GLIMS ASTER image acquisition planning

Sun May 24 15:11:34 MDT 2009

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