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Post by woodstove on Sept 2, 2009 14:54:05 GMT
Couple of arctic buoys above 80N showing under -10 now both reading -11.1. Alert -6. Eureka still fairly warm at 2. North most greenland coast at -7 Still a way to go, as there is plenty of heat left inside the arctic circle. This graph though should reflect these temperatures later today? ocean.dmi.dk/arctic/meant80n.uk.php Salt water freezes at 271K, so we are on the cusp of re-freezing beginning in earnest in the northern latitudes. Does anyone know how much open water exists currently north of 80N?? Probably not much, but it's a start in the direction of slowing down the net daily melt. The first positive day will come soon. I'm about 1/4 the way through researching an article about this year's Arctic sea ice. I have confirmed with Environment Canada that the refreeze has begun in Eureka Sound, Norwegian Bay and the Canadian Arctic Ocean. I'll be posting on this at my site by Saturday with any luck.
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Post by hilbert on Sept 3, 2009 18:11:14 GMT
Two different methods of calculation.
Ice area shows visible total actual summed together ice area over 15% concentration excluding water between ice using their own method.
Ice extent shows 'spread of ice' with all ice over 15% concentration counting as 100% ice using their own method.
So if there is no water between the central mass of ice they will be the same if they use the same method and exclude the same under 15% of ice and water.
Neither method takes account of quantity of ice so if all of the ice is bunched together to form ice ridges many metres high the amount of ice is shown as being less.
So, if ice area stays about the same, but ice extent is dropping, does that mean that the ice is concentrating together? Thanks.
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Post by radiant on Sept 3, 2009 20:39:36 GMT
Two different methods of calculation.
Ice area shows visible total actual summed together ice area over 15% concentration excluding water between ice using their own method.
Ice extent shows 'spread of ice' with all ice over 15% concentration counting as 100% ice using their own method.
So if there is no water between the central mass of ice they will be the same if they use the same method and exclude the same under 15% of ice and water.
Neither method takes account of quantity of ice so if all of the ice is bunched together to form ice ridges many metres high the amount of ice is shown as being less.
So, if ice area stays about the same, but ice extent is dropping, does that mean that the ice is concentrating together? Thanks. Could be. The latest north pole cam data shows the wind in the last 10 days has tended mainly to have moved around to the north and then to the north west almost for the first time since end of July whereas previously it was mainly from the south. And for cam watchers i notice we finally have a sub zero internal cam temperature of minus 3 displayed on the web cam positioned at 83.824 -1.308 www.arctic.noaa.gov/latest/noaa1.jpg
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Post by kiwistonewall on Sept 3, 2009 20:51:32 GMT
Two different methods of calculation.
Ice area shows visible total actual summed together ice area over 15% concentration excluding water between ice using their own method.
Ice extent shows 'spread of ice' with all ice over 15% concentration counting as 100% ice using their own method.
So if there is no water between the central mass of ice they will be the same if they use the same method and exclude the same under 15% of ice and water.
Neither method takes account of quantity of ice so if all of the ice is bunched together to form ice ridges many metres high the amount of ice is shown as being less.
So, if ice area stays about the same, but ice extent is dropping, does that mean that the ice is concentrating together? Thanks. Yes, though there are two conclusions depending on which side of the fence you are on. (If you try and sit on the fence, everyone throws stuff at you! ;D) 1. The Warmer: The melting ice means that the remaining ice is shattered and more easily moved by wind & current into pressure ridges. The ice more easily escapes into the Atlantic down the coast of Greenland, and into the Canadian Archipelago. Ice continues to escape the Arctic in greater amounts each year with a summer ice-free Arctic on the cards in coming decades. 2. The Skeptic: The recovering ice is less able to resist the wind and current over much of the Arctic, and is being compressed. The compressed area ('old ice') has been increasing in recent years, and each year brings a greater recovery, as the compressed old ice survives to the following year. (I think I have produced both 'sides' of the argument impartially.) If the Sun IS in a slowdown, then the ice is coming back. If AGW is a reality, the ice is doomed. Or thirdly - we are totally ignorant and anything might happen!
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Post by ron on Sept 3, 2009 21:52:24 GMT
How does one determine the direction of wind using n,w,e & s at the pole? Is the direction based on longitude lines? Barring that, one might imagine being the wind direction forecaster for the North Pole might be one of the easiest jobs on earth: "Today, winds from the south. Tomorrow, the winds will be from the south. This weekend, southerly winds will rule throughout."
