GLIMS ASTER image acquisition planning
william.sneedjr at maine.edu
william.sneedjr at maine.edu
Mon May 25 11:53:44 MDT 2009
Hi Jeff & all others.
What I did a few years ago for Svalbard was to plot the scene center
with a 60 km circle for each of the usable (our definition) images,
one plot for each of 4 years.
I could certainly do the same for 2006, 2007, and 2008 for NE
Greenland. I'm not sure I could get the years 2000-2005 done in time
for your meeting but (with Gordon's blessing) I can try.
....bill....
>
> Bill and all GLIMSters,
> Thanks. Just what we need. You might consider preparing 1 or 2 or
> 3 ppt slides summarizing this. I can take your tabular data and
> prepare a nice slide, but if you have something that is map or
> image-based, that would be good to supplement the numbers.
> I'd like to present this at an ASTER STAR Committee meeting in a
> couple weeks. (I won't be at the meeting, but I'll give a
> presentation to Mike Abrams to present for us.)
> --Jeff
>
>> Date: Sun, 24 May 2009 17:11:34 -0400
>> From: william.sneedjr at maine.edu
>> To: gordon.hamilton at maine.edu
>> CC: jeffreyskargel at hotmail.com; tulaczyk at pmc.ucsc.edu;
>> stearns at ku.edu; glims at flagmail.wr.usgs.gov;
>> michael.j.abrams at jpl.nasa.gov; leon.maldonado at jpl.nasa.gov
>> Subject: Re: GLIMS ASTER image acquisition planning
>>
>> Hi Gordon...welcome back....greetings to all others....
>>
>> I've finished looking at the 400 images from 2006. Bounding box for the
>> search was UL: 83.59N & 38.45W and LR: 74.92N & 15.4W for the dates
>> 01 June through 25 September.
>>
>> --- 266 images were above 80.0N.
>> --- By my eye, 187 images had 80% or more cloud cover.
>> --- 29 images were of the ice sheet as opposed to coastal glaciers and
>> ice caps.
>> --- 43 or more had heavy to light snow cover (no surprise given the
>> starting date but they're of limited usefulness to me, anyway).
>> --- 29 or more have an odd orangy-yellow tint. Non-GLIMS settings?
>> Radiometric problems?
>>
>> Coverage of Peary Land and Kronprins Christian Land glaciers and
>> ice caps seems pretty good. Sadly, the same can't be said for the large
>> glaciers to the south. There is one decent image of Nioghalvfjerdsfjorden
>> from 26 June and two others from mid/late July with considerable clouds
>> but usable, as we've defined it. No images of Zachariae Isstrom. Two
>> images of Storstrommen and part of L. Bistrup Brae from mid-June
>> but with snow cover.
>>
>> Bottom line: a literal handful of images for 2006-2008 of these four
>> large glaciers.
>>
>> For the years 2000-2005, my original search was confined to just
>> Nioghalvfjerdsfjorden. (I should revisit these years to see what's
>> available for the other three glaciers and the rest of this quadrant.)
>>
>> 2000: 4 images
>> 2001: 2 images
>> 2003: 11 (!!)
>> 2004: 4
>> 2005: 4
>>
>> ....see ya Tuesday....bill...
>>
>>> Jeff--
>>>
>>> I am just back from East Greenland, so I am jumping into this discussion
>>> a bit late. Also, I will be heading back to Greenland in a few weeks, so
>>> regrettably I will not be at the team meeting in Kyoto. Slawek raises a
>>> very important point and it needs a thorough discussion.
>>>
>>> Examining the number of scene acquisitions per year over Greenland (and/or
>>> Antarctica) is a very crude way of determining the success of ASTER and/or
>>> GLIMS imaging in these incredibly important parts of the glacierized world.
>>> Bill just sent me a quick analysis of scene numbers/usability for the last
>>> few years over selected parts of Greenland. Sure, some years have a lot of
>>> image acquisitions (e.g., 400 scenes for the NE quadrant of Greenland in
>>> 2006) but the vast majority of these images are unusable for any kind of
>>> quantitative analysis, such DEM generation, velocity mapping, melt pond
>>> depth extraction, or margin mapping (e.g., for the same quadrant in 2006,
>>> only ~15 images out of the 400 were somewhat usable).
>>>
>>> A lot of the most important glaciers in Greenland (e.g., Kangerdlugssuaq,
>>> Helheim) have *no* useable images in recent years (2007, 2008), which means
>>> we have been unable to use ASTER to track the behavior of some of the key
>>> glaciers contributing to sea level rise (we have had much better success
>>> with ALOS data).
