Dear colleagues, 1. ERRATUM: The recent GLIMS Update (summary of miniworkshop) contained a factual error. In the description of Kimberley Clark's results, it should have been stated that "there was a reduction of 3.62% glacier extent in Kenai Fjords National Park." (not Katmai as stated) Thus far, the work by Dorothy Hall's group (including Kimberley Clark) pertains to the Kenai Peninsula. 2. FELLOWSHIP. Gordon Hamilton reminds me that the great work Leigh Stearns is doing* is being done under a NASA fellowship gained under the program I mentioned a few weeks ago. So apply! *Hamilton, G.S., V.B. Spikes and L.A. Stearns. 2005. Spatial patterns in mass balance of the Siple Coast and Amundsen Sea sectors of the West Antarctic Ice Sheet. Annals of Glaciology, 41, in press. *Stearns, L.A. and G.S. Hamilton. 2005. A new velocity map for Byrd Glacier, East Antarctica, derived from high-resolution ASTER satellite imagery. Annals of Glaciology, 41, in press. *Stearns, L.A., G.S. Hamilton and N. Reeh. 2005. Multi- decadal record of ice dynamics on Daugaard Jensen Gletscher, East Greenland, from satellite imagery and terrestrial measurements. Annals of Glaciology, 42, in press. 3. Additional notes on mini-workshop offered by Siri Jodha Singh Khalsa (FURTHER NOTES ADDED BY KARGEL IN CAPS).
Bruce Molnia (Alaskan glacier changes)
There are around 50 outlet glaciers of the Juneau ice field. 49 are Retreating; Taku has advanced anomalously (although it also experienced recent retreat). PRESENTATION LATER BY CHRIS LARSEN EMPHASIZED THICKENING OVER THE TAKU GLACIER'S SURFACE. REALLY AMAZING ANOMALY. New glaciers have formed in Alaska in 3 places.
Bill Sneed (working with Gordon Hamilton, on Svalbard glaciers)
Said they saw 100 m thinning based on ASTER DEMs 2004-2005. I THINK THIS WAS OVER AN EXPANSE OF DECADES LEADING UP TO 2004-5.
Jeff Kargel (ASTER coverage in Alaska)
Claimed there were 49,000 ASTER scenes over glaciers with GLIMS gains. THAT'S A GLOBAL FIGURE, AND IT INCLUDES NO FURTHER WINNOWING ACCORDING TO CLOUD COVER OR OTHER QUALITY METRICS. IT'S POSSIBLY A FACTOR OF TWO MORE THAN LAST YEAR, AND MOST ALPINE GLACIER REGIONS HAVE BENEFITED. ALASKA IS NOW WELL PLASTERED WITH ASTER IMAGERY, WHICH WAS NOT THE CASE A YEAR AGO. Said Waleed told him GLIMS needs to make use of 3rd dimension (i.e. elevation) YES, WALEED ABDALATI WAS QUOTING AN UN-NAMED REFEREE OF A GLIMS PROPOSAL, WHO EMPHASIZED THE NECESSITY OF UTILIZING THE 3RD DIMENSION. WE HAVE KNOWN THIS AND VARIOUS GROUPS IN GLIMS HAVE BEEN WORKING HARD TO DEVELOP VARIOUS QUANTITATIVE METHODS TO UTILIZE TOPOGRAPHY IN GLACIER MAPPING. BUT CHRIS LARSEN'S QUALITATIVE APPLICATION OF GOOGLE EARTH DATA CAME IN REALLY HANDY AND DROVE HOME THIS POINT AS JUST ABOUT NOTHING ELSE COULD HAVE AT THAT MOMENT.
Chris Larsen (elevation changes in Alaska from DEM comparisons)
based on airport runways, claims +/- 5m accuracy of SRTM DEM Detected elevation dependent bias in comparing SRTM with laser altimetry profiles along glaciers. There was a seasonal difference. May have to do with radar penetration depth. Filtered out slopes greater than 15 deg to eliminate difference due to misregistration of STRM and map-based DEMs. Turns out that mapping slopes less than 15 deg in the Alaskan coast range corresponded to glacier locations quite well. Glaciers are flatter than the mountains they are in. THIS IS A KEY ATTRIBUTE THAT ENABLES USE OF TOPOGRAPHY AS A POWERFUL METHOD OF GLACIER CLASSIFICATION. A BRIEF SUMMARY OF SOME GLIMS WORK (BY PAUL, KAAB, BISHOP, AND SOME OTHERS) IS PROVIDED IN THE REMOTE SENSING OF ENVIRONMENT PAPER BY KARGEL ET AL. (2005), AND SUMMARIZED IN MORE DETAIL IN A SUBMITTED REVIEW PAPER BY RAUP ET AL. SOME KEY REFERENCES ARE: Paul, F., Huggel, C., Kääb, A. (2004). Mapping of debris-covered glaciers using multispectral and DEM classification techniques. Remote Sensing of Environment, 89(4), 510-518. Kääb, A., Huggel, C., Paul, F., Wessels, R., Raup, B., Kieffer, H., Kargel, J. (2003a). Glacier monitoring from ASTER imagery: accuracy and applications. EARSel Proceedings, 2, 43-53. See cires.colorado.edu/~braup/pubs/kaeaeb_earsel.pdf Berthier, E., Arnaud, Y., Baratoux, D., Vincent, C., Remy, F. (2004): Recent rapid thinning of the "Mer de Glace" glacier derived from satellite optical images. Geophys. Res. Lett., 31 (17), L17401. Html version available: http://66.102.7.104/search?q=cache:mNdog6TM340J:lgge.obs.ujf-grenoble.fr/Ser viceObs/images/GRL2004BerthierMNT.pdf+%22recent+rapid+thinning%22+berthier&h l=en&ie=UTF-8 PDF maybe available: www-lgge.ujf-grenoble.fr/ ServiceObs/images/GRL2004BerthierMNT.pdf Rabus, B., Eineder, M., Roth, A., Bamler, R.. (2003). The Shuttle radar topogaphy mission - a new class of digital elevation models acquired by spaceborne radar. ISPRS Journal of Photogrammeútry and Remote Sensing, 57, 241-262.
Ella Lee Ella gave details on the USGS method of classifying ASTER scenes for ice/water/debris. Each scene had to be individually tunned.
YES. BUT PAUL GEISSLER THEN GAVE DETAILS ON A NEW METHOD THAT DOES NOT REQUIRE INDIVIDUAL TUNING AND IN THEORY SHOULD ACHIEVE IMPROVED CLASSIFICATION RESULTS. WE LOOK FORWWARD TO SEEING THE NEW METHOD TESTED AND HOPEFULLY IMPLEMENTED BY DEBORAH SOLTESZ AS A GLIMSVIEW MODULE. Sincerely, Jeff Kargel