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Chris Reynolds
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Ooops, Forgot the link to the poll. http://forum.arctic-sea-ice.net/index.php?topic=1086.0
Toggle Commented Dec 10, 2014 on PIOMAS December 2014 at Arctic Sea Ice
Crandles has posted a poll on the forum asking when people think we will start to regularly see no ice (at all, as I understand it) in the Arctic Ocean, which would be during late summer. I think it would be very interesting if all forum members could vote. Note, this is for no ice at all, not virtually ice free (e.g. <1M km^2 extent). Osteopop, But there is no cessation of loss(levelling) within the Arctic Ocean, just regional effects outside the Arctic. So I see no evidence for your initial claim that: "...when the winter extent stops decreasing and even grows - what is more natural than this also affecting the summer minimum in due time?"
Toggle Commented Dec 10, 2014 on PIOMAS December 2014 at Arctic Sea Ice
Damn, didn't think I'd posted the above, while pondering how to follow up I changed my mind and did some graphs. All this is done using Wipneus's calculation of regional extent. Osteopop, Here is the decline in extent on day 90 (late March) from 1979 to 2013. https://farm9.staticflickr.com/8664/15984536852_0e91651117_o.png I've not done the calculations, but I'd be surprised if the claimed levelling is outside the error bounds of the linear trend. That said, there might be a levelling, to examine this I break down the data into regions. First, here is the Arctic Ocean (Beaufort, Chukchi, ESS, Laptev, Kara, Barents, Greenland, Central, CAA). https://farm9.staticflickr.com/8564/15362944314_14a347ff5e_o.png There is no sign of a levelling within the Arctic Ocean, why is this? I have broken down the Arctic Ocean into two subsets, land bounded seas are Beaufort, Chukchi, ESS, Laptev, Central and CAA. The Atlantic seas are Kara, Barents, Greenland, the regions most exposed to Atlantic influence. https://farm8.staticflickr.com/7524/15797924490_f97d5626a3_o.png The landbound Arctic Ocean extent in March is 'maxed out' with minimal variation and negligible trend. However in the Atlantic sector, under the influence of warming Atlantic ocean waters the downward trend is significant. This Atlantic sector decline account for virtually all Atlantic ocean extent decline, and 55% of the decline slope of overall northern hemisphere extent decline for day 90. There is no evidence of a cessation in decline during recent years in the Arctic Ocean. So what of decline in the rest of the northern hemisphere? I have plotted the total extent for the northern hemisphere excluding the above defined Arctic Ocean. https://farm9.staticflickr.com/8640/15985198135_731ebc8c15_o.png In this graph we see an increase in extent in the timeframe (~2005 onwards), against the long term trend, though not necessarily outside the assoicated error bounds. What is going on here? I have graphed extent for the Pacific (Okhotsk & Bering), the Atlantic (Baffin & Gulf of St Lawrence), and Hudson Bay. https://farm8.staticflickr.com/7541/15983208961_5ec54af991_o.png Hudson Bay plays no role, it is 'maxed out' by day 90 (late March). The extra-Arctic Atlantic can be viewed as having a pause in loss since 2005, while the extra-Arctic Pacific can be seen as having an uptick. So based on this I don't see any grounds for claiming that conditions within the Arctic are driving a pause in winter peak sea ice extent. Note that none of this data is hidden. The entire dataset is available here: https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data I use "nsidc_nt_nrt_detail.txt" Wipneus has put a lot of work into producing it (I know from the work I put into my PIOMAS derived data), yet people continue to assert things without first referring to such data. When they do so they may be challenged with the data. However as it is the job of those proposing ideas to do the hard work, and as the data to do that work is available, do not be surprised if people get a bit short with your use of their time.
Toggle Commented Dec 9, 2014 on PIOMAS December 2014 at Arctic Sea Ice
Osteopop, Where is the winter maximum in extent or area set? 1) Inside the Arctic Ocean. or 2) Outside the Arctic Ocean.
