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Aaron Lewis
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1) A gram of water vapor condensing on the surface of the GIS melts 7.5 g of ice resulting in 8.5 g of melt water on top of the GIS. 2) Water falling down a moulin converts its potential energy to kinetic energy, and then to heat. The water is at 0C because it has been transferring its energy to the ice around it. 3) Large ice sheets are complex structures subject to huge gravitational forces. Suddenly form a cylinder of ice a kilometer tall, and the ice at the base would explode. This does not happen in ice sheets because the ice at the base is under compression supplied by an infinite series of buttresses formed by ice at lower elevations. As moulins perforate the buttresses this support is lost. 4) Ice sheets are not designed by engineers with some margin of safety. They are at structural equilibrium. Suddenly formed holes (moulins) in the foundation disrupt that equilibrium. 5)Once the potential energy of a column of ice exceeds the compressive strength of the ice structure at the base of the column, the ice structure at the base of the column fails rapidly. This adds to the stress on the ice structure at the base of adjacent columns of ice; they fail, and so forth. 6) The difference between a structurally competent column of ice and one that fails is likely a fraction of a degree in temperature. Once a progressive structural failure begins, it can propagate into colder, stronger ice. Rate of propagation is a function of the total energy of the ice column. The higher the total energy, the faster the propagation. 7)Water/ice slurry from ice sheet collapse cuts its own channels. Current fjord system under the GIS was likely formed this way. Such deep fjords dug by solid ice would be wider. No, those channels were dug by cavitation in water as a walls of ice collapsed into them. I do not much worry about the kind of slippage we see in mountain glaciers. Nor, do I worry much about plastic flow as the ice warms and softens.
I would say that the Arctic has changed since 2005. Now, it has more water vapor over the region. The water vapor rises, condenses, and when the sun is low in the sky (spring & late summer) the clouds are warmed by sunlight. That warming drives a stable spring and late summer low. I doubt if this bit of geometry is in your climate texts. In the old days, the air over the Arctic was dryer and colder. Snow and ice tended not to absorb sunlight. Lows were driven by other mechanisms. Heat from direct insolation in this process is trivial compared to the amount of latent heat advected into the region from the south by this circulation. Thus, a bit of heat from sunlight on the sides of the cloud column results in circulation patterns and substantial sea ice melt. This is a powerful feedback from additional moisture in the Arctic atmosphere.
Toggle Commented Jul 25, 2013 on Second storm at Arctic Sea Ice
My expectation is that the Arctic will move to a regime of two, large, stable cyclones per year; one in spring, and one in late summer. I think a naming system based on year and season (or day of the year) would be convenient for historical records. Then somebody reading this history in 20 years does not have to find a separate list of storm names and dates.
Toggle Commented Jul 22, 2013 on The Naming of Arctic Cyclones at Arctic Sea Ice
Global warming has been acting on the Arctic for a long time. The difference between the cold, dry environment of an Arctic cyclone in 1920 [320 ppmv CO2] and the almost as cold, almost as dry environment of an Arctic cyclone in 1960 [350 ppmv CO2] was small, but real. However, by 2012 [397 ppmv CO2], an Arctic cyclone was in a much warmer, much wetter environment. GAC-2012 was a different kind of storm. Serreze & Barrett, 2008) describe an intermediate form of Arctic storm in intermediate conditions. To rank Arctic cyclones strictly on the basis of central pressure is like comparing desert dust devils to real tornadoes, and tornadoes to hurricanes. These are three different phenomenon that occur in three different environments. The Arctic "then" is not the Arctic "now". The Arctic now is warmer, wetter, and produces different kinds of atmospheric phenomena. GAC-2012 and PAC-2013 are different from the Arctic cyclones from before 2005, when the Arctic was drier and colder. If you remember, more than a year ago I predicted that in 2013, a large Arctic cyclone would fracture the ice this year. One could not make such predictions about traditional Arctic cyclones. They were too small and localized to cause wide spread ice fracturing and movement. They were fueled by one lobe of the 500 mb jet stream coming across Siberia. Today's, Arctic cyclones suck in latent heat from both the North Atlantic and the Pacific (across Alaska) at the same time. This is a sea change from the kind of storms that Serreze & Barrett,(2008) address. Further, I predict that PAC-2014 will be larger and more stable. GAC/PAC are more closely related to polar vortex and global circulation phenomena than to the traditional Arctic cyclones. In the past, latent heat from the oceans had a more zonal flow at the southern edge of the Arctic. Now, that latent heat from the North Pacific and North Atlantic is transitioning to a more meridional flow into the Arctic. I expect more persistent Arctic cyclones are a part of what is driving increased meridional atmospheric circulation. Ultimately, meridional atmospheric circulation will drive additional meridional ocean circulation. This additional meridional ocean circulation will carry a good deal of heat into the Arctic. Such enhanced ocean circulation is the pathway to a year-round, sea ice free Arctic. I suggest that GAC-2012 and PAC-2013 mark the trail head to a sea ice free Arctic.
