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Jim Hunt
South West England
Recent Activity
Gergyl - Perhaps you'd like to take a look at the ongoing discussion about these matters over on the Arctic Sea Ice Forum? Piomas vs. CryoSat The "ICESat domain" at 7.2 million km2 is very much smaller than the complete "Cryosphere Today domain", and the CT "Central Arctic Basin" is smaller still. If we're lucky perhaps "Wipneus" is computing the appropriate mask as we speak? He has tantalisingly stated over there: "I might add Cryosat later"
Toggle Commented 6 hours ago on CryoSat-2 sea ice thickness maps at Arctic Sea Ice
I'm afraid I don't believe anything I read about the Arctic in the Daily Mail! As far as I can tell from the Barneo journal and the Head North blog that runway has been happily in use both before and after the AN-74's "emergency landing" https://forum.arctic-sea-ice.net/index.php/topic,1189.0.html
Toggle Commented 4 days ago on PIOMAS April 2015 at Arctic Sea Ice
Cincinnatus - I've asked the Army. I'll let you know what they have to say for themselves. Meanwhile Ice Tethered Profiler 83 is already reporting back from the North Pole Environmental Observatory 2015 buoy farm. The field notes state that it's sat on an ice floe which is currently 1.8 m thick: https://forum.arctic-sea-ice.net/index.php/topic,1149.msg50072.html#msg50072
Toggle Commented 4 days ago on PIOMAS April 2015 at Arctic Sea Ice
Cincinnatus - The buoys in the Beaufort are generally delivered, and sometimes even collected again, by icebreaker. See the start and very end of this video for example: http://obuoy.datatransport.org/monitor#buoy8/movie That doesn't explain the mystery of the missing mooring data though.
Toggle Commented 5 days ago on PIOMAS April 2015 at Arctic Sea Ice
P.S. I got interrupted in the middle of typing my previous message and hadn't read your most recent one, so.... Chris - Thanks very much. The AARI ice type analysis I linked to also suggests there's currently a lot of thermodynamically thickened first year ice in the vicinity of the North Pole. Hence my agreement with Neven, for much the same reasons he mentions.
Toggle Commented 5 days ago on PIOMAS April 2015 at Arctic Sea Ice
Pjie2 - I plugged a crude FDD calculation into my 2013F spreadsheet (based on -1.8) and came up with 4338 for April 10th 2015 compared with 4363 in 2014 Chris - I'd choose the thinnest ice I could find that I was confident I wouldn't inadvertently fall through. Probably 3 on your list. However another ice mass balance buoy should be up and running in the vicinity by now: http://psc.apl.washington.edu/research/npeo-2015-field-reports/ If I can understand Google's translation correctly they had to manually remove a pressure ridge whilst clearing the Barneo runway, so there are certainly some about. More pics on the forum: https://forum.arctic-sea-ice.net/index.php/topic,1189 Whilst on a Russian theme, the Barneo team are also constructing the 41st AARI North Pole drifting station, after a brief hiatus. Whilst I'm loathe to predict anything in the Arctic this far in advance, I'm inclined to agree with you re the Beaufort. Neven - Agreed also. See: http://www.aari.ru/resources/d0015/arctic/gif.en/2015/20150407.GIF
Toggle Commented 5 days ago on PIOMAS April 2015 at Arctic Sea Ice
How thick do you suppose the ice is at the North Pole currently? Hot off the presses from Barneo:
Toggle Commented 5 days ago on PIOMAS April 2015 at Arctic Sea Ice
Pjie2 - We have indeed been over this discussion about buoys before! However I haven't come across your "biomass" analogy before, so thanks for your succinct overview. Extending the analogy, in the heat of summer the grass wilts and some of it dies. Re the "tedious semantic argument", the stuff about buoys being "mounted into thin 1st year ice" because "thinner ice allows better precision of measurement" is nonsense. However hopefully we can all now agree that what I described this time last month as "a very small sample from a very large Arctic" doesn't provide a particularly good handle on the "the average Beaufort ice thickness"? You seem to be suggesting that the buoys can however provide a better handle on thermodynamic growth, and then melt in due course. Have I got that straight? Navegante - 2013F is unusual in that it survived longer than a single season and also finished up in roughly the same position after drifting around the Beaufort Sea for twelve months. For more detailed information on snow cover than the buoys provide you'll have to wait for the 2015 IceBridge quick look data to be released. Here's last year's: http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#IceBridgeSnow
Toggle Commented 6 days ago on PIOMAS April 2015 at Arctic Sea Ice
Cin, Cin - 2.5m for 2012M. In recent years buoys initially installed near the North Pole have regularly found themselves in the Fram Strait a few months later. FYI last year lots of money was spent on lots of "one year buoys" in the Beaufort Sea: https://forum.arctic-sea-ice.net/index.php/topic,938 2014F is part of that project. As Kevin puts it "You're talking out of your ass". Please desist.
