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Timothy Chase
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Congratulations, Neven, to you and your blog's community of regular commenters. Like many no doubt, I rarely have something to add, but I visit almost daily during the melt season and intermittently throughout the rest of the year. Like a great many, no doubt, I consider this the first resource to turn to if I want to know what is currently going on in the Arctic or wish to check on the latest papers. Here you will find essays that integrate the latest news, seek to explain various trends and phenomena, the latest imagery, charts, links to the official websites with the latest news, and in the comments a diversity of often very well informed views. I am glad to see that the blog is getting the kind of exposure it deserves.
Neven wrote, "I'm a bit conservative. As soon as I'm used to something and it works, I keep using it. When I was younger I would eat spaghetti every evening for three months." I can identify with that some. Between navy and college there was a point that I ate oatmeal three meals a day for two weeks so that I could save enough money to get some books I really wanted. Human Action by Ludwig von Mises and Modern Times by Paul Johnson were among them.
Toggle Commented Jul 24, 2013 on Second storm at Arctic Sea Ice
Sushi, you are probably right. Naming something the "Great Cyclonic [insert name of skeptic here]" is probably a poor idea, especially if the storm suddenly peters out. Wrong effect indeed!
Toggle Commented Jul 23, 2013 on The Naming of Arctic Cyclones at Arctic Sea Ice
Erimaassa wrote, "It's a bit difficult for me to think these events by human names." I personally find Robert's suggestion of naming a low pressure system after the Koch brothers somewhat appealing.
Toggle Commented Jul 23, 2013 on The Naming of Arctic Cyclones at Arctic Sea Ice
Steve, could be. I seem to remember that resolution is also an issue in the Arctic. Temporal resolution was one of the issues that Gavin dealt with regarding the Arctic atmosphere -- longer intervals were sufficient at lower altitudes, but shorter intervals are required to more accurately model the Arctic, and I believe it is Serreze who argues that regional modelling does better with the Arctic involving changes to ocean circulation. In any case, it helps to give references when you quote from papers. Open access, pp. 2-3: Mauritsen, Thorsten, et al. "Tuning the climate of a global model." Journal of Advances in Modeling Earth Systems 4.3 (2012).
Toggle Commented May 6, 2013 on PIOMAS May 2013 at Arctic Sea Ice
"Does anybody know of a modeled reason for an increasing rate of melt for MJJ versus OND" If I could try my hand at this... Climate models are based on physics, and while they can't include all of the different processes that are involved, the interactions or unlimited resolution. They can be expected to at least get at some of the core processes at sufficient resolution to see some of what is going on. In terms of winter, it doesn't really matter how much ice melts during the melting season, so long as the temperature drops below freezing in the Arctic basins, the area that was lost will be iced over. And the Arctic is surrounded by land that has essentially prevented a larger area from freezing in past decades, so until the globe warms enough during the winters that a significant part of the Arctic remains above freezing, you shouldn't see much of a trend there. But with the summers the temperature goes above freezing, and the longer the period of time and the higher the temperature, the more the melt. With greater melt you will see more ice albedo feedback, not simply with sea ice being replaced with darker ocean that absorbs more sunlight, but with partially melted ice being darker than ice that has never melted. Old ice has had the salt and other impurities melted out of it, and has been compacted with each melting season it survived, increasing the albedo and raising the melting temperature. But less of it survives the melt season nowadays. Young ice will tend to have more salt in it, more green algae, and will tend to be thinner, permitting dark ocean to show through. Ice that is weak will more easily be broken up, and broken ice will permit larger waves to form and travel through it, breaking up the ice even more. And with larger waves there should be more mixing with the deeper, warmer, saltier ocean water below. I wouldn't expect all the models to capture each of the processes. But many will capture a number of them, perhaps all of them, and probably a fair number of others that I haven't even thought of. Anyway, my two cents.
