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Jeff Id at 03:16 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
#34, First, we're discussing the recovery since 07. Your first graphs show the drop to 09 from 1980-2000 mean so it's not evidence. In the last graph you show the 07 minimum seems to be reflected in 08. Probably due to some filtering or something. We know very well that 07's minimum was not a typical year right? Your grpah shows very little drop from 06. You can see the slight recovery in 09 in your graph, and in the video, perhaps this is 08 because 09 minimum was better. Enough so that some NSIDC guys are even admitting it. As to the warming argument, the net energy transfer from a slightly warmer yet mostly well below freezing environment is small in comparison to even a very slight flow change of water. Stir a glass of ice cubes and you can see the effect. The melting arctic ice situation is far more related to currents than the small warming in my opinion. -
Jeff Freymueller at 03:00 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
#28 Jeff Id, cool video. Worth the 2 days of processor time! As far as the temperature trends on the continent go, you are basically handwaving here. All data have noise. Why would the data noise cause a particular pattern of (slight) positive and negative temperature trends? Why do you think that the makers of this figure did not understand the level of noise in the data and compute adequate error bars? Why, other than your opinion that the pattern seems unlikely, should we think that the pattern is not actually correct if it is larger than the uncertainties? I'd also add that in terms of where impacts of warming are observed in Antartica, the figure seems about right -- only small changes over most of the continent, but significant changes on the Antarctic Peninsula. I'm not sure what other claims some people are making, but your figures seem to be pretty consistent with Figure 2, and this pattern of temperature change seems quite consistent with the observed impacts. I'm curious why you would refer to the loss of the ice shelves as "contamination". There are two questions here: (1) is the measurement of delta-T over time accurate? (2) is a linear trend an adequate representation of the changes? As far as the ice shelves go, they certainly call into question the use of a linear model with time (2), but unless spatial smoothing is applied they will not "contaminate" anything. Suppose that the same figure with the same colors simply had the numbers next to the color bar multiplied by 26 y, and the title changed to Change in Temperature, 1981-2007? Given that most of the ice shelves were labeled, it seems pretty clear to me that the labeling was applied so that people would not misinterpret the changes as some kind of oceanic "hot spot". -
CO2 levels during the late Ordovician
Sorry, the ~33 degrees C is an average over the day. Looking at lunar surface temps (higher than the Earths would be, as the moon has a lower albedo), night temperatures without the atmosphere would be about -153 C. Wear warm socks... -
CO2 levels during the late Ordovician
RSVP - if you read the entire graphic, the surface exchanges are +168 insolation, +324 back radiation (reflected to the surface), total of 492 w/m^2. The outgoing is 24 convection, 78 transpiration, 390 IR, total of 492 w/m^2. 492 = 492, dividing by 492 leaves 1=1; the equations are balanced. As to nightfall, I believe this is a daily average, adjusting for Earth surface area and angle of solar incidence. Regarding atmospheric temperature; part of the atmospheric temperature is due to direct insolation (67 in this diagram), and a larger part is due to ground IR (390-40-324=26 absorbed), convection (24), and evaporative heat transfer (78). Meanwhile that 324 w/m^2 reflected by the atmosphere - it is reflected to the ground, warming it, increasing ground temperatures and then indirectly warming the atmosphere through the aforementioned pathways. GH gasses act as insulation. They slow heat loss from the Earth; more insulation/lower loss causes an accumulation of more solar energy, leading to a warmer Earth, radiating more energy at the surface. That balances out the steady state condition at 1=1, solar input to radiative output. If the back radiation went from 324 to (say) 325 w/m^2 due to higher CO2 (atmospheric outgoing changing from 235 to 234), the extra 1 w/m^2 energy imbalance will heat the surface until thermals/evaporation/radiation increased to match it. I think that's pretty straightforward. As to that warm glow - I think the estimate is we're ~33 degrees Centigrade warmer than we would be without GHG heating. That would be a noticeably colder night... -
RSVP at 02:06 AM on 17 March 2010CO2 levels during the late Ordovician
KR And there does seem to be something strange about the lovely graphic. 1) 342 incoming, somehow becomes 390 outgoing. That doesnt even makes sense at noon. But if you were considering a 24 hr average, it makes even less sense. 2) The graphic shows 342 incoming. Nice Sun shine, I can relate. But then it shows 324 back radiation. That isnt far from 342. I should be feeling a nice warm glow as I step outside at night, but this is not my experience. Out till which hour in the evening does this last? Thanks in advance. -
Peter Hogarth at 02:04 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Ken Lambert at 01:39 AM on 17 March, 2010 I fear energy and temperature are being a bit confused. Ponder that word "Latent". Melt/freeze Phase change involves energy, certainly, but no temperature change. Agree though that latent heat plays a role in all this. -
CBDunkerson at 01:52 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Jeff, do you have a source for your claim that multi-year ice has recovered since 2007? It contradicts every study I've seen on the matter. For instance;
As to your view that warming had nothing to do with thick multi-year ice breaking up and being exported out of the Arctic... I suppose we'll just have to agree to live on different planets.
