sokolow

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Everything posted by sokolow

  1. Sure! I believe you -- my only angle is "global how" and "global how much" matter a lot, for land ice, especially given the potential for bizarre precipitation regimes. Conversely, with the potential for strong regional variability its worth caution trying to interpret glacial fluctuations, and also worth caution when (for example, not that we do this itf) taking climate into account in discussing human migration, changes in tool & resource use, &c. I guess I was curious because none of the mainstream stuff I'd been reading made it sound that grim for North Atlantic crew; I had the impression the catch theory- obs- and modelwise wasn't tropical atlantic temps, but lack of a distinct outlet for the proposed Laurentide drainage reorganization. I'd come away with the idea that while the question is still open & intriguing, if researchers could give a plausible account for drainage its not just Broecker himself, but a large body of evidence & consensus that would end up, as per Richard Alley's bluntly titled 2007 paper, coming around to saying "Wally Was Right." As in the meltwater injection framework isn't by any means marginal -- it has a strong evidential & theoretical underpinning with useful explanatory & predictive power.
  2. I guess my comment there is given a YD signal in the Andres core that's not just "broadly contemporaneous" or "synchronous within the limitations of the dating method employed" but indeed a temporally well-resolved regionally representative YD signal with necesary magnitude and diachronic "shape" that is highly synchronous with YD records in the northern hemisphere isn't necessarily a deathblow to a North Atlantic meltwater injection framework -- that doesn't invalidate the causal chain. And AFAIK theirs is one of relatively few such southern hemisphere paleorecords, such that marine records from offshore NZ and Oz are open to alternative explanation and sometimes standing in complex relation to terrestrial records. My impression was that "complex" is the word for southern hemisphere YD temperature signals in terms of chronology, magnitude, shape, and regional coherency -- that's my impression because the NZ glacial complex the Andres team cites has in years since proved to be a giant pain in the butt, datingwise, and it would be nice to have a check to bring back to chronologies of glacial fluctuations in the Southern Alps.
  3. Thanks. I hadn't seen that particular one but FWIW I always wondered if the fixation on Lake Agassiz was some kind of reverse Bretz, where he had a channeled scabland evidencing massive outburst floods, but no source for the water until they reconstructed Missoula -- and with Agassiz here we have a lake but disputed evidence for the location of its outlet(s) and / or breach. So the fixation is building in the antiholistic assumption that a catstrophic, sudden eastward draining of Agassiz is the only mechanism of freshwater injection. Congrats to your friend in advance! I guess I don't know I'd found an arguement for synchroneity of cooling off of moraine radiocarbon and surface exposure dating of valley glacier fluctuations
  4. I guess I had thought that the freshwater melt hypothesis was not only still plausible, but also still retains its status as most likely forcing mechanism for the YD cold event? IDK if there's a good broad field review that summarizes the state of the field (your friend's lit review?)
  5. n/p ... and yeah i didn't catch tornado strength addressed in the paper or in his quotes from the press release. My guess is the author of the science daily splasher took Elsner's spoken / the paper's claim that when deep convection kicks off, its more likely to go severe and took that to mean "tornadoes are more severe"Also I went to go reread the splasher and turns out he's active on Twitter as @hurricanejim, and he's posted a personal copy of both the paper as well as his code for anyone who wants to screw with it. Looks like he's amenable to questions @hurricanejim Interested in our new tornado study? Find it here ... Code for replication is here paper (pdf link top of the pubs list) http://t.co/Y2OAA5DM5L code http://t.co/iPI82a7afP
  6. Most reviewers (and many editors!) for most journals don't get paid. No-one I know has been paid as a referee or a reviewer. Probably we all know but never really say out loud good review is incredibly time consuming specialist work that requires a person to simultaneously carry out the most brutal attacks on someone's work you can think of while simultaneously imagining & suggesting constructive ways those critiques might be answered. How many reviewers can do that, or choose to, or have the time to? Even complying with quality metrics to figure that out in a standardized way would be a giant timesuck pain in the a$$.Too, most papers get two, maybe three referees. The referees are bought into trying to deconstruct what might be an elaborate interdisciplinary and multi-method analysis by several authors who are each deploying his or her expert training in novel ways. A stunning amount of peer review manages to totally miss blatant errors because two sets of eyes working in their spare time (anonymously & apart from their own research) are not sufficient. It wouldn't be possible to have peer review full stop if people actually charged consulting rates that reflected their training; it's almost neccessary that it's mostly volunteer work donated in the name of science & scholarship. The editorial staff of journals and journal services add a lot of value -- but a huge chunk of the value is straightup dealing with vast numbers of document pages, basic quality control, managing the metadata, getting all the text & figures & citations into a common format, and corralling a months long communication & revision process between authors and their reviewers. I know a guy whose sole job it is to fix shoddy figures and graphics submitted by actual big -S scientists leading multimillion dollar labs. Some of which graphics are constructed from improperly used clip art, textbook figures, and GIS results they don't own the rights to. Re: access the practical test IMO is that access is attainable but every man and woman reading threads like the ECS or FSU tornado study who wants to participate has to haul down to the library and ILL / dl the pdf for themselves -- even on a huge forum full of weather nerds, how many people can do that, and how does that change the timeframe for discusison? Unless there's an open discussion copy, or that its been unlocked. Fair use limits the kind of sharing we can do without getting the board (any board) in trouble.