Toggle Commented 7 days ago on PIOMAS April 2015 at Arctic Sea Ice
Cincinnatus - Perhaps it would have been better if you had stated your point more clearly at the outset? You're also putting word in Ghoti's mouth that (s)he never said. On August 11th 2014 2013F was undoubtedly installed on multi-year ice and according to its "gauges" that ice was 1.5 m thick. What makes you so sure that 2014F wasn't installed on multi-year ice? What makes you so sure that "the buoys are preferentially installed onto the thinner ice there" for that matter? Here's a learned paper about ice mass balance buoys: http://www.chrispolashenski.com/docs/a57a149.pdf Can you see this bit? The perennial ice cover has been retreating faster than the seasonal ice cover. This has significantly increased the area of the seasonal ice zone, while decreasing the area of multi- year ice for which the current IMB systems are designed. In recent years, ice <1 year old has represented as much as 70% of the maximum winter ice extent in the Arctic, an increase from about 40% in 1985.
Toggle Commented Apr 10, 2015 on PIOMAS April 2015 at Arctic Sea Ice
Bill - It seems we were both doing a lot of typing simultaneously! The type field no longer refers to the ice type information from the ice mass balance buoy "field reports". For the last couple of years it's been used instead to differentiate between "traditional" and "seasonal" buoys, which are constructed very differently. By way of example 2015A is installed on fast ice near the coast of Alaska, but you wouldn't know that from simply reading its web page. "Seasonal" buoys can't handle thick ice, but assuming that "SIMB" necessarily implies "first year ice" seems to me to be a step too far.
Toggle Commented Apr 10, 2015 on PIOMAS April 2015 at Arctic Sea Ice
Cincinnatus - The topic is in fact the "Pan-Arctic Ice Ocean Modeling and Assimilation System". Scroll back to the top if you don't believe me. Kris talked about ice thickness across "the entire Arctic". Ghoti linked to a map of the entire Arctic. You suggested following that link then reading an introduction to ice mass balance buoys. I did that, and it starts as follows Monitoring changes in the volume or mass of the Arctic sea ice cover is crucial for developing our understanding of climate change processes and their impacts. which seems to be on topic to me. You also said "Those buoys (gauges, actually) measure changing ice thickness. They are mounted into flat 1m ice". Then you gave a list of buoys which at deployment were apparently sat on ice ranging from 132-173 cm. Apart from demonstrating your hole digging expertise, what (on topic) point are you endeavouring to make? If you wish for some reason best known to yourself to arbitrarily restrict the discussion to active ice mass balance buoys in the Beaufort Sea then please address the issues I raise about 2013F and 2014F. You may wish to read the March PIOMAS thread first: http://neven1.typepad.com/blog/2015/03/piomas-march-2015.html You may also be interested to learn that this year's deployment of one or more ice mass balance buoys near the North Pole has been delayed due to a minor technical difficulty:
Toggle Commented Apr 10, 2015 on PIOMAS April 2015 at Arctic Sea Ice
Cincinnatus - I didn't "confirm everything [you] said". By way of example, and at the risk of repeating myself: 337 cm for 2014D. By way of another example 2014F was deployed on August 11th 2014. If it wasn't on multi-year ice already it became so shortly afterwards.
Toggle Commented Apr 10, 2015 on PIOMAS April 2015 at Arctic Sea Ice
Neven - What's "obvious" to Cincinnatus is some way from the truth. I'm an engineer, and this is the way I see it. Ice mass balance buoys are not mounted on ridged multi-year ice, hopefully for obvious reasons! These days they are most often mounted on first year ice that's expected to get thicker rather than melt out in short order. Maybe that's because there's not much "planar" multi-year ice to be found in this day and age? This time last year one was installed on 3+ meter ice north of Greenland, but it didn't last very long: http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201314-imbs/#2014D However one buoy in the Beaufort Sea has survived a whole season and therefore can certainly be characterised as sitting on "multi-year" ice: http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2013F The assorted "gauges" on that buoy show the (thus far presumably unridged) ice to be less than 2m thick.
