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Chris Reynolds
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Osteopop, Yet during that ten years we have seen 2007 and 2012 both record crashes in summer extent - yet you prefer to ignore them. Now based on two year's weather driven behaviour of the pack you claim we have turned a corner and the ice is recovering? We have various indices and only CO2 shows a linear relationship with annual average ice extent. Any moderately educated person would immediately put CO2 at the tope of the list of prospective causal drivers of the decline. They would then look at the prospects for CO2 decreasing and conclude that the prospects of ice declining are good as long as CO2 continues to increase. Beyond that is a lot of detail, which is why I directed you to the models, which are tools for encompassing the detail. Yes there is an inflection ongoing (IMO), but it will not lead to a recovery of sea ice. There's been an ongoing and lengthy discussion about this over at the forum. Other factors have predictive values on various timescales. But the root cause of the long term decline in sea ice is anthropogenic warming, which is largely driven by CO2 - the largest single factor. The only bias going on here is in your thinking. My thinking remains fluid, and able to be changed based on new evidence - as my recent claim of an inflection in volume loss shows.
Toggle Commented 4 days ago on ASI 2014 update 5: low times at Arctic Sea Ice
Osteopop said: "The area had one of the colders winters in memory, and plenty of time to build thickness." NCEP/NCAR JFM average surface air temperature for a grid box 60N to 80N, 240E to 300E, covering the Canadian Arctic Archipelago. So only one of the coldest years in living memory if you're under 16 years old. Meanwhile, for the whole Arctic (north of 65degN), in NCEP/NCAR 2014 was the warmest JFM winter since 1948. So how thick was the ice in April 2014? According to PIOMAS it started off about the same as the last four years. The CAA is only just entering the period where, historically, loss rates pick up. I have no opinion on whether the NW passage will open up this year.
Steve, Yep, I've been using them too, they are excellent.
Toggle Commented Jul 21, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Neven, We'll know by late August whether the MYI transport into Beaufort/Chukchi has impeded ice melt - I'm in no position to correct you or anyone else on that point at the moment. :) I've said it before, but it's worth repeating. Anyone curious about the effects of the warming of the North Atlantic on the Barents Sea need only compare historic sea ice early the last century with recent summer levels. The decline really is remarkable.
Toggle Commented Jul 15, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Apropos the claim "We have seen 18 years without a rise in global mean surface temperature." It has moved me to publish a post I wrote some time ago.
Toggle Commented Jul 15, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Correction, end of penultimate paragraph. "without anthropogenic forcings (CO2 being the largest single such forcing), CO2 does not decline" should read "without anthropogenic forcings (CO2 being the largest single such forcing), sea ice does not decline"
Toggle Commented Jul 15, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Osteopop, "It also seems obvious that we have turned some sort of corner when it comes to Arctic sea ice, since we have seen the winter maximum stall already, and now the summer minimum has started fluctuating wildly and bottoming out." There is a good reason why the winter volume maximum has stalled: Most of the loss of volume has come from loss of multi year ice (thinning). That process is now coming to an end, and winter maximum volume within the Arctic Ocean is becoming dominated by first year ice, with winter volume tending towards that dictated by the thermodynamic thickening of first year ice. More here: "There's unfortunately no one number which has predictive value, there are too many variables, but I believe that at some point we will be able to find some natural relationships which have predictive skill when it comes to sea ice over the long term." This is not correct. Notz & Marotzke looked at four possible indices that might affect sea ice loss. In a similar manner I have plotted the AMO and sea ice extent: Changes in irradiance (from the Sun) are in the wrong direction, the clustering suggests a relationship of more sunlight leading more ice, this is obviously incorrect. The Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO) and Arctic Oscillation (AO) show little relationship. Other indices are discussed in Notz & Marotzke and are not likely candidates. However CO2's correlation is good as can be seen in the scatter plot. This doesn't prove that CO2 is causing the sea ice loss, however it does direct the intelligent, open minded, invesigator to put CO2 at the top of the list of possible causal factors. Models, despite their problems with regards sea ice, show a consitent pattern across a variety of different models. In that graphic the red trace is observed September sea ice extent. Coloured traces are model projections of sea ice loss with natural and anthropogenic factors. In each panel the grey traces are projections with natural forcings. Despite the differences between the various models the common qualitative conclusion is that without anthropogenic forcings (CO2 being the largest single such forcing), CO2 does not decline, with anthropogenic forcings the sea ice recedes. The indidual causal pathways through which anthropogenic global warming affects sea ice are complex. However the scatter plot relationship, and the results of numerical models present a clear case that it is humanity that is causing the decline of sea ice. Our CO2 emissions are not going to decline, sea ice is not going to recover. As others have pointed out, you could have played the same game in 2008 and 2009, 2010, 2011 and 2012 would have proven you wrong.
