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L. Hamilton
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The longterm graphs page here displays my 2013 PIOMAS graphs, but if anyone wants the updated 2014 versions, here is the bar graph of minimum PIOMAS volume: And here is a cycle plot, showing volume for each month 1979-2014:
Toggle Commented Apr 8, 2015 on PIOMAS April 2015 at Arctic Sea Ice
So IJIS has declined by 30 to 70k each of the last 5 days. Looks like their lowest-max record is safe. year,maxijis 2003,15.0661 2004,14.7014 2005,14.3961 2006,14.1324 2007,14.2097 2008,14.7748 2009,14.657 2010,14.6885 2011,14.1277 2012,14.7091 2013,14.5236 2014,14.4484 2015,13.9421
Toggle Commented Apr 1, 2015 on The Ns are calling the maximum at Arctic Sea Ice
In case others haven't seen it, the following notification came yesterday from NSIDC: Dear colleague, The National Snow and Ice Data Center is pleased to announce that the "Sea Ice Index" data set has been updated with a reduced pole hole and improved Northern Hemisphere masks for removing residual weather effects. Beginning 01 January 2008, the data will include a pole hole that covers 0.029 million sq km rather than the previous pole hole of 1.19 million square kilometers. In addition, an error in the pole hole used for data from 01 July 1987 to 31 December 2007 was corrected. These data now uses a pole hole of 0.31 million sq km rather than 1.19 million sq km. The varying pole hole sizes correspond to the orbit inclination of the satellite used to collect the input data. The new masks for removing residual weather effects are derived from the National Ice Center ice chart monthly climatologies which define more realistic boundaries for ice presence based on recent trends. These new masks have been applied to all historical data. The combination of these updates may cause slight differences in historical monthly and daily extent values ranging from -70,000 km2 to 60,000 km2. Lastly, the extent values in the daily extent .csv file have been rounded to three decimal places instead of six because anything further than three digits is outside the precision of these data. Access to the data and documentation is provided on the data set Web page at: If you have questions, please contact NSIDC's User Services Office at Data Acknowledgements Data authors: Fetterer, F., K. Knowles, W. Meier, and M. Savoie Data set DOI: Data center: NOAA@NSIDC ( Sponsor: NOAA/NESDIS/NGDC and the NOAA Arctic Research Program Best regards, NSIDC User Services
Toggle Commented Mar 11, 2015 on Mad max? at Arctic Sea Ice
Thought this was interesting -- a note originally posted on another site, and reposted here with permission -- a Dartmouth undergrad describes her impressions while helping sea ice research near Barrow. Basically there's a ton of open sea out here even though in the photos it looks like it's all frozen solid. Sea ice isn't like lake water since it's salty (obvious I know, but some people forget that salty water takes longer and colder temperatures to freeze than freshwater). The polar bears are out in full force this year because they're not getting enough to eat. So they can't be out on the pack ice since....there's not much ice out there for them to hunt on. So they're starting to be closer to the landmass, where since the sea is not as deep here, the water freezes over. So in summary, if you look from the 'beach' outside my hut, you'll see ice for miles, but if you get more than a mile out from the land, you start coming upon huge stretches of unfrozen sea ice. Just observations.
Toggle Commented Mar 10, 2015 on Mad max? at Arctic Sea Ice
The low maximum is entirely due to low ice in the Sea of Okhotsk which has nothing to do with the Arctic. Ice area looks below normal now not only in Okhotsk (~400k) but in Bering (~250k), Barents (~300k) and Greenland (~100k) as well, adding up to that minus 1.05m.
Toggle Commented Mar 10, 2015 on Mad max? at Arctic Sea Ice
Kwok & Rothrock (2009) "Decline in Arctic sea ice thickness from submarine and ICESat records: 1958–2008" Geophysical Research Letters doi: 10.1029/2009GL039035 [1] The decline of sea ice thickness in the Arctic Ocean from ICESat (2003–2008) is placed in the context of estimates from 42 years of submarine records (1958–2000) described by Rothrock et al. (1999, 2008). While the earlier 1999 work provides a longer historical record of the regional changes, the latter offers a more refined analysis, over a sizable portion of the Arctic Ocean supported by a much stronger and richer data set. Within the data release area (DRA) of declassified submarine sonar measurements (covering ∼38% of the Arctic Ocean), the overall mean winter thickness of 3.64 m in 1980 can be compared to a 1.89 m mean during the last winter of the ICESat record—an astonishing decrease of 1.75 m in thickness. Between 1975 and 2000, the steepest rate of decrease is −0.08 m/yr in 1990 compared to a slightly higher winter/summer rate of −0.10/−0.20 m/yr in the five-year ICESat record (2003–2008). Prior to 1997, ice extent in the DRA was >90% during the summer minimum. This can be contrasted to the gradual decrease in the early 2000s followed by an abrupt drop to <55% during the record setting minimum in 2007. This combined analysis shows a long-term trend of sea ice thinning over submarine and ICESat records that span five decades.
