tag:blogger.com,1999:blog-1367053740188758246.post4889020197098033008..comments2023-06-21T00:39:34.443-07:00Comments on Dosbat: PIOMAS November 2014Chris Reynoldshttp://www.blogger.com/profile/16843133350978717556noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-1367053740188758246.post-44350037988704023882014-12-18T10:09:17.815-08:002014-12-18T10:09:17.815-08:00Regards the Chylek paper, they detrend before find...Regards the Chylek paper, they detrend before finding the 'see-saw' so I don't see how this can be informative about the impact of CO2 and anthropogenic GW on sea ice. The issue reminds me of a paper that took the derivative of global temperature and found a strong role for the ENSO. This was then touted around the 'net as showing that the ENSO drives global warming. Of course when one takes the derivative one removes the trend of increase so all that paper did was show a role for the ENSO as variations imposed on the trend of anthropogenic global warming. Likewise Chylek seemed to find an underlying factor of possible oscillation superimposed on the global warming driven trend.<br /><br />However in the case of the ENSO paper they had loads of 'cycles', in the case of the Chylek see-saw the results remain dubious because they have but two apparent cycles, and it's hard to be sure one has removed the effect of the global warming happening during the latter period.<br /><br />I read that exchange some time ago. Dr Curry has a long history in sea ice, however on this I think she is wrong from a practical point of view. Yes amplifying factors such as ice albedo feedback drive most of the volume loss. But the results of GCMs show no ice loss without anthropogenic forcing (e.g. Overland & Wang). Therefore the issue is not to disentangle the relative roles of natural variability and amplifying feedbacks, but to step back and see the wood for the trees - human driven global warming is driving the loss of sea ice.<br /><br />The next few years will show whether the AMO/PDO has had a large role in the volume loss of the last 20 years. I think we need to be patient and let the natural process teach us.<br /><br />I hope you have a good holiday too. Four more days of work then the firm shuts down until the New Year.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-32974656517519260472014-12-17T20:23:00.801-08:002014-12-17T20:23:00.801-08:00Thanks for the response Chris
Interesting AMO pap...Thanks for the response Chris<br /><br />Interesting AMO paper here.<br />http://onlinelibrary.wiley.com/doi/10.1029/2010GL042793/full<br /><br />JC"s comments are good here<br />http://www.climatedialogue.org/melting-of-the-arctic-sea-ice/<br /><br />Few charts I posted today are here https://twitter.com/NJSnowFan/status/545336804443164672/photo/1<br />What moves first, the AMO or surface temps you think. Spike in the PDO is having big effect on Sea ice growth and Chukchi sea I see. Don't look like it is going to end up thick and will melt out fast in the spring. Next year though will be a different story because PDO will be heading down with Solar. https://twitter.com/NJSnowFan/status/545212747622146048<br /><br />Why do I feel the PDO will track solar, well it did with the lower cycle during the 1970 also.<br />History repeating.<br /><br />Have a good day and Happy Holidays to you and Family.@njsnowfannoreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-72645818777483835132014-12-16T11:52:06.830-08:002014-12-16T11:52:06.830-08:00Hi NJ Snowfan,
I'm fine, hope you are too.
I...Hi NJ Snowfan,<br /><br />I'm fine, hope you are too.<br /><br />I presume you'e using the long unsmoothed dataset from PSD?<br />http://www.esrl.noaa.gov/psd/data/timeseries/AMO/<br />Let me have a URL if I'm wrong.<br /><br />Yes, Autumn typically shows a drop in recent years, but sticking with October subtracted from November...<br /><br />Have you tried graphing them and comparing with the AMO annual average time series? I note that the Nov-October difference reached a similar low in 1931/1933, but this was actually during the rise of the annual average AMO into the 1940s +ve phase. Taking a seven year average shows that period to have been a double peak, I don't think we can rule that out for this cycle peak.<br /><br />So the AMO may be starting to trend down, but on the basis of what we have (and two cycles is frustratingly short!), I'm not certain it will do so at the moment.<br /><br />Now the AMO might have a role in the poor melt seasons of 2013 and 2014, and if it is going negative that might have implications for sea ice. But I have yet to read a convincing case that there's a role for the AMO in the 2013/14 melt seasons. And as I showed you last time we chatted, there is a far from convincing relationship between the AMO and the current decline of sea ice, which contrasts against the very good agreement between CO2 and sea ice loss.<br /><br />If by this time next year we're seeing another volume increase (as per PIOMAS) then I think the AMO might turn out to be a reasonable candidate. However October Cryosat 2 data shows a _drop_ in volume between October 2013 and 2014. And the PIOMAS gain over last year is within the uncertainty for October volume, so strictly speaking we cannot say PIOMAS has shown a gain this year! <br /><br />That noted I still think there's a gain in volume this year, I don't trust Cryosat 2 yet. <br /><br />And yes, I will keep following the AMO.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-22608693941947202622014-12-15T15:05:51.571-08:002014-12-15T15:05:51.571-08:00Hope All I well Chris.