Toggle Commented Jul 15, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
Osteopop, Crucial to any claim of a continuing recovery of sea ice is understanding what caused it to decline. What do you think caused it to decline?
Toggle Commented Jul 14, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
k eotw, A large element is likely to be differences in concentration. In 2010 compactness of the pack was far lower than this year.
Toggle Commented Jul 13, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
PIOMAS data is out, my prediction for 2014 has leapt up. It is now 4.6 to 5.1M km^2 September sea ice extent. Some quick reasoning is given here:,917.msg30899.html#msg30899
Toggle Commented Jul 7, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
John Christensen, Average summer SLP anomaly 2007 to 2012 (this overlaps the anomaly period but the same calculation, without overlapping makes a similar pattern). Average summer SLP anomaly for 2013. Average SLP anomaly for 18 June to 3 July 2014. This year, after the shift on 18 June, is looking like another summer typical of 2007 to 2012. Where it is not typical is over the North Atlantic through to Europe, we'll see how that shapes up, but so far 500mb geopotential height has not been unusually large over Greenland. And what has been happening from 2007 to 2012 is not the Arctic Oscillation / North Atlantic Oscillation. It just looks like it because the loading pattern picks up similar features, notably the high over the Arctic. Here is the summer (JJA) SLP anomaly for years prior to 2007 with an AO index of less than -0.2. Here is the summer SLP anomaly for years after 2007 with an AO index of less than -0.2. Note the lack of deep low tendency over Asia in the post 2007 data, note the close ring of responding lows around the Arctic high. Note the more intense shift over Greenland and the deeper low tendecy over the UK and Western Europe post 2007. That UK low is due to the jet being steered by the Greenland ridging that has been anomalous in recent years. James Screen has examined European summer rainfall and compared the atmospheric pattern associated with wet European summers and loss of sea ice. In the following graphic 'observed' is the pattern due to wet summers, 'simulated' is the pattern simulated in response to loss of sea ice. If you didn't know which was which could you tell, I couldn't. Image from this paper. I mentioned anomalous Greenland ridging, this can be seen in 500mb Greenland geopotential height. Here is the monthly correlation of gridded SLP north of 20degN with the summer pattern for average SLP summer (JJA) 2007 to 2012, the 'summer pattern correlation'. And here's a comparison of summer pattern correlation and summer AO index. The two are not the same. I maintain that we have a new pattern that looks like the AO, but is not, and is due to sea ice loss.
Toggle Commented Jul 7, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Henry, I used May temperatures north of 80 because most people here use the DMI Arctic Temperature plots, and they're north of 80 too. Here's a plot of temperature north of 70 (grid area weighted), which covers the Arctic Ocean, but takes in more of the surrounnding land. Plot from here: Your calculation with regards losses from a date to the end of the season applied to the same date this year is something I keep an eye on. However as I've said on the forum several times: The period of largest summer losses is 2007 to 2013 - that's the dataset we can reasonably draw comparison with for the 2014 melt season, due to the massive changes since 2007. This is a short period and I am far from convinced that it shows us all of the potential variability of the thinned ice after the volume losses of 2007 and 2010. My spreadsheet used for the SIPN prediction I made in June, using May PIOMAS data, is now ready for the July prediction, using June PIOMAS data. If I assume that in 2014 the May/June PIOMAS volume loss is the same as in 2013, the resulting prediction is: Upper.. 4.848 Central 4.311 Lower.. 3.774 And "<" indicates previous minimae within the prediction bounds. 2007, 4.300 < 2008, 4.730 < 2009, 5.390 2010, 4.930 2011, 4.630 < 2012, 3.630 2013, 5.350 Now that is only a prediction, it suffers from the same issue of the limited number of years available (post 2007) as does the method of subtracting previous summer losses from current extent/area. The advantage I claim for my prediction technique, limited though that may be, is that it use volume. Volume/thickness governing the effectiveness with which open water can be produced by a given thinning during the melt season. I've only used 2007 to 2012 data to 'train' the method, using 1979 to 2013 data to derive the basic relationship between volume early in the season and September extent. And in all the years 2007 to 2012 the hundcasts are successful - by definition because I've used the stats for the 2007 to 2012 period to 'train' the method. It may turn out that 2014 is another 'muted melt' year like 2013. But the weather (SLP) so far has been close to the 2007 to 2012 average, not like 2013.
