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Post by thermostat on Jun 12, 2012 2:29:01 GMT
Thermostat: I know you missed being present on this board for awhile. Do a scholar search for the recent paper confirming Antarctica was warmer as well during the MWP. And the hydrological studies from South America, as well as the stalagnite studies from China....etc....etc. The evidence is more than ample. As far as Arctic Ice during the Holocene optimum, there are now at least two papers establishing that it was ice free. One was written by a Sweedish scientist if memory serves me. As far as SS being a reliabe read, nope it isn't. There are papers that I posted on that very thread that never saw the light of day. In fact, it became quit contrarian......and I was/am banned from that site. That is ok tho, the few that go there can continue to be delusional. Someone has to be. Sigurdur, A recent paper in Science described the Arctic Sea Ice during the Holocene thermal maximum, "A 10,000-Year Record of Arctic Ocean Sea-Ice Variability—View from the Beach" www.sciencemag.org/content/333/6043/747.abstractWhen reading through the back and forth of the latest research it is generally not possible to draw definitive conclusions.
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Post by sigurdur on Jun 12, 2012 2:48:59 GMT
Thermostat: A 1,000 kilometers north of Greenlands north shore would be viturally at the North Pole. So with that in mind......it can easily be stated that the Arctic was ice free during the Optimum.
Not worth argueing about so I will leave it at that.
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Post by thermostat on Jun 12, 2012 3:13:58 GMT
Getting back to the present, the winter weather pattern drove sea ice toward the North American side and resulted in relatively thin first year ice on the Siberian side. While recent weather has reduced ice extent on the North American side, the Siberian ice in the East Siberian Sea, the Laptev Sea, and Kara Sea appears vulnerable to increased melting (forget the remaining Barent's Sea Ice, its already gone arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.6.html). Such melting historically occurs later in the summer. It will be something if it starts in June this year.
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Post by thermostat on Jun 14, 2012 2:52:44 GMT
As noted in various other discussion threads on this forum, the Arctic Sea Ice has taken a beating in recent weeks. Corresponding with this ice reduction has been a persistent Arctic dipole anomaly. The current weather forecast for the Arctic predicts that this is about to change; www.wetterzentrale.de/topkarten/fsecmeur.html (see N-hem; 850hPa-Temp.,SLP) The current forecast calls for a low pressure system to establish itself between Alaska and Eastern Siberia and for this system to persist for an extended period. It will be most interesting to see how this change in the weather affects the melt. As mentioned in my previous post, the affect of new weather pattern on the Siberian side will be something to observe (some are suggesting that it will increase melting north of Russia; we'll see.
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Post by thermostat on Jun 14, 2012 4:16:10 GMT
The Point Barrow Alaska Fast Ice has been an issue on the Arctic Sea Ice forums over recent years but has not appeared to be such a big deal this year. In any event, people can follow this intriguing saga via the Point Barrow webcam (which has been down for some time now, but, whatever.) www.cnn.com/2012/06/13/justice/florida-teen-shooting/index.htmlThe "Recent Visitors" link in the left side will show you others worldwide who are following this year's melt. That said, some have suggested a relatively late date for this year's Point Barrow breakup. Personally, I doubt it.
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Post by throttleup on Jun 14, 2012 11:44:00 GMT
The Point Barrow Alaska Fast Ice has been an issue on the Arctic Sea Ice forums over recent years but has not appeared to be such a big deal this year. In any event, people can follow this intriguing saga via the Point Barrow webcam (which has been down for some time now, but, whatever.) www.cnn.com/2012/06/13/justice/florida-teen-shooting/index.htmlThe "Recent Visitors" link in the left side will show you others worldwide who are following this year's melt. That said, some have suggested a relatively late date for this year's Point Barrow breakup. Personally, I doubt it. FWIW... The 2011 Barrow Sea Ice breakup occured 3/4 July...seaice.alaska.edu/gi/data/barrow_breakup/brw_fc_2011
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Post by throttleup on Jun 14, 2012 11:55:40 GMT
For those who may find this of interest:Cool site: www.aoos.org/The Alaskan Ocean Observing System (AOOS)... lots of info on Alaskan conditions.