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RSVP at 01:45 AM on 17 March 2010CO2 levels during the late Ordovician
KR 1+1-1=1. Do you agree? If so, we agree on something important. Next step. Heat (1) that would otherwise radiate into space is impeded (so you say) by the CO2 (i.e., never leaves, or is returned which is equivalent). Now, this either elevates the surface temperature, or it elevates the atmosphere's temperature. Which is it? It cant be both. If you don't agree, please let me know how this unit of energy heats both atmosphere and surface simultaneously. Thanks in advance. -
Ken Lambert at 01:39 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Berényi Péter makes some good comments. Think about the mechanism of ice formation and the heat balances involved. Phase change in frezing ice on water involves liberating the latent heat which is 80 times the amount to change the temperature of liquid water by 1 degC. Applying cold air at sub-zero temperatures to the sea surface liberates the latent heat as the water freezes. Heat has to go somewhere - it slightly warms the air. More ice = warmer air immediately surrounding the water-ice phase change. -
Berényi Péter at 01:08 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Global Sea Ice (kudos to the Air Vent) Notice ice dynamics around Antarctica. -
On the reliability of the U.S. Surface Temperature Record
Love that (US) data! Not an answer to Tamino but in the same ball park -
Jeff Id at 01:04 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
#29, I don't agree. The warm water from the south would have made no difference with a half degree C either way. The thickness argument is also false in my opinion. The thicker ice just got pushed out. The weather pattern change in 2007 is very much visible in the video linked in my last comment and there has been a recovery in multi-year ice since the 2007 minimum. -
Peter Hogarth at 01:02 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Jeff Id at 00:03 AM on 17 March, 2010 Nice animations! Winds causing anonalous 2007 minimum: the same scientists might also add that this may not have have been possible if the ice was not significantly thinner. You have done enough work on Arctic ice extent to appreciate that the 2007 values and subsequent "recovery" are against a significant multi-decadal background trend of reducing ice extent and thickness (as well as a significant regional warming trend over the same period). -
CO2 levels during the late Ordovician
RSVP - I actually consider the CO2 reflection of IR back to the ground _considerably_ more important than mass heating of the atmosphere. Very little of that IR goes into molecular heating of gases; CO2 is an efficient radiator. It does, however, reduce radiation losses from the ground, and change the steady state temperature conditions of the surface - in order for the steady state thermal conditions to stabilize with a lower percentage IR loss to space, the ground warms up and emits more IR. Hence global warming. More of the atmospheric heating comes from convection/conduction and evaporative heat transfer than from direct IR. And increasing GH gasses directly reduce the percentage of IR loss. See this lovely graphic, which appeared in the course of the "Is CO2 a pollutant" discussion: http://www.windows.ucar.edu/earth/Atmosphere/images/earth_rad_budget_kiehl_trenberth_1997_big.gif This shows an excellent overview of the steady state thermal condition. It's not the heat capacity of the atmosphere at all, but the rate of energy flow in and out of the ground/atmosphere system. Even with a _zero_ heat capacity of the ground and water (for a thought experiment), the greenhouse gas energy flow rates would set the steady state condition - the heat capacities act as inertial buffers on the steady state condition and on dynamic events (clouds, storms, El Nina, insolation, etc.) -
CBDunkerson at 00:39 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Jeff, your argument that sea ice changes in the Arctic are due to currents rather than warming is a false dichotomy... they are clearly due to currents AND warming. Without warming the ice does not break up as much and thus forms greater bottlenecks at the 'drain' points. Further, the marked decline in Arctic sea ice volume and thickness (which has continued since 2007) indicates that ice growth is not keeping pace with ice loss... a situation which only the measured warming explains as there has been no marked ongoing change in Arctic currents. -
Jeff Id at 00:03 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