Toggle Commented Jun 18, 2013 on On persistent cyclones at Arctic Sea Ice
Less than 1 million km^2 average ice extent for month of Sept. 2013. That is functionally 0 for critters like polar bears, walrus, & seals. Large areas will have dispersed ice that will not register as ice extent, e.g., ice will remain a hazard for shipping. This estimate is based on sustained low pressure in polar region continuing to drive the polar cyclone that pulls latent heat from the south. Thus, ice melt is based on hemispheric heating, rather than on direct local solar heating. The latent heat then condenses on the ice, thereby keeping local atmospheric pressure low, and driving the cyclone. (I do know that wind driven by phase changes in water is not part of the conventional wisdom on weather. See for example; Makarieva, A. M., Gorshkov, V. G., Sheil, D., Nobre, A. D., and Li, B.-L.: Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics, Atmos. Chem. Phys., 13, 1039-1056, doi:10.5194/acp-13-1039-2013, 2013) I suggest that the slow start of the melt season is the result of warm/weak ice spreading out across the surface of the water. That increase in area of ice detected fools PIOMAS into overstating current volume.
My feeling is that the Arctic cyclones that formed a few years ago over intact/competent sea ice are inherently different from the current generation of Arctic cyclones that are occurring over fractured sea ice, and thereby have access to more water vapor. The practical impact is that Arctic cyclones are getting larger, more powerful, and more persistent.
The cyclone is breaking the ice, and then banging the pieces together, forcing spray into the air. The spray wets the ice, so sublimation is not required to move water vapor into the atmosphere. The wet ice has a lower albedo than ice covered with snow or frost. Sublimation occurs in dry conditions, cooling and hardening the ice. I wish this were the case.
A "Polar Vortex" is driven by cold, dry air. This "cyclone" is mostly driven by water vapor. If I am correct, you will always see a leg of "jet stream" at 300 mb over the Arctic, near the top of the cyclone. That is, the segment of jet stream and the cyclone are two aspects of the same circulation, rather than the jet stream blocking surface weather. As long as we have large patches of sea ice surrounded by water vapor, such cyclones are likely to be stable and persistent, with any highs that intrude into the space tending to be transitory. Lack of snow at the perimeter of the circulation helps supply water vapor to drive the circulation. I strongly agree that the negative snow anomaly is part of the system generating the cyclone(s). This summer, I do not see "blocking" so much as "stranding". The jet stream no longer moves and transports weather systems as it did in the past. If the metaphor is a conveyor belt, then with blocking, the conveyor belt is running, but the blocked weather system is not on the conveyor belt. With stranding, the conveyor belt is broke. The foundation for a working jet stream is cold, dry, and competent Arctic Sea Ice. These days that occurs only in the winter. In coming summers, I expect regional geographic features drive regional circulation patterns (and weather) that generates segments of jet stream flows rather than a global jet stream that transports a sequence of weather systems over regional features. My view is very different from a global circulation that generates Rossby waves.
