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Post by StuartG on Aug 8, 2011 22:00:23 GMT 1
"It is getting warmer, but the glaciers are not rebuilding, just the opposite in fact." It's Summer Eamonn that's why. Unless You're talking medium long term. [30-50 years] in which case it may well be. What You're really suggesting is that because of human activities the World is warming towards an uncontrollable extent. That is not proven. However, attempts at proving this theory have been made, and success claimed. However this is not even been proven 'beyond reasonable doubt' or anywhere near it. Not enough of the variables have been understood and taken into account in the algorithms of the 'climate models'. To quote "*There are many additional factors that shape computations of the global climate and they require the biggest of today's supercomputers, which calculate algorithms beyond the comprehension of mere mortals or our intuition" from 'Ziggy Switkowski is chancellor of RMIT University.' www.theaustralian.com.au/news/opinion/a-degree-of-uncertainty-about-how-much-the-planet-is-warming/story-e6frg6zo-1226110445328---- One thing is clear — summer sea ice in the Arctic Ocean has been far from constant during the past 10,000 years. For big slice of that time, between 8,000 and 5,000 years ago, there was much less — by half — ice than now. The new study, to be published in the Journal Science, suggests that there was only half as much ice during that relatively warm period, known as the Holocene Climate Optimum. " " The new study shows that, as ice disappears from one region, it may build up somewhere else, probably as a result of shifting wind patterns. That wind factor hasn’t been completely accounted for in most current studies on the loss of sea ice, the researchers said.Since sea ice comes and goes without leaving much of a record, accurate observations of its extent only go back as far as the 1970s, the beginning of the satellite era, when photographic images began allowing scientists to map and measure the ebb and flow of the ice. " “Our studies show that there are great natural variations in the amount of Arctic sea ice,” Funder said. “The bad news is that there is a clear connection between temperature and the amount of sea ice. And there is no doubt that continued global warming will lead to a reduction in the amount of summer sea ice in the Arctic Ocean. “The good news is that, even with a reduction to less than 50 percent, of the current amount of sea ice, the ice will not reach a point of no return — a level where the ice no longer can regenerate itself even if the climate was to return to cooler temperatures,” he explained, pointing to the recovery of sea ice after the warm period of the Holocene. “Finally, our studies show that the changes to a large degree are caused by the effect that temperature has on the prevailing wind systems. This has not been sufficiently taken into account when forecasting the imminent disappearance of the ice, as often portrayed in the media,” Funder says. summitcountyvoice.com/2011/08/07/global-warming-ancient-driftwood-offers-sea-ice-clues/---- No doubt some documents can be found to say the contrary, and that's the point. There are not enough indications of confirmation on AGW to allow leglislation on a world scale to be allowed. Already these 'facts' for AGW has caused a lot of additional cost to an already increasing cost base, so that even in stable countries like Germany we get reports in the press of.... "Meanwhile, the report in business journal WirtschafsWoche, also quoted Robert Hoffman, head of communications company 1&1 as saying that taxes to subsidise renewable energy sources were too high. “Essentially, we’re subsidising the construction of solar-powered roofs… So we end up paying double,” he said. Hoffmann said that his company was looking at locations where “green electricity exists without the extra costs”." www.ifandp.com/article/0012852.html and used in radio4scienceboards.proboards.com/index.cgi?action=gotopost&board=natter&thread=939&post=13433 ---- StuartG
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Post by marchesarosa on Sept 16, 2011 17:35:24 GMT 1
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Post by marchesarosa on Sept 17, 2011 10:14:53 GMT 1
Some think the declining summer Arctic ice is the result of the inflow of warmer water into the arctic melting the ice from below plus variation in wind direction rather than of a rise in Arctic air temperature due to CO2. In fact it is possible that surface air temperatures are driven by melting ice rather than vice versa. Even the NSIDC has gone on record stating: "Igor Polyakov at the University of Fairbanks, Alaska, points out that pulses of unusually warm water have been entering the Arctic Ocean from the Atlantic, which several years later are seen in the ocean north of Siberia. These pulses of water are helping to heat the upper Arctic Ocean, contributing to summer ice melt and helping to reduce winter ice growth. Another scientist, Koji Shimada of the Japan Agency for Marine-Earth Science and Technology, reports evidence of changes in ocean circulation in the Pacific side of the Arctic Ocean. Through a complex interaction with declining sea ice, warm water entering the Arctic Ocean through Bering Strait in summer is being shunted from the Alaskan coast into the Arctic Ocean, where it fosters further ice loss. Many questions still remain to be answered, but these changes in ocean circulation may be important keys for understanding the observed loss of Arctic sea ice.” Thanks to Joe D'aleo at WUWT wattsupwiththat.com/2011/09/16/arctic-ice-refreezing-after-falling-short-of-2007/#more-47437
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Post by marchesarosa on Sept 17, 2011 10:23:35 GMT 1
See also this paper about to be published by the American Meteorological Society journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-11-00070.1Recent changes of arctic multiyear sea-ice coverage and the likely causes by Igor V. Polyakov, Ronald Kwok, and John E. Walsh Takes a while to load.