#23 That's an interesting observation about the ice shelf. There is indeed sea contamination of edge pixels in the data. Maybe you're right. Yes I was referring to Fig 2 here. There is a red loop all around the continent. This is caused for reasons other than a smooth continuous temp trend. Once you look at the data you realize that it is extremely noisy, not just a little and that's why there is a need for other methods. As far as sea ice, the continental trend was part of your point above. My understanding of the region is that there isn't nearly as much warming as some say when simply looking at actual surface temp data. What you have is basically a stable (slightly rising) temp over 50 years with some trend in the peninsula region. http://noconsensus.wordpress.com/2009/08/31/area-weighted-antarctic-offset-reconstructions/ I do agree that this isn't what determines sea ice from year to year. Tenths of a degree don't matter much. The same is true for the Arctic, the loss of sea ice was due to currents. There is a video at this post which is interesting. You should ignore the significance calcs. in the post as they aren't of good quality. -- too much autocorrelation. http://noconsensus.wordpress.com/2009/12/09/sea-ice-copenhagen-update/ The plots were made by summation of the NSIDC data. In the video, you can see the ice flowing, rotating around the Antarctic and pushing along landmasses in the Arctic. Some cloud cover is visible in the data and it shows that the low in 2007 was created by high speed winds pushing ice out of the drain. This explains the rapid recovery we've seen in the Arctic and makes the claims of sea ice loss by global warming far less likely. Most scientists I've read or discussed with, seem to agree with this being the mechanism for ice level change. #25, even your point 2 is about two times higher than the actual surface data shows. It's the same trend that Steig et al came up with. We're not alone with the lower trends BTW, several older papers (basically pre AGW hype) had the same trends as shown in the first link in this comment. -
Peter Hogarth at 00:00 AM on 17 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Jeff Id at 10:36 AM on 16 March, 2010 Jeff is referring to the significant amount of detailed analysis done on Antarctic weather station and satellite derived temperature trends by Ryan O et al which has been trumpeted as “falsifying” Steig 2009 on WUWT and elsewhere. Ryan O adds “I should have said that all reconstructions yield a positive trend, though in most cases the trend for the continent is not statistically significant”. I perhaps oversimplify, but Ryan is claiming that the temperature rise averaged over the whole of Antarctica is about half of the overall temperature rise Steig published. A measured response from Steig, and discussion is to be found on RealClimate. At the end of the day I will direct people at published papers, data, and results. if Jeff or Ryan do publish, and after independent review the science does move forwards, then great, I’ll point to this as “more recent work” etc, (at least until the next results or updates are published…) Now, back to the Antarctic Ocean and sea ice... -
Arkadiusz Semczyszak at 22:56 PM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
"The out-flowing undersea of cold and salty water makes the sea level of the Atlantic slightly lower than the Pacific and salinity or halinity of water at the Atlantic higher than the Pacific. This generates a large but slow flow of warmer and fresher upper ocean water from the tropical Pacific to the Indian Ocean through the Indonesian Archipelago to replace the cold and salty Antarctic Bottom Water. This is also known as Haline forcing (net high latitude freshwater gain and low latitude evaporation)." (Wikipedia). -
Arkadiusz Semczyszak at 22:02 PM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
1. As a result of weakening of the THC on SH (= strengthening of NH), warm air does not reach as far south as before. Reflects their energy earlier. Hence the current warming of the southern ocean. Warms, however, only one of its zone. On N and S from it we have a cooling. This is typical of Bond's event. For a better understanding I recommend to work: "Quaternary glacial and climate history of Antarctica" Ó. Ingólfsson, 2004. Steve Goddard - he is absolutely right, that the anger. 2. "The new analysis shows that Antarctic surface temperatures increased by an average of 0.22°F (0.12°C) per decade between 1957 and 2006." - "ScienceDaily (May 8, 2008) — Computer analyses of global climate have consistently overstated warming in Antarctica, concludes new research by scientists at the National Center for Atmospheric Research (NCAR) and Ohio State University.", "While the observed Antarctic temperatures rose by about 0.4 degrees Fahrenheit (0.2 degrees Celsius) over the past century, the climate models simulated increases in Antarctic temperatures during the same period of 1.4 degrees F (0.75 degrees C). The error appeared to be caused by models overestimating the AMOUNT OF WATER VAPOR in the Antarctic atmosphere, the new study concludes. The reason may have to do with the cold Antarctic atmosphere handling moisture differently than the atmosphere over warmer regions." - http://www.sciencedaily.com/images/2008/05/080507132855-large.jpg - "This map of Antarctica shows the approximate boundaries of areas that have warmed or cooled over the PAST 35 YEARS. The map is based on temperatures in a recently-constructed data set by NCAR scientist Andrew Monaghan and colleagues." -
James Wight at 20:33 PM on 16 March 2010Scientists retracted claim that sea levels are rising