  7. All true & good points -- replied in banter threadhttp://www.americanwx.com/bb/index.php/topic/38652-climate-change-banter/?p=3033670
  8. The upshot of the section on clustering is they look at touchdown locations and conclude, Then comes the wrap-up. The gist of their summary & conclusions can be drawn from the latter half of the abstract, but the following portions bear on their interpretation of results and caveats on those findings, which I gather are gonna be of interest to you all,
  9. First they look at tornadoes per year, and the authors note that mean annual rate is 505 tornadoes per year and the median rate is 474 tornadoes per year. They then observe that even given the inter-annual variation in the annual number of tornadoes, their statistical methods identify no long term trend -- its flat. They go on to plot the number of days with least one tornado, calling those days 'one-tornado days, which varies a lot around a mean of 128/year -- max in 1979, min in 2013. They then say that in contrast to tornadoes per year, Their next move is to say that the ratio of blockbuster days to a one-tornado day stands as the conditional probability of a big day The next subsection of the paper deals with spatial clustering.
  10. They use the SPC archive for all reported tornadoes over the period 1950–2013 with the download link for the files they used as www.spc.noaa.gov/gis/svrgis/zipped/tornado.zip , saying they restrict their analysis to tornadoes rated EF1 and higher per SPC guidance, their description of the data and guidance taken from Verbout & crew (2006) "Evolution of the U.S. tornado database: 1954–2003."
  11. @bob Not really. What there is is a relationship between traditional outlets and prestige b/c a pretty big chunk of the high impact / big name journals & their archives are pay for play. Not too much most individual researchers can do about that because junior scholars have to gun for big name journals (to get hired), tenure track scholars have to gun for big name journals (to stay hired), and senior scholars have to gun for big name journals (to raise the profile of their department & their teams in order to secure funding from the Uni and the granting agency / as well to make sure your 2nd, 3rd, 4th, etc. authors who might be junior or int'l scholars get their contributions in recognized outlets). Like we were explicitly instructed by our mentors to sit on our first papers rather than take the CV hit comes from publishing record made up entirely of "mediocre" journals. Also think about how much of the argumentative structure every paper rests on a lit review & field history which resides in journal archives held behind paywalls. Not only can persons without comprehensive access not read work their taxes paid for, you can't even work through the citation chain for papers that are free. Changing institutions or going private changes access; I was abroad for a while and my overseas affiliation had a different access set which meant I was nagging colleagues to send me articles. Long enough out of the academy and you end up having to pay to access the published versions of your own research. It's terrible. @ORH / everyone if noone else has access I'll do my best to summarize it in enough detail for everyone else to critique it
  12. So here is a neat thing, in terms of land ice. Outside the polar regions studies of glacial ice and cores from icecaps and other bodies often come from fairly high altitudes, in relatively isolated & exposed places that by and large are above the boundary layer and hence have the same qualifiers as 3000m+ met stations like those at Sonnblick and the Jungfraujoch vs. "where people actually live." But there's also ice masses in caves -- "mini cave glaciers" -- some of which display seasonal deposition in their stratigraphy reaching back hundreds or even thousands of years. Image from a team at Ruhr Uni