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Post by marchesarosa on Sept 17, 2011 10:34:44 GMT 1
Recent changes of arctic multiyear sea-ice coverage and the likely causes by Igor V. Polyakov, Ronald Kwok, and John E. Walsh
Introduction:
Recent changes of Arctic ice coverage Changes in the arctic ice cover over the past several decades have been remarkable. Over the period 1979-2010, Northern Hemisphere sea ice extent for September, the end of the summer melt season, is characterized by a linear rate of decline of more than 11% per decade, and the trend appears to be steeper for the last decade. For every year since 1996, the September ice extent has fallen below the 1979-1999 mean. The four lowest September ice extents, including the record minimum in 2007, have all occurred during the past four years. Winter ice extents are also declining but at a slower rate, and the 2011 winter maximum ice extent was close to the lowest in the satellite record. The observed decrease of ice extent is accompanied by thinning. Using a combination of submarine and satellite records, Kwok and Rothrock (2009) found a ~1.8m decrease in mean winter ice thickness in the central Arctic since 1980, with the steepest rate of sea-ice thickness decline, 0.10–0.20 33 m/yr, during the last five years.
In addition to the diminishing extent and thinning, the ice cover has become younger. At the end of the 2010 summer, only 15% of the ice remaining in the Arctic was more than two years old, compared to 50 to 60% during the 1980s. There is virtually none of the oldest (at least five years old) ice remaining in the Arctic (less than 60,000 km2 compared to 2 million km2 during the 1980s). Between 2005 and 2008 (Figure 1), the Arctic Ocean lost 42% of its multiyear ice (MYI = ice which survives at least one arctic summer) coverage. The decline of the MYI winter coverage of the Arctic Ocean during the last decade has been not monotonic. QuikSCAT/ASCAT satellite records for 1999–2009 show that since 1999 MYI area has decreased, with a total loss of more than one million square kilometers (~14% of the Arctic Ocean area) as evidenced by comparing the MYI area in each of the last three years of the record with that in each of the first three years (Figure 1). Over this period there were short-term recoveries of MYI coverage between 1999 and 2002, when the area increased by more than 6×105 km2. Since 2007, the recovery of MYI coverage has been moderate and is localized in the eastern Arctic Ocean; of particular interest is that MYI coverage resembles the bathymetry defining the Eurasian Basin (a combination of the Amundsen and Nansen basins, shown in Figure 4), pointing to the possible importance of oceanic processes affected by the shelf break. In this article, we consider the potential roles of both the atmosphere and the ocean in the decline of MYI coverage in the Arctic Ocean.