Yet another example of contrarians twisting scientific results to get the opposite conclusion. By the way, shouldn't this argument be categorised under "Sea level predictions are exaggerated"?Response: Good point, have moved this to the more appropriate category. Thanks for the suggestion. -
Riccardo at 19:41 PM on 16 March 2010Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
shawnhet, climate models are a description of how the climate works. You plug in the physics and chemistry of the atmosphere, land and oceans, and let them describe how they evolve. They can be (and actually are) used for other planets as well, or to describe the climate milions of years ago or to predict the impact of eventually known or assumed natural forcings. No AGW here. The anthropogenic climate change theory, instead, tells us that current human emission patterns will result in a significant impact on our climate. It can be tested in many different ways and climate models are a usefull tool, but the theory is not a priori included. In your example a PDO driven climate change is the theory that need to be tested. To test it you could do several things including modelling it. You should work out the physics of the PDO and its interactions with the other pieces of the picture and see the results. Again, your model would be a tool not the theory itself. -
James Wight at 19:18 PM on 16 March 2010There is no consensus
I've got yet another statement by a scientific organisation that you might like to add to your list. Recently in Australia, the CSIRO and the Australian Bureau of Meteorology released a joint statement on climate change .Response: Thanks for pointing this out. I actually read the CSIRO/BoM report earlier this week (an excellent read, particularly for Australians) but it never occured to me until reading your comment to add this to the list of scientific organisations endorsing the consensus. A case of failing to see the forest for the trees. -
RSVP at 16:48 PM on 16 March 2010CO2 levels during the late Ordovician
KR and CBDunkerson I am quite aware of this idea that each little CO2 molecule acts as an isotropic IR radiator, creating a situation not unlike how bumpers and flippers in a pinball machine delay the ball on its path downward, however, you cant get something for nothing, and the only extra energy that will hang around, will be that associated with an increase in the net heat capacity of the atmosphere, which is a direct function of the mass and heat capacity of the extra gas in question. So I am acknowledging that anthropogenic CO2 should affect an increase in temperature of the atmosphere, however, it can't do this any more than what is associated with its inherent heat capacity, and as I said above, 100 ppm doesnt seem like much to me. And as such, I think this is different from acknowledging AGW, which basically attributes glaciers receding and notable worldwide average temperature increases to the extra CO2. -
yocta at 16:29 PM on 16 March 2010There is no consensus
Oracle2world, what Riccardo stated in his post is essentially correct. Science is not Occam's Razor or parsimony or whatever you want to call it. People may use such approaches in the method of discovery but the model has to explain the evidence. Watch this video, and see what consensus in science actually means. Note to John: Perhaps you could link directly to Naomi Oreskes talk here or when talking about her survey here Of course I would obviously recommend you screen the talk and its suitability yourself first :PResponse: Thanks for the suggestion - I've added Naomi Oreskes' latest talk to What does Naomi Oreskes' study on consensus show? -
shawnhet at 15:50 PM on 16 March 2010Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
Riccardo: This is a quite common misunderstanding of the meaning of model. They are "just" a mathematical expression of more or less complicated physical laws, the theory is the big picture. Think about Arrhenius, his theory is the same we debating today but the model calculations are enormously different. No, the GCMs are, in fact, the hypotheses. They make different(hopefully more) predictions than Arrhenius did. I am not sure how long Arrhenius thought it would take the climate system to equilibrate to an addition of CO2, but I very much doubt that it was as long as is proposed under the current theory. This is not that different than, for instance, Newton and Einstein's theories of gravities. In terms of the big picture(ie the vast majority of circumstances), their predictions are essentially, however, for some phenomena the predictions are different. Hence, different predictions mean different hypotheses. "It really surprises me that you "don't care what they describe". How do you test a model if not with as many as possible actual data and, eventually, new and still unrecognized effects? The future is uncertain by definition, especially when it will be at least in part decided by human actions and unpredictable natural forces. If, say, the sun decides to slow down for some decades, will it disprove the ability of GCM? No, of course, you'll plug in the new data and run them again, but it's not a prediction. Indeed, climatologists do not the word "predictions", the say "projections"" We may be using the word "describe" differently here, so I'll be a bit more clear. Let's assume arguendo that it is possible both to describe 1.the current climate as either the result of the forcing, strong feedbacks, and weak natural variation or 2. as the result of forcing, weak feedback and strong natural variation. If we assume, 1 and 2 are both equally good descriptions of the climate, then what? How do we know which one is valid? The answer is, we try to find distinct predictions of 1 & 2 to falsify one or both. We don't say that because we can describe the climate in one or the other terms that we have answered the question. ""I can do just about as good a job as the GCMs by assuming a zero feedback model with a strong influence from the PDO." You sure could do it, but do you have any solid physical basis for it or you're just playing with numbers? As we all know, a correlation is just a hypothesis , then comes the physics. A model works differently, you plugin the physics and see the outcome. This is exactly why we CAN scientifically say that X is better than Y, just a correlation would not suffice." But you can't just plug in the numbers, you first have to build the framework (I would say hypothesis) that you plug the numbers into. As to the relationship between correlation and mechanism, mechanisms are great, but they are not necessary to perform science. I do not need to know how the PDO influences climate to predict that, for example, each unit on the PDO index raises/lowers the global temperature by X deg. C. The very complexity that requires the construction of climate computer models makes the simple physics, obviously makes the kind of mechanism you ask for nearly impossible too. The fact that climate is complex, however, doesn't preclude there from being detectable relationships between small parts of the system(like the PDO index) and the whole. Cheers, :) -
Tom Dayton at 15:21 PM on 16 March 2010CO2 levels during the late Ordovician
For any readers of gallopingcamel's latest objection that CO2 does not correlate well with temperature, you should read CO2 is not the only driver of climate. I've given up on gallopingcamel him/herself. -
Jeff Freymueller at 15:11 PM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
And, again, the focus of this posting is on sea ice and sea surface temperature. So while I am interested in hearing more about the questions of the previous comment, they are relevant to questions about sea ice only if the actual sea surface temperature measurements here are in error. For that question, the changes on the continent don't really matter. -
Jeff Freymueller at 15:08 PM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
#22 Jeff Id: "In Fig 2, you can see the red band encircling the entire continent with a blue center." Sorry, but I don't see this. Are you referring to Figure 2 of this posting, or of some paper? In Figure 2 of the posting, the brightest red spots are indeed at the edge of the continent, but labeled "former site of Larsen B ice shelf" and so on. The "trend" here is presumably due to the loss of the ice shelf revealing the unfrozen ocean beneath. Admittedly, this is probably a step function change in time rather than a trend, but the result hardly seems unreasonable. The blue vs. red patterns I see on the continent bears some resemblance to high vs. low elevation at least for East Antarctica, although that is just eyeballing. Most of West Antartica is red, so there is no simple relationship between trend on the figure and distance from the coast, pole, or anything else. The "ring" you suggest is quite distorted -- why are you convinced that this particular shape is a clear symptom of the "noise problem"? If you are really talking about some other figure, can you post that one? As for removing the error, it is certainly true that sometimes you can put bounds on the errors but not remove them. Can you be more specific about what bounds you estimate on errors in trend here? -
hank at 14:11 PM on 16 March 2010Watts Up With That's ignorance regarding Antarctic sea ice
Oh, and someone noted the Comiso book chapter isn't "peer reviewed" -- but if you read it, it's a compilation about the whole range of work and methods and statistical approaches, citing peer reviewed papers for each statement. Just one example, where it points out that the models are consistent with the observations: "The trends are all negative in the northern hemisphere and all slightly positive in the Southern Hemisphere, as has been reported previously [Parkinson et al., 1999; Zwally et al., 2002], but with slightly different values. This phenomenon suggests that the climates of the two hemispheres are not closely coupled. The results, however, are consistent with predictions from some Global Circulation Models [Manabe et al., 1992]..." -
hank at 13:49 PM on 16 March 2010Watts Up With That's ignorance regarding Antarctic sea ice
> Comiso It says (updated from Comiso, 2003) in the text. -
gallopingcamel at 13:17 PM on 16 March 2010CO2 levels during the late Ordovician
