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Post by jimcripwell on Aug 5, 2009 16:16:23 GMT
neilhamp writes "The NSIDC report is out"
Thanks. It is an interesting report. Mark Serreze is a dyed-in-the-wool warmaholic. The recent slow down in the rate at which the Arctic sea ice is melting, started on July 31st; so, in principal, it could have been included in this report. It was not, even though the trend is obvious from the graphs NSIDC includes in it's report.
Some more "back of the envelope" calculations. The last 5 days rate of daily decrease of ice has been about 47,000 sq kms. If we assume we are 30 days from mimimum, then at this rate there will be about 5,300,000 sq kms at minimum. If Kiwi is right in his estiamte, 6,000,000 sq kms (and I hope he is), then for the next 30 days the melt rate needs to average about 26,000 sq kms per day. In other words, for kiwi to be correct, we need to see a further reduction in the rate of daily melt. I know this will eventually happen; the question is when.
In September, NSIDC must produce another report. I assume they neglected to note the current slower rate of melt, in the hope that the melt speeds up again soon. If it does not, then the September report will be, to say the very least, interesting. Reminds me of the ancient Chinese curse - May you live in interesting times.
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Post by radiant on Aug 5, 2009 17:25:19 GMT
The ice a few hundred kilometres off greenland looks very broken now with plenty of water. Since the arctic ice is just travelling around and around you can imagine it is similar all across the region now.
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Post by socold on Aug 5, 2009 18:11:04 GMT
neilhamp writes "The NSIDC report is out" Thanks. It is an interesting report. Mark Serreze is a dyed-in-the-wool warmaholic. The recent slow down in the rate at which the Arctic sea ice is melting, started on July 31st; so, in principal, it could have been included in this report. It was not, even though the trend is obvious from the graphs NSIDC includes in it's report. Some more "back of the envelope" calculations. The last 5 days rate of daily decrease of ice has been about 47,000 sq kms. If we assume we are 30 days from mimimum, then at this rate there will be about 5,300,000 sq kms at minimum. If Kiwi is right in his estiamte, 6,000,000 sq kms (and I hope he is), then for the next 30 days the melt rate needs to average about 26,000 sq kms per day. In other words, for kiwi to be correct, we need to see a further reduction in the rate of daily melt. I know this will eventually happen; the question is when. In September, NSIDC must produce another report. I assume they neglected to note the current slower rate of melt, in the hope that the melt speeds up again soon. If it does not, then the September report will be, to say the very least, interesting. Reminds me of the ancient Chinese curse - May you live in interesting times. "The average pace of ice loss during July 2009 was nearly identical to that of July 2007. Ice loss sped up during the third week of July, and slowed again during the last few days of the month."
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Post by jimcripwell on Aug 5, 2009 19:13:11 GMT
socold writes ""The average pace of ice loss during July 2009 was nearly identical to that of July 2007. Ice loss sped up during the third week of July, and slowed again during the last few days of the month.""
Oh Wow, Golly Gee!!!!! This does not do justice to what actually happened. It gives the impression, to me, that the slow down at the end of the month merely compensated for the speed up in the third week.
The last day of July saw the rate of daily ice melt decrease to HALF the average rate for the whole of July. This trend continued until the day the report was written, and shows up on it's graphs. If NSIDC had written this up, maybe I would start to believe they are unbiased.
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Post by socold on Aug 5, 2009 19:31:30 GMT
I only wanted to correct the claim that they neglected to note it.
Whether or not they noted it enough is an entirely different and subjective complaint.
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Post by douglavers on Aug 6, 2009 10:32:19 GMT
ice-glaces.ec.gc.ca/Ice_Can/ANIM-CMMBCTCA.gifThe ice on Hudsons Bay is almost gone. Presumably, with a very late melt the water itself will remain close to freeze temperature as it will have very little time to pick up extra heat. This will mean an abnormally rapid refreeze - should be interesting to watch in a [very] few weeks.
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Post by radiant on Aug 6, 2009 10:56:18 GMT
ice-glaces.ec.gc.ca/Ice_Can/ANIM-CMMBCTCA.gifThe ice on Hudsons Bay is almost gone. Presumably, with a very late melt the water itself will remain close to freeze temperature as it will have very little time to pick up extra heat. This will mean an abnormally rapid refreeze - should be interesting to watch in a [very] few weeks. Yesterdays 30 day Canadian ice forcast says: ice-glaces.ec.gc.ca/prods/FECN15G/20090805000000_FECN15G_0004503882.pdfSince ice still lingers near Churchill, neither of the following events has occurred yet: an open water route across Northern Hudson Bay and the open water route into Churchill; both these events were forecast to occur during the last 10 days of July, but have been affected by the delayed breakup in southwestern Hudson Bay.A satellite picture would describe this much better! CIS says that Hudson bay will be clear by third week of August. Anybody know a daily source of satellite images?
