On the orbital forcing of Martian water and CO2 cycles: A general circulation model study with simplified volatile schemes
On the orbital forcing of Martian water and CO2 cycles: A general circulation model study with simplified volatile schemes
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关于火星水和二氧化碳循环的轨道强迫：采用简化挥发方案的大气环流模型研究
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
D. Mccleese
中科院分区：
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作者：
M. Mischna;M. Richardson;R. Wilson;D. Mccleese
[1]利用地球物理流体动力学实验室火星环流模型，研究了火星水和二氧化碳循环随轨道和自转参数变化的变化。该模型允许对近日点的倾角、偏心率和自变量以及表面冰的位置和厚度进行任意指定。对地面和大气之间的二氧化碳交换进行了模拟，产生了地面冰和地面气压的季节性循环。允许水在地面和大气之间交换，云的形成得到处理，云和水汽都通过模拟的风和扩散进行输送。不允许与地下交换水和二氧化碳，也不处理水蒸气和云的辐射效应。正如简单的热平衡模型所表明的那样，二氧化碳的季节循环在高倾角时变得更加极端。最大气压基本保持不变，但随着更广泛的极地夜晚更多的二氧化碳凝结，最低气压大幅下降。水汽和云的丰度随着倾角的增大而急剧增加。地面冰的稳定位置随着倾角的增大而向赤道方向移动，因此在45°倾角下，水冰只在热带地区稳定。冰在空间上不是均匀的，而是优先在热惯性高或地形较高的地区发现。近日点的偏心率和自变量可以通过改变两极太阳辐射的时间分布来对地表冰的分布进行二阶修正。进一步的模型模拟揭示了这些分布在各种初始条件下的稳健性。我们的发现揭示了火星上中纬度和低纬度地区近地表富含冰的沉积物的性质。
[1] Variations in the Martian water and CO2 cycles with changes in orbital and rotational parameters are examined using the Geophysical Fluid Dynamics Laboratory Mars General Circulation Model. The model allows for arbitrary specification of obliquity, eccentricity, and argument of perihelion as well as the position and thickness of surface ice. Exchange of CO2 between the surface and atmosphere is modeled, generating seasonal cycles of surface ice and surface pressure. Water is allowed to exchange between the surface and atmosphere, cloud formation is treated, and both cloud and vapor are transported by modeled winds and diffusion. Exchange of water and CO2 with the subsurface is not allowed, and radiative effects of water vapor and clouds are not treated. The seasonal cycle of CO2 is found to become more extreme at high obliquity, as suggested by simple heat balance models. Maximum pressures remain largely the same, but the minima decrease substantially as more CO2 condenses in the more extensive polar night. Vapor and cloud abundances increase dramatically with obliquity. The stable location for surface ice moves equatorward with increasing obliquity, such that by 45° obliquity, water ice is stable in the tropics only. Ice is not spatially uniform, but rather found preferentially in regions of high thermal inertia or high topography. Eccentricity and argument of perihelion can provide a second-order modification to the distribution of surface ice by altering the temporal distribution of insolation at the poles. Further model simulations reveal the robustness of these distributions for a variety of initial conditions. Our findings shed light on the nature of near-surface, ice-rich deposits at midlatitudes and low-latitudes on Mars.