[GLIMS] Special rock glaciers

[Frank Paul]

Hi Jeff

Although I agree to disagree (as you know), I like your slides! You can create additional triangles for criteria such as 'temperature', 'ice contents', 'flow velocities', or 'water release' to stay in the picture of a continuum by the range of physical properties. All fine! However, in my opinion things break down when it comes to criteria such as 'response to climate change' (advance/retreat) or mass balance (gain/loss). And this is actually what 'we' currently measure and model. As (active) rock glaciers can only advance and gain mass (i.e. grow over time), they do not fit into currently available schemes to model their response to climate change (or their mass balance). One might even say they are doing the opposite, i.e. advance and gain mass under higher temperatures.

In other words, it is not just an issue of maybe similar physical or geomorphological properties (and being special end-members of a continuum), but it is a simple yes/no thing (e.g. glaciers have an ELA, rock glaciers do not). Hence, to not confuse related computations, there must be a possibility to deselect their polygons in a database. In my opinion they are thus not a special class of mammals (dogs or babies), but belong more to the plants (maybe Redwood Trees that also need hundreds of years to properly grow up? ;)

All the best, Frank


On May 5, 2020, at 11:56 PM, Jeffrey Kargel wrote:

> Dear GLIMS folks,
> I am not sure whether this attachment will go through to the GLIMS list. I prepared this
> to address an issue that has arisen many times in GLIMS discussions over the past 20 years, including at today's GLIMS/RGI virtual meeting. A question was raised "Is a rock glacier a type of glacier?" There are different views, and as of today's meeting it became
> much more of an academic point, as it was reconfirmed that rock glaciers will be included
> in the GLIMS database. (This is as it has been for quite a few years, but the matter keeps coming up). 
> This presentation gives my views on the matter, and it also provides a schematic concept
> that can be put to use. Maybe not now in the GLIMS database, but whenever the detailed
> dynamical characteristics and rock-ice composition of glaciers comes up in research.
> Cheers,
> Jeff Kargel
> 
> <Glacier-rock glacier discrimnation-rock-ice-flow-schematic.pdf>_______________________________________________
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