Toggle Commented May 31, 2013 on If this is real... at Arctic Sea Ice
The truth that “sea ice warms our winters”, depends on where one lives. Sea ice does tend to stabilize the NH jet stream circulation that carries heat from the N Atlantic to Britain/Europe, and from the Pacific to the west coast of North America. In the past, this circulation has stabilized the continental weather. Sea ice was a year-round sink for latent heat. It also provided huge thermal inertial. As a year-round sink, sea ice cooled the NH, even as it helped drive the atmospheric circulation that moderated the weather on the continents. While sea ice helped drive circulation patterns that kept the continents warm in winter, sea ice per se, never warmed our winters. Loss of year round Arctic sea ice will result in a more north/south oriented atmospheric circulation which will drive North Atlantic Drift water into the Arctic proper. The combination of these changes in atmospheric and ocean circulation with the changes in the Arctic albedo will result in a much warmer Arctic. The Arctic will become a year-round source of latent heat. This will disrupt the jet stream. This is a sea change. Loss of a stable jet stream means that heat transfer to the interior and heat transport out of the interior of Eurasia and North America will be erratic. This is the so called “cold continent” effect. The best I can estimate is hot summers with winters punctuated by occasional, ferocious snow storms. Slide 31 is the most important slide because reminds us that global warming and sea ice loss was going on before satellite. That means that the feedbacks in slide 34 have been operating for some time. Canada has infrastructure build on permafrost. Collapse of permafrost results in nutrients in near shore waters that alter fisheries' productivity. Mix of forest species changes resulting in changes in timber industry and wild life. The one class of wild life that is certain to flourish over the next 2 decades in Canada is mosquitoes.
The climate is a non-linear feedback system. Ed Deming and others have used industrial control systems to show that non-linear feedback systems do tend to fail catastrophically when they drift or are forced out of control. A good example of such a catastrophic surface is a railroad car filled with liquid phosphorus that derails and ruptures. No statistical model of that car developed while the car sat empty on a rail siding for 6 weeks tells you how that car is going to behave when it is in a train wreck. And, that model from the rail siding does not tell you what other kinds of chemical products in other rail cars of that train are going to be ignited by the burning rail car of phosphorus. And, that statistical model of that car, does not tell you about a bit of corrosion on a train signal wire in the Utah desert. However, it is possible to statistically estimate the corrosion, the train cargo mix, and to take precautions. These are the kind of risk assessments that industry does when a failure rate of 1 in a million is catastrophic. This approach requires a systems view. The question is what is the state of the climate system now, compared to some time in the past when it was known to be in equilibrium? It turns out that we can treat the climate like a legacy industrial system. The last time we know the system was in equilibrium was 1880-1910, but we do not have good data for that period so we use 1930 to 1960. September Arctic sea ice extent is a good proxy for albedo, an important negative feed back loop, so we take the standard deviation of September Arctic sea ice in the period 1930 to 1960 and see how many SDs we are currently above the September Arctic sea ice in the period 1930 to 1960. We take the total ocean heat content as a proxy for the state of the climate and calculate the standard deviation for the period 1930 -1960. Then we check to see how many SD we are currently above the mean for the period 1930-1960. Then, we look at Deming’s rules of thumb for systems in/out of control and we see, that if our climate was a rail car full of phosphorus, it just did a double back gainer into the Motiva oil refinery. Yes, that is a 1-in-a-million event. At Bechtel, we said such things do not happen. Now, I know that such events do happen, and I am able to witness interesting times. The three important charts are: one showing total greenhouse gas content of the atmosphere (units unimportant), a chart of Arctic sea ice with units of standard deviation from a baseline period, and chart of total heat content of the climate system with units of standard deviation from a baseline period. Then, you need a bit of industrial engineering to see what they mean.