Toggle Commented Dec 9, 2014 on PIOMAS December 2014 at Arctic Sea Ice
The oceans are acidifying. Therefore the oceans are not the source of the increase in atmospheric CO2. When I was a sceptic such trash was doing the rounds, I am amazed to see it is still being claimed, especially when sceptics (well he was one when I was one) such as Ferdinand Engelbeen have thoroughly destroyed the argument and demonstrated how the CO2 increase is man made. http://www.ferdinand-engelbeen.be/klimaat/co2_origin.html The correlation between CO2 and sea ice is with global CO2, not local CO2 levels above the ice. Inertia isn't a bad analogy, but what is actually happening is latency caused by energy storage. It takes time for land and ocean to warm causing a lag behind insolation in the annual cycle. Strictly speaking inertia refers to a mechanical effect, but there is the term 'thermal inertia'. http://nathaniel.putzig.com/research/ti_primer.html
Toggle Commented Dec 9, 2014 on PIOMAS November 2014 at Arctic Sea Ice
I forgot to add to the above. Whilst there may be something subtle that indicates a common cause to the weather patterns of summer 2013 and summer 2014, the largescale pattern doesn't seem to me to indicate a common new pattern due to a regime shift. Jun to Aug 2013 https://farm8.staticflickr.com/7465/15791815057_9acc599277_o.png Jun to Aug 2014 https://farm8.staticflickr.com/7511/15951778986_a4a67ab3f1_o.png
Toggle Commented Dec 8, 2014 on PIOMAS December 2014 at Arctic Sea Ice
I've had to correct the regional volume graph at the start of my blog post. http://4.bp.blogspot.com/-BuwFfRShAA8/VIXhj7ado6I/AAAAAAAABPg/KYy3dnoFDvU/s1600/PIOMAS%2BRegional.png The data displayed reverted to September data after copy and paste - odd Excel bug. Osteopop, You tend to favour a shift that drives a reverse of sea ice loss because, as amply demonstrated in the past, you are driven by an agenda which dictates your conclusions. I do not have enough information to say either way whether a changed of typical summer atmospheric regime is starting. I think we will know in a few years if summer considitions continues to be adverse to ice loss. However, given that sea ice extent loss is so clearly correlated with increases in CO2. And given that the loss of volume from 1995 to 2012 has been driven by the ice/ocean albedo feedback. And given the wide variety of weather that has not led to a recovery of the summer sea ice. The conservative position remains that the process of sea ice loss will continue. Although of course I think we will enter a long(ish) tail of persistence of the summer sea ice that is not implied by statistical extrapolation of volume loss.
Toggle Commented Dec 8, 2014 on PIOMAS December 2014 at Arctic Sea Ice
Iceman, To be clear, what is going on with volume at present is not, in my opinion, part of the emergence of a long(ish) tail of the 'sigmoid' form. The last two years of poor summer melt weather could have happened at any time in the last ten years or so and have had a similar effect. That weather issue is seperate from my argument that winter volume had hit a floor with a slower rate of volume loss dictated by the tending of winter thickness to the thickness of thermodynamic growth (roughly 2m thick ice). As I have said before, actually it's a nuisance for me because I will probably have to wait several more years for the floor in winter volume to be regained.
Toggle Commented Dec 7, 2014 on PIOMAS December 2014 at Arctic Sea Ice
DrPhilosopher, http://farm7.static.flickr.com/6189/6159788844_e2509273a8.jpg and http://farm8.staticflickr.com/7058/6993704168_03751afb94_o.jpg Note that the second plot in the above image shows irradiance and sea ice, from that plot one would come to the conclusion that a higher level of insolation leads to more sea ice, this is obviously absurd. This relationship happens because the decline in sea ice driven by human activities has happened as solar insolation has fallen as we have left the Grand Solar Maximum of the mid to late 20th century. As JD Allen points out, the insolation decline will have little effect. Those above images are from these two sources (in order). Johannessen 2008, "Decreasing Arctic Sea Ice Mirrors Increasing CO2 on Decadal Time Scale." https://bora.uib.no/bitstream/1956/2840/1/200806005.pdf Notz & Marotzke, 2012, "Observations reveal external driver for Arctic sea-ice retreat" http://www.mpimet.mpg.de/fileadmin/staff/notzdirk/2012GL051094.pdf In the following image of model runs the coloured lines include anthropogenic forcings, the grey lines don't. http://2.bp.blogspot.com/-yUAq3OcQwfE/Uy34AqBls_I/AAAAAAAAAP0/ndGeBbkh2vM/s1600/WangOverland+2012.JPG Put simply, without human impacts there is no decline of sea ice. That image is from Wang & Overland, 2012, A sea ice free summer Arctic within 30 years? - CMIP5 Update. http://projects.iq.harvard.edu/files/climate/files/wangoverland2012.pdf
Toggle Commented Nov 22, 2014 on PIOMAS November 2014 at Arctic Sea Ice
Wayne, We'll know over winter if PIOMAS is correct as Cryosat and IceBridge data comes out. Personally I have no doubt PIOMAS is reflecting increased thickness and volume correctly. Susan, Thanks for that.
