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Gareth
Waipara Valley, NZ
Recent Activity
Hi Neven, Petermann and Greenland watchers will enjoy (well, "enjoy" is perhaps the wrong word) the interview with Jason Box in the latest Climate Show: http://hot-topic.co.nz/the-climate-show-7-box-and-boxsters-the-cryosphere-special/ He's off to the Petermann in March to recover the images from the Extreme Ice Survey cameras, which should have spectacular images of the ice island calving.
Toggle Commented Feb 17, 2011 on Open Thread 6 at Arctic Sea Ice
AD, have you got a link for that Hansen 120% quote? Sounds more like something Bill Ruddiman might have said...
Toggle Commented Dec 1, 2010 on Open Thread 2 at Arctic Sea Ice
Dormice? With a very Wattsian look to them... ;-)
Toggle Commented Nov 23, 2010 on Open Thread 2 at Arctic Sea Ice
For the interested, the latest issue of The Climate Show includes an interview with Kiwi yachtsman Graeme Kendall, who sailed through the NW Passage a couple of months ago, solo and in only 12 days (from Nuuk to Alaska). Worth a listen/view, even if I say so myself... ;-)
Toggle Commented Nov 3, 2010 on Open Thread 1 at Arctic Sea Ice
Kevin -- yes, non-linearity is the way to look at it. The presence of melting/freezing ice represents a plateau for temperature. You'll get seasonal and regional excursions first, as you observe in Nunavut, but they won't dominate the Arctic average until the sea ice is gone. Won't be long... One consequence of the current behaviour of the Arctic is that it makes the current generation of climate model projections less than useful. If they don't get the Arctic right, they can't by definition get the Northern Hemisphere right. It remains to be seen if the models and runs for AR5 can do any better. In the meantime we're left with a big chunk of the climate system warming well ahead of schedule -- how long before other sectors start to join in?
Toggle Commented Oct 22, 2010 on Open Thread 1 at Arctic Sea Ice
Kevin, I think lag is the wrong word to use. When ice is melting or forming, the sea surface (by definition) has to be at freezing point, and this keeps the air above it close to 0ºC. Have a look at the DMI Arctic temperature plot. In summer it never gets far above zero, despite all the heat coming in to the system. However, when the ice has gone, all that heat can go into warming up the ocean and the air above it, and temps can/will rise much more rapidly. While the sea ice cover is decreasing, you will see larger and larger parts of the Arctic with positive temperature anomalies in summer and autumn. When reductions in winter extent are showing up, you will also see big positive anomalies in winter in ice free regions. That rate of warming may be much faster than currently observed. It would be interesting to know what the models suggest might be the outcome...
Toggle Commented Oct 22, 2010 on Open Thread 1 at Arctic Sea Ice
Hi Kevin, I think you need to distinguish between air temperatures and ocean heat content. It's principally the latter that's melting ice at the moment, and it will be OHC abetted by albedo flip that tips the Arctic into a perennially ice free state. At that point the air temps will be free to increase to PETM levels. Worth remembering that GCMs have a problem with coping with the very warm high latitudes during the PETM, so what they're telling us at the moment may not be very helpful...
Toggle Commented Oct 20, 2010 on Open Thread 1 at Arctic Sea Ice
Kevin, Artful Dodger has posted a couple of useful papers in comments at Hot Topic. And I'm definitely going to use your acronym... I like the sound of BOTBOTE: Mma Ramotswe's new helper, perhaps.... ;-)
Toggle Commented Oct 19, 2010 on Open Thread 1 at Arctic Sea Ice
Yes, tell them I enjoyed their reports all summer and was pleased to help spread the word. Meanwhile, I suspect they'll be able to sail to the North Pole in winter in the 2040s...
Toggle Commented Oct 18, 2010 on Open Thread 1 at Arctic Sea Ice
Hi Phil, The variability is overlaid on the trend, and it doesn't matter whether you take 30, 20 or 10 year trends, they're all down and the more recent years show the decline accelerating. Unless there's a big turnaround, big enough to see volume increasing significantly over a good number of years -- not just one or two -- then I'm pretty confident I'm at least in the right ballpark. The PIOMAS modelling assimilates as much real data as is available, so while it will never be exactly right, it should never be dramatically wrong on hindcasts -- and that's what in effect were looking at.
Toggle Commented Oct 16, 2010 on Open Thread 1 at Arctic Sea Ice
Here's a little something for you all to get your teeth into... ;-)
Toggle Commented Oct 16, 2010 on Open Thread 1 at Arctic Sea Ice
Alternatively, go here, click on the little map, on the next page click on Northern Hemisphere in the sidebar, and then you can choose the forecast you want from the drop down menus. Not so "dramatically" coloured, and I think easier to read.
Toggle Commented Oct 9, 2010 on Open Thread 1 at Arctic Sea Ice
Thanks for all the hard work, Neven, and for creating a place where Arctic issues can be discussed without the sturm und drang of sterile debate with deniers. I look forward to further posts as the mood (and freeze-up) takes you... Cheers
Gareth is now following Neven
Sep 23, 2010
The Antarctic situation reflects a recent shift in the Southern Annular Mode (our equivalent of the NAO). SAM's been strongly positive over most of the SH winter, which has tended to keep the cold "bottled up" over Antarctica, thus favouring the growth of lots of sea ice. It's recently dropped into negative territory, which has allowed the polar front to meander northwards, and brought snow to southern NZ, and strong equinoctial winds. More on annular modes here, and the current index here (though NOAA call it the AAO, just to be confusing.
Here's another perspective: the European Centre for Medium-Range Weather Forecasts (ECMWF) forecast for the northern hemisphere. At the moment there's a low pressure system just to the north of the Canadian archipelago and high pressure over Russia - the inverse of the Arctic Dipole. That low is forecast to intensify over the Beaufort Sea into next week and could bring a lot of wind to the region - blowing ice east against the gyre. It'll be interesting to see what that does to the ice. By next weekend, however, the situation reverses. High pressure's back over the Beaufort, and low pressure over Siberia, and the ice might well start compacting a bit. "Century breaks"coming soon? You read it here first... ;-)
Worth noting that Lindsay's projection is statistical, although based on PIOMAS data. Zhang's is a model projection. Meanwhile, the regular Potsdam update has moved out to 5.0. I suspect we haven't seen the end of the summer's drama yet...
Here's an interesting titbit: Ron Lindsay at the University of Washington has updated his September prediction using late June PIOMAS data: "the predicted extent is 3.96 +/- 0.34 million square kilometers. The R2 value for this predictor is 0.84. which now indicates a high degree of skill in the forecast." http://psc.apl.washington.edu/lindsay/September_ice_extent.html
Gareth is now following The Typepad Team
Jul 8, 2010