kingpointnorth
Tourist
Reged: 10/27/07
Posts: 10
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The attached kmz file may be of interest to this discussion as well. Here I have used Google Earth to doucment observed or suspect permafrost failures in the North Yukon and Western NWT.
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jean_thie
Cartographer
Reged: 12/06/06
Posts: 96
Loc: Ottawa, Canada
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Hi, Kingpointnorth,
This is an exceptional selection of permafrost failures/ regressive thaw phenomena. Some of them are as impressive as the melting of glaciers. Did you find these permafrost failures with Google Earth or did you just use GE to map them? Of course they are part of the natural dynamics of permanently frozen sloping or eroding landscapes and it would be interesting to know if the regression has accelerating in the last 30-40 years. Do you have an answer?
I am studying a few of your sites on various satellite imagery and older aerial photographs. Do you have more information on your Red Marked site?
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Jean Thie
Executive Director, Canadian Institute of Geomatics
www.geostrategis.com
Google Earth - An Exceptional Ecosystem Science Tool!
Monitor Permafrost Melting with Google Earth
Fire Ecosystem Interpretations with Google Earth
Map Glacial lake Agassiz!
Find the longest beaver dam in the World with Google Earth!
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jean_thie
Cartographer
Reged: 12/06/06
Posts: 96
Loc: Ottawa, Canada
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EXPLORING PERMAFROST MELTING WITH GOOGLE EARTH:
RETROGRESSIVE PERMAFROST THAW IN THE TREVOR RANGE YUKON
An excellent selection of sites in the Yukon showing significant slides and regression of permafrost in mineral soils was made available on Google Earth by "kingpointnorth"
In the context of climate warming, it is interesting to look at some of these sites over a period of 50 years or more. Aerial photography has been taken in the North since the mid 1920's. From the 1950's on aerial photography becomes a more dependable source of information for comparison.
Figure 1 below shows a glacier like retreat of land based permafrost. It is based on a comparison and interpretation of a series of aerial and satellite images. The left is an 1966 July Aerial photo (A19650-67) draped over a Google Earth. To the right is the Google Earth high resolution Digital Globe July 2004 image. The grey dotted lines show the permafrost melting/ erosion edge in 1966. The Yellow dotted line is derived from a NASA Landsat 1990 low resolution image interpretation (WorldWind) and the orange dotted line is represents the GE 2004 digital Globe image.
The maximum regression distance over the 38 year period is about 850 meters, while the active edge is close to 890 meters in length. Average regression rate would be in the order of 20 meters per year . Most of it, certainly volume wise, in the last 14 years. There ar no indications that this slide has been triggered by wildland fires as there is no evidence of fire history on the aerial and satellite images.
This melting and regression rate is comparable to other rates documented in the Yukon. Form example Burn and Friele (1989 Arctic vol. 42 no.1, p31-40) measure regression rates of up to 16 meters per year in retrogressive thaw slumps near Mayo, Yukon Territory
more information at: http://www.geostrategis.com/p_permafrost-slides.htm
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kingpointnorth
Tourist
Reged: 10/27/07
Posts: 10
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Hi Jean,
Thankyou for your response and interest. Nearly all of the failures were identified using Google Earth. Many are suspect due to the low resolution coverage over most of the Yukon. Those that fall within the high resolution coverage areas are easily identifiable and in some areas numerous. As the high resoultion coverage improves I keep adding more sites. The numbers are significant indeed.
I have had the opportunity to fly across the Peel Plateau on several occasions. In 2005 we did pass by the larger site marked in red; at the time I was able to photograph this and a few other failures along our flight path. I understand that others have as well but to what extent I am not sure.
After inspecting the red marker site from the air, photographing it and then later looking to see if I could pick it out on Google Earth (sometime later in 2005 or early 2006), it did not take long to find more features that had the same or similar characteristics - a few dozen to start with. At that time it was all low resolution coverage but with the newer high resolution coverage the total number is now in the hundreds (I have lost count). Some are in the range of 1km in length. I continue to look and add to my list as time permits.
I can send you the photographs of those that I have flown over if you like. I have not been on the ground so can't offer any more details or measurements.
The red marker site does show that the failure has gone through a transistion from being active and then partially stablizing. It appears to me it most likely created the small lake immediately upstream. I have looked at WorldWind and found this site but the resolution is such I think it would be hard to meaure change over time. The use of aerial photos from the past 40 to 50 years is probably the only way to do this comparison (such as what you have done so well) . I have no idea if the rate of change has accellerated or not.
I have discussed this briefly with Panya Lipovsky her with the Yukon Government but I don't know if she has had a chance to look at this in more detail.
I will sign off for now. Please stay in touch. Let me know if I can send you the photos.
Cheers,
Doug Davidge (kingpointnorth)
Edited by kingpointnorth (02/09/08 10:03 AM)
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jean_thie
Cartographer
Reged: 12/06/06
Posts: 96
Loc: Ottawa, Canada
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Hi Doug,
Your selection of permafrost slide markers is really very interesting. Each of these sites warrants further studies. Your photograps would certainly be of interest. Why not add them to this discussion thread.