Toggle Commented Jul 7, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Sorry Henry, Another clarification: "I still think that reading too much into the season from June state isn't sound" should have been written as: "I still think that reading too much into the season from June state extent or area isn't sound"
Toggle Commented Jul 6, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Henry, May was just as cool in 2014 as in 2013. Yet as in 2013 PIOMAS volume anomalies dropped. That being the spring volume loss, which has started to be more aggressive after the 2010 volume loss. That this spring loss happened in 2013 despite much cooler temperatures indicates that ice state is the dominant factor. In this blog post... I have looked at ice state and atmosphere as candidates for the increase in seasonal area/extent loss since 2007. Despite the change of weather in 2013, losses between months were still predominantly greater than the 1980 to 1999 average (as seen in anomalies from that average). CT Area. NSIDC Extent. Which implies that while 2013 had an effect, ice state in the post 2007 situation was the dominant factor. Looking at Wipneus's area and extent data based on NSIDC gridded concentration, I think people (not just you) are expecting too much of the ESS in June. For the East Siberian Sea (ESS), the 1980 to 1999 average loss of extent from 1 June to 30 June was 10.45k km^2. 2014 saw an increase, not a loss, of 9.03k km^2, whereas, for example 2012 had a loss of 12.3k km^3. For comparison, average July losses for the ESS from 1980 to 1999 were 150k km^2, even 2013 lost 212k km^2, 2012 lost 274k km^2. In 2007 July saw a loss of 618k km^2. So I think it is too early to draw conclusions about the rest of the season based on June extent or area losses in the ESS. Especially in view of the May ice thickness from the ESS through to the Beaufort Sea. It is worth pointing out that while June 2014 losses in Kara are small (73k km^2 vs avg loss from 2010 to 2013 of 342k km^2), next door in Laptev June losses have been the greatest on record (since 1979), at 150k km^2 they dwarf the 50k km^2 losses in June of 2012. In a nutshell, I still think that reading too much into the season from June state isn't sound, and that we will see ice state play a strong role this melt season as in 2011 and 2012. Neither of those years was really good melt weather. Yet 2011 was a tie with 2007 (considering all indices of extent & area), and 2012 was a large new record. PIOMAS will give an indication, but without that June data - I expect thinner ice this year to give enhanced ice area & extent loss over what one would expect for the pre 2010 period. I guess I'm betting on a melt rate similar to 2011 and 2012. If I apply the day to day losses of extent in those years from 4 July 2014 and caculate the minimum, applying 2011 gives a minimum of 4.33M km^2, applying 2012 gives a minimum of 3.71M km^2. This rules out 2013. 2007 and 2011 are within that range, and 2008 and 2010 are close to the upper bound. 2012 is close to the lower bound - but I suspect (the literature is somewhat split on this) that the August Cyclone had a role in the 2012 low being as low as it was. So I'm saying that something in the region of 2007 or 2011 is very likely this year, as long as the weather doesn't turn 2013ish. I don't expect that to happen, I think this year's summer average SLP will be more like the 2007 to 2012 average than 2013. Sorry for another long winded reply.
Toggle Commented Jul 6, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Sorry Henry, When I said 'impossible to call' I should have clarified. Without PIOMAS data and without knowing whether the highs (that are predicted to re-assert will continue all summer), I am finding it impossible to say whether 2012 is totally unobtainable. As can be seen from my earlier comment - I don't think a re-run of 2013 is at all a realistic prospect.
