将冰川体积转换为质量:使用多少冰密度?-地江南体育网页版球科学堆栈交换江南电子竞技平台 最近30个来自www.hoelymoley.com 2023 - 03 - 30 - t19:40:02z //www.hoelymoley.com/feeds/question/4391 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/4391 13 将冰川体积转换为质量:使用多少冰密度? Jan Doggen //www.hoelymoley.com/users/595 2015 - 02 - 09 - t09:22:36z 2015 - 02年- 17 - t04:30:58z 在0°C(大气压下)时，冰的密度为0.9167 g/cm3。< / p >

I know of two factors that may influence this (are there more?)

  1. Pressure

    The glaciology faq (Common Questions and Myths about Glaciers) at the Alaska Science Center of the U.S. Geological Survey (USGS) mentions for glacier depth:

    A good guess is that the ice thickness is about one-half of the surface width of the glacier. Although few glaciers have been measured, the measured thicknesses range from a few tens of meters for small glaciers to about 1,500 meters for the largest glaciers in Alaska.

    Does the density of ice change significantly with depth?

    The Wikipedia article on ice mentions the density of ice increasing slightly with decreasing temperature, and the different phases of ice under pressure, but nothing on density.

  2. Inclusion of air

    Googling for pressure ice density the (my) first search finds Density of glacier ice at the International Glaciological Society. This focuses on air in glaciers making the density lower, and concludes that at larger depths we reach that 0.92 limit:

    enter image description here

What would be a good average to take?

 //www.hoelymoley.com/questions/4391/-/4393#4393 12 将冰川体积转换为质量:使用多少冰密度? 彼得很 //www.hoelymoley.com/users/81 2015 - 02 - 09 - t14:27:26z 2015 - 02 - 12 - t12:28:04z 这是一个不平凡的问题。当你观察冰川的体积变化时，你通常会减去两个数字高程模型，以获得两者之间的差值。首先，你必须区分冰山崩解减少体积的冰盖和更普通的有融化过程的冰川。当然也有冰川崩解，所以有可能对任何一个特定的冰川进行详细介绍，所以在这里我只讨论最常见的情况，那就是一个较小的冰川，处于融冻状态。由于冰川的移动和堆积-融化过程，冰川表面的高程变化幅度不同。表面材料可以是(1)冰川冰，(2)雪，(3)在融化季节幸存下来的雪)或(4)超强冰，它们的密度或多或少都不同，你需要评估哪种材料被去除了。冰的密度约为900kg /m ，冰的密度约为600kg /m3，但必须记住，冰是通过变质过程转化为冰川冰的，因此密度随深度从600到900kg /m3。在温带冰川中，冰的转变发生在大约30米深的地方，尽管很少有关于实际发生过程的研究。雪的密度有很大差异，但考虑到平均水平，我想说，在冬季(寒冷)条件下，它会在350到500公斤/米3之间变化，而在融化的积雪中，它会在550公斤/米3左右。叠加冰更接近于冰，可能在800—900 kg/m3的上限范围内变化。更糟糕的是，雪叠加了雪，雪又叠加了冰。 This means that in the accumulation area, volume change can result from both a reduction in a snow cover and the firn layer. In the zone near the equilibrium line there can be a loss of both firn and ice. this is also where the superimposed ice will play a role.

So there is no simple density to use since the loss you try to estimate will involve varying types of densities spatially as well as vertically. For annual changes, you can largely ignore the vertical distribution, but with volume changes covering larger periods where climate change influences the longer term location of the equilibrium line and the size of the accumulation area, vertical layering also has to be included.

As a first approximation, a surface zonation of ice snow and possibly firn can be used and perhaps lumping snow and firn with a single density of around 600 kg/m3 can be used. I would, however, say that to some extent any choice you make will be wrong, so being aware of complexity and the limitations is the only way forward.

EDIT:

A couple of useful sources relating to the question:

Huss, M., 2013. Density assumptions for converting geodetic glacier volume change to mass change. The Cryosphere [Open Access]

Moholdt, G., (Referee) Interactive comment on “Density assumptions for converting geodetic glacier volume change to mass change” by M. Huss. The Crypshere Discuss. [Open Access]
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