Toggle Commented May 5, 2013 on PIOMAS May 2013 at Arctic Sea Ice
Aaron Lewis writes, "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." You are correct that regression to a trend presupposes that over the short-run negative feedbacks dominate, and it is certainly possible that at some point this will no longer apply, e.g., in the case of bifurcation, where the noise of the system is amplified rather than dampened. However, I what I have seen so far among participants have been disagreements over what sort of trendline best fits the data or will best forecast the behavior of the system, whether it should be exponential, for example. But I have not seen people arguing that trendlines per se are no longer applicable. Furthermore, I am not aware of any evidence that suggests that, in the Arctic's current state, trendlines per se have lost their predictive value.
Toggle Commented Apr 29, 2013 on 2012/2013 Winter Analysis at Arctic Sea Ice
Dave Willis wrote,"In theory, a system that is basically stable regresses to the norm after an extreme event..." The way I think of it is that we are in a system that is no longer in quasi-equilibrium, has a trend, and for such a system, the trend takes the place of the norm. The tend is what the system regresses to.
Toggle Commented Apr 29, 2013 on 2012/2013 Winter Analysis at Arctic Sea Ice
Sigh... Correction:Since the bulk of the earth's land is in the Northern Hemisphere, we expect to see the Northern Hemisphere warm more quickly than ocean Southern Hemisphere.
Toggle Commented Oct 6, 2012 on More vids at Arctic Sea Ice
PS I had written:For the most part, the southern hemisphere is warming more slowly than the northern hemisphere. (Please see Tamino's Jan 11, 2008 "Hit You Where You Live" and Jan 17, 2008 "Down Under" available at Back from the Dead: Lost Open Mind Posts.) This is about what we would expect, given the models....Rather than leaving it at that, I should have mentioned that ocean has greater thermal inertia, and therefore warms more slowly than land. Since the bulk of the earth's land is in the Northern Hemisphere, we expect to see the Northern Hemisphere warm more quickly than ocean. This is the physics which is getting captured by the models.
Toggle Commented Oct 6, 2012 on More vids at Arctic Sea Ice
Djprice537 asked:Should we expect the extent to eventually match other years in the past decade in January through March or will we see a shift downward in maximum extent?Bruce Worden wrote:The winter maximum is in a declining trend, just not as dramatic (yet) as the summer minimum....The way I have heard it explained here before is that the Arctic Ocean is largely land-locked, so when the Arctic Ocean freezes, in most directions it can freeze only up to the land's edge. So even though winters warm more rapidly than summer or fall you are not going to see much of a downward trend in winter sea ice extent for a while. A nice contrast with this is the Southern Ocean around Antarctica. For the most part, the southern hemisphere is warming more slowly than the northern hemisphere. (Please see Tamino's Jan 11, 2008 "Hit You Where You Live" and Jan 17, 2008 "Down Under" available at Back from the Dead: Lost Open Mind Posts.) This is about what we would expect, given the models. However, there are very few places where the Southern Ocean is actually cooling, and most are right up by the coast of Antarctica. Nearly all of the Southern Ocean is seeing some warming. (Please see Why is southern sea ice increasing? (intermediate) for a good map of land and ocean surface temperature anomaly trends.) But the Southern Ocean is also seeing a freshening of the surface water due to continental ice melt. The fresh water has a higher melting point than the saltier sea water below, and given its lower density, it is resulting in greater stratification, so that the saltier, warmer sea water below has less of an effect on surface sea ice formation. And even then, most of the Southern Ocean is actually seeing a decline in sea ice. The majority of sea ice growth has been in the more southern Ross Sea, where the East Wind Drift carries much of the fresh water melt from the West Antarctic Peninsula. Thus even though the Southern Ocean isn't land-locked, there has been a small upward trend in sea ice.