Toggle Commented Jul 5, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Henry1, I'm finding it impossible to call right now. In the Arctic Ocean, compaction (=Area/Extent) has shot up as area has failed to fall but extent has fallen over the last few weeks. This cannot be maintained, compaction falls in the summer. Losses of extent are not unusual for recent years in most of the Arctic Ocean in June, however loss of area has been more normal for the 1980 to 1999 period. It is in July that greatest extent losses occur, and losses in June imply high losses in July - in line with recent years. The extremely good melt weather has backed off over the last few days, reducing extent losses. However GFS and ECMWF both show the strong highs that have led to high losses from 18 June to 30 June returning. Limiting consideration to the immediate vicinity of the Arctic Ocean, 18 to 30 June has been quite reminiscent of 2007, more like that year than any since. A lot depends on how much thinning has happened in this June. May thickness (PIOMAS) in Beaufort, Chukchi, and the East Siberian Sea was of the order of 50cm down from May 2012 and May 2013. Add the fact that the weather is far more conducive to melt than it was in 2013, and seems likely to remain so for at least another week (it may become the pattern typical of July and August), and I think concluding that area failing to drop below past normals is risky. My 2014 CT Area prediction was made using the long term average losses from June 20 to minimum and the deviation from that average for the 2007 to 2012 period. It worked last year, against the expectations of many. This year I suspect it may fail. If I had to bet on it I'd say that Area will start to drop faster than the bseline average (I use 1980 to 1999), as we get further into July. My heuristic prediction for CT Area is 3.3 to 2.9M km^2, I've lowered the bottom end of the range because current information suggests to me that 2014 could easily match 2007 and 2011. Weather-wise this is not 2013, and CT Area anomalies continuing level (as they have been for the last week) suggests a 2013 finish to the season. This is not, in my opinion, realistic.
Toggle Commented Jul 5, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Rob, I've done a blog post on the spring volume loss in PIOMAS back in February this year. I didn't manage to pin down the exact cause, but it seems to be associated with the thinning of ice and movement from ice of 2 to 3m thick into the 1 to 2m thickness band. Most regions in the Arctic Ocean participate, but the Central Arctic region is the greatest single contributor. Crandles pointed out that in an SIPN presentation Dr Blanchard Wrigglesworth shows results from PIOMAS when April thickness is artificially thinned by 1m. You'll need day 1 morning 1 from 57min onwards. What happens in PIOMAS is that when current April ice thickness is thinned by 1m, the ice rapidly retreats such that by the end of July the only remaining ice is the residual thick multi year ice off the northern coast of the Canadian Arctic Archipelago. This is then slower to melt, the resulting shape in terms of anomalies would be similar to what is being observed now, with an aggressive spring volume loss, and after about 21 June (solstice) anomalies rise as the late summer losses are similar to the past climatology. However in the experiment where ice is thinned by 1m the spring volume loss must be much more aggressive as a proportion of total volume. Basically thinner ice melts faster in the spring than thick ice. The exact reason for this - I don't know. However the increase in June NSIDC Extent losses after 2010 seems to me to imply that what is happening in PIOMAS is real.
Toggle Commented Jul 5, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice Errant ) and . on the link above. Thanks for the info Bibken.
Toggle Commented Jul 4, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Well it's not even checkmate with June numbers, the weather could shift. I won't say this is interesting - it's just the sort of thing that interests me. ;) Using PIOMAS gridded data. Arctic Ocean Sea Ice volume loss from May to June. 1980 to 1999 average loss is 1.8k km^3, from 2007 to 2009 it's 2.48k km^3, from 2010 to 2013 it's 3.63k km^3. Even 2013 had a loss of 3.06k km^3 from May to June. 2012 lost an eyewatering 4.17k km^3!! June 2013 average SLP was more like early June 2014. My guess is that June 2014 will have lost more than June 2013. If I put 3k km^3 loss off May's volume into my prediction method for NSIDC September average extent, I get 4.89 to 3.81M km^2. That rules out 2012, 2013, and argues against 2009 and 2010, but includes but includes 2007, 2008, and 2011.* Fingers crossed for good melt weather and a June loss in the Arctic Ocean of over that for 2013. *As I've pointed out already on the forum, I doubt that we have seen the full range of possible outcomes of weather acting on thinner ice since 2007 and then 2010. I suspect that 2013 shows us the higher limit but havve doubts that 2012 really shows us the lower limit of what is possible.