Ice export and atmospheric dynamics It is conceivable that a large fraction of the MYI area loss is due to wind-driven export of sea ice through the straits connecting the Arctic Ocean with the sub-polar basins. On average, ~700,000 km2 of sea ice (or ~10% of the area of the Arctic basin) is exported annually via Fram Strait (for geographical notations, see Figure 4), the major gateway of arctic ice export. Much of the export is MYI. Data collected by the International Arctic Buoy Programme suggest that the thinning of the sea ice in the early to mid-1990s was attributable to an increase in ice area export through Fram Strait. Through that time period, this increased export has been linked to the positive phase of the Arctic Oscillation, which increases the cross-strait gradient in sea level pressure. More recent atmospheric circulation anomalies dominated by a dipole pattern (which is different from the Arctic Oscillation) also seem favorable to increased advection of sea ice towards Fram Strait. On the other hand, longer- term satellite observations show that, over the past 30 years, there has been a negligible increase in the measured ice area export through Fram Strait. The decrease of ice concentration at the strait compensated for the increase in the sea level pressure gradient across Fram Strait, resulting in a statistically insignificant trend in the Fram Strait area flux (Kwok, 2009, p. 2438, see also Figure 2). Moreover, recent work has shown that decreases in MYI area in the Beaufort Sea due to the melting of mobile summer ice is anotherfactor that should be considered as a contributor to the observed loss in coverage.
Interannual variability in sea-ice export through Fram Strait is significant, with a low of 516,000 km2 in 1984–85 and a high of 1,002,000 km2 in 1994–95. An anomalously large wind-driven export event (for example, the peak 1994–95 export) could have a long-lasting impact on the survival of the MYI ice cover, especially when large export events are superimposed on a warming trend. With lower annual replenishment of the MYI area or reduced survival of seasonal ice through the summer, episodic large outflows could be detrimental to the maintenance of MYI coverage in the Arctic. Regional ice melt/growth complemented by ice flux through other passages (like Nares Strait) have also contributed to the observed MYI area decline. Thus, the role of wind-driven export on the loss in MYI coverage remains an open question.
Notably, there is an ongoing build-up of MYI in the Eurasian Basin.Analysis of satellite- derived ice motion showed that the inflows of ice into the Eurasian Basin from the western Arctic Ocean in 2004–09 were too small (< 0.04×106 km2) relative to the total MYI area change to account for the observed increase. Therefore, it seems that the observed increase in MYI in this region must be due to the survival of seasonal ice. Atmospheric thermodynamics and melt
Changes of MYI coverage are tightly coupled to the observed changes in surface air temperature (SAT) (Figure 2). Positive SAT trends over recent years (1990–2008) are the strongest in the maritime zone flanking the Arctic Ocean (Figure 3). Warming in the Arctic since 1987 is evident in the time series of SAT anomalies from the three coastal stations. Strong warming in the central Arctic (>80oN) is also evident in fields from the ERA-Interim reanalysis (http://data-portal.ecmwf.int/data/d/interim_mnth/), which are constrained by satellite retrievals, radiosonde profiles, surface observations and other data sources (Figure 3). Between 1999 and 2009, the overall decrease of MYI area was consistent with the general warming trend shown in SAT records. The moderate increase of MYI area in the Eurasian Basin fit well with the lower temperatures (relative to 2007) during the last several years (see time series in Figure 3). While large-scale high-latitude warming helps drive the observed reduction of sea-ice extent and thickness, local warming over the areas of reduced sea-ice coverage suggest that SAT rises are partially a response to, rather than a driver of, declining ice coverage. Furthermore, SAT changes account for only part of the overall atmospheric thermodynamic forcing of the ice cover, which is orchestrated by a complex combination of various atmospheric parameters and feedbacks.
Fast-ice (motionless seasonal sea ice anchored to the sea floor and/or the shore which melts and reforms each year) thickness measurements are invaluable for isolating the impact of atmospheric warming. Records of fast-ice thickness provide annual measures of ice growth due almost entirely to atmospheric thermodynamic forcing over the vast and shallow Siberian shelves, where there is negligible deep ocean influence on local ice formation. Fast- ice thickness records are available through 2009 from several locations along the Siberian coast (see the map showing these locations in Figure 3). Using a composite record of fast-ice thickness over the last several decades from 15 locations along the Siberian coast, it was shown that added surface melting in the eastern Arctic due to atmospheric thermodynamics caused ~0.3 m of ice thickness loss. In particular, the updated thickness records from six fast-ice locations around the Laptev Sea show fluctuations in concert with changes of MYI area (Figure 3). These correlated changes suggest that the atmospheric thermodynamic forcing plays an important role in shaping Arctic MYI coverage.