Bochum, layering clearly visible: Like ice caps, these can be cored (if awkwardly and not without difficult access). Image from a microbiology team at Uni Innsbruck. Kern (2013) in his article "Cave ice – the imminent loss of untapped mid-latitude cryospheric palaeoenvironmental archives," points out that cave ice offers two complementary advantages compared against surface alpine ice cores, which are that you get regional spread on account cave ice usually comes from nonglaciated terrain, and also the atmospheric chemistry, inclusion, particulate, and precip records can come from lower altitudes below the boundary layer. However, cave ice studies are a relatively new field. This means that there's still a whole lot of work to be done sorting out how the specifics of deposition alter the chemical profile of cave ice, what kinds of ice flow and floor topography interactions are happening that mess up stratigraphy in nonobvious ways, periods of hiatus consequent to reduced deposition or increased ablation, and how air movement affects conditions for each specific cave -- so for instance Lava Beds Natl' Monument has some potentially long-lived ice masses, but interpreting past wastage in the cores is complicated by having to consider possible circulation changes resulting from passage collapse, or growth of the ice body itself. That's particularly pressing when your models for ice accumulation are founded on various mechanics of cold-air trapping & pooling. Any of you all who've had the joy of doing mine, tunnel, or sewer work can imagine how much fun it would be to reckon that out. And there's other issues: one guy had his study complicated by the fact that in previous decades the locals had gone through and mined the cave glacieret for their iceboxes. Consequently when dating or building a chronology from ice cores, you're really hoping for a straightforward stratigraphy lots of organic detritus to give points for radiocarbon dating, though it doesn't always doesn't give conveniently narrow values. So the team led by Hercman (2010), for their paper "The first dating of cave ice from the Tatra Mountains, Poland and its implication to palaeoclimate reconstructions," ended up relying on moths imprisoned in the ice wall, and then using historical investigations from the 1950s and earlier to constrain their RC dates. So doing, her team argue that the entrapped moths have dates likely in the 17th-18th centuries -- the LIA. Their team also noted a very strong unconformity in the ice layers, and they interpret the erosion boundary as representing melt occurring during the MWP, with older ice below and LIA-age above. Icewall of moth death from their paper: Stoffel and colleagues (2009) worked with Swiss cave ice to assemble a timeline using dendrochronology and RC methods to date tree embedded trunks, branches, etc., presenting their findings in their paper "Evidence of NAO control on subsurface ice accumulation in a 1200 yr old cave-ice sequence, St. Livres ice cave, Switzerland." Their figures for stratigraphic analysis and chronology below the fold. They attempted to correlate periods of ice accumulation in St. Livees against reconstructions of past NAO indices, offering their study as a useful supporting proxy for long-term trends in cold season precip. At any rate, like with small-ice-body / "ice patch" archaeology, cave ice is a relatively new field of paleoclimate research. As plain from the title of the Kern paper, its an archive similarly threatened by loss through melting. Worse, the recent strong negative mass balances are mostly affecting the top meter or so of these ice bodies, meaning that what's getting slagged off are precisely the layers needed for doing calibration against instrumental records. Figure showing cave ice melt in caves with long-term investigation, from the 2013 Kern paper. Note the relative density of the observational record from Europe.