From there you can get to the data portal...data.aoos.org/maps/sensors/#b=62.05016407358141,-153.40576171874997,59.875477787601206,-146.59423828124997&l=sensor-stations ... and if you click on "Explore Map" from the link above you can find out just about all you want to and more regarding local conditions, web cams, etc.
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Post by thermostat on Jun 16, 2012 1:51:37 GMT
The recent melt of Arctic Sea Ice is generating lots of comments among Arctic Sea Ice junkies. One topic getting discussed a lot is the apparent lack of effect of the 'severe' winter in Alaska, and in particular, the large Bering Sea Ice extent. Now that the Bering Sea Ice has pretty much melted away, what is most interesting is that this year's increased freeze event in this region does not seem to be having an adverse effect on melting in the Chukchi Sea. The present Chukchi melt is also interesting because it had appeared that relatively thick ice had accumulated here. see for example this recent LA Times story, www.latimes.com/news/nation/nationnow/la-na-nn-arctic-drilling-rig-kulluk-20120525,0,7450238.story "The heaviest polar ice in more than a decade is clinging to the northern coast of Alaska and could postpone the commencement of offshore oil drilling in the Arctic until the beginning of August — a delay of up to two weeks, Shell Alaska officials said Friday." Right now, looking at Cryosphere Today's data set, the Chukchi Sea is below normal for this date. This year's melt looks a lot like other years in this century,with the exception of 2011 where the early melt here was even more rapid. It appears that the severe winter in Alaska did not extend to the Beaufort Sea. This region is also well below average for this date. The rapid June melt continued through this week as indicated by the unusually low reading of Sea Ice Area at Cryosphere Today, arctic.atmos.uiuc.edu/cryosphere/ (click on recent Arctic ice area), as well as the low Sea Ice extent values being reported by sites like IJIS www.ijis.iarc.uaf.edu/en/home/seaice_extent.htmand the DMI center for Ocean Ice ocean.dmi.dk/arctic/icecover.uk.php
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Post by thermostat on Jun 16, 2012 2:01:41 GMT
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Post by thermostat on Jun 16, 2012 2:18:37 GMT
Getting back to the Alaskan side and the unexpected melting here, the question being discussed is, 'where did the heat come from' (since it takes heat to melt ice). The Bering Sea temperature is below average, so this does not appear to be a likely source. Obviously, the extended solar irradiation of the Arctic Summer can introduce significant amounts of heat into the system where ice albedo is reduced, but this effect cannot explain the initial opening of extensive polynas which has occured all around the Arctic Sea early in the melt season this year. Events this year are most consistent with 'melting from below'. I personally favor the interpretation that heat is flowing into the Arctic from more southerly ocean sources. Given the ongoing increases in ocean heat content, advection of such heat into the Arctic Sea will increasingly drive Arctic Sea Ice 'melt from below'.
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Post by thermostat on Jun 18, 2012 3:57:16 GMT
A couple of other interesting indicators of the Arctic Sea Ice melt are also being followed closely this summer, the Northwest Passage and the Nares strait. Interest in the Northwest passage is presently focussed on the thin condition of the ice, as indicated by the blue color showing water below (indicative of thin ice), as observed in recent satellite images; for example today: rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r04c02.2012169.terraAlso, the Nares strait on the northwesterm shore of Greenland is of interest. rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c02.2012165.terraThe North Water Polynia southwest of the Nares Strait ice bridge has been conspicuously large this spring. Opening of the Nares strait provides an alternative route for multi-year ice to exit the Arctic and recently this phenomenon has become an important mechanism contributing the Arctic Sea melt. The current projection is for the present Nares sea ice bridge to break down in July, but there is active speculation that it could rupture earlier this year.
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Post by thermostat on Jun 18, 2012 5:54:17 GMT
Another fringe factor to watch, Hudson's Bay. Looks like this ice is likely to melt substantially, soon.