Steve, Sounds like it may be pushing the strict definition, but Neven's appearance at the SIPN conference, and the use of graphs published here by commenters may swing the decision should Neven want to nominate you (given that he's on another continent. If you were to go I'd look forward to your posts. And I agree you're grounded enough in the science to do a good job.
Toggle Commented Oct 28, 2014 on PIOMAS October 2014 at Arctic Sea Ice
Thanks for the post Neven, and thanks for the recommendations. David Appell, Thanks I wasn't aware of that meeting. https://royalsociety.org/events/2014/arctic-sea-ice/ Average volume for all days 1979 to 2012 is 20.47k km^3, 1/6 of that is 3.41k km^3. Summer is a bit hard to pin down (does it include September?), JJA average volume for 2012 was 10.00k km^3, JAS average was 5.96k km^3. So the scenario painted is a sort of super 2012 situation. However in a model experiment involving PIOMAS that Dr Blanchard Wigglesworth asked for a reduction of early spring ice thickness by 1m resulted in a very aggressive spring melt, and the remnant thicker ice off northern Canada surviving through the summer. So it looks like such a situation. The extreme low volume not implying totally ice free in September, but a rapid spring loss followed by a reduced late summer rate of volume loss. The following is a screenshot of the presentation. https://farm3.staticflickr.com/2942/15323588435_2e17d3b6bc_o.png Left column is 'control' typical behaviour for recent years. Right column is 'experiment' the result of the artificial thinning of ice. Months from June to September go down the columns. From here: https://www.youtube.com/watch?v=wLzGABwoNK4&feature=youtu.be Hat tip to Crandles. :)
Toggle Commented Oct 9, 2014 on PIOMAS October 2014 at Arctic Sea Ice
"Wow, over 100 comments, might be something interesting about Arctic sea ice in all that", thought I. Vinyards? Back to the forum, nothing interesting going on here.
John, If you're right (the 'if' is not meant to cast doubt, it just means I don't know), then you use the appropriate tool for the job. And in your case the NAO seems appropriate.
Toggle Commented Sep 13, 2014 on PIOMAS September 2014 at Arctic Sea Ice
John Christensen, Hurrell, 2000, Climate: North Atlantic and Arctic Oscillation (NAO/AO). Extract from the Encyclopedia of Atmospheric Science - used in place of the peer reviewed paper I can't find at present. http://www.cgd.ucar.edu/staff/jhurrell/docs/hurrell.NAO.EAS03.pdf "That the NAO and AO reflect essentially the same mode of tropospheric variability is emphasized by the fact that their time series are nearly identical, with differences depending mostly on the details of the analysis procedure." Or checking in my Favourites I find a link to this page: http://www.jisao.washington.edu/wallace/ncar_notes/ "It follows that the NAO and AO are synonyms: they are different names for the same variability, not different patterns of variability. The difference between the terms is in whether that variability is interpreted as a regional pattern controlled by Atlantic sector processes or as an annular mode whose strongest teleconnections lie in the Atlantic sector." Figure 1 on that page is an amusing summary of the relationship.