Ocean heat
In addition to atmospheric thermodynamics, the Arctic ice cover is affected by the thermal state of the Arctic Ocean. Enhanced upper-ocean solar heating through openings in the ice and consequent ice bottom melting were observed in the Beaufort Sea in summer 2007. This is a manifestation of the ice-albedo feedback mechanism, in which warming leads to a reduction of ice coverage and decreasing albedo, resulting in further sea-ice retreat. The sea- ice reduction in the Canadian Arctic that began in the late 1990s as a result of increased influx of warm summer waters of Pacific origin clearly shows the thermodynamic coupling between the Arctic ice and the ocean interior.
Further, oceanographic observations carried out in the Eurasian Basin of the Arctic Ocean suggest that the thermal state of the Arctic Ocean interior has an impact on the Arctic ice cover. Observational and modeling results suggest that gradual warming of intermediate waters of Atlantic origin, the so-called Atlantic Water (AW) of the Arctic Ocean, helped precondition the polar ice cover for the extreme ice loss observed in recent years. Polyakov et al. (2010) argued that, on a time scale of several decades, ice thickness losses due to anomalous ocean heat flux could be comparable to losses due to local atmospheric thermodynamic forcing. Observations in the 2000s documented a new pulse of AW warming. Based on all data prior to 1999, the most extreme 2007 temperature anomalies of up to 1oC and higher relative to climatology were observed in the interior of the Eurasian and Makarov basins (see Figure 2 from Polyakov et al. 2010). On the other hand, observations carried out during several recent years showed cooling along the Eurasian Basin margins (Figure 4).
The patterns of temporal AW temperature changes in the Arctic Ocean’s Eurasian Basin and of MYI coverage are in good agreement (Figure 2), suggesting a plausible role for anomalous oceanic heat in recent changes of the Arctic ice cover. Unfortunately, no direct evidence for such a link can be found in large-scale long-term measurements of oceanic heat fluxes. Does evidence exist to suggest a link between the AW heat and the state of Arctic sea-ice over the recent decade? The Arctic Ocean interior, away from the boundary and upper mixed layer, is considered to be a low-energy and, correspondingly, a weakly-mixing environment. The resulting turbulent heat fluxes from the AW layer in the Arctic Ocean interior are small, less than 1W/m2. There is, however, a wide range of flux magnitudes that vary, depending on geographical location, from just a fraction of 1W/m2 in the Canadian Basin to O(100) W/m2 north of Svalbard. A double-diffusive mechanism resulting from the different diffusivities of heat and salt provides an important alternative to turbulent mixing in the eastern Eurasian Basin. Diffusive instability (cold and fresh water above warm and salty water) maintains staircase structures formed by layers of near-uniform water temperature and salinity interleaved with strong-gradient thin interfaces. Double-diffusive heat fluxes in the lower halocline of the Eurasian Basin interior based on Ice-Tethered Profiler data are ~1– 2W/m2. Double-diffusive heat fluxes across several diffusive layers occupying the 150–250m depth range and overlying the AW core from the eastern Eurasian Basin are ~8 W/m2 (Polyakov et al. 2011). These fluxes provide a means for transferring AW heat upward over more than a hundred meter depth range towards the upper halocline. The intermittent nature of staircases in the upper halocline makes it difficult to evaluate the double-diffusive heat fluxes; a specialized field experiment may be necessary to complete such an evaluation.