Toggle Commented May 20, 2013 on The Four Charts That Really Matter at Arctic Sea Ice
We have a good idea of the distribution of clathrates. We understand the dissociation of clathrates. We have some understanding of ocean dynamics. However, if one puts these 3 concepts together for an engineering estimate of methane release rates, then one is an "alarmist". And, in this usage, "alarmist" is the strongest possible slur. We have theory. We have 15 years of field observations of increasing methane releases from the polar regions. We have satellite data showing increasing atmospheric concentrations of methane. We know that right now, significant amounts of clathrate are near conditions that would induce instability and dissociation. In the next few years, global warming will accelerate massively as we lose the albedo cooling of the Arctic sea ice. At that point, ocean warming will massively increase, and large amounts of clathrate will be exposed to conditions favoring dissociation. These are known knowns. There are unknowns, but the system behavior is very likely to be driven by the knowns. In the next couple of decades we can expect significant clathrate instability and dissociation. To put it crudely, we have already triggered the "Clathrate Bomb". The good news is that it had a 50 year fuse. The bad news is that we triggered it circa 1985 as CO2 concentrations passed 350 ppm, thus we can expect real effects within 2 decades. It is time to take global warming seriously. The public does not take global warming seriously because "Climate Science" did not take global warming seriously. Anybody that leaves carbon feedback out of general circulation models, does not take global warming seriously. Signed, Your Loyal Alarmist PS Storms Issac, Isabel, and Sandy were real effects of global warming. Global warming says there is more heat in the system. Thermodynamics says that more heat in the system affects all weather. The system oscillates, but much of the oscillation is forced by the accumulation of additional heat. The behavior of the highly forced system is different from the behavior of the system near equilibrium. Between drought and flood, we will not be allowed to forget or ignore global warming. Historical precedents no longer apply to our climate system.
Toggle Commented May 15, 2013 on Party like it's 1989 at Arctic Sea Ice
Less than 1 million km^2. The residual ice may not be a continuous ice pack, but I do not know how it will appear the various eyes in the sky. Physically, it will not be zero, but much of the residual may not register as sea ice. Based on expectation of sea ice forming cold pole(s) that drive large scale transport of latent heat into the Arctic. These weather fronts will also provide storm mixing, raising surface salinity and lowering the melt temperature. These winds will also breakup the ice, increasing its surface area, and reducing its detection. Water vapor in the atmosphere will prevent the imported heat from being radiated into space. The surface of all sea ice in July/August will be covered with a film of water, which will decrease its albedo. Also, this summer there will be more low albedo open water. The main point is that with the changes in large scale atmospheric circulation, the entire northern hemisphere will act as a heat collector and heat store to melt Arctic ice. I think the sea surface height anomalies in the Newfoundland sea and the Barents sea over the last year point to a reorganization of North Atlantic ocean circulation that will facilitate transport of heat farther north. I may be a year or 2 ahead of myself here, but all of the statistical measures of system stability that I learned from Ed Deming, say that the system is out of control and will rapidly transition to another state.
Steve, The first thing I do every morning is look at GOES WV, to see what are the circulation patterns. Then I look at http://squall.sfsu.edu/gif/jetstream_norhem_00.gif. Since we do not have good numbers for Arctic systems stability when forced by increased water vapor transport into the Arctic, what I am looking for are 1-in-a-million events. Those can be picked out with a mark-1 eyeball. In 1970, there were still Native Greenlanders that had never seen rain. In 2002, I started tracking rain in Greenland. In the next consecutive 60 months, it rained somewhere on Greenland every month. I take that as a 1-in-a-million event. Now, I see more WV flowing into the Arctic than in 2007. (And 2012! Last year there were a few storms. This year there was an extended parade.) By 1970 standards, the snow in the high Arctic this spring was a 1-in-a-million event. It took a huge amount of latent heat to produce all that snow. In 1970, all that latent heat would have driven weather/atmospheric circulation much farther south.
Toggle Commented Apr 30, 2013 on 2012/2013 Winter Analysis at Arctic Sea Ice
Timothy Chase, Different kinds of systems, behave differently as they are stresses. In the Arctic Ice system, we have a non-linear feedback system that is tethered to physical constants such as the freezing point, of water at different salinities, and the density of air under different conditions. As the heat content of the system trends upwards, suddenly some non-linear feedback loops no long function, and system rapidly transitions to a new state. The rate of system transition from one state of equilibrium to another state of equilibrium may be hugely more rapid than the (previous) trend in heat accumulation. When feedback systems go "out of control", previous trends do not predict future system behavior. The system does not regress to a trend, it progresses to something very different.
Toggle Commented Apr 29, 2013 on 2012/2013 Winter Analysis at Arctic Sea Ice
From my view, the three things that make the start of the 2013 melt different are: the increased areas of higher salinity, increased water vapor flow into the Arctic Basin in March/April, and the anomalous low sea surface heights in South of Greenland and in the Barents Sea. Together, these indicate different atmospheric and oceanic circulation patterns that will result in ice melt patterns that we have not seen before. In retrospect, I consider the early spring ice cracking to be partially a by-product of these ongoing changes in circulation.