Toggle Commented Oct 6, 2012 on More vids at Arctic Sea Ice
Timothy Chase is now following Kevin O'Neill
Oct 1, 2012
Seke Rob wrote: Yes, nothing new, an amazing recovery [like the European Ryder Cup team had last Sunday]... nothing to do with warming of the globe... but all special passing of winds and oceanic oscillation. One just wonders, how there can be 5% more vapor in the air on world average, without global warming, when 7% = 1C temperature rise. Heat-less vapor adding... I'd like to know the trick that nature is playing on physics.The amount of water vapor varies a great deal from place to place and one time to another depending upon the daily temperature, relative humidity, altitude, precipitation. So obviously you are measuring it wrong. Can't expect to do any better with that than with temperature. Poleward migration of the animals? Their confused. Plants blooming earlier in the year? Probably something that the government is spraying. Larson A and B ice shelves in Antarctica? Its my understanding explosives were used. Its all pretty straightforward when you put your mind to it.
FrankD wrote:Just to expand Kris' point slightly, as the dry air descends from the mountain / plateau it also increases in pressure and warms, thus making the relative humidity even lower.So as moist air rises up over the mountain the decrease in temperature, resulting in a rise in relative humidity, as the humidity of saturation against which relative humidity is measured is a near exponential function of temperature. Consequently, the rising air loses moisture through precipitation, much like when maritime air rolls in over the Olympics or Cascades, or as moist equatorial air rises in the tropics as part of the Hadley cell circulation, then subsides in the subtropics, with relative humidity falling with the rise in temperature as the air descends to the surface, giving rise to deserts. And of course in the subtropical deserts the drying out that results reduces moist air convection, raising temperatures near the surface higher, and likewise raising the lapse rate (that is, the rate at which temperature falls with increasing altitude) from the 6.5°C/km average to roughly 9.8°C/km. This becomes more of an issue during heat waves, resulting in positive feedback that makes the heat waves more severe, and will become more of an issue in the United States as the dry subtropics move poleward with the expansion of the Hadley cells under climate change.
Something I wrote up at the British Centre for Science Education that might be relevant in some ways here... A conspiracy of silence
Alan Clark wrote:Collincr, I share your disbelief at what people believe who should know better. A few years ago there was a confrontation between Richard Dawkins and a young-Earth creationist who claimed that evolution contradicts the second law of thermodynamics. He was a professor of thermodynamics! [Wikipedia: Andrew McIntosh]I thought that name sounded familiar. Back in 2006-7 I was with the British Centre for Science Education, and McIntosh was/is one of the Young Earth Creationists trying to push creationism into the British educational system. There is more on him at the BCSE, and if you follow the links, a great deal more on other key individuals and organizations in the UK that are trying to push creationism into the schools. You might think that Great Britain wouldn't have a problem with this sort of thing, but there has been a religious revival of sorts in the past couple decades, and a number of wealthy individuals, including US citizen and dominionist Howard Ahmanson who largely funded the Discovery Institute here in the US, have been funding it. In some ways things are tougher in Britain as it has no tradition of the Separation of State and Church.
Wayne and Kris, For what it is worth, the partial pressure of water vapor increases roughly as an exponential function of temperature, even for below 0°C, increasing roughly ~8% for every 1°C, doubling for every 10°C. At 0°C it is 4.6 mmHg, at 10°C it is 9.2 mmHg, at 20°C it is 17.5 mmHg, at 30°C it is 31.8 mmHg, etc. This would mean that at -40°C it would be roughly 1/64 what it is at 20°C, although if I remember correctly, around -20°C it begins to deviate quite substantially from an exponential function, dropping off at lower temperatures more rapidly than a pure exponential function would suggest.
Chris, I am glad that I have been able to return the favor. I have enjoyed your insights a great deal and those of others over the past few weeks. I also like to think that you can reward people by engaging with them, acknowledging their insights, extending them, and further illuminating a given subject. I only wish that I had more to contribute. But this isn't exactly my area of expertise, which I suppose is part of the reason why it interests me.