November AMO data came o...Hope All I well Chris.<br /><br /><br /><br />November AMO data came out the other day, Largest November decline since 1933. There have only been 7 November since 1856 where Nov fell .200 or more. 2013 and 2014 are the only 2 November's that ever had back to back .200 declines ever on record.<br /><br />AMO is trending down and Arctic sea ice trending back up. Reverse Feedback about to occur once AMO goes back to negative phase.<br />Many are saying 5-7 years but I see it happening in 2015.<br />1995 went + 2005 was peak and 2015 should go back negative.<br /><br /><br /><br />@njsnowfannoreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-62341769494462952812014-12-08T13:58:04.703-08:002014-12-08T13:58:04.703-08:00Oh, Yeah. That looks much better. Kara and Barent...Oh, Yeah. That looks much better. Kara and Barents both ahead of recent years.<br /><br />Thanks for all the good work you do. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-82480554731710413912014-12-08T10:16:33.055-08:002014-12-08T10:16:33.055-08:00Anonymous,
Agreed, thanks for that. Iceman, essen...Anonymous,<br /><br />Agreed, thanks for that. Iceman, essentially it's an outcome of the thicker ice being mainly restricted to the Central Arctic region. In the other regions in the periphery of the Arctic Ocean PIOMAS volume was similar to the other post 2007 years, although extent and area were up.<br />http://dosbat.blogspot.co.uk/2014/10/the-fast-transition.html<br /><br />So we still see the "monomodal" peak of thermodynamically thickening ice as well as the thickening of the thicker mass of ice.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-20712827965484016312014-12-08T10:08:12.445-08:002014-12-08T10:08:12.445-08:00Anon,
Thanks for catching that, I should have spo...Anon,<br /><br />Thanks for catching that, I should have spotted the low volumes in recent years. The graph I posted was done for November but on copying and pasting reverted to the September data. This is the second time I have had this problem with Excel.<br /><br />Anyway, November for Kara is 0.614m thick, the volume is 443.4km^3. <br /><br />443.4 / 0.000614 = 722325km^2.<br /><br />This is close to the calculated area of grid cells containing ice in November, which is 437943.5km^2, the difference being about 1%.<br /><br />There is a difference here because when calculating thickness, in line the the PIOMAS graph of thickness, cells with ice of >0.15m is left out of the calculation of thickness.<br /><br />Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-2481027662420300442014-12-08T09:43:51.725-08:002014-12-08T09:43:51.725-08:00Iceman
I'd see the bifurcation as part of th...Iceman <br /><br />I'd see the bifurcation as part of the simple freeze physics (Thorndike graph) described in the post.<br /><br />If you go back to August post <br />http://dosbat.blogspot.ca/2014/09/piomas-august-2014.html<br />You can see the distribution at the end of the melt season. Peak in the 1.2-2.2m thickness. A month or two of refreeze and some of this ice may have thickened and is joined by a new peak (0.8m) which must be the areas of ice formation in what was effectively open water. It looks much more like the product of a portion of ice thats lasted through a couple of weaker melt season in conjunction with normal refreeze processes in open water.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-59898413564356880622014-12-08T05:11:16.205-08:002014-12-08T05:11:16.205-08:00Your fifth figure (pentad averages of thickness di...Your fifth figure (pentad averages of thickness distribution) is quite fascinating. Unlike 2013, which appears as a reversal in the long-term leftward movement of the distribution peak, 2014 looks more like a bifurcation. The peak seems consistent with the long-term trend, while the middle thickness range shares characteristics of a decade or so ago. There were some signs of this shape emerging in the 2011 distribution (in your sixth graph), but 2014 is more distinct. I can't help seeing the past and future engaged in a massive tug-of-war.icemannoreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-48000166326705528612014-12-08T04:14:08.080-08:002014-12-08T04:14:08.080-08:00Anon,
I will double check when I get home, but it&...Anon,<br />I will double check when I get home, but it's the same code used for the whole of the time series, all regions.<br /><br />Two things.<br /><br />That's for all November, not just the last day of November.<br /><br />You get weird results comparing indices like CTArea and PIOMAS.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-83405091738893296392014-12-07T15:08:29.788-08:002014-12-07T15:08:29.788-08:00I like your posts; read all of them.
A bit confus...I like your posts; read all of them.<br /><br />A bit confused by your first Figure. It shows Kara as having virtually zero volume in 2014. Though a quick calc. with the current CT area and your Kara average thickness suggests something near 500 km^3.<br /><br />It's been quick to freeze this year, can't see why it's show as near zero.<br /><br />Did I miss something? Anonymousnoreply@blogger.com