Your red marked site is very interesting since it shows very recent as well as 50 year old slide scar areas. The relative recent disturbed bare soil is clearly visible on both sides of the creek. Also the adjacent areas on both sides show significant sliding area which appear to have been stabilized and are recovered with vegetation.
I have taken some time to study your red marked site in more detail using air photos from 1950, 1953, 1972 and 1977, as well as Landsat. the image below shows my interpretation . You are right that the pre 1950 slide caused the formation of the little lake upstream. The pre 1950 slide appears to have been a sudden event. The pink arrow shows the slide path, which also blocked the creek flow, and created a small lake upstream. The the water erosion from the displaced creek started to undermine the north facing slope which showed a steady regression for the next 27 years before stabilizing. Just before the 1990's additional regression occurred on the south facing slope (thin orange line) also occurring as a sudden failure. The new slide areas (yellow dotted line) developed between 1990 and 2000.
Retrogressive Slide on 1950 and 1953 Aerial Photos
The 1950 photo ( A12847-144) was taken on August 2nd, 1950 at a height of 20'000 ft. Original scale 1:40'000. The pink arrow shows the flow direction. The slide, on the south facing slope occurred as a sudden event blocking the flow of the creek and creating a small lake upstream. The drainage channel was pushed into the opposite slope which started to collapse. Both sides continued to melt, but most of the regression in the following decade is in the north facing slope. The 1953 airphoto (A13753-22) was taken on 27 July from 35'000 ft.
1972 and 1977 Air photos
During the next 20 years the North facing slide is regressing. The 1972 and 1977 air photos show that the creek is pushed back again (yellow marker). In this 5 year period the North slide appears stable, and some further sliding occurred on the south facing slide (from blue dotted line to the light blue-grey dotted line). There are no signs of fire scars in the vegetation on these photos, but a fire scars ( (dated between 1958-1978) were identified in close to the Salter Hill area, about 5 km distance from this slide area. 1972 Airphoto (A22972-119) taken on 11 July, from 35'000 ft; 1977 air photo (A24761-133) taken on August 1, from 35'000 ft.
NASA Landsat Pseudo Colour 1990 (left) and 2000 (right). The pink arrow on the 1990 satellite image shows that the south facing slope has become active again. Also the light blue arrow shows the start of the next phase on the north slope. The 1950 and 1970 slide areas still look reasonably stable and are covered with vegetation again. The red arrow on the 2000 image shows a part of the 1950 slide which has become active again: the small dark black area- a mudflow The yellow arrow on the 2000 image points to the dark purple active slide area essentially very similar to the Google Earth image (2007). No fire scars are visible on each of the images.
Fire History for the Yukon 1946-2004 . The map below depicts the wildland fires since 1946. Source: Source: Yukon Energy, Mines and Resources . The Caribou River area described here is marked with the red marker near (1). The closest fires on this map was (3) which occurred between 1990 and 1999. The Trevor Range Site (green marker) is identified with a (2). It will be interesting to study the blue markers provided by kningpointnorth in relation to fire history. A cursory review of some of the sites in recent and older burn areas seems to imply a link with the fires. Legend: Grey= 2000-2004; Red=1990-1999: Pink=1980-1989; Green= 1970-1979; Orange= 1960-1969; Yellow=1950-1959; Light Green= 1946-1949 (not on this part of the map)
Doug, you could add the fire map as overlay to your collection of markers. As you already can see, many of your markers are in burned and non-burned areas. I have looked at a number of the sites in recent burn areas, where the fires appear to be the cause of the slide. Fires can also have an impact on increased stream flow and therefore increased erosion.
Fires are already so abundant in this part of the world. If they double in frequency as result of climate warming, retrogresive thaw slides would certainly become more abundant. It would be interesting to study this with your markers and the existing fire history,
It is so far my impression from your markers and these preliminary analysis that ther could be twice as many slides today than there were 60 years ago.
Cheers,
Jean
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Jean Thie
Executive Director, Canadian Institute of Geomatics
www.geostrategis.com
Google Earth - An Exceptional Ecosystem Science Tool!
Monitor Permafrost Melting with Google Earth
Fire Ecosystem Interpretations with Google Earth
Map Glacial lake Agassiz!
Find the longest beaver dam in the World with Google Earth!
Edited by jean_thie (02/26/08 06:24 PM)
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sateliteoflove
Tourist
Reged: 12/02/07
Posts: 21
Loc: Netherlands
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Hi, Jean Thie and others,
Am I right to assume that there is no way to prove permafrost melting occurs other than bij comparisson to earlier aerial photgraphs?
I am not a scientist, rather an artist who wants to convey the feeling of urgency of global warming issues using Google Earth as a source of inspiration (check my weblog http://googleearthart.blogspot.com )
The first painting I made in this Google Earth series was of a part of the Russian Tundra. I found a strong image I could use as inspiration, but I have no idea if there is any evidence of permafrost melting on that location. Are there maybe teltale signs (like a large number of small lakes which could all go anaerobic)? If I'm to make a statement of some sorts with my paintings, I would should at least know a little bit of what I'm talking about.....