Lack of MYI recovery since 2007 The absence of substantial MYI recovery between 2008 and 2009, despite the cooler conditions in 2009, implied by the change in fastice thickness, points to a role of the large thermal inertia of the ocean compared to the atmosphere. Specifically, heating of the near surface and intermediate waters of the deeper basins over the last decade, where MYI has historically formed, may be delaying the autumn freeze-up, thereby reducing the length of time for ice growth to occur and hence the maximum ice thickness. This role of atmospheric thermodynamic forcing includes the effect of the albedo-temperature feedback, which was triggered by a combination of higher air temperatures and wind patterns conducive to ice retreat in years such as 2007. As noted previously, additional warming added as heat from the Atlantic and Pacific layers may also have contributed to the reduction of ice thickness. The reduction of ice thickness decreases the likelihood that the ice will survive the following summer’s melt and become MYI. In this respect, the reduction of MYI is driven by, and perhaps even contributes (via the reduced ice thickness) to the albedo-temperature feedback. Thus, the rapid loss of sea ice in response to the atmospheric and oceanic forcing of the past decade appears to have introduced some degree of irreversibility, at least over timescales of several years, into the loss of MYI. Conclusions This article addresses probable causes of the observed reduction of the Arctic Ocean's coverage of MYI over that past decade. There is evidence of the increasingly important role of atmospheric thermodynamic forcing in shaping recent changes of the Arctic MYI. In addition to direct MYI melt due to high-latitude warming, the impact of enhanced upper-ocean solar heating through numerous leads in decaying Arctic ice cover and consequent ice bottom melting has resulted in an accelerated rate of sea-ice retreat via a positive ice-albedo feedback mechanism. The pan-Arctic role of this feedback is yet to be quantified. Analysis of satellite ice motion suggests that the role of ice export through straits connecting the Arctic Ocean with sub-polar basins may be elusive. This situation probably differs from the situation that existed in the early to mid-1990s, when enhanced ice export through Fram Strait was caused by anomalous winds associated with the positive Arctic Oscillation phase. The possible long-lasting impact of anomalous winds such as those in 2004–05 or 2007 (especially when superimposed on a warming trend) on the state of MYI should not be ruled out. An intriguing feature of the scenario described here is the potential contribution of oceanic thermodynamic forcing to the recent changes of the high-latitude MYI coverage. Available observations suggest a thermodynamic coupling between the heat of the ocean interior and the sea ice. In the Canadian Basin, the impact of Pacific water warmth has been recently documented. While vertical AW heat fluxes are negligible in the Canadian Basin, turbulent mixing may be strong enough in the western Nansen Basin to produce a sizeable effect of AW heat on sea ice. In the eastern Eurasian Basin, double diffusion provides an important alternative to weak turbulent mixing for upward AW heat transport. However, this contribution to sea-ice loss remains uncertain pending new field experiments that will provide estimates of upward AW heat fluxes.
The fact that the rate of MYI recovery observed in recent years shows a delay relative to thermodynamic forcing indicates that MYI is resistant to recovery. However, the relative roles of dynamic and thermodynamic factors in recent changes of the Arctic MYI cover remains to be determined. Quantifying these roles is a high priority if we are to develop reliable forecasts of the future state of Arctic ice coverage.
For further reading........
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Post by marchesarosa on Sept 17, 2011 12:13:37 GMT 1
Why does change in Multi Year Ice loom so large in the imagination of alarmists?
After all Antarctica has no multi year sea ice, does it?
The only reason it exists in the Arctic basin is because it is virtually land-locked - otherwise it would probably just float away. It's just geography, isn't it?