John Cook says "CO2 is a strong driver of climate". This claim fails at all time scales. If this were true it would be easy to show correlation between CO2 concentration and global temperature. Modern times. There is good correlation between the variables from 1850 to 1998. Looking back from 1850 the correlation breaks down unless you re-write history by denying the Medieval and Roman Warm Periods. Looking forward, the variables have diverged over the last 12 years. Last 700,000 years. CO2 and temperature proxies correlate very well through several glaciations. However, CO2 frequently lags temperature by ~600 years. While correlation does not imply causation, it would be more plausible to suggest that temperature drives CO2 concentration than the opposite. Last 600 million years. See (#39) on this thread. Starting late in the Ordovician, Scotese et al. say there was a sharp drop in temperature followed by a rise. Hot, cold and then back to hot. Royer uses Berner's CO2 reconstruction which show fluctuations that are too small to account for these changes unless you torture the data by taking liberties with the large error bars. -
Jeff Id at 11:45 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
So many questions. Lessee. We quantified it from a dataset released by Comiso and the NSIDC. I've not worked with ALL other peoples data. However the errors in trend are actually visible in your figures. In Fig 2, you can see the red band encircling the entire continent with a blue center. There is considerably more variance in the center vs the edges which you would expect from ocean dampening, however expecting a long term trend difference in a ring shape is a different story. Certainly, you can claim it's reasonable as some have, but in reality it's just a symptom of the noise problem. The center of the continent varies many times greater and because of the difficulties that creates, it has substantially more trend error. It turns out that in the case of the Comiso dataset when the AVHRR data was compared to the surface stations at the same points, statistically significant differences were discovered. Steig would not be surprised by this, nor would Comiso. The error cannot be removed easily because the satellites have considerably more spatial information than a hundred individual temp stations with intermittent readings. On a daily spatial basis, it's easy to imagine that cloud contamination would create problems on a variable basis. One could simply correct the average slope, but that just makes it into surface information so that doesn't make sense. I've not investigated the difference between buoy data but again, it's not as simple as an average trend check. -
Doug Bostrom at 11:28 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Jeff Id at 11:08 AM on 16 March, 2010 If you can identify an error, quantify it, why can it not be removed? If you cannot quantify the error, by what means do you assess the amount of error and for that matter how do you ascribe the error at all? Why does scattering of the AVHRR temperature error record against buoy data not show an error trend and not show an overall bias? Finally, where is data showing an overall trend upward in this purported uncorrected error? Many more people than Comiso have worked on cloud correction, successfully as it turns out. -
Berényi Péter at 11:24 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Antarctica is a curious heat engine. There is about a 100 W m-2 deficit in average annual insolation relative to outgoing longwave radiation to space. The difference is supplied by dry air sucked in from milder latitudes 500-1000 m above the ice sheet surface. Ice is highly reflective in the short wave portion of em spectrum, but it is pitch black in thermal IR, so emissivity is high. Radiative surface cooling is very strong, especially because of low atmospheric water vapor. Air close to surface gets cold and heavy, starts to roll downhill, more air is sucked in from above. Even the low moisture contents of air is deposited on surface as floating ice needles and hoarfrost. As air gets to ever lower levels, its pressure increases. Normal reaction would be adiabatic warming, but contact with surface keeps cooling it. Due to high elevation of Antarctica, gravitational pull on dense cold air accelerates it, at shores this katabatic wind reaches gale force. Blows sea ice north, coastal polynyas open up. Sea surface cooled by strong cold winds, excess sea ice production, deep water formation facilitated by salt rejection in sea ice. Works in high gear during winter. Significant fall sea ice area increase in last four decades indicates this heat sink getting more efficient. Wind speed and pressure trends would tell more than temperature alone. -
Jeff Id at 11:08 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
