This week:
I downloaded L5 imagery for Rainier and am in the process of finishing up the downloads of L5 for Hood as well. Here is my final list of the dates that look best for Rainier. The gallery of Rainier images now have several options for each year but the dates below are the ones that look best to me. I’d love your opinion on the ones that I’ve starred.
1984 - 8/4 - This is the only image available even remotely near the right time of year.
1985 - 8/23 - Again, the only day without significant cloud cover.
1986 - 9/11
1987 - 9/30
*1988 - Either 10/2 (cloudy in parts) or 8/31 (earlier but not cloudy).
1989 - 9/19
1990 - 9/22
1991 - 10/11
*1992 - 8/26 because 9/27 looks to have snow.
1993 - 8/29 - Early but the only one that was cloud free
*1994 - 7/31 is best 9/1 is very cloudy as you can see and 10/3 had many clouds and spots in image... this is a horrible year and I’m not sure what options I have.
1995 - 9/20
1996 - 10/8
*1997 - 8/8 - the only date without significant clouds but it still has a few...
1998 - 9/28
1999 - 9/7 Landsat 7
2000 - 9/25 Landsat 7
2001 - 9/20 Landsat 5
2002 - 9/23 Landsat 5
2003 - 9/26 Landsat 5
2004 - 10/14 Landsat 5
*2005 - 8/14 Landsat 5 or 10/17 L5 (partly cloudy) or combo of L7 9/7+9/23 SLC Off
2006 - 9/2 Landsat 5
2007 - 9/21 Landsat 5
2008 - 10-25 Landsat 5
If I can use that one early date of 8/14 of L5 for 2005 I can avoid the whole SLC off striping issue for Rainier. What do you think. The worst year by far is 1994. I’ve posted the best images in the gallery for that year... and they look bad, except for 7/31 which is really early... HERE is a quick link again to the Rainier Gallery.
To the right is the gallery for Mt. Hood that I’ve started as well. Once I have received the L5 images for 2001 onward I’ll post the best ones like I’ve done for Rainier and ask for your input on those as well.
Next week:
Next week I hope to have the Hood images narrowed down.
Questions:
• Please take a look at the dates that I’ve starred above to see which image you think is best for me to use for those years from the gallery I’ve posted.
• What is the best data that I should download from the snowtel sites? I assume SWE is probably the most important. Is there any other specific data I should be looking for?
• If I can avoid the SLC issue by using L5 imagery from 2003 onward instead of L7 could I do that? It would avoid the issue of trying to combine months to fill in the stripes of no data for each year.
Hope all is well. Emily started a new job this past week and her parents have been here visiting so we’ve been pretty busy showing them around the state. They leave this Friday. Hope the skiing is well there. If I can find a glacier to ski with good snow in September I will have managed to get runs in every month of this year - a first for me. :)
1 comment:
Anne
Jon,
Sept. 1, 3PM:
I see that for many years you have August data. That is too early unless it's the last week of August. Please look at the Landsat 4 archive as well (this will work for 1982-2000).
If you can't find a decent image for 1994 with which to compare the 1994 glacier outlines, then use 1995. This comparison will help you determine the threshold to use.
As for the SNOTEL (not "snowtel") data, you should use the daily SWE data.
Check the SNOTEL data to see if there was new snow for the October image dates -- they might be too late in the year.
L5 is preferred to SLC-off L7 data unless the date is too early.
Monday, August 31, 2009 - 07:54 PM
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