tag:blogger.com,1999:blog-1367053740188758246.post845897391928608525..comments2023-06-21T00:39:34.443-07:00Comments on Dosbat: Northern Hemisphere Blocking.Chris Reynoldshttp://www.blogger.com/profile/16843133350978717556noreply@blogger.comBlogger14125tag:blogger.com,1999:blog-1367053740188758246.post-28829086587461275332013-01-19T05:23:12.599-08:002013-01-19T05:23:12.599-08:00Steve,
"In addition to the apparent alignmen...Steve,<br /><br />"In addition to the apparent alignment of NH blocking event increase and Arctic sea ice reduction, we have the flattening of global surface temps and and reduction of NH snow cover, all with a step change around 2002. (Did I miss anything?)"<br /><br />There was also Zhang's finding of the AD becoming more dominant around 2003.<br /><br />We could also include the post 2000 abatement in global warming in datasets that exclude the Arctic - e.g. CRU. Foster & Rahmstorf and Kaufman et al however attribute to ENSO/Solar/Sulphates.<br /><br />"Is this all a consequence of a poleward-compressed and destabilized atmospheric circulation allowing an increased rate of heat advection into the Arctic? "<br /><br />Part of the Arctic warming is actually due to sea ice, a good part of the warming in the all seasons is linked to the reduction of sea ice. e.g. Screen & Simmonds "The central role of diminishing sea ice in recent Arctic temperature amplification" PDF <a href="http://sciences.blogs.liberation.fr/files/arctique-ann%C3%A9es-2000-tures.pdf" rel="nofollow">here</a> I must confess to having lost track of the atmospheric heat transport issue following the Graverson discussion - the impact of different datasets on the conclusion. So the best I can say is; I don't discount it, but the warming is rather surface based which seems to favour a dominant role for sea ice, rather than for increased atmos heat transport. This doesn't mean atmos and ocean transport changes are negligible.<br /><br />At present I'm picturing:<br /><br />Loss of Arctic sea ice. -> Regional warming -> Further loss of Arctic sea ice -> Change in polar to mid lat temp gradient -> impacts on mid lat weather.<br /><br />While...<br /><br />Warming from loss of sea ice reduces snow cover in spring -> possible linkage with summer atmospheric circulation shift.<br /><br />Increased humidity from lack of sea ice -> greater rate of snowfall over Eurasia -> reduction of boreal warming trend and cold outbreak events (although sea ice may have more direct role in some events).<br /><br />I'd better stop before I complicate, but that's the rough framework I see.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-1225924903488536292013-01-17T23:14:30.545-08:002013-01-17T23:14:30.545-08:00In addition to the apparent alignment of NH blocki...In addition to the apparent alignment of NH blocking event increase and Arctic sea ice reduction, we have the flattening of global surface temps and and reduction of NH snow cover, all with a step change around 2002. (Did I miss anything?) Is this all a consequence of a poleward-compressed and destabilized atmospheric circulation allowing an increased rate of heat advection into the Arctic? Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-17261622102642497892013-01-11T00:59:22.048-08:002013-01-11T00:59:22.048-08:00Judah Cohen, Francis/Vavrus and perhaps others doi...Judah Cohen, Francis/Vavrus and perhaps others doing work on this general subject have fresh AMS meeting presentations which will be available in two weeks or so. These will include videos and ppts AIUI. Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-48479342393335389732013-01-10T09:11:52.440-08:002013-01-10T09:11:52.440-08:00Clarification to my comment about applying a metho...Clarification to my comment about applying a method consistently not creating changes in a non changing dataset - this only applies if the method has no memory. As far as I can see the Wiedenman method has no memory.<br /><br /><br />Neven,<br />Thanks for that.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-60838732951882371822013-01-09T01:30:22.769-08:002013-01-09T01:30:22.769-08:00To all Jennifer Francis-fans: Here's an interv...To all Jennifer Francis-fans: Here's an <a href="http://www.sciencepoles.org/articles/article_detail/jennifer_francis_is_a_changing_arctic_affecting_weather_in_the_mid_latitude/" rel="nofollow">interview</a> on the SciencePoles website.Nevenhttps://www.blogger.com/profile/15413215743703093876noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-21332978976944744452013-01-08T21:40:52.203-08:002013-01-08T21:40:52.203-08:00Here's the MailOnlineIndia article. The third...Here's the MailOnlineIndia <a href="http://www.dailymail.co.uk/indiahome/indianews/article-2258632/Is-climate-change-causing-rise-freakish-weather-conditions.html?ito=feeds-newsxml" rel="nofollow">article</a>. The third photo remains, although come to think of it maybe that sort of thing is just DM SOP.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-29236057688544965332013-01-08T10:34:33.934-08:002013-01-08T10:34:33.934-08:00Here's a video of what I think is a vortex spl...Here's a video of what I think is a vortex splitting over the Arctic.<br />http://www.youtube.com/watch?v=wTgd4wxi-ww&feature=youtu.be<br /><br />Not sure how common these events are. The vortex fades out at the end as the overall GPH thickness falls into the cold of late winter.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-73313923246199488652013-01-08T10:14:26.500-08:002013-01-08T10:14:26.500-08:00Oale,
