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Sunkensheep
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If it was not clear, I was replying to Al Rodger "is this year's timing the result of a super icy February, a seriously melty March, or is it a combination of the two?"
Toggle Commented Mar 19, 2015 on Early record, late record at Arctic Sea Ice
I'd have to put it down to stable stratospheric conditions and a cloudy winter. There has not been the 'clear skies' that result from a large stratospheric warming event. There has also been a lack of spreading events so far this 'spring'. Speaking of stratospheric warming, here's NOAA's 50hpa temp anomaly animation showing one just getting underway in the NH. http://www.cpc.ncep.noaa.gov/products/intraseasonal/temp50anim.gif
Toggle Commented Mar 19, 2015 on Early record, late record at Arctic Sea Ice
As the dmi arctic weather link shows, these cyclones are helped along by a large (20º+) temperature difference between the pole and surrounding area. The geo-potential height shows a pool of upper cold air hanging over the arctic (and virtually nowhere else). What I'm wondering is how this situation has been maintained all summer, and why doesn't it break down? One factor would appear to be the clouds are keeping things cooler, thus maintaining the temperature imbalance and promoting more cyclones which bring yet more clouds. It would also appear that the jet stream is acting to 'cut-off' the upper atmosphere over the high arctic from the rest of the NH. (Could the Stratospheric warming earlier this season have impacted this pattern?) But that still leaves the question - what is happening to all the warm air-masses flowing into the arctic (for example the warm front above), where is that heat going?
Toggle Commented Aug 9, 2013 on Third storm at Arctic Sea Ice
3.8±0.2 Based on melt-favouring weather, that central 'hole' melting out, and some compaction at the end of the season. Surprises may be on the up-side, but I will be very surprised if the minimum is not lower than 2007. I would consider this a low-skill prediction - I have learned much from this blog and other sources over the years since 2007, but by no means am an expert.
Great post as always, Seems with the recent weather prediction, what was looking like a 2013 recovery is 'on thin ice'. I note that the relatively 'warm' conditions in Antarctica are continuing, wonder if this will have any effect on the WAIS down the track?
I notice something strange in the concentration map here ftp://ftp-projects.zmaw.de/seaice/AMSR2/ Arc_latest_yesterday_AMSR2_3.125km.png There seems to be a 'reflection' of the CAA land mask in the Ice cover on the 'opposite' side of the Arctic. I'm assuming its an image processing problem. Kevin: seems like a reversal of the 'warm arctic cold continents' pattern.
Toggle Commented Jul 6, 2013 on So, how slow was this start? at Arctic Sea Ice
A little off topic, Catalyst, a science program from the ABC in Australia, has done a nice little segment on the effects of the warming climate and melting sea ice on the weather. http://www.abc.net.au/catalyst/stories/3796205.htm Now back on topic. "Why is the ice then diverging below a low-pressure cyclone?" You can think of it this way. Because the earth is rotating counter-clockwise about the north pole, the Ice is also rotating. So it is subject to centrifugal force. The Low (because of the counter-clockwise winds) is acting to speed up the Ice, thereby creating more centrifugal force, hence greater divergence. The High acts as a 'brake' on the ice, reducing the centrifugal force, and making the ice more compact. philiponfire: I See what you mean about the NW passage, it looks rather - blue. Doubt that ice has much time left.
Toggle Commented Jul 5, 2013 on So, how slow was this start? at Arctic Sea Ice
Thought I might give the view on this from 'down-under' (or the south-east corner at least). After the crippling drought - which brought with it Stage-4 water restrictions in many areas, and serious impact on the murray-darling system - broke in 2010, support for Co2 reduction measures fell sharply. [This was also helped by major campaign by big business, and almost all privately owned media against the carbon tax]. There is a general consensus among the population that Greenhouse gas emissions are a problem, and awareness (if somewhat vague) that the arctic is melting because of them. - from the NW Passage opening, and 2007 ice loss reports if nothing else. But the arctic is far away from us, and the line pushed by the media is that Australia is too small to make a difference if it acts alone, and with other major emitters (read the USA and China, in that order) not pulling their weight, all we will be doing is 'pointlessly putting our economy at disadvantage' to those countries. What is not reported here is the other changes happening in the Northern Hemisphere - Such as those of atmospheric circulation patterns. When I mention these kind of changes eg. the shift north in the sub-tropical boundary, change in location of cyclones and anti-cyclones and frequent flooding in the UK, are quite likely the result of climate change and melting arctic sea ice, the reaction is wow! If someone were to make something along the lines of 'inconvenient truth' but instead spell out what has been happening over the past decade (when fake sceptics say 'global warming paused / stopped') - or local media was to do a decent report on it - That would have a great impact here right now, particularly coming after a rather warm summer and an highly unusual March (early Autumn) heat-wave. The only thing that would have greater impact on policy is for the USA to stop dragging their feet, as that is the most common excuse for doing next to nothing about it.
Toggle Commented Apr 27, 2013 on Perception of the Arctic at Arctic Sea Ice
* while the cooling stratosphere has caused the antarctic vortex to speed up, and the circum-polar lows to move south
Toggle Commented Jan 9, 2013 on The bunny explains at Arctic Sea Ice
A-Team: Australia is an interesting case, The North is expecting more rain thanks in part to the 'Asian Brown Cloud' (local dimming in SE Asian region), while the cooling stratosphere has caused the antarctic vortex to speed up the circum-polar lows to move south, making southern parts of the continent much more prone to drought. Neven: Events like Yasi are much more likely during La Nina years, so it depends on how warming affects ENSO.
Toggle Commented Jan 9, 2013 on The bunny explains at Arctic Sea Ice
Comparing the areas of ice, and land to the DMI map above, Seems that the lows 'want' to sit over the 'warm' / convection favouring open water, while the highs are sitting on the cold ice and continents. This would tend to be a self-reinforcing situation. Whats interesting is how 'skewed' the polar cell is. It almost looks like there are just two cells over the US, a tropical cell, and a polar cell. I wonder if, when the ice melts out completely, we will see a new atmospheric circulation system develop with a low over the polar sea, and highs over the surrounding continents. This might have the effect of keeping the arctic cloudy and relatively ice-free over the winter.
Toggle Commented Oct 28, 2012 on Looking for winter weirdness at Arctic Sea Ice
That's a worry, was hoping that the cold stratosphere, and the antarctic vortex would keep the south pole a bit isolated from the warming climate. If we have to take serious warming in the south, as well as the north into account, then sea level rise gets that bit more serious.
Negative AO will favour 'cut-off' systems, the question is does the lack and/or distribution of sea ice encourage the negative AO?
Toggle Commented Oct 27, 2012 on Looking for winter weirdness at Arctic Sea Ice
When I first saw that mslp chart, my thought was 'that makes no sense'. But obviously things are a bit different in the Northern Hemisphere. in Australia this kind of system would be an 'east-coast low'. Here it can be seen tracking along the coast, and maintaining the high pressure 'wall' http://www.ecmwf.int/products/forecasts/d/charts/medium/deterministic/msl_uv850_z500!Wind%20850%20and%20mslp!72!North%20America!pop!od!oper!public_plots!2012102700!!/ Upper level conditions also look quite favourable for it to maintain strength.
Toggle Commented Oct 27, 2012 on Looking for winter weirdness at Arctic Sea Ice
Latest CT area just under 2.24M sq.Km! would have hoped for some re-freeze by now.
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Sep 14, 2012