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Post by bluecon on Aug 6, 2009 13:40:17 GMT
ice-glaces.ec.gc.ca/Ice_Can/ANIM-CMMBCTCA.gifThe ice on Hudsons Bay is almost gone. Presumably, with a very late melt the water itself will remain close to freeze temperature as it will have very little time to pick up extra heat. This will mean an abnormally rapid refreeze - should be interesting to watch in a [very] few weeks. Yesterdays 30 day Canadian ice forcast says: ice-glaces.ec.gc.ca/prods/FECN15G/20090805000000_FECN15G_0004503882.pdfSince ice still lingers near Churchill, neither of the following events has occurred yet: an open water route across Northern Hudson Bay and the open water route into Churchill; both these events were forecast to occur during the last 10 days of July, but have been affected by the delayed breakup in southwestern Hudson Bay.A satellite picture would describe this much better! CIS says that Hudson bay will be clear by third week of August. Anybody know a daily source of satellite images? CIS uses airplanes and radar to make regular maps of the ice. Uni-Bremen shows the ice mostly gone while CIS shows ice in Hudson Bay. At Churchill is a large grain terminal and they need to bring in the freighters to move out the grain. ice-glaces.ec.gc.ca/WsvPageDsp.cfm?ID=1&Lang=eng
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Post by bluecon on Aug 6, 2009 16:54:41 GMT
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Post by radiant on Aug 6, 2009 17:42:35 GMT
Bremen satellite schematic seems accurate for around Nares strait and northen and eastern Greenland where i can see the daily satellite pictures via Danish ice service as per my thread on Nares strait. You can see pretty small details that are similar in kennedy water. To be fair to Bremen they dont differentiate open water from less than 10%. Less than 10% appears light blue on the canadian chart. ice-glaces.ec.gc.ca/prods/WIS31CT/20090805180000_WIS31CT_0004504486.pdfThe issue at hand is 'can Bremen judge ice extent *change* from satellite photography' versus Canadian satellite judgement with aircraft backup. The canadians can only have so many planes for such an enormous daily survey. Incidently what seemed like the unbroken old ice in the triangle of water called the Lincoln Sea formed by north west greenland and ellesmere island is now totally fractured and some is moving west and some is going into nares strait. The ice flow pieces are very large so ice flow is slowed. In about a week the large pieces will have been removed from this area and then it will be remnants of old ice and new ice flowing thru. Since 2007 this triangle of ice has been progressively threatened by the failure to form ice bridges deep into Nares strait as they have begun forming further away from Smiths sound. Potentially there will be no ice bridge formed in Nares strait this year. And it is possible that if a bridge forms in the Lincoln Sea it will only form in spring. The amount of ice and water going down Nares strait is not relatively massive but it must make a difference one way or another. It could for example mean a colder planet as more ice melts and more warmer water is exposed to cooling? I realise i know relatively nothing and this is just speculation more or less. Either way at this point in time i am not convinced the satellite estimates are so very wrong.
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Post by bluecon on Aug 6, 2009 18:58:37 GMT
Obviously if Churchill is socked in with ice and Uni-Bremen has shown no ice there for weeks it is very inacurate. Canadian Ice Service, a federal agency that uses observations from radar satellites that can see through clouds, along with reports from monitors in aircraft and on ships, to produce detailed reports.www.isprs.org/commission2/proceedings02/paper/064_143.pdf
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Post by radiant on Aug 6, 2009 19:41:47 GMT
Obviously if Churchill is socked in with ice and Uni-Bremen has shown no ice there for weeks it is very inacurate. Canadian Ice Service, a federal agency that uses observations from radar satellites that can see through clouds, along with reports from monitors in aircraft and on ships, to produce detailed reports.www.isprs.org/commission2/proceedings02/paper/064_143.pdfBremen shows ice of less than 10% and open water together as the same colour. CIS shows open water as white and less than 10% ice as light blue. CIS is showing most of Hudson bay as light blue. In theory therefore 90% of the ice estimation made by Bremen does not include the ice coverage of about 95% of hudson bay because there is relatively little ice in 95% of Hudson bay. Churchill is not iced in according to CIS. They show less than 10% ice and say there is not open water. I take this to mean for example that the Titantic sank because it was crossing an area which was not open water but percentage wise there was very little ice present. As you point out, CIS are using satellite images backed up by aerial recon. A satellite image would tell us what is there with some degree of accuracy unless what is there is of a small size and even a small berg can damage a boat. Obviously satellite images have their limitations but you cant say that bremen is so inaccurate if they are not actually making visible to you what you want to compare to CIS Wiki on 'open water' en.wiktionary.org/wiki/open_water3. (mainly Canadian) An area of an ocean, sea, lake, or river which is not covered by ice. 2005," Canadian Ice Service, Government of Canada, 6 Dec, p. 1 (retrieved 14 Mar. 2008), At the end of June, James Bay was generally open water except for loose ice persisting over its northwestern section
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Post by bluecon on Aug 6, 2009 20:53:11 GMT
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Post by radiant on Aug 6, 2009 21:13:41 GMT
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Post by kiwistonewall on Aug 6, 2009 21:32:44 GMT
Bremen use the JAXA which: "The AMSR-E results are preliminary because AMSR-E is still in the calibration phase" www.iup.uni-bremen.de/iuppage/psa/2001/amsrop.html!!! And all the other satellites have failed. Comparing AMSRE images with both US Alaskan & Canadian data, it appears that the AMSRE cut off for open water is about 80% ice. This leads to massive low reporting of extent. So Canada is the only reliable source of data. I've made the following point before: For something as important (so they say) as the Arctic ice there is very little real effort to gather the data. In fact, as the ice has been recovering, there appears to be a concerted effort to NOT measure it. We have the technology. It is quite possible for all the ice to be overflown by planes & measured weekly. There are towing radars that can be do this. There is the appearance is of a stage managed propaganda exercise at worst, or that governments don't care, at best. There is no incentive to track more ice. Instead we get data from the past. Only the real data needed by navigation can be relied on. I've noticed the same with weather in Australia and New Zealand. You'll find accurate reports on the agriculture websites, as the Farmers Need to know(and KNOW) what the weather is doing. The details of crop failure, frosts and other things are seldom mentioned on mainstream media, where there is a clear selection of data to show "warming". I see the presenters almost choke or get apologetic, when they have to mention "cold" "frost" etc. ;D
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