Toggle Commented Mar 4, 2015 on Thinner and thinner at Arctic Sea Ice
Earlier this year a survey-based paper, "What people know," was published in a special Arctic change issue of Journal of Environmental Studies and Sciences. An author's draft of the paper can be downloaded here: The individual graphics, showing what the public believes about trends in Arctic sea ice area, can be found at these links: Fig.1: Fig.2A: Fig.2B: Fig.3:
Toggle Commented Mar 2, 2015 on Shock news! at Arctic Sea Ice
Happy to oblige Kevin. You (or anyone else) can borrow the sea ice minimum volume (through 2014) graph here: In a similar vein here is Arctic and Antarctic minimum area: And Arctic extent:
Toggle Commented Mar 2, 2015 on Shock news! at Arctic Sea Ice
Intentionally or not it reminded me I'd said OK, and ought to follow through on such things. Send me an email if you want to chat offline.
Toggle Commented Feb 27, 2015 on Shock news! at Arctic Sea Ice
Jim, I did say I'd write something new. In the meantime there's another installment of "Polar Polling" that bridges the General Social Survey (2006, 2010) and a more recent survey question about sea ice,
Toggle Commented Feb 27, 2015 on Shock news! at Arctic Sea Ice
Here is my bar-graph version of the N and S minimum sea ice area, 1979 through 2014. Feel free to borrow:
Toggle Commented Feb 27, 2015 on Shock news! at Arctic Sea Ice
With 2014 done I've updated the cycle plots of extent/area and volume by month. Sent also to Neven in case he wants these for the blog's longterm graphs page. You're welcome to borrow these for your own purposes if useful. Also, a different rendering of 0-2000m ocean heat content, updated through 2014.
Toggle Commented Jan 25, 2015 on PIOMAS January 2015 at Arctic Sea Ice
On surveys we've been asking the public whether they think late-summer Arctic sea ice area has increased, decreased or stayed about the same compared with 30 years ago. A (very brief) new paper in the Journal of Environmental Studies and Sciences plots what that looks like. Here's the key graphic: Write me if you'd like a copy of the paper.
Toggle Commented Jan 18, 2015 on Perception of the Arctic at Arctic Sea Ice
The SEARCH Sea Ice Outlook post-season report is just published, with input from the Sea Ice Prediction Network (SIPN) project:
Toggle Commented Dec 20, 2014 on In the meantime: CryoSat at Arctic Sea Ice
Our survey research on the politicization of US public science/environment perceptions, including Arctic sea ice, hit the streets last week and has been written up with key graphics by Chris Mooney at the Washington Post: The paper itself will be open access for the next month or so, you can download a copy here: I'll have more polar results to report at the AGU meetings in a couple of weeks.
A bar graph showing annual minimum PIOMAS volume, updated through 2014, can be found here:
Toggle Commented Nov 10, 2014 on PIOMAS November 2014 at Arctic Sea Ice
The Sea Level Research Group at University of Colorado has just updated their satellite-based sea level time series, through August 2014. Sea level is still rising, consistent with independent observations of ocean heat content and glacier/ice sheet attrition. A simple graph of the CU sea level series is here: The Sea Level Research Group page has details:
Toggle Commented Nov 5, 2014 on PIOMAS October 2014 at Arctic Sea Ice
FWIW I'll be presenting some new survey research, building on earlier work that Neven wrote about: The new stuff for AGU includes surveys of public knowledge & beliefs as recently as this month. It has a bland title and abstract in the program but the presentation could be spicier, "Polar facts in an age of polarization." This at a session with papers about the human impacts of Arctic Change, Monday afternoon.
Toggle Commented Oct 29, 2014 on PIOMAS October 2014 at Arctic Sea Ice
Steve, this is a great idea. I'll be there and would be happy to help with introductions to SIPN and SEARCH folks if you'd like.
Toggle Commented Oct 29, 2014 on PIOMAS October 2014 at Arctic Sea Ice
Regarding estimates of early-1970s September sea ice extent, I took a shot at this for the graph on this blog's long-term page, also here: As noted within the graph, my 1972-78 values derive from Cavalieri et al. (2003), after regression adjustment to harmonize with 1979-2013 NSIDC values based on their years of overlap (1979-2002). FWIW the Uni Bremen extent series also extended back to 1972, with values quite similar to mine, so I suspect they used the same source.
Toggle Commented Sep 9, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Thanks, Jim. On my screen the images are slightly truncated at right, but click and you see the full series. Y'all are welcome to make use of these graphs if they're helpful.
Toggle Commented Aug 29, 2014 on ASI 2014 update 8: neck and neck at Arctic Sea Ice
Off topic for this thread but of wider interest, NOAA has just updated their global ocean heat and salt content data. I've updated the annual/three month graphs for 0-700 meters and 0-2000 meters
Toggle Commented Aug 29, 2014 on ASI 2014 update 8: neck and neck at Arctic Sea Ice
So, should we do an ASIB poll as a contribution to the SEARCH Sea Ice Outlook this month? Or leave well enough alone?
"Sea Ice Prediction has Easy and Difficult Years" is a sequel to our SEARCH SIO meta-analysis that came out in Geophysical Research Letters earlier this year. The sequel (an article for Witness the Arctic) looks at outcomes from two well-informed office pools that tried to predict September ice extent.
Also of possible interest -- the SIPN webcasts include results from a meta-analysis of SEARCH Sea Ice Outlook predictions from 2008-2013. Starts at 34:00 in this video of the first morning's presentations in Boulder: Neven posted about this SIO meta-analysis in March, It's published in Geophysical Research Letters, Write me if you'd like a copy of the paper.
Toggle Commented May 20, 2014 on SIPN presentation at Arctic Sea Ice