>>>
>>> The same is true for a lot of Antarctica outlet glaciers -- our recent work
>>> has relied on ALOS acquisitions to maintain data continuity.
>>>
>>> My own attempts at Greenland STARs have been a total bust. Maybe
>>> my requests
>>> were overrided by the GLIMS STAR?
>>>
>>> I am not sure I have any good solutions. Going back to the beginnings of
>>> the GLIMS program, the idea of collecting at least one usable image of each
>>> glacier on Earth for the ~2000-timeframe has largely been accomplished. A
>>> lot of these images are ASTER scenes, but the availability of
>>> high-resolution
>>> optical imagery has exploded since the days when the GLIMS idea
>>> was hatched,
>>> so a lot of the scenes are non-ASTER images. My guess is that the existing
>>> image archive is sufficient for a lot of GLIMS tasks (e.g., mapping changes
>>> in snow/ice extent) -- the small size of many mid-latitude ice masses
>>> necessitates the need for a long time record in order to detect change; in
>>> these cases, annual coverage is not required. The polar regions are
>>> different.
>>> The changes are bigger and happening faster, and the consequences
>>> have global
>>> implications. A lot of the really cool and high-profile science
>>> done by ASTER
>>> has been in Greenland and Antarctica (I'm trying not to be biased
>>> here!), but
>>> we have really been struggling to keep that science going with the current
>>> acquisition plan.
>>>
>>> Maybe we need to critically review the GLIMS objectives, see if the current
>>> image archive (be it ASTER or any other easily-available high-resolution
>>> imagery) is sufficient to meet that objective (and see where it
>>> does not meet
>>> that objective), then re-assess what key science questions we want to be
>>> trying to answer. The GLIMS idea is more than a decade old -- science has
>>> evolved, and maybe other glaciological questions provide a better
>>> use of the
>>> finite ASTER resource. Maybe not, but I think we need to take a close look
>>> to be sure.
>>>
>>> Okay, a long message, but I just wanted to echo Slawek's concerns.
>>>
>>> -gordon
>>>
>>>
>>>
>>> Quoting Jeffrey Kargel <jeffreyskargel at hotmail.com>:
>>>>
>>>> Slawek,
>>>> I offer this letter as an open message to the GLIMS community
>>>> (responding to your message below) in a bid to enlist the GLIMS
>>>> community's further help in evaluating the successes and failures
>>>> of the GLIMS STAR in the Southern Hemisphere in 2009, with
>>>> recognition that what elapsed there (successes and failures) is
>>>> apt to be a model of what will happen this year in the Northern
>>>> Hemisphere over the next few months. This is needed, while also
>>>> recognizing that we need good Greenland coverage, as you are
>>>> shooting for. Perhaps what we need is a one-year Greenland DAR
>>>> that supplements the coverage expected from the GLIMS STAR by
>>>> targeting possibly one-fifth of the Greenland coastline for
>>>> multiple repeat imaging (that's in addition to the current plan to
>>>> get one image on average of each part of the coastline over the
>>>> course of the summer). I would need to know what one-fifth to
>>>> cover with greater frequency, and then we could see how this idea
>>>> fares with ASTER MIssion Operations.
>>>> So far as what has actually been achieved for GLIMS STARs of
>>>> non-Greenland/non-Antarctic glaciers, I can say we're still
>>>> suffering. I don't know what it is, but there just seems to be a
>>>> very minimum priority given to GLIMS, or there's some technical
>>>> reason (the "exclusion zones" or whatever) that makes certain areas
>>>> very difficult to image. There are lots of images of glaciers
>>>> from 2008-2009, but the majority are global map or other images
>>>> that have saturated snow. (Those work well for debris covered
>>>> areas, so we don't discount the fact that we have those.) The
>>>> Southern Hemisphere GLIMS STAR has completed its summer season a
>>>> couple months ago, and the received images are fairly hit and miss
>>>> according to a random assessment of a few areas done in Tucson
>>>> and by some other GLIMS people; some really great images were
>>>> received in Jan-Feb-Mar 2009, but many areas have had no coverage
>>>> this year (or were attempted but were clouded out). So I am
>>>> fairly apprehensive about this summer's northern hemisphere GLIMS
>>>> STARs.