NeilT wrote:It may well be (almost certainly), that the standing position will change over time as our knowledge grows. Yet at least our knowledge will grow.Generally, theories cannot be tested in isolation from one-another, but rather, later theories rely upon earlier more well-established theories in terms of the design of the experiments and instruments with which they are tested, such as when we relied upon the theory of electromagnetism in order to test Special Relativity, optics in order to test General Relativity, or rely upon a correspondence principle that requires more advanced theories to arrive at the same results as earlier theories where those earlier theories were applicable. For example, we know that classical mechanics works well at velocities well below that of the speed of light, and therefore Special Relativity had better arrive at the same answers within that domain, and in weak gravitational fields, Newton's gravitational theory works well, therefore Einstein's gravitational theory should arrive at the same results within that domain. Schwarzchild relied on this principle to arrive at the value of a final constant in his solution to Einstein's field equations. (For those who are interested, I would strongly recommend Peter Gabriel Bergmann's "The Theory of Relativity.") Additionally, the justification for a conclusion supported by several independent lines of investigation is generally far greater than that which it receives from any given line of investigation considered in isolation. If the conclusion were supported by only one line of evidence and that support were removed the conclusion would no longer be supported. But if it is supported by multiple lines of evidence and all but one were removed it would still have some support. In this way it is a bit like redundant systems in a spacecraft where so long as some work the mission can still be completed. If each line of argument is fully independent of the rest and each in isolation would provide an equal amount of justification, then the probability that the conclusion is false drops as an exponential function of the number of lines of justification. This is what sometimes gets referred to as the "consilience of arguments" that more often gets discussed in the context of evolutionary biology but which is of course applicable to all empirical science. For example, the basis in physics for explaining the greenhouse effect is essentially the same as that for describing photovoltaic devices, or that which Einstein used to suggest the possibility of lasers. The same principles form the basis for our ability to perform calculations in chemistry and biochemistry at the quantum level. It is how we are able to understand and predict the behavior of tunnel diodes. In fact, the physics behind the greenhouse effect is essentially the same as that which cooks your burrito in the microwave oven. So long as someone can pretend that the reason why we believe adding carbon dioxide to the atmosphere will result in global warming is due to mere correlation they can make the case for anthropogenic global warming appear weak. But when you realize the extent to which it follows from our understanding of physics and that this is the same physics that underlies so much of the technology we rely upon in our everyday lives you realize just how absurd it is to deny that higher concentrations of carbon dioxide will increase the average global temperature. Similarly, if one were to try and argue that something other than an enhanced greenhouse effect is responsible for rising temperatures (e.g., climate cycles of some sort), not only would they have to argue for that other mechanism, but they have to explain what is preventing an enhanced greenhouse effect from raising temperatures given the rising concentrations of carbon dioxide.
Kevin O'Neill wrote:It is undoubtedly true that many modern measurements cannot be observed directly; they require sophisticated instruments that rely upon other theories for their construction and operation, and for the interpretation of their results. Scientists understand this and when hypothesis (models) and observation disagree it has often been found that it is the *observations* that are incorrect - not the hypothesis. So Duhem's main thesis and it's corollary of falsifiability are definitely applicable.Yes, I am speaking of Pierre Duhem's inseparability thesis, his empirical holism, where tests of modern scientific theories almost inevitably require appeal to other scientific theories which must be assumed to be true if the theory in the foreground is to be tested by means of experiment. The only amendment I would make is that we should be concerned with testability, not falsiability, at least in the strictest as Karl Popper conceived of it, as he in essence argued that individual scientific hypotheses (and later amended this to theories) could be tested in isolation from one another. He states:Now in my view there is no such thing as induction. Thus inferences to theories, from singular statements which are 'verified by experience' (whatever that may mean), is logically inadmissible. Theories are, therefore, never empirically verifiable... But I shall certainly admit a system as empirical or scientific only if it is capable of being tested by experience. These considerations suggest that not the verifiability but the falsifiability of a system is to be taken as a criterion of demarcation. In other words: I shall not require of a scientific system that it shall be capable of being singled out, once and for all, in a positive sense; but I shall require that its logical form shall be such that it can be singled out, by means of empirical tests, in a negative sense: it must be possible for an empirical scientific sytem to be refuted by experience. (Popper, "The Logic of Scientific Discovery," 2nd ed., 40-41)The argument I provide argues against that sort of falsiability and in favor of testability by means of an empirical holism that implies epistemic justification as a matter of degree.
