This is Lars Kaleschke's Typepad Profile.
Join Typepad and start following Lars Kaleschke's activity
Lars Kaleschke
Recent Activity
Great summary again, Neven!
By the way, we have a new reference to cite for the AMSR2 sea ice concentration data:
Beitsch, A.; Kaleschke, L.; Kern, S. Investigating High-Resolution AMSR2 Sea Ice Concentrations during the February 2013 Fracture Event in the Beaufort Sea. Remote Sens. 2014, 6, 3841-3856.
Available for free at http://www.mdpi.com/2072-4292/6/5/3841
ASI 2014 update 3: here comes the Sun (again)
During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2013 period (NSIDC has...
"Millikan measured the charge on an electron by an experiment with falling oil drops, and got an answer which we now know not to be quite right. It's a little bit off because he had the incorrect value for the viscosity of air. It's interesting to look at the history of measurements of the charge of an electron, after Millikan. If you plot them as a function of time, you find that one is a little bit bigger than Millikan's, and the next one's a little bit bigger than that, and the next one's a little bit bigger than that, until finally they settle down to a number which is higher. Why didn't they discover the new number was higher right away? It's a thing that scientists are ashamed of - this history - because it's apparent that people did things like this: When they got a number that was too high above Millikan's, they thought something must be wrong - and they would look for and find a reason why something might be wrong. When they got a number close to Millikan's value they didn't look so hard." (Feynman, 1997)
from http://www.columbia.edu/~jeh1/mailings/2012/20121226_GreenlandIceSheetUpdate.pdf
Seems to be a related phenomenon
Are scientists conservative about sea ice?
An interesting entry on the NSIDC Icelights blog (hat-top to GreenOctopus) that I also indirectly discussed a couple of months ago: Are scientists conservative about sea ice? Guest post by Walt Meier, NSIDC Scientist Arctic sea ice set a record minimum extent in September 2012, far below the...
NeilT,
those images are located north of Svalbard. I thought you meant the Canadian Archipelago. On your MODIS selection you can clearly see a divergent ice cover, single ice floes and open water, and probably not many melt ponds.
ASI 2013 update 2: shaken and stirred
During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2012 period (NSIDC has ...
Uni Bremen AMSR2 is showing significant open water in the CAB. I wonder if this really is or if it is only melt ponds.
From the blueish colors in the MODIS arctic mosaic you can infer that this is the effect of meltponds. http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r04c01.2013162.terra
See also http://www.seaice.de/Roesel_IEEE_2012.pdf
ASI 2013 update 2: shaken and stirred
During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2012 period (NSIDC has ...
Here you find some good information about the enhanced weathering method. Although it might sound good at a first glance, reducing the ocean acidification and removing CO2 from the atmosphere at the same time, it seems not to be a suitable treatment.
http://www.awi.de/en/news/press_releases/detail/item/how_much_carbon_dioxide_can_be_removed_from_the_atmosphere_if_the_mineral_olivine_is_increasingly_de/?cHash=1c8ec116a73b9819ace4ed1873bfd19b
Naive Predictions of 2013 Sea Ice
These predictions are naive in the sense that they are not based on a physical model, nor other measurements apart from the 30-odd year history of the index in question. Moreover, they are made a year in advance as winter freeze-up is just starting. The predictions are simply If ... Then stateme...
Chris,
you are absolutely right! Don't take the SMOS ice thickness as absolute value. There are large uncertainties and the thickness has always a low bias if there is thick ice (>0.5m) in the field of view.
By the way, you point to the 2012 GRL paper, not to 2010. This can be found here: http://www.the-cryosphere.net/4/583/2010/tc-4-583-2010.pdf
In this paper you find in the conclusions:
"We suggest that the retrieval should be interpreted as a lower boundary of the thermodynamic (i.e., modal or level) ice thickness."
With SMOS you can not distinguish if the ice is 60 centimeter or 6 meter thick because of the saturation of the emissivity (see Fig 1).
As an example, have a look at http://www.arcus.org/files/search/sea-ice-outlook/2011/07/images/pan-arctic/image009.png
There you see the so called "modal thickness" is about 3 meter but the average thickness is larger because of the shape of the distribution.
Unfortunately, the press release has not stressed the uncertainties. Here is some text which became not part of the press release:
"It has been shown that the measured L-band brightness temperature can be clearly related to the sea ice thickness for ice not thicker than half a meter. However, since it is not a direct measurement of thickness and the algorithm includes several assumptions, there are potential uncertainties. At first, the retrieval is influenced by open water and leads within ice cover. Because we assume a 100% closed ice cover, the ice appears to be thinner if open water is present. Secondly, the brightness temperature is influenced by changes of the ice temperature and bulk salinity. Thirdly, the brightness temperature is influenced by a snow layer on the sea ice. Despite the remaining uncertainties with respect to the absolute SMOS thickness, we can state that Arctic sea ice became significantly weaker between the years 2011 and 2012."
So, please be careful with the interpretation and comparisons to other data. Sea ice thickness is not always the same sea ice thickness. There are many thicknesses: mean thickness, modal thickness, effective thickness, and now we also have the "SMOS thickness". You have to take it qualitatively until we have more validation data which are very sparse.
Lars
More vids
I'm pretty sure someone mentioned these while I was away in slowinternetistan, but the visuals are so stunning that I'm posting them two weeks later. These videos, uploaded to YouTube by noiv, were shot by folks on one of the helicopters of the Polarstern research icebreaker. I don't know when ...
Here is another video on ice thickness. Watch out for the upcoming ESA webstory:
http://www.klimacampus.de/fileadmin/user_upload/klimacampus/6_Visualisierung/Ice_Thickness_KlimaCampus__Uni_Hamburg__ESA__Planetary_Visions.mov
(not so) Cool vids
The melting season has come to an end (more on that tomorrow in a new ASI update) and so all kinds of cool graphs, images and videos make the rounds. Unfortunately what is going on in the Arctic isn't so cool, otherwise it'd be more fun. The awe-inspiring shattering of records and the seriousnes...
Have you seen the little "polynya" that emerges at about the same position as last summer? Interesting times for sea ice research...
http://www.klimacampus.de/631+M57991a9bc34.html?&L=1
CT SIA anomaly drops below 2 million km2
With a drop of 174,867 square km for July 17th reported by Cryosphere Today (run by the Polar Research Group at the University of Illonois at Urbana-Champaign), the 2012 sea ice area anomaly has dropped below 2 million square kilometres, compared to the 1979-2008 mean: So what, one may ask. It ...
Lars Kaleschke is now following The Typepad Team
Jul 19, 2012
Subscribe to Lars Kaleschke’s Recent Activity