H/t you know who. This airborne survey does not tell us -- yet -- about permafrost melting, since it only reflects a single point in time. But repeated annually, it could become an indispensable record of the evolving (read: melting) carbon storage lockers of the North.
I wonder if similar methods have been/could be used in the shallow waters of the East Siberian Arctic Shelf? They say they got data down to 100m -- parts of the ESAS are considerably shallower than that.
Seems to be a way to gauge extent and depth of permafrost, but not organic content, over a fairly limited area. It would likely be useful for providing a cheaper and more accurate way of calibrating any satellite instrument (I don’t know of any beyond landsat type vegetation observation which is the source for the upper images of both panels of the graphic you posted) to better estimate permafrost volume. Bore holes are quite expensive. This isn’t really cheep either, apparently(?) requiring a sizable amount of Helicopter time.
ReplyDeleteThe paper is behind the $$wall, but this, by the paper’s 2nd author and 1st author on the first cited reference, is interesting.
http://pubs.usgs.gov/fs/2011/3133/
How it would work through sea water I can’t guess, but for an instrument using resistively measurement as the operating principal, I’d expect some problems.
Fig 3 in the USGS Fact Sheet (Fig 4 in the GRL paper) is especially interesting to me in the surface water and wild fire (red above the right side of the B & C transects)/permafrost correspondence. I’m at a loss as to what the units on the horizontal scale are. Statute Miles?
I also think the current fixation with the E Siberian shelf is a little over the top. Given John Mason interview for SkS with Dr Shakhova
“SkS: Your 2011 field season is reported to have located kilometre-diameter plumes of outgassing methane. Are these located in areas visited in previous seasons?
NS: These were new sites from that part of the ESAS that was investigated very sparsely before.”
as well as Dr Archer’s considerable efforts at Real Climate, and the knowledge people who responded at Revkin’s.
Yep there’s cause for serious concern, but the “don’t you realize that pieces of the sky are falling” reaction, touched off be the article in the Telegraph, needs to stop I think. It’s gotten to be the flip side of the Watts brigade’s habitual excursions far into the weeds in their cherry tree quests.
WhiteBeard
The AP’s Dan Joling picked-up on this, and has a decent article based on an interview with the GRL paper’s lead author, Burke Minsley.
ReplyDeletehttp://www.adn.com/2012/01/23/2278968/usgs-uses-airborne-tool-to-map.html
The quoted deployment height of ~30 meters, adequate clear of tree tops, is about what I had guessed. There still no mention of the rate of linear advance (ie ground speed) to get a handle on the area coverage per unit of time (expence) for this technique, but it can’t be very large, at least in relation to the E Siberan shelf, if it works there at all. And much less in a comparison to, say, North America or the earth’s surface that contains permafrost. Then there’s the issue of manpower spent in data reduction which needs to come down by orders of magnitude for this to scale.
I did manage to figure-out the horizontal scale units of the figure. It’s km along the transect.
I'm also curious if data reduction has been completed for the 1,800 km of total transect or just the three parallel 25 kn segments in the figure.
WhiteBeard
"Yep there’s cause for serious concern, but the “don’t you realize that pieces of the sky are falling” reaction, touched off be the article in the Telegraph, needs to stop I think."
ReplyDeleteSure. See any of my recent posts on the topic. BAU CO2 is certain disaster; we should not be unduly distracted by possible disaster. That said, the issue is very interesting, and disaster is possible. There is also a longstanding problem with "serious people" choosing not to discuss the fat tail of extreme climate scenarios because it gives off a "sky is falling" vibe. A) That's not a good practice either and, B) We don't take ourselves that seriously here.
Awesome background on the paper's methods, thanks. No easy substitutes for money and elbow grease, I guess.
From the USGS link in Whitebeard's first reply.
ReplyDelete"AEM is used to gather data on the electrical resistivity of materials in the subsurface below the flight path of the helicopter, which are then analyzed to interpret the subsurface lithology and the location and extent of permafrost."
Sea water is very conductive, so I don't think it'll be of use.
Actually it just might work. I've just been looking and got details of a system using 30Hz for AEM - ELF signals at such frequencies are rumoured to be able to contact submarines below the ocean.
ReplyDeleteLots on that, it's been known for decades; for example
ReplyDeletehttp://www.vlf.it/submarine/sbmarine.html
I wonder if a boat tow rather than a helicopter would suffice.
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