Redux: Proposed GLIMS definition of "glacier"

[Bruce Raup]

Hi Frank, and all,

Thanks for the summary of the EGU Splinter Meeting.  I've been meaning to 
continue the discussion on the list about the GLIMS definition of 
"glacier", and your message has prodded me into action.  I'm sure the 
discussion will be continued at the GLIMS Workshop in Cambridge, but I've 
summarized the (simple) definition and (more complex) comments at

http://cires.colorado.edu/~braup/GLIMS_temp/

I think the comments related to snowfields above the accumulation area 
still need work.

An addition to the discussion is a point made by Donghui Shangguan about
merging glaciers.  Please see the image at the above URL.

I have modified the definition slightly to be clearer about ice shelves.  
Neal -- the reason an ice shelf should be fed by two or more glaciers is 
because it seems more natural to treat ice tongues (fed by only one 
glacier, e.g. Mertz or David/Drygalski) as part of the glacier.  I also 
added that the ice should be floating on the ocean.  Perhaps we can also 
explicitly limit ice shelves to Antarctica as Frank Paul suggests.

I think that the "definition" of a glacier for GLIMS will have to be a set
of guidelines, rather than a rigid definition.  Some guidelines will be
firm, and some will have to be more flexible.  Perhaps the next iteration
should be organized as such:

Definition

Consequences (firm)

Guidelines (somewhat flexible)


At some point soon I will make this definition and discussion into its own 
section in the GLIMS Analysis Tutorial, a preliminary version of which is 
available at 
http://www.glims.org/MapsAndDocs/assets/GLIMS_Analysis_Tutorial.pdf

In a previous message (from March 2), Frank brought up a number of other 
points, one of which related to the GLIMS Glacier Classification Manual.  
I want to emphasize that this discussion of "glacier definition" is a 
different issue from whether to call an ice body a "glacier" or "ice 
field" or "ice cap".  We're trying to define guidelines for how to 
delineate a unit ice mass for inclusion into the GLIMS Glacier Database -- 
not haggle over the definitions of different terms for ice masses.

I look forward to seeing further discussion on the list.

Best regards,
Bruce

On 2006-06-09 11:55 +0200,  Frank Paul wrote:

> 
> Dear Colleagues
> 
> For those of you who are interested in the protocol of this years
> splinter meeting at the EGU General Assembly in Vienna, I have
> posted a PDF version at my ftp site. The URL is:
> 
> ftp://ftp.geo.unizh.ch/pub/fpaul/egu_splinterm_prot.pdf
> 
> It summarizes the actual status of glacier inventory work in several
> European countries (including an input from ongoing work in Alaska)
> and the problems encountered during the work. Moreover, some general
> statements related to the creation of a glacier inventory are included.
> 
> We hope to discuss some of the open points (in particular the
> proposed definition of a glacier from a remote sensing perspective)
> in more detail during this years GLIMS workshop in Cambridge.
> 
> I am looking forward to meet many of you there!
> 
> With best regards, Frank Paul
> 

-- 
Bruce Raup
National Snow and Ice Data Center
University of Colorado
449 UCB,  Boulder, CO 80309
Phone:  303-492-8814
http://cires.colorado.edu/~braup/