GLIMS Update: Global ASTER imaging reprioritization

[Jeff Kargel]

Dear Cornelius:

Thank you your comments.  My reply to Luke Copland, who had some similar
reaction, applies to you, too.  But I do want to point out that it is not
politics, just a matter of resources.  Also, I will send to you and Luke a
few powerpoint slides which suggests that Greenland's ASTER coverage is not
really pitiful.  It could be that peoples' holdings are not quite keeping up
with the recent deluge of imaging that has been taking place.  The last year
or two have been very good for ASTER in general, but most of the rest of the
world is playing catch-up to get where Greenland already is.  I could
definitely use some help in assessing the state of imaging, so if it really
is pitiful, I need a quick education to that fact.  However, what I am
lacking is a detailed synthesis and analysis of that coverage.  Nominally,
that is something the regional centers are supposed to be doing.  In any
case, my assessment-- which necessarily has to be fairly statistical--
suggests that Greenland is doing pretty well.  That assessment is based on
(A) manual assessments of cloud cover (knowing that the automatic metadata
often are incorrect) for a sample of early ASTER acquisitions, and (B) total
L1B image footprints categorized by automatic cloud assessment data.  For
"A", the results are that Greenland comes out ahead of most parts of the
world in terms of percentage of clear-sky images.  "B" shows that Greenland
is plastered with overlapping images.  And furthermore, Flagstaff's limited
holdings reveals many places--most places?-- had repeat coverage even as of
a couple years ago, and the coverage has only gotten better.  In the
powerpoints I'll be sending, I have a sample of Himalayan glacier coverage
as a point in contrast to the situation for Greenland.

But, maybe cloud problems are more serious than I have assessed; that's
where systematic help from people working in Greenland could assist me.

Finally, thanks for your superbly educated opinions on this.  I depend on
this kind of feedback that you and Luke have provided.  We will find a
satisfactory solution.

Further discussion should be addressed to me at jeffreyskargel at hotmail.com
while I am traveling for the next 2 weeks.

Cheers,

Jeff       

On 12/3/05 11:45 PM, "CORNELIS VANDERVEEN" <vanderveen.1 at osu.edu> wrote:

> Maybe I got this wrong, but it looks like Greenland is slated for dercreased
> coverage  Already, what's available is pitiful; and we're still trying to get
> complete covearage of the west coast.  Oh well, I'm sure I am in the dark as
> far as politics go.  Not covering Greenland on a regular basis seems like
> nonsense to me.
> 
> My two cents
> 
> K

DIALOG BETWEEN LUKE COPLAND AND JEFF KARGEL:

Hi Luke,

Are you back in Canada now?

You make some good points, somewhat anticipated.  I agree.  And I disagree.
It's a painful situation, but the fact is we have extensive repeat imaging
for most of Greenland, and relatively little for almost the entire rest of
the world outside of Antarctica.  I had hoped that my message would stir
some discussion, and I see it has.  Antarctica is also in a similar
situation as Greenland, and maybe lowering (but not eliminating) priorities
for both would enable some new imaging.  Maybe if the plan was such that
there would be approximately one new set of images acquired over both
Antarctica and Greenland over the next 2 years (figuring that more than 2/3
will be low-cloud scenes), then it would still free up enough imaging
resource to improve the rest of the world to a satisfactory point.

Anyway, I will be sure to take your comments to the ASTER Science Team
meeting and relay the gist of the tradeoffs and the counter-suggestions and
debate.

--Jeff

On 12/3/05 10:20 PM, "Luke Copland" <luke.copland at uottawa.ca> wrote:

> Hi Jeff,
> 
> I agree with you that GLIMS acquisitions should be reprioritized to areas
> of currently poor coverage, but this shouldn't be at the expense of losing
> all coverage in the northern high latitudes (as your suggestion for a
> moratorium there seems to suggest). ASTER provides the only low cost, high
> resolution satellite imagery source in the high arctic and is therefore
> invaluable in monitoring recent changes. Examples include the recent rapid
> retreat of the terminus of Jakobshavn Isbrae, and the loss of ice shelves
> along northern Ellesmere Island. You also need to remember that 2007-8 is
> the International Polar Year, and that if anything we should be trying to
> increase monitoring then.
> 
> My suggestion would be to reduce northern high latitude acquisitions to a
> 'background' level, but not to get rid of them altogether. If this is too
> general, then perhaps you should put out a call for specific acquisition
> requests from the groups that will be working there to get an idea of
> where acquisitions should be focused.
> 
> Regards,
> Luke
> 
> --
> Dr. Luke Copland
> Assistant Professor / Professeur Adjoint
> Department of Geography / Département de Géographie
> University of Ottawa / Université d'Ottawa
> 60 University
> Ottawa, Ontario K1N 6N5, Canada
> 
> Tel: +1 613 562 5800 x1056
> Fax: +1 613 562 5145
> 
>