  13. One thing to add to the array of ECS estimates given in the OP that I think is helpful is out of Roe and Baker's 2007 paper ("Why Is Climate Sensitivity So Unpredictable?") and which was reiterated in Roe and Bauman's 2013 paper ("Climate sensitivity: should the climate tail wag the policy dog?") is that the space for ECS between ~1.5-4.5C has been stable, reproduced in repeated studies for decades. So the figure given in the 2007 paper presents the array of estimates in the OP like so: Figure 1: Probability distribution of climate sensitivity to a doubling of atmospheric CO2, from Roe and Baker (2007) Roe and Bauman observe that the big success for climate scientists on this question is hammering down the lower bound & establishing that its "kinda really unlikely" to fall below 1.5C. But they also note that the big ol' tail of high values is intractably persistent in the results. In fact, Roe and Baker (2007) argued that the long tail of improbable-but-plausibly-not-zero values is going to appear as an intrinsic feature of attempts to model ECS. As to that, the Roe and Bauman 2013 paper opens by starightup saying: don't expect that to change because "It will require improbably large reductions in uncertainties about the radiative forcing the planet has experienced—or, equivalently, in our uncertainty about physical feedbacks in the climate system—to substantially remove the skewness" and that even given attempts to constrain that long tail, if you have to bet on it, its going to be "prudent" to assume that estimated space for climate sensitivity "will not change substantially for the foreseeable future." So Roe and Bauman say, well, fine. Change the question around and ask instead: if we were to realize one of these doomsday scenarios how fast, actually, could we cook the planet. That's a question that they argue hangs on how efficiently the oceans can act as a heat sink, i.e., there's going to be a hard geophysical limit to the timescale within which that can manifest. This has implications for research priorities, as in, there is a reason why all of a sudden everyone should care about what the oceans are up to. Roe and Bauman also kicks the can down the road to the policy jerks and economics sorcerers saying in effect, look, climate science has their business together such that the imponderbales about ECS are now less of a problem than the limitations of impact modeling: ... such that, basically, there's no point to arguing over the possibility of 10+C worth of warming: tinkering with ECS is unlikely to help tell us what to do. Instead we need to care about "what might actually happen, irl" to assorted crucial socio-environmental systems at meaningful scales with 3-6C of warming and query whether our toy econ models and the implicit values they incorporate can grasp those outcomes.
  14. Looking for an update could just as we.l unleash a back and forth argument on what the right summary is for what's going on. ¯\_(ツ)_/¯ Try the BAMS yearly state of the climate summary or the monthly summary via the NCDC http://www.ncdc.noaa.gov/bams-state-of-the-climate/ http://www.ncdc.noaa.gov/sotc/ If you care about glaciers & land ice its the WGMS bulletin http://www.wgms.ch/gmbb.html http://glacierchange.wordpress.com/2014/07/19/alpine-glaciers-bams-state-of-the-climate-2013/ With a recent global field state of field survey in: Quaternary Science Reviews Volume 28, Issues 21–22, Pages 2021-2238 (October 2009) Holocene and Latest Pleistocene Alpine Glacier Fluctuations: A Global Perspective http://www.sciencedirect.com/science/journal/02773791/28/21
  15. Moving the OHC banter to the banter zone I guess I'd thought Rossby put that on the table before he died, in advance of IGY 57-58 -- shows up all the time via the two bullet points that get quoted around from "Current Problems in Meteorology"
  16. Photographic evidence of deliberate & systematic tampering with alpine climate monitoring equipment:
  17. Having such a model would be great, because at present men and women hoping to use glaciers as historical- and paleoclimate proxies have to make do with assembling a reconstruction of glacial advance and retreat from (among other things) identifying and dating the classic signs like terminal moraine position, like we saw in the first post on the Matthes map. The previous page also has lots of discussion about methods (including art historical ones!) for reconstucting the position of the glacier front. In short, fluctuations of glacier length is often the easiest (""only"") evidence we can retrieve. That, of course, tells us about changes in glacier length over time. And that's great. But getting from length to climate requires several steps, as we saw up above; the climatic setting frames accumulation and ablation, which we translate into volume changes expressed as mass balance. Mass balance in combination with glacier geometry and climate sensitvity in turn are expressed as length changes. ... with the result being that glaciers are a rich source of information for reconstruction of past climate, with the caveat that glacier length is a filtered, smoothed, and delayed indicator. It takes time for large ice bodies to respond to changes in mass balance, and the delay is set by glacier size, shape, and slope, and can range from a mere decade or so to hundreds of years. Seasonal and yearly mass balance are a more direct measure of the relation between glacier and climate. So ultimately it is possible to use glacier length