GLIMS Update ( URGENT): Impending Revision of ASTER Glacier Imaging Plan

[Jeffrey S Kargel]

Dear GLIMS Colleagues,

Last week I presented to the U.S./Japanese ASTER Science Team an informal
proposal to modify the ASTER glacier imaging plans (Science Team
Acquisition Requests, STARs). I invite your comments on an urgent basis and
your continuing attention to this issue in the next few days.  Rick Wessels
is currently conducting an assessment of prior imaging success history and
will soon provide ftp access to this assessment along with a file of the
current GLIMS glacier image acquisition parameters.   An outline of a
revised plan has received tentative approval from the U.S. ASTER Science
Team leader and ASTER Geology Working group leader, but the reformulated
STARs must still be computed and submitted for approval through the ASTER
STAR Committee.

This proposed plan would, for a 1-year period only (January 1, 2003 through
Dec. 31, 2003), substitute the present GLIMS ASTER STARs with a modified
version designed to come closer to accomplishing the foremost goal of
GLIMS: to obtain at least one cloud-free glacier image of every glacier.
Although also very important, repeat imaging has lower priority than
gaining at least one good GLIMS scene of each glacier.  As you know, there
has been variable success and failure in imaging the world's glaciers with
GLIMS acquisition parameters.  We have discovered a possible technical
cause for exceptionally poor coverage of Alaska (where only one strip of
GLIMS images have been obtained over the life of the mission); for other
regions notorious cloudiness or possible non-optimal season start/stop
dates has hindered acquisitions.  In other cases, Greenland and Antarctica
especially, nearly complete coverage of most areas (Antarctica Peninsula
being a key exception) has been accomplished, partly through the ASTER
Global Map campaign; in fact there is significant repeat imaging already of
some regions.

More urgent than conducting ASTER glacier imaging as usual, we must adopt a
temporary revised plan that is based on prior success in obtaining glacier
images for each particular area.  The strategy would be to increase
priority for areas that have no adequate images, and decrease priority for
areas that have already been imaged, with the exception that a few selected
top priority areas will retain high priority for repeat imaging.  Rick will
be developing an algorithm which would be applied partly on a
manual-inspection basis, which we propose to do here in Flagstaff.  We will
not be inspecting the glacier scenes themselves, but the metadata that
pertain to successful acquisitions.  Before we submit the revised STARs to
the STAR Committee and ASTER Mission Operations, we will provide access to
the proposed revised STARs for your inspection and recommendations.  The
ground rules (tentatively approved) for development of arevised STARs are:

   1. Increase the number of discretionary HIGH PRIORITY scenes, using
additional ones to fill in high priority areas of regions that have poor
coverage to this date.  Existing HIGH PRIORITY designations will be
retained, so this move will be a supplement to the existing plan.

   2. Modify start/stop dates of some regions to better reflect the best
imaging seasons.  I need input from RC Chiefs if you desire any changes;
otherwise they will remain the same.  If you already know your glacier
image acquisition parameters, you may provide recommended changes right
away; otherwise, wait until Rick provides ftp access to the existing STAR
parameters.

   3. Shift priority of coverage up or down or even to zero based on prior
success history.  This revision of priority woud not affect scenes that are
designated a priori as HIGH PRIORITY.  Rick is developing a detailed
algorithm that will compute these changes, and you will be informed of the
results before they are implemented.

   4.  Attempt to have no significant change in the overall number of GLIMS
ASTER scenes.  The intent is to have well-covered areas have less coverage
in the next year, and poorly covered areas have increased coverage.

   5. On January 1, 2004, the existing STARs will be re-implemented.

Please submit any comments to me and to Rick Wessels (rwessels at usgs.gov),
who will be in charge of recomputing the STARs.  Stay tuned for more
details from Rick in coming days.

--Jeff K

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Energy conservation isn't just "green" and future-oriented, it's for
economic prosperity, national/allied security, and global peace.
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Dr. Jeffrey S. Kargel
U.S. Geological Survey
2255 N. Gemini Dr.
Flagstaff, AZ 86001
U.S.A.

Telephone (+1) (928) 556-7034
Fax (+1) (928) 556-7014
Email: jkargel at usgs.gov
Home email: jkargel at flaglink.com
Home phone: (+1)(928) 527-4196