« Graphs of the Week | Main | Scientists receive first CryoSat-2 data »

Comments

Feed You can follow this conversation by subscribing to the comment feed for this post.

Glacierchange.wordpress.com

The blue swath is not so much an artefact as a simply a differently color-contrast to this image. It is worth noting that all you have do is change the name and the story for the largest glacier draining east and west Greenland (Jakobshavn) are the same 40 years of stability, rapid acceleration and retreat. The Kangerdlugssuaq has been the focus of autosub work which was not entirely successful. The Kangerdlugssuaq does not have an extensive an inland penetration of high velocities noted by Joughin et al., (2010) figure 9as the Jakobshavn.

Glacierchange.wordpress.com

Forgot that the most telling point is the higher snowline in 2010 then 2009. This is the same as we see on Petermann and Jakobshavn bottom image, so the higher snowline in mid-summer is wide spread.

Neven

The snowline is indeed telling. I hadn't noticed it yet. Thanks, Mauri.

logicman

Nicely spotted! I missed this one entirely.

The blue blob is a cloud shadow. You may want to check out this false color mosaic segment which shows the cloud and its shadow:
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r02c02.2010201.terra.367.250m

Great post!

Neven

Thanks, Patrick. Perhaps Werther can enlighten us on how the h*ll he spotted that blue swath. On the other hand, it helps if you know that a big glacier exists there. I know now.

logicman

"it helps if you know that a big glacier exists there"

Big glaciers? In Greenland? You're joshing me, right? :-)

btw, watch the two former tributaries for retreat. Previously they were held up by the back-pressure from the main stream. Now that there is no back pressure on the tributaries you effectively have 3 glaciers and 3 calving fronts where there was one. And of course, the main stream is free of the back-pressure of the tributaries. Watch out for some acceleration.

Bob Smith

NSIDC has an update

Peter2010

The mysterious NOAA Cam 2 temperature variation solved..

As this got myself and couple others curiosity going a couple of days back, so i thought i'd revisit it as my speculative 'its the ice melting off the enclosure' didn't seem right. So i did a little delving and this is what I've discovered..

- Every 6 hours, Cam_2 takes a set of up to 6 images. (speculate that some images drop via comm. loss)
- a 2 to 3 minute separation between each image capture in the set.
- Internal Temp start at ~4.5C and typically ends the last shot at ~12c

The reason for the ~8c temp variation is very likely due to the camera flash, causing an increase of about 2c per shot.
The additional heat is then lost within 6 hours, and starts the next cycle again at 4.5c internal temp.

Shot Cycles taken at (+/- 10 minutes)
01:0X
07:0X
13:0X
19:0X

Why is this of interest? resolve confusion on interpreting internal cam temperature.
The temperature variation may affect the image quality or colour (can anyone confirm this?)

http://www.arctic.noaa.gov/npole/index.php
http://www.arctic.noaa.gov/npole/2010/images/noaa2-2010-0719-070708.jpg
http://www.arctic.noaa.gov/npole/2010/images/noaa2-2010-0719-071708.jpg

Peter Ellis

Can a flash really heat the camera by a whole 2 degrees? I'd be more inclined to suspect that there's a heater in there to get rid of condensation, rime etc. - hence also the reason for taking several exposures to make sure at least one comes out.

Peter2010

Peter, I did consider a heater, but things start getting complicated, eg a far bit of additional power needed, larger enclosure enclosure, deviating from the KISS model - lots more things that could go wrong. But in a sealed, insulated container (think deep space probe), a cam flash would give off additional heat.

checking NOAAA site again and "The instruments typically continue to transmit data for months after the solar-powered web cams stop"..

solar power heater in frigate NP, its improbably but not impossible.

logicman

From the horse's mouth: "This system used large solar panel arrays, blowers and heaters to keep the lenses clear."
http://www.oceantronics.net/NOAA.htm

Also note that when the sun shines and charges the batteries - they warm up.

hth :-)

Peter2010

thanks for that link logicman.. prompted me to delve a bit further into the background on these cam...
i believe the 'heaters and blowers' are to keep the solar panels clear, as for the Cam "NOAA is keeping the device turned off except for just ten minutes every six hours, in order to conserve its solar-charged battery power".
Also, If you look at the CAM specs, there is no need for a heater for it to function well.