as a multicentury climate proxy, but at present most methods for doing so have taken a real glacier, such as the Aletsch, ... and reduced it to the most minimal & simple yet robust and useful model. Here you can see a number of different efforts to conceptualize and schematize different types and aspects (size, thickness, shape, slope) of glacial ice. The following figures are from various papers from the 90s forward and are here so we can see how glacier modeling relies on the same ideas about glaciers we learn in school. If you'd like the cites, let me know. Envisioning glaciers with accumulation areas that act as reservoirs and relating that to fluctuations of the terminus -- a clear mirror for conceptualizing instances such as the Careser in the post above. The length of time needed for response and nature of glacier recession depends strongly on slope and size. Glaciers need to be treated by class ranging from steep thin mountain glaciers to thick valley glaciers -- and also by climate setting. Size classes and idealized geometries depicted in plan view: One of the leading scientists in this area is Johannes Oerlemans, who has been working on models for glacier retreat since the 80s, and the figures above come largely from projects he was involved in. A feature of one of his methods is they emulate the clean-cut imagination of a glacier (as given two posts up) retreating dynamically and as a coherent, flowing mass going from one equilibrium state to another via melt at the terminus. In short many simple representations express long-term changes in glacier area & volume as changes in glacier length, for cases where the retreat of the tongue is a relatively limited fraction of the glacier's overall length. From the post above, we might say they describe the case of small rises in ELA as depicted in the figure from Vacco (2010). Overall there's a number of different ways to tackle the problem and researchers (Gerard Roe out of U Washington, say) may argue for one or the other more or less complex approach. The following diagram is taken from a 2014 paper by Peano and crew ("Glacier dynamics in the Western Italian Alps: a minimal model approach") explaining Oerlemans' method as given in his monograph "Minimal glacier models," Wherein width is fixed by an appropriate value and ice thickness is assumed to be constant along the entire glacier length, set to a mean ice thickness H. The variable H is then knocked out of the equation by assuming the perfect plasticity of the glacier, such that H can be filled in from length, slope, and pair of derived constants. ... and this reflects Oerlemans' position that for global studies, where detailed information is lacking, fewer inputs is better: his intent is to be able to derive temperature changes from local precipitation, absolute length, and slope. In 2005 (""Extracting a climate signal from 169 glacier records") and again in 2012 (with first author Paul Leclercq), Oerlemans used an implementation of this model to treat glacier length fluctuations as a proxy to reconstruct climate. The global and Europe-regional reconstructions from the 2012 paper "Global and hemispheric temperature reconstruction from glacier length fluctuations" are given below. Note the discrepancy between the instrumental record and the proxy for Europe. The lengthy (heh) discussion above offers a possible explanation as to why: its not great at capturing situations of rapid change where volume change occurs mainly via downwasting along a large fraction of the glacier surface. In short, the model doesn't capture conditions where thick ice can't melt "back" fast enough for the mass loss from melting "down" to be reflected in retreat of the terminus. (There's also other reasons why such models might get wonky including debris cover, elevation feedback, and shading effects.) The "long term, filtered, and delayed" aspect of length models here returns with a vengeance. Vincent and colleagues (2004) emphasize this in their paper "Ice ablation as evidence of climate change in the Alps over the 20th century," and argue that glacier monitoring should utilize mass balance measurement in order to capture the ongoing rapid fluctuations, which are not well captured by terminus retreat. Meanwhile, the catastrophic disintegration and imminent disappearance of long-term monitered ice bodies such as the Careser means that national and international research groups working in the Alps will need to select new ones with a keen eye towards their potential for longetivity, lest they find themselves monitoring bare rock. Refining glacier models to capture additional aspects of melt behavior is also key to forecasting glacier survival, which Mauri Pelto has argued for the case of the Pacific Northwest.