#18, I've recently been part of a group that submitted for publication on the subject, the raw instrument is quite accurate as you correctly assert. Where you go wrong is in misunderstanding that the readings are contaminated by cloud data. Comiso has spent years trying to correct for clouds. If you're really interested, half of my blog work was on the topic. If the data were good for trend the surface/sat data combining methods would not be required. The total length of the data is biased warm but it's caused by noise, there are subsections which were biased cold. AVHRR consists of several satellites, with different instruments that drifted in different directions over time, there were statistically measurable steps and trends between sat and surface at several points. -
Doug Bostrom at 10:38 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Jeff Id at 07:44 AM on 16 March, 2010 To say "the AVHRR data is biased warm" is a rather gross oversimplification, isn't it Jeff? Any readers wondering why or how or especially if yet another instrumentation record should prove faulty should be sure to use Google scholar to get the full story on Jeff's assertion. The raw accuracy of the data product is excellent. See: Validation of AVHRR and MODIS ice surface temperature products using in situ radiometers Meanwhile, the scatter of AVHRR derived temperature data against drifting buoy measurements has remained constant or even decreased slightly over the past two decades, is now in the range of 0.5 degree C, meaning that even if this data proved to have a warm bias that bias is not for some mysterious reason increasing. In turn this implies that temperature trends can in fact be extracted with reasonable confidence from AVHRR results. "AVHRR is biased warm" seems to be a variation of the famous "Watts' Fallacy" regarding surface station records. or numerous other articles on this topic. -
Jeff Id at 10:36 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
#14, Steig et al is also flawed. They chose two few PC's for their analysis which caused the oversampled peninsula warming to be spread around the continent. There are a lot of stations in the peninsula. When the number of eigenvectors is increased or a regridding of surface station data is used, the trend drops to about 0.06C/Decade with some cooling since 82. -
Ned at 10:00 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
We're mostly talking about sea surface temperatures around Antarctica, right? AVHRR is very widely used for producing SST. I haven't looked into the source for fig. 1 and fig. 2, but the claim that you can't get reliable SST measurements from AVHRR is a new one to me. -
Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
(#88) So true, Philippe; "...any scientific field that is studied enough will, at some point, see the emergence of some level of consensus, unless no significant progress is being made..." From my viewpoint as someone with a degree in Philosphy: at one point 'Natural Philosophy' was _all_ of science. As consensus accumulated in various aspects we got Chemistry, Physics, Math, Biology, Engineering, etc. Now the only questions really left under the Philosophy tent are those that people are still arguing over after thousands of years, like 'why act justly when you won't get caught', 'what is the nature of the universe', and 'tastes great vs. less filling!' -
CO2 levels during the late Ordovician
My apologies, the first time I tried that and I put in a bad URL: CO2 and IR animation -
CO2 levels during the late Ordovician
RSVP - here's a link I found for a fun animation of this. The animation only shows one direction of emission, unfortunately, rather than a spherical distribution, but it's still a useful illustration: CO2 and IR animation -
CO2 levels during the late Ordovician
RSVP - CO2 absorbs then re-emits the energy, with fairly high efficiency. Some absorbed IR will (small percentage chances) be converted to molecular motion (hitting another air molecule at a high energy level prior to re-emission), a _very very__ small percentage will break molecular bonds (energy is low, but we're dealing in probabilities here), but the vast majority is incoherently re-emitted in a random direction as the electron shell of the CO2 molecule returns to its low energy state. I work with fluorescent dyes - this is fairly basic in molecular/photon interactions. This changes part of the IR vector from UP (hemispheric emission pattern from the ground to the sky) to spherically symmetric, sending some of it back down to the ground; the ground loses energy more slowly as a result. Even if it doesn't head straight back down, the IR now has a longer atmospheric path length, increasing the chances of hitting water vapor or other heating events in the atmosphere itself. CO2's not a mirror of IR, it's a randomizer. And ~50% (simplifying multiple absorption events, sums of series, etc.) of what gets randomized heads back down. -
Riccardo at 09:05 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Although not stated espicitly, it is customary to report clear sky skin temperature. As far as i know the latter correlates quite well with in situ measurements (see for example Scambos et al. 2006, Annal. Glaciol. 44,345) -
Peter Hogarth at 08:41 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Jeff Id at 07:44 AM on 16 March, 2010 I would hope then that Steig 2009 can be trusted, and on the NASA webpage Satellites Confirm Half-Century of West Antarctic Warming we get a 2009 update on the images in this post.