Toggle Commented Sep 12, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Blaine, The problem I am having is as follows: 1) I have read multiple references in papers, granted mainly winter, if I recall correctly, to AO/NAO like patterns. The formation of the AO/NAO patterns by land/sea masses is likely to apply to other patterns driven by various factors related to Arctic climate change. Yes the 2007 to 2012 summer pattern is like the AO/NAO, but I view it as significantly different enough to justify viewing it differently. 2) The AO/NAO has not in the past driven strong Dipole like behaviour within the Arctic. 3) The AO/NAO has not in the past been associated with the unusually high geopotential heights seen over Greenland. https://farm4.staticflickr.com/3858/15166606982_47c6d17e6b_o.png 4) 2007 to 2012 all fall within the eleven lowest NAO indices for June July August. Excluding 2014 from the 2007 and 2012 due to its complication. Here is average SLP for 2007 to 2012. https://farm6.staticflickr.com/5588/15022681310_66645458a5_o.png Here is average SLP for the ten lowest NAO years excluding 2007 to 2012. https://farm4.staticflickr.com/3883/15186330706_d65cccaf38_o.png I've presented these as averages, not anomalies as some have complained about the 1980 to 2010 anomaly period partly covering 2007 to 2012. The shift to a more Greenland centred behaviour after 2007 seems clear to me. Needless to say, similarity in the Pacific and Atlantic is irrelevant as this is topographically driven, and topography has not changed. Yes the AO/NAO are essentially the same thing. I use the AO because it reflects Arctic Ocean dominant pressure. Summer Pattern Correlation. I've resorted to using correlation because my maths aren't up to PCA, which would have been a preferred method. June July August 1979 -0.440 -0.297 0.386 1980 -0.081 0.738 -0.262 1981 0.516 -0.389 -0.571 1982 0.724 -0.539 0.023 1983 -0.800 -0.134 -0.272 1984 -0.048 -0.114 -0.588 1985 0.249 0.265 0.446 1986 -0.670 -0.081 0.250 1987 0.721 0.209 0.486 1988 -0.557 0.485 -0.241 1989 -0.639 -0.695 -0.032 1990 0.015 -0.334 0.478 1991 0.016 -0.197 -0.862 1992 -0.232 -0.499 -0.388 1993 0.285 0.382 0.048 1994 -0.797 -0.622 -0.442 1995 -0.400 0.657 -0.157 1996 -0.654 -0.733 -0.340 1997 0.795 0.252 -0.600 1998 0.669 0.147 -0.261 1999 -0.636 0.399 0.680 2000 -0.181 0.140 -0.097 2001 -0.304 0.189 -0.166 2002 -0.576 -0.489 0.179 2003 0.254 -0.088 -0.423 2004 0.382 -0.557 0.475 2005 0.463 0.260 0.386 2006 -0.682 -0.097 0.027 2007 0.725 0.759 0.532 2008 0.612 0.774 0.567 2009 0.685 0.784 0.436 2010 0.660 -0.405 0.639 2011 0.787 0.788 0.824 2012 0.633 0.316 0.459 2013 -0.755 -0.126 -0.463 2014 0.470 0.394 0.656 Correlations with NAO by month. Jun Jul Aug 1979 to 2014, -0.870, -0.657, -0.517 2000 to 2014, -0.837, -0.780, -0.580 1979 to 2006, -0.857, -0.574, -0.288 Note the drop in correlation through the summer when the post 2007 period is excluded. However I will defer to your expertise and desist from mentioning the matter again. I'm busy enough with sea ice and the day job.
Toggle Commented Sep 11, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Rob, I've looked at the stratosphere with regards the 2007 to 2012 period, but found little conclusive. My hunch remains that the Greenland ridging is a central issue, either a parallel result of the same underlying causal issue, or an element of cause itself. https://farm4.staticflickr.com/3858/15166606982_47c6d17e6b_o.png I've not done the math yet. But I have previously taken average GPH500 north of 20 degN (IIRC) and subtracted it from the Greenland GPH to get an idea of the behaviour of the Greenland ridge when adjusted for the overall rising of the atmosphere with AGW. The result is a striking jump in GPH at 500mb over Greenland. http://farm4.staticflickr.com/3705/10230342105_4765d6ffda_o.png I am still working on this problem.