  18. One example from the previous page came from a team including Luca Carturan of the University of Padova, showing mass balance, areal extent, and comparative photograph of the Careser glacier in the Ortler-Cevedale group as reported in their 2013 paper "Decay of a long-term monitored glacier: the Careser glacier (Ortles-Cevedale, European Alps)." In their paper you can see how you have a glacier moving downvalley, fed by an accumulation basin, In their paper we can see that first the tongue retreats, then the entire accumulation area progressively fragments by thinning. Watch how the elevation craters across the entire glacier area, indicating progressive thinning of the ice body along with the appearance of outcropping areas of rock. So glacier melt includes retreat of the terminus, but thinking of retreat solely in terms of the tongue receding doesn't well at capturing the next stage of glacier thinning -- where the whole ice mass is downwasting rather than backwasting. Glacier recession over prominent topographic obstacles either apart from or in tandem with rapid climate change offers the possibility that large portions of the glacier tongue might become separated from the glacier body. No longer fed by the parent glacier, these separated portions of low- or no-ice flow can stagnate, and become "dead ice." This ice then melts out in place. The following figure is from Vacco (2010) given below. The authors note that if movement of the ELA is small enough, the glacier can retreat across the obstacle in a dynamic way -- as a river of ice. However, if the the ELA rises fast enough, ablation burns off enough ice thickness to disconnect the tongue. Stagnant ice and "dead ice" leave their own characteristic landforms and also specific patterns of sediment deposition. The following figures are from a pair of papers aimed at describing dead-ice melting, let me know if you'd like the cites. Probably the easiest type of dead ice landform to imagine are ice-cored moraines. And the easiest example of separation of the glacier snout being retreat over features like cliffs, as in the Fellaria glacier, whose tongue detached in 2006. It makes, as one WGMS researcher commented, little sense to talk about retreat in length in such a case. The picture is from Flickr and the figure is from a 2012 paper by Diolauti and colleagues, "Evidence of climate change impact upon glaciers’ recession within the Italian Alps." Powerful shifts in topography assist in producing dramatic examples of glacier breakup and dead ice production, but a group of authors with David Vacco as lead published a paper in 2010 ("Numerical modeling of valley glacier stagnation as a paleoclimatic indicator") saying that in fact, it is possible to model glacier behavior in such a way as to distinguish between glacier breakup due to topography as opposed to breakup as a result of massive downwasting consequent to large magnitude, rapid climate change. If such were the case, they argue that researchers could use evidence derived from the characteristic landforms and sediment deposits left by stagnant glacier melt as a paleoclimate indicator for rapid warming. If that were true, it would allow us to recognize instances in past climates where deglaciation is marked less by orderly retreat of a glacier via melt at the terminus and more by downwasting across large portions (or all of) the glacier, thinning, stagnation, disintegration, and collapse. Previously stagnant ice melting was a phenomenon mainly discerned in the breakup of continental ice sheets, while valley glaciers were largely considered to undergo dynamic retreat. The late 20th century has provided several case studies of glacier melt via powerful downwasting. As you can see in the Vacco figure, the authors take Mickelson (1971) as a useful example. Evaluating Vacco and crew's proposition exceeds my training and knowledge, but given the debate in interpreting and synthesizing observations of landforms and sediments in order to determine whether retreat of the ice sheets through (say) Appalachia was marked by stagnant ice deposition, I'm skeptical. However, the Vacco paper is a good pointer to the necessity of having models for deglaciation via rapid loss of thickness.
  19. So upthread Coventry mentioned this: Here's some more on the implications of that which is also an excellent opportunity to post cool maps and diagrams from Matthes' Geologic History of the Yosemite Valley (1930)http://www.nps.gov/history/history/online_books/geology/publications/pp/160/contents.htm Because where this post is going requires a detour through Geology 101 which I promise has a point in the next post. The cool map is spoilered because it is large. PLATE 39.—MAP OF ANCIENT GLACIERS OF THE YOSEMITE REGION. By F. E. Matthes. The map is a good reminder of what alpine glaciers "are" AKA big ol' rivers of ice formed when the summer snow line drops far enough to allow annual accumulation of ice and snow. Get enough of it, it starts to flow downhill and its tongue pushes past the summer snowline. Below the summer snowline, the tongue ablates. So the classic view of the glacier we all got taught as kids (from the Yosemite webpage) depicts a balance between a zone of accumulation above, zone of ablation below: And the relation between the two, roughly speaking, is the mass balance. When accumulation is greater than ablation, the glacier will advance or thicken. When ablation is greater than accumulation, it will thin or retreat. Lots of factors can contribute to either -- some of the glaciers that still persist in say the Pyrenees recieve important contributions from avalanche, while as we know from the Greenland thread, dust and soot can darken glacier surfaces and accelerate ablation. However, mass balance is often reduced to winter precipitation and summer temperatures. Arriving at that cool Matthes map is essentially an exercise in matching various geomorphological evidences to topography to answer: how far down the valley did the glacier reach, and how much of the valley did the glacier fill, at what times, and in what sequences? The Matthes USGS working paper diagrams this: "FIGURE 22.