Dear Jeff, I have been working on Baffin Island, Bylot Island initially and now looking at the southern regions. I have reported previously on the availability of ASTER imagery through Fiona Cawkwell, the RC for Canada, but she mentioned that it would be useful to send you information for the more recent acquisition. Twenty-one images with 50% or less cloud cover were acquired between 10 July and 10 Sept. 2005. Of these, 10 were good, usable images, the rest being cloudy over ice. One of these is from the Cumberland Peninsula and the remainder from Eastern Baffin Island. The 2004 picture is summarized below because I think it provides useful information about the distribution of ASTER images. It is also typical of earlier years. Although a large number of scenes have been acquired, very few are clear-sky images with low snow cover (ie. taken between late July and early September). Also, when clouds are present in part of a scene, they often cover the ice masses, hence the low number of good summer images. ASTER 1A Imagery East Baffin Cumberland P. Hall P. Meta-Incog.P. 2004 (01/06 to 30/9) 161 60 15 7 Cloud Cover 60% or less 47 21 3 0 July to early Sept. 21 50 15 0 Good images 8 1 0 0 Earliest date of good image 20 July 26 August For the period 2000 to 2003, the number of usable images for Eastern Baffin Island is 5, for Cumberland Peninsula - 8, Hall Peninsula - 9 and Meta Incognita Peninsula - 0. In summary, we have only 41 good ASTER images for the whole of Baffin Island. Any new acquisition used for mass balance purposes should be taken between late July and early Sept. I suspect cloud cover will always be a problem here. Hope this helps. Good luck with your meeting. Cheers, Evelyn --On 06 December 2005 03:38 +0000 Jeffrey Kargel <jeffreyskargel@hotmail.com> wrote:
Fiona et al.:
Thanks! Good to have this kind of info (your msg below). Thanks, too, to many others who have written on this matter. (Good to know that GLIMS Updates actually are read; maybe this last couple days will increase readership!) For those of you at Fall AGU, please remember that there will be a miniworkshop tomorrow (Tuesday) at 5:30-9:30 PM at the Hyatt at Fisherman's Wharf in the Kargel conference suite. This issue at hand will be discussed. Please consider staying afterward for refreshments.
Your synopsis suggests that maybe we can leave imaging open for about July 10-August 10 for Greenland and get most of what we've been getting that is most useful. The narrower window would reduce the number of images but those we get may be better. If you can suggest other ideas, or take it subregion by subregion and suggest imaging windows that way, it would help. But I have a better idea than this quick rush to decisions.
We need a working group, "ASTER Himalayan, Alaskan, and Greenland GLacier Imaging Negotiations Group" (ASTER HAGGLING), with three teams, one each for the Himalaya/central Asia, for Alaska, and Greenland/High Arctic. It doesn't need to be just GLIMS people, as the ASTER imaging is a wider community resource. (This is always true. We have never yet held a closed meeting.) We need solid data on ASTER imaging to date: results, failures, coverage, gaps, success-by-month results, success/failure as a function of gain settings, coverage by year data, info on other data sources, ideas on where we need to be in 3 years. We need a set of users/advocates for that region. Each teams needs to make a proposal for a revised ASTER imaging plan for their team's area; be prepared to haggle and winnow it back. I will moderate the whole group. I need a leader for the Alaska team. Mike Bishop is hereby volunteered for the Himalaya team. I need a team lead for Greenland/High Arctic. Each team needs team members in addition to the leader. Each team puts their best foot forward with the view of increasing image acquisitions for Alaska and the Himalaya area, and maintaining imaging for the Greenland/High Arctic area. I anticipate that eventually Greenland and Ellesmere imaging will be halved, and that's what I will push for and probably eventually insist on (unless ASTER Mission Ops gives us a higher quota.). But we want that half to have improved quality on average. And the increased Alaska and Himalaya region coverage also has to have improved quality over what has been acquired.
I suggest that Bruce Raup, David Gaseau, and John Dwyer should assist the entire working group as communal resources.
--Jeff K
From: Fiona Cawkwell <fiona.cawkwell@ualberta.ca> To: luke.copland@uottawa.ca CC: msharp@ualberta.ca, jeffreyskargel@hotmail.com, Jeff Kargel<jkargel1054@earthlink.net> Subject: Re: GLIMS Update: Global ASTER imaging reprioritization Date: Mon, 5 Dec 2005 12:22:38 -0700
Martin, Jeff, Luke
Luke's assessment of the northern Ellesmere situation is correct - most of the imagery available north of about 82.5N is either cloud covered or relatively early in the season (mid-June) when there is still considerable snow cover on the ground - there is no Landsat coverage this far north so some ASTER imagery is better than nothing, but cloud-free summertime (July) imagery would be better still, so I would certainly not advocate a reduction in image acquisition of this region.
As far as the rest of the QEI is concerned - there is one-time clear ASTER coverage of most of the ice, the exception being parts of Devon which are particularly susceptible to cloud cover and also Melville Island (again due to cloud coverage). However there is very little (less than 10 good images) level 1B imagery available from the summers of 2004 and 2005 making detection of change problematic, and I would certainly echo Luke's comments on the need for a means of processing these data online or ourselves. I appreciate the huge demand for images from other regions, but with ASTER being the only good source for the northern polar regions and with a substantial baseline of data from 2000-2002 it would be a shame from a scientific viewpoint if this supply of data were to be curtailed, particularly with the upcoming IPY.
Fiona
Hi Jeff & Martin,
A quick search of the current ASTER database for northern Ellesmere shows that some images are available, but that many of these are cloud-covered. Hence the overall coverage is patchy - for example, I found clear scenes for Yelverton Inlet and Ayles Ice Shelf (western part of N. Ellesmere), but none for the Ward Hunt Ice Shelf to the east.
Jeff - ASTER imagery provides a crucial resource for this region as it is the only available source of high resolution imagery since it is too far north for Landsat 7.
Following on from John Dwyer's message, a big help would the ability to process L1A to L1B ourselves - either via an on-demand online interface, or via standalone Windows/DOS software. Of the scenes that are available, most haven't been processed to L1B yet.
Cheers, 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
-- Dr Fiona Cawkwell Post Doctoral Research Fellow Department of Earth and Atmospheric Sciences University of Alberta Edmonton Alberta, T6G 2E3
tel. 780 492 7821 fax. 780 492 2030 fiona.cawkwell@ualberta.ca http://www.ualberta.ca/~cawkwell/fiona_cawkwell.html
---------------------- EK Dowdeswell, Geographical Sciences work: E.K.Dowdeswell@bristol.ac.uk home: J.A.Dowdeswell@blueyonder.co.uk