailed. As a result, a cold climate state might have been achieved by the condensation of atmospheric CO 2 onto ice caps. On the other hand, the low atmospheric pressure, which is buffered by the CO 2 ice cap and likely close to the present pressure, would be unstabilized if the CO 2 ice albedo decreased. This may have led the climate into a warm state with high atmospheric pressure owing to complete evaporation of CO 2 ice cap. Through the albedo feedback mechanisms of H 2 O and CO 2 ices in the atmosphere-ice cap system, Mars may have experienced warm and cold climates episodically in its history.