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Post by thermostat on Jun 21, 2012 2:15:33 GMT
The Point Barrow Alaska Fast Ice has been an issue on the Arctic Sea Ice forums over recent years but has not appeared to be such a big deal this year. In any event, people can follow this intriguing saga via the Point Barrow webcam (which has been down for some time now, but, whatever.) www.cnn.com/2012/06/13/justice/florida-teen-shooting/index.htmlThe "Recent Visitors" link in the left side will show you others worldwide who are following this year's melt. That said, some have suggested a relatively late date for this year's Point Barrow breakup. Personally, I doubt it. FWIW... The 2011 Barrow Sea Ice breakup occured 3/4 July...seaice.alaska.edu/gi/data/barrow_breakup/brw_fc_2011throtleup, Thanks for the info. Clicking on the Barrow Sea Ice site it is nice to see that the webcam is working again. seaice.alaska.edu/gi/observatories/barrow_webcamLooking at the Modis satellite images, the fast ice just down the coast from Barrow has substantially broken up over the past few days (see day 172 here and click on 250 m to zoom in rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r05c03.2012172.terra). Given the solar irradiance that has occurred this year as well as the local fast ice breakup so far, it looks like the Barrow ice will go earlier this year than last year.
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Post by thermostat on Jun 21, 2012 3:55:29 GMT
A couple of other interesting indicators of the Arctic Sea Ice melt are also being followed closely this summer, the Northwest Passage and the Nares strait. Interest in the Northwest passage is presently focussed on the thin condition of the ice, as indicated by the blue color showing water below (indicative of thin ice), as observed in recent satellite images; for example today: rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r04c02.2012169.terraAlso, the Nares strait on the northwesterm shore of Greenland is of interest. rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c02.2012165.terraThe North Water Polynia southwest of the Nares Strait ice bridge has been conspicuously large this spring. Opening of the Nares strait provides an alternative route for multi-year ice to exit the Arctic and recently this phenomenon has become an important mechanism contributing the Arctic Sea melt. The current projection is for the present Nares sea ice bridge to break down in July, but there is active speculation that it could rupture earlier this year. No sooner said than the Nares Strait ice starts to break. This Modis image from day 170 shows a chunk breaking off of the Nares strait ice bridge rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c02.2012170.terra(click on 250m to zoom in.) Blue vs white indicates relative thickness of the ice. Historically, once the ice bridge breaks, the upstream ice will exit into Baffin Bay. Opening of the channel all the way to the Lincoln Sea provides for additional export and melt of multi-year Arctic Sea Ice. en.wikipedia.org/wiki/File:Lincoln_Sea_map.pngThe cognoscenti nevertheless maintain that a breakup here is still 3-4 weeks away (based on thermal imaging of the ice). hmm...
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Post by thermostat on Jun 23, 2012 3:40:46 GMT
Happy Summer Solstice to everyone!
This thread has turned into more of a blog than a discussion forum, but, whatever.
Solar irradiance in the Arctic has now reached its annual peak and will subsequently decline. Solar energy added directly to the arctic system will now have it's effect, in combination with additional thermal energy coming from various adjacent sources, of course.
Right now, a persistent low pressure system north of Alaska has become a key weather system affecting Arctic Sea Ice Area as mentioned above. The thing here is that while high pressure north of Alaska, and in particular, the dipole anomoly, drives Arctic Sea Ice export (and reduces Sea Ice Area), low pressure over this same region drives Sea Ice expansion. The total amount of sea ice is defined by sea ice volume, but Sea Ice Area is a more readily measurable parameter, so that is something to appreciate as this year's melt proceeds.
Persistent low pressure such as is presently occurring will increase sea ice distribution, increasing sea ice extent. It will not per se affect Sea Ice Area, but, that said, distributing the existing relatively thin ice over a broader area, where heat that has been added to the system can more easily melt this ice and thus promote sea ice reduction, could be a non obvious consequence of a weather pattern that appears to be reducing the melt. This could especially be the case here in June, where fragmentation and dispersion of the ice pack could have a particularly significant impact on meltiing later in the melt season.
The take home message is that daily changes in Sea Ice extent, as are commonly followed, do not tell the whole story about what is happening in the Arctic Sea.
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