—Longitudinal profiles of Yoesemite and Merced Glaciers in the El Portal (EP) and Wisconsin (W) stages of glaciation. The lake basins on the treads of the glacial stairway are indicated in black. The vertical scale is twice the horizontal." "FIGURE 23.—Section across Tenaya canyon and the Little Yosemite, showing the highest levels reached by the Tenaya and Merced Glaciers during the earlier and later ice stages." For the last few millenia in places like the Sierra or the Alps, much of that hangs on the identification of assorted types of moraine (lateral, medial, terminal, recessional...) Moraines are of course what you get from all the rocks and crap a glacier scours out or carries downstream when the ice melts back. The wiki page says bulldozed, and I think bulldozed is right. One of the most dramatic moraine complexes is Norway's "Trollgarden" aka the troll wall, which is a couple kilometers long (pixs shamelessly snagged from GIS via ut.no and visitnorway.com) So in building its foundation for the reconstruction of the glacial history of Yosemite, the Matthes paper treats an idealized version of this: "FIGURE 17.—Idealized sketch of a glacier leaving successive moraine loops as it melts back. In the Sierra Nevada, where the glaciers carried relatively little rock débris, many of the moraines are of the sharp-crested, clean-cut type here portrayed." "FIGURE 19.—Sketch showing in section lateral moraines such as are situated in tiers one above another on the north side of Little Yosemite Valley. The loose rock grains washed down from them accumulate to form sandy terraces between the crests" This whole long post was in service of saying that this particular view of valley glaciers and the characteristic glacial landscapes they leave is very much a "clean cut" view whereby glacier recession is described by the dynamic, orderly movement of the terminus as the glacier seeks to retreat to a geometry where its zone of accumulation is a certain proportion to its zone of ablation as the summer snow line -- lets just say "equilibrium line altitude" or ELA, rises, leaving features such as terminal and recessional moraines. But like Coventry said -- a lot of glaciers are now wholly below their ELA. What then?
  20. Libraries have been pushing this for a literal generation and there's a boycott movement in the universities. There's been slow movement by the Feds pushing their agencies to implement open access policies. The Association of American Publishers, of course, hates all this and has fashioned custom lawsuits to sue universities for supposed copyright violations in classroom use while whining about how publically owned or subsidized open access journals unfairly exclude commercial enterprises from scientific publishing, in what amounts to a socialistic attack on free enterprise. I will let you imagine what the profit margins for some of those operations are.
  21. While its on my mind from the other thread and because weird glaciers in odd places are neat (click to read about the unwitnessed disappearance of South Africa's glacier) http://blog.environmentalresearchweb.org/2009/12/21/the-most-surprising-glacierize/ -- here's an interesting case of revisions that could potentially result from a possible wx station screwup. I don't see that anything has come of this abstract in terms of papers under considerstion or any changes in the Meteo France data for Port-aux-Français or BEST's handling of its station changes, so maybe the identification of error was in error. Maybe someone who has the BEST raws could look at the metadata. If nothing comes up I'm going to email the authors because I'd love to hear the story and hear what kinds of reinterpretation they think would be needed if they turned out to be right about the temperature time series:
  22. This is pretty awesome: "The origin of Lake Vättern." Keep reading until you get to the rebound description & estimated magnitude! http://sciencythoughts.blogspot.com/2014/07/the-origin-of-lake-vattern.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+SciencyThoughts+%28Sciency+Thoughts%29 ... Out of curiosity speaking of Scandinavia anyone ever been to Lofoten?
  23. Mauri Pelto posted up his summary of the 2013 WGMS tables for the latest BAMS State of the Climate http://bit.ly/1rbVPil tldr: the glaciers are melting. Figure 1: The mean annual balance reported for the 30 reference glaciers to the WGMS. And the cumulative annual balance for the reference glaciers 1980-2012. In other news spent some time at the library could not find the historical reference I was looking for, but digging around in the Yearbooks of the Imperial and Royal Geological Institute 1850-1878 I saw a lot of beautiful watercolors and sketches, and this wonderful map of krakow: y/w!! I love them weird glaciers in odd places, like the glaciers of Nevada.
  24. Presently reading HERBERT MASCHNER AND OWEN K. MASON The Bow and Arrow in: Northern North America in Evolutionary Anthropology 22:133–138 (2013) which takes as its departure point some of the dynamics that go with technology choice for atl-atl & dart v. bow & arrow and what that means depending on what you're trying to get done with your deadly projectiles in environmental & resource context, context of other technologies, etc. Adding it here because of the hunting kit stuff from upthread, and its a great idea for GLOHV crew's snow cams for when winter rolls round. fn.55 Rasmussen K. 1931. The Netsilik Eskimos: social life and spiritual culture. Copenhagen: Gyldendalske Boghandel, Nordisk Forlag.