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Post by StuartG on Sept 17, 2011 13:33:04 GMT 1
MM, Re:« Reply #62 Today at 10:14 » "Igor Polyakov at the University of Fairbanks, Alaska, points out that pulses of unusually warm water have been entering the Arctic Ocean from the Atlantic, which several years later are seen in the ocean north of Siberia. These pulses of water are helping to heat the upper Arctic Ocean, contributing to summer ice melt and helping to reduce winter ice growth. Well perhaps that's because of the volcanoes [seamounts] they have found... radio4scienceboards.proboards.com/index.cgi?action=gotopost&board=witter&thread=810&post=13875amongst others... So, why do they get in a tizzy? StuartG
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Post by marchesarosa on Jan 21, 2012 18:19:08 GMT 1
Below is the full duration of the NSIDC SEA ice data. From 2.8 gb of data. The graphs of the Arctic and Antarctic are plo tted on equal grid scales having a pixel resolution of 25km. The satellite ice data comes from the NSIDC Sea Ice Concentrations as collected from the Nimbus-7 SMMR and DMSP SSM/I Passive Microwave systems Thanks to Jeff Condon, here noconsensus.wordpress.com/2012/01/17/full-length-nsidc-sea-ice-data/
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Post by marchesarosa on Jan 22, 2012 15:27:17 GMT 1
Map showing location of Wegener Neumeyer Antarctic station www.awi.de/fileadmin/user_upload/Infrastructure/Stations/Neumayer_Station/Neumayer/Observatories/AirChem/map_neumayer.jpgNeumayer station which is located on the Ekström Ice shelf, about 8 km from the Atka Bay. During the summer months, the bay and the nearby coastline are mainly free of sea ice and there is always open water present. The prevailing winds are from the East, but with strong switches to westerly winds from time to time. Northern wind directions are very rare, ensuring that the data are not subject to contamination from the base. Air masses advected to Neumayer generally passed over the continent for 2 to 3 days, but were marine before that. Alfred Wegener Institute Neumayer Station III: Antarctic Cooling Over The Last 30 Years! By P Gosselin on 16. Januar 2012 It’s official: the Alfred Wegener Institute Antarctic Neumayer-Station III is a meteorological observation station that’s been measuring air temperature and other magnitudes in Antarctica for 30 years, which is the period of time used to define climate for a region. The results are clear and indisputable. The AWI writes in its press release: " At the Neumayer Station it has not gotten warmer over the last 30 years.” More comments here notrickszone.com/2012/01/16/alfred-wegener-institute-neumayer-station-iii-antarctic-cooling-over-the-last-30-years/
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Post by marchesarosa on Mar 19, 2012 12:49:41 GMT 1
The picture we usually see for the trend of the last few decades is all downhill but if you add in the pre-satellite era data that was illustrated in the earlier IPCC First Assessment Report it changes the picture somewhat. It is soooo important not to "cherry pick" start and end points when graphing, isn't it? Looks a tad more "cyclical" than linearly downhill, don't you think? Anthony Watts says "The folks at NSIDC are putting together an almost continuous record of sea ice to 1961 from satellite, they are pulling up old imagery and data, even going so far as to find old equipment to play it back. So they must be able to make use of it." Interesting discussion of the pre-satellite sea ice data here wattsupwiththat.com/2012/03/18/sea-ice-news-volume-3-2/#more-59466
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Post by marchesarosa on Mar 19, 2012 12:52:40 GMT 1
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Post by marchesarosa on Mar 19, 2012 13:01:11 GMT 1
Antarctic Sea Ice is above average, too.
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Post by marchesarosa on Mar 22, 2012 14:43:34 GMT 1
www.bbc.co.uk/blogs/paulhudson/Recovery in Arctic sea ice continuesPaul Hudson | 17:35 UK time, Wednesday, 21 March 2012 Arctic sea ice has staged a strong recovery in the last few weeks, reaching levels not far from normal for this time of the year..... more
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Post by marchesarosa on Mar 24, 2012 9:12:53 GMT 1
For those who are interested! The following is from a new paper about the Arctic Ocean by Carpenter and Timmermans called "Temperature Steps in Salty Seas" published in Physics Today, March 2012. Volume 65. Issue 3. pp. 66. “Bodies of water tend to settle into a state in which the fluid density increases with depth. That tendency, called density stratification, is often a dominating influence on the physics of lakes and oceans. The phenomenon, however, is more complicated when the water contains dissolved salts. Along with heat, salts act to change the density of water—the higher the salinity, or concentration of dissolved salts, the denser the water. If salinity increases with depth, then a water body can maintain density stratification even as its temperature increases with depth. Likewise, density stratification is possible for the reverse situation in which temperature and salinity