GLIMS Update: Global ASTER imaging reprioritization

[william.sneedjr at maine.edu]

Quoting Jeff Kargel <jkargel1054 at earthlink.net>:

> Dear GLIMS colleagues,
>
> YOUR COMMENTS AND SUGGESTIONS ARE NEEDED.
>

Greetings Jeff:

Our e-mail system isn't rendering your first message correctly,
"returned images having 3/410% clouds." Should this be greater than
or less than?

I've found that images with less than 35% cloud cover frequently
have some useful parts but realistically less than 25% are the most
useful. With this in mind herewith some numbers for Svalbard and
Franz Josef Land gathered from LPDAAC this morning.

Svalbard:  	Search box:  9E to 24E, 76N to 81N
	Period: 2005-04-01 to 2005-09-30
	Day & Night
	L1A....673 images...519 with cloud cover equal to or
		greater than 35%....154 with less than 35%
	L1B....17 images...4 of those 17 are of only the ocean
		so only 13 include some land ice


Franz Josef Land:
	Search box:  45E to 65E, 80N to 82N
	Period:  2005-04-01 to 2005-09-30
	Day & Night

	L1A....295 images...211 with cloud cover equal to or
		greater than 35%....84 with less than 35%

	L1B....18 images

________________________________________________________

Here are some Svalbard numbers previously compiled for the years
2000 through and including 2004. The search box was slightly
different, 10E to 34E and 76.5N to 81N. Period was July 01 through 
September 30 for each year and only Day images were recorded.
The numbers are for L1B images only.

"Usable" I defined as any image with less than 35% cloud cover
and containing some small snippet of cloud-free land.

2000:  194 L1B images....20 usable
2001:  93  L1B images....40 usable
2002:  7   L1B images....7  usable
2003:  17  L1B images....10 usable
2004:  16  L1B images....7  usable

These numbers were compiled in June 2005 and I'm sure they haven't 
changed a bit.

The availability of the Windows/DOS-based L1A-to-L1B conversion 
software has allowed us to use L1As from these year that will probably
never get converted otherwise. However, I have no sense of what those
numbers might be. I've recently been collecting 2000-2004 L1B images of 
Franz Josef Land
but haven't yet looked through them for "usable" images. I'll do so
if it would be helpful.

Finally, we are not overwhelmed with repeat coverage for large parts
of Svalbard (the area I'm most familiar with). Finding 8 or 9 glaciers
in the archipelago with 2 or more years of ASTER imagery for my thesis 
work has been a real chore.

bill sneed
graduate student
climate change institute
univ. of maine, orono