Toggle Commented Sep 10, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Robert, You can see what you think from a previous post comparing PIOMAS, ASCAT, and the Drift Age Model, here: http://dosbat.blogspot.co.uk/2013/02/ascat-piomas-and-dam.html QuikScat was the previous system before ASCAT. If you scroll below the text on this link you'll see a sequence from 2000 comparing QuikScat in January and PIOMAS in January. http://dosbat.blogspot.co.uk/2013/08/seeking-understanding-vs-spouting-empty.html I use January because any ice that is over 2m in Dec/Jan is very likely to be multi year ice because first year ice hasn't had the time to thicken to 2m by that stage in the winter.
Toggle Commented Sep 9, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Hell, four replies in a row... Robert, I'm not doubting what you say, it's anecdotes like yours that I use to caution myself against getting to concerned with small differences in area/extent/volume. As for the reality of th PIOMAS volume increase. Most of it is in the Central Arctic (Cryosphere Today regions). In ASCAT (a type of satellite radar) multi-year ice shows up as white, first year ice shows up as greyer. http://manati.star.nesdis.noaa.gov/ascat_images/ice_image/ I'll be checking there to compare PIOMAS ice over 2m thick in December and/or in January, if PIOMAS is right then the mass of thicker ice around that time should agree in shape with the white area in ASCAT around that time.
Toggle Commented Sep 9, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Good Lord, how did I miss it. PlanetDufus is repeating the Global Cooling scare in the 1970s carp.... The Myth of The Global Cooling Consensus. Peterson, Connelly, Fleck, 2008, BAMS. Numbers of scientific papers published citing Warming, Neutral, and Cooling. https://farm4.staticflickr.com/3922/15004416149_e727f05a77_o.png "In July 1979 in Woods Hole, Massachusetts, Jule Charney, one of the pioneers of climate modeling, brought together a panel of experts under the U.S. National Research Council to sort out the state of the science. The panel’s work has become iconic as a foundation for the enterprise of climate change study that followed (Somerville et al. 2007). Such reports are a traditional approach within the United States for eliciting expert views on scientific questions of political and public policy importance (Weart 2003). In this case, the panel concluded that the potential damage from greenhouse gases was real and should not be ignored. The potential for cooling, the threat of aerosols, or the possibility of an ice age shows up nowhere in the report. Warming from doubled CO2 of 1.5°–4.5°C was possible, the panel reported. While there were huge uncertainties, Verner Suomi, chairman of the National Research Council’s Climate Research Board, wrote in the report’s foreword that he believed there was enough evidence to support action: “A wait-and-see policy may mean waiting until it is too late” (Charney et al. 1979). Clearly, if a national report in the 1970s advocates urgent action to address global warming, then the scientific consensus of the 1970s was not global cooling." So who was talking about an ice age - the press, as you imply with your reference to the NYT. It was not a consensus amongst scientists. You believe the scare stories you read in the press, imprinted with your own bias from your choice of newspaper. I'll continue to read the actual scientific papers and make up my own mind.
Toggle Commented Sep 9, 2014 on PIOMAS September 2014 at Arctic Sea Ice
John, I agree. The position A is however somewhat limited, it neglects the critical role of preferrential loss of thick ice (first year ice volume is increasing) and the role that this has had in facilitating ice loss events like 2007 and 2012. Note that there are other volume loss events as big as 2007 (and 2010 - which was not associated with area/extent loss event). http://farm9.staticflickr.com/8438/7911627906_4b1c45096e_o.jpg This is because those earlier volume losses happened with thicker ice, so they were not able to reveal open water leading to massive area/extent losses. The role of AGW is in the long term volume loss, and most of this volume loss has come from loss of older thicker ice. The role of weather driven events like 2007 is in 'taking advantage' of thinner ice. Turning to this year, there are factors such as the Greenland ridging and low/high pressures between Siberian coast and the central pack, both associated with the strong Arctic Dipole between 2007 and 2012. The presence of those factors this year (to me at least) seriously begs the question 'what was different in 2014?'