decrease with depth. But because salt and heat diffuse at different rates, those density-stratified states can become unstable.” “…….the Arctic Ocean…..is similar to a lake in that it has a limited connection to the bordering Pacific and Atlantic oceans. Relatively warm and salty Atlantic waters enter the Arctic through narrow channels close to Greenland. Being slightly denser than the surface waters of the Arctic, the Atlantic water descends to a depth of a few hundred meters as it circulates. The surface waters of the Arctic are extremely cold and fresh due to water flowing into the ocean from rivers in the surrounding continents and contact with the cold Arctic air, among other things. That cold, fresh surface water overlies the warm, salty Atlantic inflow; thus the conditions needed for double diffusion are in place.” Earlier in the article, the authors describe this “double diffusion” as ” [D]ouble diffusion…….requires at least two components that affect water density (usually temperature and salinity) and …. the components must have different molecular diffusion speeds. Double diffusion occurs over vast areas of the world’s oceans….the outcome is a staircase structure of the water column,….. The steps exist because vertical fluid motions are constrained by the stable density gradient. But neither how the staircases form nor what determines the thickness of the layers is entirely clear, and both constitute active areas of research.” The article continues “The strong salinity stratification of ….. the Arctic Ocean limits mixing and effectively isolates the deep waters from the surface…..” “The Arctic contains enough heat in the deep ocean to entirely melt the sea-ice pack. However, across much of the central Arctic Ocean, the staircase structure indicates that upward transport of deep heat is minimal. Density stratification acts as a cap on the transport of heat from the deep Arctic, and oceanographers are carefully watching the staircase for indications of changing heat transport.” “Instruments tethered year-round to drifting sea-ice floes have enabled scientists to obtain a detailed picture of the double-diffusive Arctic staircase, even in the most remote and hostile regions of the ocean. The results of those intensive measurements show that each individual step of the staircase extends across almost the entire ocean basin. That means mixed layers on the scale of 1 m in the vertical have horizontal extents on the order of 1000 km, an aspect ratio of 106! A sheet of paper the size of a football field would have a similar aspect ratio.” “In addition to discovering the immense horizontal scales of the staircases, scientists have made advances in resolving the tiniest scales of variability. So-called microstructure profilers fall freely through the water column collecting measurements that can resolve turbulent fluctuations at a scale of just a couple of millimeters. Measurements …..in the Arctic Ocean have contributed to a growing body of evidence suggesting that the interfaces separating mixed layers are nonturbulent; transport across them is by molecular diffusion. Evidently, the individual staircase steps that stretch across vast regions of the Arctic Ocean are ultimately linked by the molecular collisions responsible for diffusion.” Prof Roger Pielke Sr comments on his blog here pielkeclimatesci.wordpress.com/2012/03/23/interesting-climate-science-relevant-article-temperature-steps-in-salty-seas-by-carpenter-and-timmermans-2012/This is quite a remarkable finding as: 1. Models must have vertical resolution of less than 1 meter to resolve the vertical stratification of temperatures at vertical spacings near the stratification interfaces! 2. The ocean component of the climate model equations must include molecular diffusion of temperature and salinity. 3. Until this feature of the Arctic Ocean is better understood, claims about how the Arctic will change in the future should be viewed with skepticism.
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Post by marchesarosa on Mar 27, 2012 0:35:12 GMT 1
Beaucoup Bering Sea IcePosted on March 26, 2012 by Anthony Watts NASA reports in Bering Sea Teeming with Ice that “…the Bering Sea has been choking with sea ice. “ For most of the winter of 2011–2012, the Bering Sea has been choking with sea ice. Though ice obviously forms there every year, the cover has been unusually extensive this season. In fact, the past several months have included the second highest ice extent in the satellite record for the Bering Sea region, according to the National Snow and Ice Data Center (NSIDC). The natural-color image above shows the Bering Sea and the coasts of Alaska and northeastern Siberia on March 19, 2012. The image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. Black lines mark the coastlines, many of which have ice shelves or frozen bays extending beyond the land borders. Continue reading → wattsupwiththat.com/2012/03/26/sea-ice-news-volume-3-number-3/--------- Yes, it may be mild in south east Canada and the US eastern seaboard but that is not the whole story. The Pacific northwest has been lashed with snow storms and very cold. All part of "normal variability" alas!
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