Research of precipitaion on ancient-Mars

古火星降水研究

• 批准号: 11640429
• 负责人: ABE Yutaka
• 金额: $ 2.3万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640429/
• 关键词: Mars; Paleoclimate; Water circulation; Inclination of spin axis; General circulation model; land planet; 気候; 降水; 自転軸; 古環境

Many fluvial features on Mars indicate active hydrologic cycle on ancient-Mars. In this study, we investigated a water cycle on an idealized planet by using a general circulation model and applied its results to ancient-Mars. Following results are obtained : 1. Three climate regimes are recognized : A.Frozen regime : when the surface temperature is below the freezing point all the year, the entire surface is covered by ice and the hydrologic cycle is essentially stoped due to very low temperature. B.Upright regime : when the summer temperature exceeds the freezing point and the inclination of the spin axis is smaller than the width of the Hadley cell, low latitude area is dried and no precipitation occurs. C.Oblique regime : when the surface temperature is higher than the freezing point and the inclination of the spin axis is larger than the width of the Hadley cell, precipitation occurs in the low latitude areas during summer and winter. 2. Present Mars is in the upright regime with its inclination 23-24 degrees. Ancient mars, however, could have large inclination as large as 60. Thus, Mars likely experienced transition among different climate regimes. In particular, in the oblique regime, summer temperature gets high, this suggests that the oblique regime coincides with the 'past warm and wet climate' on Mars. 3. Cold and wet Mars is unacceptable because in such a situation the surface is entirely covered by snow and 'snow ball Mars' appears.

火星上许多河流特征表明古火星上有活跃的水文循环。在这项研究中，我们利用一般循环模型研究了一个理想行星上的水循环，并将其结果应用于古火星。实验结果如下：1；a .冻结状态：当地表温度全年低于冰点时，整个地表被冰覆盖，由于温度非常低，水文循环基本上停止。b .直立状态：当夏季温度超过冰点，自转轴倾角小于哈德利单体宽度时，低纬度地区干燥，无降水发生。c .斜向状态：当地表温度高于冰点且自转轴倾角大于Hadley单体宽度时，夏季和冬季低纬度地区出现降水。2. 目前火星正处于倾角23-24度的直立状态。然而，古代火星的倾角可能大到60度。因此，火星可能经历了不同气候制度之间的过渡。特别是，在斜向状态下，夏季温度变高，这表明斜向状态与火星“过去温暖潮湿的气候”相吻合。寒冷潮湿的火星是不可接受的，因为在这种情况下，火星表面完全被雪覆盖，“雪球火星”就出现了。

项目成果

Abe.Y., A.Numaguchi: "Water circulation om paleo-Mars : effect of spin-axis inclination."Proceedings of the 33nd ISAS Lunar Planetary Symposium. 189-192 (2000)

Abe.Y.、A.Numaguchi：“古火星的水循环：自转轴倾斜的影响。”第 33 届 ISAS 月球行星研讨会论文集。

Abe.Y., and A.Numaguchi: "Water circulation on a land-planet : an implication for paleo-Mars."Lunar and Planetary Science XXXII. #1551(CD-ROM). (2001)

Abe.Y. 和 A.Numaguchi：“陆地行星上的水循环：对古火星的影响。”月球与行星科学 XXXII。

Abe,Y.,and A.Numaguchi: "Water circulation on a land-planet : an implication for paleo-Mars"Lunar and Planetary Science. XXXII. #1551 (2001)

Abe, Y. 和 A. Numaguchi：“陆地行星上的水循环：对古火星的影响”月球与行星科学。

Abe.Y.,A.Numaguchi: "Water circulation om paleo-Mars : effect of spin-axis inclination"Proceedings of the 33nd ISAS Lunar Planetary Symposium. 33. 189-192 (2000)

Abe.Y.、A.Numaguchi：“古火星水循环：自转轴倾斜的影响”第 33 届 ISAS 月球行星研讨会论文集。

Y. Abe, Y. Kobayashi, & A. Numaguchi: "Water circulation on a land-planet : an application to paleo-Mars Environment"Bull. American Astronomical Soc.. 31.4. 1147 (1999)

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