一个有趣的观点考虑来自你的假设恒定速率的降水。许多地球系统过程有重要的随机变化(或高维混沌)。考虑冰的质量守恒定律:冰层厚度变化量=(降水、质量)——(选择你最喜欢的过程,质量)。(质量)和(质量)过程有明显的随机变化,无论是在空间和时间。当你把一个随机变量,一个特殊的事情发生了:你得到一个随机游走。下面的图显示了5随机漫步[![随机漫步][1]][1]<子>(来源:[jburkardt people.sc.fsu.edu] (https://people.sc.fsu.edu/ ~ jburkardt / m_src / random_walk_1d_simulation / walk_5_steps_500_plot.png)) < /订阅>注意几个不同的随机漫步和时间分开吗?一个随机游走的属性,标准差所有走在一起,随着时间的平方根。如,所有的传播在给定的时间点上,生长时间的平方根成正比。如果随机游走并不是随机的,而是是恒定的,你会一条直线(这是你描述的这种情况)。 So here is the first point to be made: a constant rate of precipitation leads to a linear increase in ice thickness, growing without bound. By adding in some randomness to approximate nature better, the rate at which the ice thickness grows is fractional with time rather than linear. A true random walk is still unbounded, and so there are clearly some negative feedback mechanisms at play as mentioned in the previous posts. Second point (actually answering your question). As this is a 2d surface, you could model glacial topography as 2D random field. In the absence of forcing, the dynamics of glacial topography is effectively a diffusion equation. A randomly forced diffusive surface has a natural (or internal) cutoff length scale, or scale above which ice won't grow. However, this cutoff scale would be a function of ice surface diffusivity, rather than a feedback mechanism between the system and forcing. So this is all to say, it could be a feedback mechanism, or it could be set internally by the material properties of the system. I'll look and see if anyone has written papers on this yet. The figure below shows an example of a 2D random field. I don't know how exactly it was generated, but it's basically the kind of solution you would get from a 2D diffusion equation with random forcing. ![2d random noise][2] [1]: https://i.stack.imgur.com/suiBL.png [2]: https://i.stack.imgur.com/veC49.png