Toggle Commented Sep 9, 2014 on PIOMAS September 2014 at Arctic Sea Ice
BDS, Read Lindsay & Zhang, 2004, The Thinning of Arctic Sea Ice, 1988–2003: Have We Passed a Tipping Point? http://journals.ametsoc.org/doi/abs/10.1175/JCLI3587.1? My blog post on that paper is here: http://dosbat.blogspot.co.uk/2014/03/what-caused-volume-loss-in-piomas.html L&Z find (fig 3) a small increase in Arctic Ocean thickness from around 2.5m in 1950 to around 3.25 in 1987. By 2004 thickness is down to 2m. Annual average thickness. PlanetDufus, Walsh and Johnson 1978, yes I have previously read it. Your point in linking to it? 1) Check out figure 8. What does that tell you? What would the situation look like using data for the last 20 years? The changes during the 1953 to 1977 period have marked spatial variability. Whereas since 1995 there has been a marked decline of extent in all regions. 2) Check out figure 5. That does not show that 1979 is a high point, in fact that study shoes that the 24 month running mean is greater over the period 1965 to 1973. Yes the overall trend over that period is up, no, that does not mean 1979 is a high point. 3) Stop wasting my time. 4) er... 5) that's it.
Toggle Commented Sep 9, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Sorry Neil, I'm doing a really poor job of understanding and/or of explaining. When you say: "That Ice, of the same area, was not of the same consistency. It was 1mkm^2 more FYI than at the beginning of the 2012 melt season. So how could it be only 40kkm^3 less than 2012. Where did all that extra volume come from?" I read it as more or less what I outlined (as you quote in the comment above) and my answer is the same. Maybe I'm tired. I'll think about it over the next few days. With a bit of luck someone will read this exchange and reconcile us.
Toggle Commented Sep 8, 2014 on Ever sailed to 85N? at Arctic Sea Ice
Neven, You're no dolt. You allow the evidence to form your opinion, that's a sign of intelligence. :) NeilT, JD Allen, Well put. Perhaps it could be put more simply: If people would just drop the political carp and approach the issue of Arctic sea ice loss with an open mind they would find the most exciting area of research in current science. OK, I'll have to comment on the Himalaya issue. I've never read WG2, I'm interested in the science so I stick to WG1. But if WG2 is anything as big as the WG1 (The scientific basis report) to find a screw up in one paragraph is not surprising. In around 2007 when I was seriously doubting my scepticism I downloaded AR3 WG1 Scientific Basis. Chose about ten pages at random and went through the references to see if they supported the text. Since then I use the Scientific Basis as my first port of call when reasrching something AGW related, it is sound, reliable, and conservative. Like the sort of technical consultant you don't regret hiring.
Toggle Commented Sep 8, 2014 on PIOMAS September 2014 at Arctic Sea Ice
Right, I'll try to wade through the carp to salvage something of interest (WTF have the Himalaya got to do with the Arctic - unless we're talking Rossby wave breaking???). Robert, I've heard others say the same sort of thing. I've also noticed areas of apparently no ice on MODIS that have ice in NSIDC. Two things to note: 1) The CAA has always been tricky because there is so much coast, coast presents problems with the sensors, looking at raw NSIDC Concentration data there is generally ice shown all around the UK - now we know that isn't there. NSIDC mask out this data, but it is possible the mask doesn't catch all such spurious data. 2) In the area of the CAA an NSIDC grid box is typically around 640kmsq in area. That's 25 X 24 km. It is conceivable that you could fly over a grid box and not be able to see the entire grid box - I'm not 100% convinced about that but it is a possibility. Actually I'll add another: 3) No remote sensing product is perfect, even different sea ice products from the same platform give different figures. My solution to this is rather amateurish, I stick to one product on the assumption that whatever problems apply now apply in the past. So at least comparisons in time are likely to catch changes. It is possible that 2014 has been overestimated, but my guess is it will be a small effect. I am by no means as expert as the Polar Science Team, but I process the gridded PIOMAS data they provide and, frankly, spend an unhealthy amount of time sat at my laptop playing around with data extracted from the gridded data. When there is an inconsistency, such as that which led Dr Zhang to re-work to V2.1, I tend to notice it too (I did with that). I've got lots of oddities I can't explain, but all look like problems with my comprehension, not the model. Personally I don't think PIOMAS is wrong this year. I'm looking at the atmosphere for the answer as to why 2014 was such a boring melt season.
Toggle Commented Sep 8, 2014 on PIOMAS September 2014 at Arctic Sea Ice