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Post by radiant on Sept 3, 2009 22:26:36 GMT
How does one determine the direction of wind using n,w,e & s at the pole? Is the direction based on longitude lines? Barring that, one might imagine being the wind direction forecaster for the North Pole might be one of the easiest jobs on earth: "Today, winds from the south. Tomorrow, the winds will be from the south. This weekend, southerly winds will rule throughout." You have a point there but the cams and weather stations 'at the pole' are positioned near the pole on a large ice flow and then drift with the flow. As far as i can see any Buoy placed near the pole will tend to drift south to pass down the eastern side of greenland The cam has been south of 85 North for 6 weeks and is now just south of 84 North www.arctic.noaa.gov/images/weatherdata/2009/pos_2009.gifwww.arctic.noaa.gov/weather_data/2009/07100_hdr.wx
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Post by woodstove on Sept 4, 2009 14:19:53 GMT
While the graph below is promising, the NWS forecast for Barrow sounds like the wind could amplify late-season melting near Alaska, at least. (Forecast pasted below graph.) NWS Statement as of 4:52 PM AKDT on September 03, 2009 ... Another period of strong winds Friday and Friday night... A west to southwest wind of 25 to 35 mph along the western and northern Arctic coast will diminish rapidly from west to east this evening as an area of low pressure offshore passes east of Demarcation Point. Another low currently in Russia will strengthen and move to near wrangel island on Friday afternoon. The low will then continue to track east and into the Beaufort Sea on Saturday. A southwest wind will increase to 25 to 40 mph along the western Arctic coast on Friday morning. The stronger wind will spread east to Barrow by Friday evening... and then east along the Beaufort Sea coast Friday night. The strong wind will cause the seas to build to 8 to 11 feet... with the highest seas offshore. The duration of the strong wind at any one spot is expected to be about 18 hours... and due to the longer duration of the strong wind some beach erosion is possible. At this time coastal flooding is not expected... but the situation will continue to be closely monitored. Continue to monitor the latest forecasts from the National Weather Service office in Fairbanks for the latest updates. -ends-
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Post by pidgey on Sept 4, 2009 15:55:08 GMT
Is it my imagination or has the warmers' attendence been slipping lately? They out sunning themselves while there's still some to get?
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Post by Col 'NDX on Sept 4, 2009 19:53:25 GMT
Thinking up their next "plan of action", I suspect..
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Post by walterdnes on Sept 5, 2009 5:55:05 GMT
Arrgh, the latest IARC JAXA numbers are either late or missing. The last update is September 3rd, only 64,688 km^2 above the 2005 minimum. The ice decreased only 18,437 km^2 from September 2nd to the 3rd, so it's still conceivable that 2009 could end up with a higher min than 2005.
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Post by kiwistonewall on Sept 5, 2009 6:20:10 GMT
Composite of Jaxa image (semi transparent) overlay on NOAA as at 4th September. As far as Jaxa are concerned, all the ice in the yellow & green coloured areas has already melted! -- it likely will melt over the next fortnight or so, but the Jaxa decline will be slower than reality, as reality tries to catch up.
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Post by msphar on Sept 5, 2009 16:39:28 GMT
Hard to speculate why JAXA missed but they did miss on both the prelimiary release and the final number. I find this strange. I looked for reports of Japanese holidays which might have coincided, saw none. There was a full moon last night but not aware of relationship. It seem odd, coming at the brink of the turning point. Maybe they just got bored with the mudanity of the process ? Or maybe they were just busy packing their bags early for Copenhagen ?
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Post by kiwistonewall on Sept 5, 2009 21:50:35 GMT
It has happened before - several days with no Jaxa data. I suspect that at times they adjust the algorithm, and spread the adjustment out over several days to prevent sudden discontinuities. They foreshadowed future changes some months ago.
I'm sure that they must realise their algorithm, is not reading a lot of ice that is there, though I am not convinced that any satellite signal in the Microwave can truly differentiate ice-snow-sea-weather that accurately.
The summer problem has been well discussed - large pools of surface water simply fool the sensors with a reflection like, well, a water surface! (up to 25% of the ice can be missed)
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Post by matt on Sept 5, 2009 23:36:34 GMT
Is it my imagination or has the warmers' attendence been slipping lately? They out sunning themselves while there's still some to get? Hi Pidgey! Looks like the winning number will be 4.75-5.25, better known as 5. That's in the Warming Square and below the long-term trend of 5.6. It will be interesting to see how thickness turns out. Will this be a third record minimum volume in a row? In any case, the volume will be below the long-term trend, which means the prognosis is now worse. Here's a nice article that discusses the 50 year trend in arctic sea ice. They used declassified submarine data to create a thickness record from 1958-2008. www.spaceref.com/news/viewpr.html?pid=29103
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Post by msphar on Sept 5, 2009 23:37:03 GMT
Not to worry, JAXA has a published policy which applies in this case:
"JAXA may change or delete the information on the Site, or may suspend or terminate the operation of the Site without any prior notice. JAXA is not responsible to you for any inconvenience that may be caused by such changes or deletion of the information, or by such suspension or termination of the operation of the Site. "
Looks like they thought of everything.
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