“The new analysis shows that Antarctic surface temperatures increased by an average of 0.22°F (0.12°C) per decade between 1957 and 2006. That's a rise of more than 1°F (0.5°C) in the last half century. West Antarctica warmed at a higher rate, rising 0.31°F (0.17°C) per decade. The results confirm earlier findings based on limited weather station data and ice cores”.
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Peter Hogarth at 08:05 AM on 16 March 2010CO2 levels during the late Ordovician
gallopingcamel at 11:53 AM on 15 March, 2010 In your reference Shaviv (I haven't seen this before?) was trying to respond to Royer around 5 years ago. It is hardly a direct rebuttal to the subsequent influential 2006 paper by Royer. Since then the evidence for CO2 (as a driver and amplifier) has continued to increase both in the paleo-record and in recent times, whilst very little convincing weight has been added to the evidence for the Cosmic Ray (Galactic or otherwise) hypothesis. As more work is done, and we look in more detail at the paleo records it is fair to say the scales are tipping further and many hitherto unresolved questions are finding answers (as in Young). This does not preclude other drivers (or most likely, combinations or drivers) of climate, but in the decades of intense research "CO2 as a significant factor throughout the history of the planet" has survived, and new corroborating evidence continues to emerge, plenty of it discussed here! -
Jeff Id at 07:44 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
The trends in figures 1 and 2 cannot be trusted. They are from Satellite AVHRR skin temperature measurements. This instrument is easily confused by cloud contamination, well documented by Comiso. The problem is the key reason that Steig 09 was required to combine surface trend information with satellite spatial information to determine a trend for the antarctic. The AVHRR data is biased warm. -
Ned at 07:34 AM on 16 March 2010Antarctica is gaining ice
Geo Guy writes: In a nutshell their findings identified ice mass loss in East Antarctica to be minimal but in the western part of the continent identified widespread losses along the Bellingshausen & Amundsen seas in the amount of 59% over ten years. In the Peninsula area losses were estimated at 140%. Here's a link to the Rignot 2008 paper. Just to be clear, since readers might be confused how the peninsula could lose 140% of its ice ... From 1996 to 2006, annual loss of ice mass from West Antarctica increased from 83 Gt/yr (+- 59) to 132 Gt/yr (+- 60), which is a 59% increase in the rate of loss. Likewise, annual loss of ice mass in the peninsula increased from 25 Gt/yr (+- 45) to 60 Gt/yr (+- 46), a 140% increase in the rate of ice loss. I think these kinds of regional-scale analyses nicely complement the continent-wide GRACE data. GRACE tells us, with a pretty high degree of confidence, how much mass Antarctica is losing per year. Studies like this one help elucidate the different components of the mass balance budget that should add up to the net change in mass as measured by GRACE. -
Riccardo at 07:16 AM on 16 March 2010Antarctica is gaining ice
Geo Guy, I think that upon reading the text and not just looking at the figures, the two sentences "While the interior of East Antarctica is gaining land ice, overall Antarctica is losing land ice at an accelerating rate. " and "The ice gained in the interior is roughly balanced by the ice loss at the edges." address your point and quite well describe what is going on down there. -
MattJ at 05:58 AM on 16 March 2010Watts Up With That's continued ignorance regarding Antarctic sea ice
Yes, clearly, "Steve is depriving himself and his readers of the opportunity to explore the complex and fascinating question of Antarctic sea ice." But that IS what some people out there want. Scientists may be interested in "complex and fascinating quesitions", but neither the general public nor the politicians manipulating them care. They prefer a simple answer even if it is clearly wrong. -
papabob at 05:54 AM on 16 March 2010Watts Up With That's ignorance regarding Antarctic sea ice
I have quit discussing the subject with the folks to whom melting glaciers, thinning arctic shelf ice, thinning of the Greenland Ice Cap and other phenomena are just "natural occurances" and warming has nothing to do with them!!
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