Toggle Commented Apr 10, 2015 on PIOMAS April 2015 at Arctic Sea Ice
Bill - Re 15% DMI. The Internet Wayback Machine suggests Oct/Nov 2012. Sorry, but I can't get the link to work! The 30% version is of course still available at: http://ocean.dmi.dk/arctic/old_icecover.uk.php
Toggle Commented Apr 6, 2015 on PIOMAS April 2015 at Arctic Sea Ice
Chris - Re "post 2006 stabilisation", see for example this archive of a recent GWPF article: https://archive.today/HRAXT That the minimal extent of Arctic ice has “paused” is admitted by Swart et al (2015) with a hat tip to DavidR: http://forum.arctic-sea-ice.net/index.php/topic,578.msg49511.html#msg49511
Toggle Commented Apr 6, 2015 on PIOMAS April 2015 at Arctic Sea Ice
G man - We're obviously wasting our time here. Bill posted the exact same link that you originally posted in an endeavour to point out to you that you're trying to compare apples with oranges once again. It seems you didn't get the message. You also seem convinced that "lake ice" has no bearing on your original question about differences between the DMI and NSIDC extent metrics. Having now done your due diligence, what's your explanation for those differences?
Toggle Commented Mar 26, 2015 on Early record, late record at Arctic Sea Ice
G man - So should I believe some guy on the internet who talks about things that "appear obvious" or someone from DMI who writes academic papers about sea ice concentration algorithms for a living? Aren't you even slightly curious about the apparent difference of opinion at DMI? The climo map you link to says it's "for the Arctic ocean" but nonetheless shows some pretty colours in the Baltic. It's also circular instead of rectangular. Weird, huh?
Toggle Commented Mar 25, 2015 on Early record, late record at Arctic Sea Ice
G man - For the umpteenth time, the answer I received said "The Great Lakes are included in both the old and the new version of the OSISAF data". The verbiage accompanying the "new" version of DMI extent says: "The plot above replaces an earlier sea ice extent plot, that was based on data with the coastal zones masked out." If most of the Great Lakes were masked out in the "old version", it doesn't imply they are also mostly masked out in the "new" version. Quite the reverse in fact.
Toggle Commented Mar 24, 2015 on Early record, late record at Arctic Sea Ice
G man - Perhaps you could point your contact at DMI at the answer I received from my contact at DMI last year around this time, and ask for further clarification? Whilst you're at it perhaps you might remind them that their web site (the bits I'm looking at at least) explicitly refers to "Total sea ice extent on the northern hemisphere" everywhere except in the title of their "new" graph? http://ocean.dmi.dk/arctic/icecover.uk.php
Toggle Commented Mar 24, 2015 on Early record, late record at Arctic Sea Ice
G man - What was the question you asked DMI, what was their precise answer, and who provided it? Have you bothered to read this yet? http://forum.arctic-sea-ice.net/index.php/topic,782.msg22214.html#msg22214 I take it that you are aware that there is more than one DMI "Arctic package"?
Toggle Commented Mar 23, 2015 on Early record, late record at Arctic Sea Ice
I could have saved you going to all that trouble G man, since I asked DMI that very question quite some time ago. Please do let me know if you receive a different answer to the one they gave me. In the meantime I feel sure you must have many happy hours ahead of you reading the relevant manual: http://www.osi-saf.org/biblio/docs/ss2_pmseaice_3_11.pdf If you'd like to start crunching the numbers yourself there's even some instructions on how to go about doing so over on the forum: http://forum.arctic-sea-ice.net/index.php/topic,782.0.html Please do not hesitate to ask if there's anything there you do not understand.
Toggle Commented Mar 20, 2015 on Early record, late record at Arctic Sea Ice
G man - At the risk of repeating myself, and as you can check for yourself by clicking the links I helpfully provided, whatever your views (or indeed mine) on the matter may be the OSISAF concentration data on which DMI base their numbers include the Great Lakes. The NSIDC concentration data, on the other hand, do not: ftp://sidads.colorado.edu/pub/DATASETS/nsidc0081_nrt_nasateam_seaice/browse/north/nt_20150319_f17_nrt_n.png Hopefully you have learned by now that even at NERSC area != extent? just in case: http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_ext.png Can you provide any photographic evidence, photoshopped or otherwise, of wolves eating ice seals?
Toggle Commented Mar 20, 2015 on Early record, late record at Arctic Sea Ice
G man - You're trying to compare apples with oranges. Your first link is to a graph of area, not extent. Which is why the numbers are lower than those quoted by NSIDC. Your second link is (despite the title!) to a graph of Northern Hemisphere ice extent, including the Great Lakes, which is why the numbers are higher than those quoted by NSIDC, for 2015 at least. Compare e.g. http://osisaf.met.no/p/ice/nh/conc/imgs/OSI_HL_SAF_201503191200_pal.jpg and http://osisaf.met.no/p/ice/nh/conc/imgs/OSI_HL_SAF_201103191200_pal.jpg
Toggle Commented Mar 20, 2015 on Early record, late record at Arctic Sea Ice
NASA have a video out too, along with this associated article: http://www.nasa.gov/content/goddard/2015-arctic-sea-ice-maximum-annual-extent-is-lowest-on-record/
Toggle Commented Mar 19, 2015 on Early record, late record at Arctic Sea Ice