Toggle Commented Apr 29, 2013 on 2012/2013 Winter Analysis at Arctic Sea Ice
Randall, In the course of AGW, could this become a normal and stable winter circulation pattern? This would be a mode not considered by Dr. Francis. It seems to me that in the past, the Arctic was better able to absorb the heat and shut the event down, whereas a "SSW" event with a sea ice free Arctic might form a sustained circulation loop of a nature not considered by the models.
Weather is the internal work as the Earth functions as a comes to equilibrium after differential heating. The differential heating is caused by day/night, summer /winter cycles, geothermal, and etc. The laws of thermodynamics apply to the energy flows that are weather. There is no question of causality. All the heat (including global warming) in the Earth's weather systems affects all the weather on Earth. If the weather is weird, then it is because there is more heat in the system than there was in the recent past. We think of snow as cold. However large snow events require large amounts of water vapor - and water vapor is latent heat. When you think of a snow storm as a flow of latent heat, then more snow as a result of global warming is very likely.
To extend A-Team's remark above, PIOMAS also does not consider the fact that the ice is no longer as uniform as it was in the past. Prior to 2000, the ice was subject to very slow circulation and mixing. Now, ice that circulates into some parts of the Arctic simply melts. PIOMAS considers ice fungible. However, today some ice may be partially melted and contain films or pockets of water or air. Thus, while the 2013 and 2012 volumes may be similar, the actual energy required to melt the ice is less in 2013. My evidence for this it the weakness in the ice resulting in this year's cracking events. Yes, there were some wind events, but the take away was not that the wind was so strong, but that the ice was so weak, e.g., the ice was already well on its way to melting. The extent of rapid cracking says there is a lot of ice that is well on its way to melting.
Toggle Commented Apr 7, 2013 on PIOMAS April 2013 at Arctic Sea Ice
Steve, Likely, the area of deep water formation at the north end of the North Atlantic Drift (NAD) moved into the Arctic Basin and the NAD carried heat into the Arctic.
The melting sea ice is indicative of huge energy flows. Just because the sea ice is gone does not mean the energy flows will stop. Rather, the ongoing, very large, energy flows will drive will drive extremely intense weather events. Shipping and oil production will be limited as a result of very frequent, intense weather events.
The sun is up, the albedo is down, and race has started. It is a long race, and a day or two at the start does not matter. Given the fractured nature of the ice, I expect that 2013 will be the biggest sea ice melt event in recorded history.
Toggle Commented Mar 21, 2013 on Max reached (?) at Arctic Sea Ice
However wonderful PIOMAS is, it is a model based on limited data. Error bars are from internal consistency, rather than armies of samplers fanning out across the ice to field check the data. Data quality going into the PIOMAS is marginal - and that is the fault of congress not investing in better remote sensing. We do not have funding for appropriate, real time, field checking of sea ice conditions. The Arctic weather is doing things we have never seen before. I would not pin my hopes on a couple of month's results.
Toggle Commented Mar 13, 2013 on PIOMAS March 2013 at Arctic Sea Ice
"Melt" is a process where the ice absorbs 333.55 kJ/kg and re-arranges it chemical bonds. The energy can come from mechanical processes, radiation, conduction, or latent heat. Right now it is cold and dark, but there is mechanical energy, so that is what ice is absorbing. Every fracture breaks chemical bonds and starts a cascade of changes in bond structure. We have arrived at point where even when the Arctic is cold and dark, there is enough energy around to melt ice. This is the basis for a year-round, ice free Arctic. We will not have year-round, sea ice free Arctic within the next 5 years, but soon.
Toggle Commented Mar 6, 2013 on The cracks of dawn at Arctic Sea Ice
In the old days the ice was colder, stronger. Much of the stress was less than the amount required for fracture. The ice was able to relive stress by cold flow and deformation rather than by fracture. Where fractures did occur they were smaller and films of water in the fractures refroze quickly because the surrounding ice was cold enough to absorb the heat without approaching its melt point. Now the is weak and warm. It breaks rather than flowing.