I've included the KMZ file of the location. The painting is on my weblog.
I'd be gratefull for any wise words on the issue.
Keep up the good work!
Evert Schut
Edited by sataliteoflove (03/12/08 05:27 AM)
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jean_thie
Cartographer
Reged: 12/06/06
Posts: 96
Loc: Ottawa, Canada
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Beste Evert,
You pose some interesting questions about permafrost melting. Using Google Earth as an artisitic source of inspiration is a great approach. Permafrost landscapes provide particularly fascinating landscapes often reminiscent of modern art and no better way to see these than with satellite or airphoto images.
To answer your questions:
1) Satellite and air photos provide especially effective tools to study environmental change over time. Field work, sample sites, data collection and monitoring are critical components of satellite based landscape studies. There are global monitoring networks have reasonably long records of permafrost monitoring (active layer dynamics, ground temperature, permafrost depth etc.). The Global Terrestrial Network for Permafrost is an example: http://www.gtnp.org/index_e.html. A good practical example is the East Siberian and Alaskan Transect Project: http://www.gi.alaska.edu/snowice/Permafrost-lab/projects/projects_completed/proj_transects.html
2) The image of the Siberian Tundra you used shows a typical permafrost wetland landscape. It is in the continuous permafrost zone and it does not show any dramatic melting, but it demonstrates typical arctic lake permafrost dynamics. In fact a number of lakes have disappeared over time and within the dried up lake bottoms permafrost is building again.
3) To understand the relationship between permafrost melting and climate change, you have to understand that the building of permafrost (aggradation) and the melting of permafrost (degradation) are two processes that occur more or less simultaneous. The active layer of soil which freezes in winter and thaws in summer is an example of this. The figure below demonstrates the varying thickness of the active layer and the aggrading permafrost which is filling in a former lake again. ( source: http://piru.alexandria.ucsb.edu/collections/geosystems/geosystems17-17.jpg
4) Your blog talks about methane and the BBC series. It is interesting to note that one of the research sites is quite close to your “painting”. I have inserted below one of the illustrations and provided a link to the location on GE. This study talks about the melting of Yedoma , a Pleistocene loess permafrost with a high ice content and rich in organic matter. Source: http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html
The landscape studied here is different from your area; in particular fewer thaw lakes and more sloping terrain. If you study this area in detail you can also see the rich fire history. Wildland fires occur frequently and are expected to increase significantly due to global warming.
5) For comparison I have included an image from Barrow Alaska showing the age of thaw lakes in ice rich permafrost. The source: http://www.geography.uc.edu/~kenhinke/dtlb/
Gegroet
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Jean Thie
Executive Director, Canadian Institute of Geomatics
www.geostrategis.com
Google Earth - An Exceptional Ecosystem Science Tool!
Monitor Permafrost Melting with Google Earth
Fire Ecosystem Interpretations with Google Earth
Map Glacial lake Agassiz!
Find the longest beaver dam in the World with Google Earth!
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sateliteoflove
Tourist
Reged: 12/02/07
Posts: 21
Loc: Netherlands
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Dear Jean,
Thanks a lot for your extensive reply! I just read through quickly and it looks like I will have to do quite a lot of further reading before I can say anything about permafrost melting with even the slightest authority.... Lucky for me an artist can get away with an 'artists impression', but I feel it's my obligation to at least know a bit more about what's really going on. I hope you will bear with me and my lay questions.
From your reply I understand that the thaw lakes are quite natural in a wetland permafrost environment. The BBC documentary gave me the impression that the (anaerobic) conditions in the lakes cause methane production, so is this also a natural process? So are scientists worried about an increased rate of methane emissions as result of increased melting of permafrost (leading to more and bigger permafrost lakes)? Or is the methane production in this area itself something new? Or perhaps the production of methane is not restricted to deep lakes?
Have any esimates been made of the total increase in methane emissions in artic zones? I think I read somewhere that the IPPC models have not yet taken this into account. Is that right?
Between the lines of your reply and other posts I get the impression that increased fire damage is at least as big an issue as methane emissions. I know, reading between the lines is risky business. Perhaps you can put me straight?
Thanks again for your efforts! Cheers
Evert.
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Evert Schut
http:/googleearthart.blogspot.com
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kingpointnorth
Tourist
Reged: 10/27/07
Posts: 10
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I will upload individual photos of a few of the permafrost failures I was able to photograph from a helicopter in 2006 using a 10 megapixel camera. This site is located on the Bonnett Plume River just upstream of it's confluence with the Peel River. The low angle of the photo does not allow for a good overlay on GE but you will be able to see a great deal of ground level detail. Cheers....
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kingpointnorth
Tourist
Reged: 10/27/07
Posts: 10
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This is the 2nd oblique photo upload to this discussion showing a permaforst failure in the upper Eagle River watershed. This site is located about 16 km east of the Eagle Plains Lodge along the Dempster Highway. The photo was taken from a helicopter using a 10 megapixel camera.
Cheers
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