The proverb is interesting and may have a k...Oale,<br /><br />The proverb is interesting and may have a kernel of truth: Long spells of easterly winds in Finland could be associated with low index AO winters. In such a set up the easterlies dominate the weather throughout the winter season - could cause late springs.<br /><br />No I'm not planning any articles elsewhere. I am just an amateur.<br /><br />Steve,<br /><br />If I hadn't found it interesting I wouldn't have got so into it.<br /><br />Yes the method used to define blocking does change the outcome. I've read one paper that finds no trend, but they use a different method for indentifying blocks. However this issue doesn't seem to me to address the substantial changes throughout the recent decade. If one applies a method consistently, and automation dictates consistency, then changes in the resultant data set cannot be argued to be due to the method. They must be in the underlying data. One might argue that _what_ a given method shows could be questioned, however one cannot argue that a regime shift is not in the source data. <br /><br />Thanks for the SSW paper, it's on my reading list, although I've read the abstract. I've been seeing vortex splitting in NCEP/NCAR recently by messing around with the scaling so that activity at 50mb level in the Arctic stands out. I'll post a video of such an event in a while. <br /><br />I think you missed a link to the press article you mentioned.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-38078617331250406742013-01-08T04:58:59.931-08:002013-01-08T04:58:59.931-08:00Wow, Chris, I'm impressed! Thanks so much for...Wow, Chris, I'm impressed! Thanks so much for diving into this.<br /><br />I have a number of half-formed comments I'm thinking about, but for now I just have a couple of questions and a couple of links:<br /><br />The post mentions the technical note but not the paper. Have you read the latter? I tried, but didn't have a lot of time to do so and got rather frustrated trying to extract the main points from the translation. I plan to take another stab at it, but I suspect you can do better. FYI Lupo says the real translation will be available in two or three months.<br /><br />How sensitive is the analysis to the way blocking events are defined?<br /><br />On Twitter just now O.Bo linked to an in-press <a href="http://www.atm.ox.ac.uk/user/mitchell/mitchell2013_jclim.pdf" rel="nofollow">paper</a> about SSWs that at a quick glance appears to make considerable progress, although causation of blocking events is a little orthogonal to your present effort.<br /><br />Finally, Leo Hickman linked to an interesting article in the Indian edition of the MailOnline, which I hadn't known even existed and is oddly not linked in any obvious way from the main Mail site. There seems to be some blocking event relevance, although the papers look to be a little hard to locate. In any case, there does seem to be a lot of Indian interest in this stuff.<br /><br />Also, I can't resist wondering whether the third photo amounts to some sort of editorial comment directed by the Indian Mail employees toward their British overlords. :) Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-50214608861631014192013-01-07T23:15:22.847-08:002013-01-07T23:15:22.847-08:00Respects. An old finnish proverb came to mind, can...Respects. An old finnish proverb came to mind, can't remember the exact words but it stated something like, "easters continue for 3 days, if not three, then six, if not six then nine, if not nine then 12. if they continue for longer it's best to make more wood for the spring will be late." I'm not asking to confirm or debunk this but it would be funny if a proverb from 19th century would prove correct. Are you planning a scientific article about this?<br />Oalehttps://www.blogger.com/profile/14032383453035968859noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-17109334762183252742013-01-07T14:32:51.437-08:002013-01-07T14:32:51.437-08:00Impressive stuff, Chris!Impressive stuff, Chris!Nevenhttps://www.blogger.com/profile/15413215743703093876noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-56827703144504857552013-01-06T22:42:01.271-08:002013-01-06T22:42:01.271-08:00Capt Pithart,
Thanks for the info. I tend to igno...Capt Pithart,<br /><br />Thanks for the info. I tend to ignore denialists these days, seeing them as largely irrelevant. Whatever the individual's views his data is interesting.<br /><br />Arcticio,<br /><br />Blocking tends not to mean rain because it blocks out the weather fronts that mean rain. But this year's high rainfall and flooding in the UK are just the start due to the new summer circulation pattern.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-59599580556238999422013-01-06T18:59:44.180-08:002013-01-06T18:59:44.180-08:00Excellent. And I hope for everybody living on an i...Excellent. And I hope for everybody living on an island at 0°W that blocking = rain is not written in stone.arcticiohttp://www.arctic.ionoreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-38318685322236866172013-01-06T18:55:43.891-08:002013-01-06T18:55:43.891-08:00Hi, thanks for the post, it's very interesting...Hi, thanks for the post, it's very interesting! Just wanted to note that Anthony Lupo has been a speaker at Heartland's ICCC in 2009, and has been paid by Heartland 750$/month for work on the denialist NIPCC report. He has signed a plethora of denialist petitions such as the recent Qatar open letter, stating »The hypothesis that our emissions of CO2 have caused, or will cause, dangerous warming is not supported by the evidence.«<br /><br />This of course doesn't mean that his peer-reviewed science is bad, just a heads up to be alert when reading or promoting him.Captain Pitharthttps://www.blogger.com/profile/09288784102433651043noreply@blogger.com