Kevin O'Neill wrote:On many denier sites its not uncommon (and quite irritating) that many don't even realize the 'data' they're using (often to criticize models) is itself the output of a model. Weather forecast? Model output. DMI temps? Model output. Satellite temps? Model output. Sea ice extent? Model output. Sea ice area? Model output. Sea ice volume? Model output. Every model is both an hypothesis and a tool. Each makes assumptions, has limitations, and carries an associated uncertainty.Sounds a lot like 19th century philosophy of science to me. I am thinking along the lines of the essay "Quelques reflexions au sujet des theories physiques" by Pierre Duhem circa 1892, published in the book "La Theorie physique: son objet et sa structure" in 1906, translated into English as "The Aim and Structure of Physical Theory" in 1954. I approve.
Ned Ward wrote:I think the reference to "Antarctic ice increasing" is probably referring to the work of Zwally et al. using ICESat to estimate mass balance of land ice in Antarctica.I found the abstract: If true this would be due to increased precipitation in the form of snow resulting for a time in the accumulation of mass rather than mass loss, something that was actually predicted by some of the models. Ned Ward wrote:Of course Watts, Goddard, etc. have all seized on this as "GRACE is wrong"...Gee, something that hasn't yet passed peer review simply must be given more weight... Ned Ward wrote:... but it will be interesting to see how it plays out.I wish the politics didn't even enter into the equation. Regardless of how this particular issue is resolved, both ICESat and GRACE offer perspectives that have their limitations and value. Reality, and the curiosity that is our fundamental motive for its discovery, should always come first. The fundamental error of creationists and other ideologues consists of losing sight of this.
Chris Reynolds wrote:I wish [the deniers would] just shut up. And, having just spent half an hour looking for information on a certain topic - I wish they'd stop polluting Google with their poorly considered blather.You could narrow your search a bit. I put together a couple of tools. The first is a search engine for over a hundred websites (I am counting all Nasa, Noaa, Nsidc only once) and blogs, with eleven narrower, more specialized searches. The second is a search tool, a browser extension, although currently it is only for Google Chrome. It gives you immediate, right-click access to the internal search engines of a fair number of websites, access to the specialized searches of the search engine I linked to above as well as Google Scholar and some other useful tools. Plus you can expand it to include other search engines and web tools. I have TinyURL, Wayback Archive, Web Cite, and Whois domain tool. Here is a little demo video. I like to think of it as an extensible swiss army knife, but I call it CG Detective.
CORRECTION Second paragraph, first sentence should have been:But if she meant Greenland's ice sheet and the Antarctic's sea ice, then given the melt from Antarctica's ice sheet you have the freshening the surface waters, raising the melting temperature.
Djprice537, I understood as much, and as you did, it is a good idea to keep responses short. But I was "helping out" the troll, providing the missing literature on the ice sheets. She was thinking ice sheets, wasn't she? Bringing up Greenland... But if she meant Greenland's ice sheet and the Antarctic's sea ice, then given the melt from Antarctica's ice sheet freshening the surface waters, raising the melting temperature. And you have the freshening of surface water leading to greater ocean stratification as salt water is denser. This isolates the surface from the warmer waters below. Both of which help to explain why there has been comparatively small expansion of sea ice around Antarctica, although there are other aspects. Since most of the melt is from the West Antarctic Peninsula, given the East Wind Drift, much of it drifts towards the Ross Sea. As such, it is no surprise that sea ice has expanded in that region. But in most other places the trend is down.