# Operating temperature: -40 to +48 deg. C
# Power requirements: 7.2VDC-10VDC, 1A, 9VDC power supply included
# fully isolated relay or photo flash trigger, rated at 28VDC 2A or 125VDC 0.5A
# 5VDC 50mA regulated power supply

http://thing1.linuxdevices.com/articles/AT4739871225.html
http://www.noaanews.noaa.gov/stories/s898.htm

The images will track the North Pole snow cover, weather conditions, and the status of NOAA's Pacific Marine Environmental Laboratory's North Pole instrumentation, according to James Overland, head of NOAA's North Pole Project. Although the webcam is capable of transmitting camera video at the rate of an image per second, NOAA is keeping the device turned off except for just ten minutes every six hours, in order to conserve its solar-charged battery power. Four times a day, the webcam wakes itself up and places a phone call to NOAA so that its data can be collected (the data is transferred by 2400 baud modem, through the Iridium low earth orbit satellite system, using PPP).

The webcam contains a temperature sensor, allowing the temperature of its local environment to be monitored -- note the temperature reading in the lower left-hand corner of the above photo (Click here for an enlarged photo). Various configuration parameters -- including zoom, frequency of photos, and other camera settings -- can be remotely configured via web access.

Kevin McKinney

Now, if only we knew what happened to webcam 1. It's now 2 weeks & counting since the picture updated.

The temps from the cam 1 location are weird, too--they suddenly dropped 12C yesterday at 1300, stayed there, more or less, for about 16 hours, then rebounded to a fairly normal
-2.1C. I for one am really curious about this. . .

Kevin McKinney

Prelim melt is about 60K today. Back to the mean or thereabouts. . .

Werther

Hi Neven… my short lived worry/excitement on the blue swath on K.glacier. It appeared on the mosaic 20/7. The melting season gets me looking for change for the last 4 years (creating more social then actual icesheet-worries). Since I got to MODIS a ‘quick scan’ around Greenland is easier then ever.
Though I like maps since I was a child, I’m still easily tricked. The Terra-version showed me later that it was blueish shadow of an oval cloud over the nunatakker to the southwest. Still a strange feature, but not a meltpond out of a suddenly opened ‘moulin-channel’ (that would really be something).
Why the interest? Discussion 4 years ago at the presentation of KNMI regional climate models/sea level rise. I wonder what a still small rise like 15 cm/10 years would do to fragile coastlines. An amateur calculation shows that mean retreat of some 4 kilometers around the G. icesheet would produce something like that. Of course in steps in a geometrical array, beginning at a melt rate of 250 cubic km going up to 1500/y, some 4000 ckm after 10 years.
This year up to now is the warmest ever, Greenland is surrounded by +2-+5 SST anomalies… NASA SLC is now +3,26 mm/y..is it happening? as Anu wrote ‘Science is interesting, but slowwwwww’. Anyone willing to check the math? You may be interested in: Greenland ice sheet surface temperature, melt and mass loss:
2000–06 / Journal of Glaciology, Vol. 54, No. 184, 2008

dorlomin

Would a change in the thickness and strength of the arctic sea ice to the North of Greenland affect the speed of outflow of the glaciers up there? I am thinking a bit like the ice shelfs in the Antarctic.

Nick Barnes

:dorlomin: No, not much. Ice shelves in the antarctic are hundreds or thousands of metres thick. The arctic sea ice is only a few metres at most.
There is, of course, an albedo effect: sea not covered by ice will be warmer, which can have an effect on the adjacent land ice. Also weather effects: waves and tides are greater, precipitation patterns change, and so on. All of that can affect land ice.

Neven

Werther, thanks for the comment and thanks again for pointing out the blue swath. The same happened to me a while ago when looking at Jakobshavn right after the north side of the glacier retreated. A weird looking shadow made me go haywire thinking that perhaps a huge part of the ice sheet surrounding the glacier had collapsed. I guess it's part of glacier initiation rituals. ;-)

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Your Information

(Name is required. Email address will not be displayed with the comment.)