>>>> Greenland was one big area where GLIMS was going really well, and
>>>> of course that was a great thing. I just wish something like the
>>>> Greenland coverage we had year after year (several received
>>>> low-cloud scenes of most parts of the coast each year) would happen
>>>> just once in the lifetime of GLIMS for nonpolar glaciers; or even
>>>> just one good image per season (with GLIMS gains) of most
>>>> glaciers would be a great improvement. It just has not been
>>>> achieved so far in 9 years of ASTER. I realize that we have
>>>> acquired lots of GLIMS scenes over the life of ASTER, so I am not
>>>> issuing an all-out complaint, but certainly there remain serious
>>>> inadequacies. I have not done the analysis to see whether on
>>>> average the Southern Hemisphere did significantly better in 2009
>>>> than in other years under the old STAR. I just know that there
>>>> are quite a few significant glaciers that were not imaged, and
>>>> some that were imaged had saturated snow (gains indicative of the
>>>> global map program).
>>>> Let me know whether you think the "one-fifth plan" will work
>>>> acceptably (plus an expected average of one summer image of the
>>>> other areas under the newly implemented STAR). We will need to do
>>>> something similar for Antarctica next austral summer.
>>>> --Jeff
>>>>
>>>>
>>>>> Date: Wed, 20 May 2009 13:26:45 -0700
>>>>> Subject: Re: US Mtg agenda
>>>>> From: tulaczyk at pmc.ucsc.edu
>>>>> To: Michael.J.Abrams at jpl.nasa.gov
>>>>> CC: kargel at hwr.arizona.edu
>>>>>
>>>>> Jeff,
>>>>>
>>>>> Let's talk about this. If at all possible, I would love to see more
>>>>> coverage of Greenland/Antarctica without subtracting from your focus
>>>>> on the smaller glacier systems.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Slawek
>>>>>
>>>>> On 5/20/09, Michael Abrams <Michael.J.Abrams at jpl.nasa.gov> wrote:
>>>>>> Slawek,
>>>>>>
>>>>>> Could you also discuss this with Jeff Kargel before the meeting (He is
>>>>>> not attending). The GLIMS STAR was changed to reduce Greenaland
>>>>>> coverage. Not sure about antarctica.
>>>>>>
>>>>>> Michael Abrams
>>>>>> ASTER Science Team Leader
>>>>>> Group Supervisor, Land Surface Processes
>>>>>> NASA/Jet Propulsion Laboratory
>>>>>> Mail Stop 183-501
>>>>>> 4800 Oak Grove Dr.
>>>>>> Pasadena, CA 91109
>>>>>> 818-354-0937 FAX: 818-354-5148
>>>>>> michael.j.abrams at jpl.nasa.gov
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Slawek Tulaczyk wrote:
>>>>>>> Dear Mike,
>>>>>>>
>>>>>>> Could we reserve time for a discussion on increased data acquisition
>>>>>>> over margins of Antarctica and Greenland?
>>>>>>>
>>>>>>> Cheers
>>>>>>>
>>>>>>> Slawek
>>>>>>>
>>>>>>> On Wed, May 20, 2009 at 10:29 AM, Michael Abrams
>>>>>>> <Michael.J.Abrams at jpl.nasa.gov> wrote:
>>>>>>>
>>>>>>>> attached is US Team meeting agenda for monday morning. let me
>>>>>>>> know of any
>>>>>>>> changes/additions/etc.
>>>>>>>>
>>>>>>>> mike
>>>>>>>>
>>>>>>>> --
>>>>>>>> Michael Abrams
>>>>>>>> ASTER Science Team Leader
>>>>>>>> Group Supervisor, Land Surface Processes
>>>>>>>> NASA/Jet Propulsion Laboratory
>>>>>>>> Mail Stop 183-501
>>>>>>>> 4800 Oak Grove Dr.
>>>>>>>> Pasadena, CA 91109
>>>>>>>> 818-354-0937 FAX: 818-354-5148
>>>>>>>> michael.j.abrams at jpl.nasa.gov
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Professor Slawek Tulaczyk, Ph.D.
>>>>> Department of Earth and Planetary Sciences
>>>>> University of California, Santa Cruz, CA 95064, USA
>>>>> phone: 831-459-5207, fax: 831-459-3074, tulaczyk at pmc.ucsc.edu
>>>>
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>>>
>>>
>>> --
>>> Gordon Hamilton, Assoc. Professor
>>>
>>> Climate Change Institute
>>> University of Maine, Orono, ME 04469
>>>
>>> gordon.hamilton at maine.edu
>>> 207-581-3446 (ph/voicemail)
>>> 207-581-1203 (fax)
>>
>>
>>
>> --
>> william a. sneed
>> climate change institute
>> university of maine, orono, ME, 04469 USA
>> 207-581-1491
>> william.sneedjr at maine.edu
>
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--
william a. sneed
climate change institute
university of maine, orono, ME, 04469 USA
207-581-1491
william.sneedjr at maine.edu
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