[GLIMS] ASTER Science team update: Alaska & Himalaya

[Jeffrey Kargel]

Dear GLIMS colleagues:
This may be my final post for the ASTER meeting, about ASTER imaging of the Himalaya and Alaska, and the backlog of image processing. My presentation will be available, as always (when I attend an ASTER meeting), on the JPL ASTER website. There will be a slight update of it to include some of your ASTER-support testimonials.
--Jeff Kargel


  1.  Backlog of image processing. From October 2022 to July 2023, acquired images were not processed to Level 1A due to software bugs (connected to the drifting orbit), as I have reported on. The backlog as of yesterday was cleared up going in reverse chronological order from July 2023 back to February 4, 2023. The remaining backlog of processing to Level 1A going back to Oct 2022 will require 2 more months to clear up.
  2.  Himalaya imaging: I have confirmed two improvements in Himalaya imaging, though any of you doing Himalaya work will want to do your own searches and see if things are better or worse in your specific area of interest. Last year I changed the GLIMS Science Team Acquisition Request (STAR) for the Himalaya to include two seasons of imaging as an experiment, which hopefully is working well to increase the total number of images as well as extend the seasons of coverage. In addition to October 10 to December 10 imaging with a 20% cloud tolerance, I added 01June to 31 August with 50% cloud tolerance. The two seasons are separate requests, so an ugly cloudy scene in the summer monsoon season does not count as satisfying the dry-season request. Not surprisingly, many of the June-August images are very cloudy, especially clouds where the glaciers are. However, a spot check reveals some images that have relatively clear-sky conditions or portions of images where glaciers are clearly evident. So, we are getting some monsoon-season coverage! When I get a chance, I will look in more detail and either retain it as is, modify it, or delete this monsoon period of coverage, but my spot check is favorable so far. In addition, there is the fall dry season where we should get good imagery as usual. I have a slightly delayed start of the season (to October 10) in hopes that late monsoon cloud activity does not cause acquisition of somewhat cloudy images in September to be counted as satisfying the GLIMS request. It's a gamble and a tradeoff. As always, there will be other images from other periods acquired under non-GLIMS requests. If you look for last year's fall images, whether in the Himalaya or elsewhere, most are still part of the backlog of acquired images that have not been processed yet after the processing debacle that started when the orbit began drifting, so be patient. By mid November 2023 the backlog should be cleared, and you'll find your images.
  3.  Alaska imaging: We truly are getting a lot of Alaska imagery. As any Alaska GLIMS person will know, for twenty years we had lackluster Alaska acquisitions due to the mysterious "exclusion zone," which was explained many times to me, but I never understood it or understood why it could not be shifted to somewhere else for a change. I railed about this gap of coverage during every ASTER meeting that I attended. The exclusion zone finally was lifted a couple years ago, and so in recent years, certainly this year for sure, we have gotten a lot of Alaska coverage. Better late than never.



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://nsidc.org/pipermail/glims/attachments/20230913/d48fb5b0/attachment.htm>