arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1102.5137astro-ph.EP
收藏

风增强的辐射和尘埃的相互作用(WEIRD)和火星上局部沙尘暴的增长和维持

Wind-Enhanced Interaction of Radiation and Dust (WEIRD) and the Growth and Maintenance of Local Dust Storms on Mars

Scot C. Randell Rafkin

摘要:

一个辐射动力学正反馈机制(风增强辐射和尘埃的相互作用:奇怪的)本地化的火星尘埃扰动以前被发现在高度理想化的数值实验操作。数值模拟被用来测试在更现实的条件下的辐射动态WEIRD反馈机制的存在和定量效果。比较的情况下,扬起的灰尘是辐射活跃和辐射被动阐明的灰尘辐射强迫的热力学和动力学结构的大气的重要性。奇怪的反馈机制确实在现实条件下起作用,尽管它可以被各种其他强制机制所掩盖和削弱。全球范围内增加的灰尘负荷被发现加速当地的风,同时减少当地的自然强迫的影响。尘埃的局部增强产生了类似于理想化实验中看到的许多基本特征的热和动力学响应。暖心低层的发展、旋转风的倾向和在最强沙尘暴中心相交的辐合边界与WEIRD一致。在尘埃辐射强迫的帮助下,局部和区域性的风暴能有效地在边界层上方产生升高的尘埃层。与地形相关的无处不在的持续热环流也可以将尘埃注入行星边界层上方的自由大气中,但它们的效率低于沙尘暴。尽管地表的日照大大减少,但大气层最低层中的高浓度灰尘会使地面和近地表空气显著升温。

英文摘要:

A radiative-dynamic positive feedback mechanism (Wind Enhanced Interaction of Radiation and Dust: WEIRD) for localized Mars dust disturbances was previously found to operate in highly idealized numerical experiments. Numerical simulations are used to test for the presence and quantitative effect of the radiative-dynamic WEIRD feedback mechanism under more realistic conditions. Comparisons between cases where lifted dust is radiatively active and radiatively passive elucidate the importance of the dust radiative forcing on the thermodynamic and kinematic structure of the atmosphere. The WEIRD feedback mechanism does operate under realistic conditions, although it can be masked and diminished by a variety of other forcing mechanisms. Globally increased dust loading is found to accelerate the local winds while simultaneously diminishing the impact of local physiographical forcing. Local enhancements of dust produce a thermal and dynamical response that resembles many of the essential features seen in the idealized experiments. The development of a warm core low, rotational wind tendencies and convergence boundaries intersecting at the center of the strongest dust storms are consistent with WEIRD. Local and regional storms are effective at producing elevated dust layers above the boundary layer aided by the radiative forcing of the dust. Ubiquitous and persistent thermal circulations associated with topography can also inject dust into the free atmosphere above the planetary boundary layer, but they are less efficient than the dust storms. High concentrations of dust in the lowest levels of the atmosphere produce a significant and dramatic heating of the ground and the near-surface air despite greatly reduced insolation at the surface.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