Toggle Commented Jul 4, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Hans, I see. That was based on May numbers, we've yet to see whether June has reduced that difference.
Toggle Commented Jul 4, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Hans, The regions being Baffin and Hudson - I'm not sure about El Nino, I think it's just warming within the normal variation. But the slow start in the Arctic Ocean has shown it up. Just checked NCEP/NCAR, the temperatures for 18 June to 30 June in Baffin were normal, Hudson was caught between warmer than average on the east, cooler on the west. I've not been able to satisfactorily tie down the reason for such strong recession in those regions. Whilst I was on that site: I thought I'd do a regression of NINO3.4 and surface temperature. Over much of the eastern US, including Hudson Bay, as NINO3.4 index for June goes up, temperature goes down. But I don't have any statistical confidence on that! I've been sceptical of the talk of ENSO impacting sea ice, on that plot there is a warming with +ve ENSO on the Pacific sector of the Arctic Ocean. But I've not found a strong link, and from what I've read in the literature the paper that found a role for ENSO had to use some complicated maths to extract a small regional signal. However as I type this I deleted the sentence ending that paragraph - an expression of doubt. Because when I do a regression of NINO3.4 with sea level pressure for June I get: In which a high NINO3.4 gives a high pressure over the Arctic Ocean. The current synoptic pattern doesn't tally with that strongly, I still think the high pressure over the Arctic has a loss of sea ice role in it. But maybe the building NINO has a role in the current high pressure.
Toggle Commented Jul 3, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
My June Status blog post is now available. "...June thinning will play a large role in the rest of the season, thinner ice needs less thinning to reveal open water and cause extent or area to drop. In respect of this it is worth noting that for the ESS May 2012 average thickness was 2.28m, May 2013 average thickness was 2.31m, but May 2014 thickness was 1.76m; about 50cm thinner than either 2012 or 2013. The picture is similar over Chukchi and Beaufort..."
Toggle Commented Jul 3, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Neven, I really don't know what PIOMAS will bring. If daily gridded data is released this month I may be using that in addition to the monthly data - the change after 18 June has been so remarkable.
Toggle Commented Jun 30, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
I've noted your post in my latest blog post, just published. The title sums up my opinion: "2014 is not being handed its hat, it's just getting started." I still see 2012 as unattainable, but 2007 and 2011 are a real possibility. What we need for high export out of Fram is an intense Greenland ridge, this hasn't happened so far. Here's the average SLP for summer (JJA) 2007 to 2012. Since 18 June 2014 has been shaping up in a similar pattern. The gap in the pattern being the high protrusion into the Atlantic. Given the broader similarity I expect an anomalous Greenland ridge to build as the summer proceeds.
Toggle Commented Jun 29, 2014 on ASI 2014 update 4: high times at Arctic Sea Ice
Wayne, I disagree. The CT Area June anomaly cliff is a feature of 2007, 2011, 2012 and 2013 that has led to lower summer CT Area (even in 2013 when June drops lowered end of June area substantially. NSIDC Extent anomalies show strong drops throughout June and early July in many recent years, these play a role in recent record lows. In both cases these drops in anomaly are definitely not part of the long term behaviour but are clearly a new behaviour (driven by increased open water formation efficiency with thinner ice - IMO). I can post graphs if needed. *** Since posting my CT Area prediction above (and the corrected NSIDC Extent prediction based on that), I've had nagging doubts about it. Given the April/May ice state from PIOMAS, and the behaviour since 18 June I think that method will be wrong this year. Now on top of >100k average daily losses since 18 June, we have a 250k loss in NSIDC Extent for the most recent data. The following graphic shows the years from 2007 to 2013 relative to 2014. Put simply each year's trace is that year's extent minus the extent for 2014. Note that 2014 is rapidly closing the gap on 2010. However 2010 is not at issue with regards the minimum. In 2010 a large export of MYI slowed losses in the remainder of the melt season. 2014 could easily challenge 2011 and 2007, I think there's a good chance of a second place behind 2012.