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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 118451 to 118500:

  1. Websites to monitor the Arctic Sea Ice
    Berényi Péter, it's not about what I think but what THEY say, at least in the published papers. Maybe you have access to secret informations, do you? If not, you're just playing war games, not science. I know you can do much better than blindly follow people at WUWT, be skeptical of what they say there too.
  2. Berényi Péter at 06:44 AM on 31 May 2010
    Websites to monitor the Arctic Sea Ice
    #19 michael sweet at 05:27 AM on 31 May, 2010 The red color shows ice AT LEAST 5 meters thick. Much of that ice was 10 or more meters thick (some was over 30 meters thick) in past years. You cannot integrate it as 5 meters thick.This results in underestimating the ice volume in past years Perhaps it was. But there is not much red in any PIPS map. For example the one for 14 September 1999 does not have any.
  3. Berényi Péter at 06:30 AM on 31 May 2010
    Websites to monitor the Arctic Sea Ice
    #16 Marcel Bökstedt at 02:12 AM on 31 May, 2010 The difference between the navy data and PIOMAS is striking, even if the graph above of navy data only covers one particular date (is that correct BP?) Yes, that's correct. It is only for 28 May. I could do it for the entire year, but a huge amount of data (about 250 MB) is required to be downloaded and I am not sure the Navy would tolerate it :) Anyway, I've also did it for 14 September, the day Arctic sea ice extent was lowest in 2007. At that time of the year ice volume inside 70N is about all there is. Interesting to note that mid September ice volume was lowest in 2008, not in 2007. The low in 1999 is also unheard of. #17 Riccardo at 03:06 AM on 31 May, 2010 PIPS is designed to predict ice concentration essentially near the ice edge and it is tested against this field I don't think so. For submarines armed with strategic nuclear missiles ice thickness is a deciding factor anywhere in the Arctic. They simply can not do their job if the ice above is too thick. The Navy also have its own devices to monitor ice conditions including submarines, spy satellites, aircraft and drift buoys. PIPS do have a sophisticated data assimilation facility developed in more than twenty years.
    Moderator Response: [Sph] Bad images removed.
  4. Peter Hogarth at 06:15 AM on 31 May 2010
    Why Greenland's ice loss matters
    FerdiEgb at 06:30 AM on 29 May, 2010 michael sweet at 01:06 AM on 31 May, 2010 easily beat me to a response on similar lines. We see the same Winter variance/Summer "clipping" to just above melt point over the Arctic sea ice.
  5. michael sweet at 05:27 AM on 31 May 2010
    Websites to monitor the Arctic Sea Ice
    BP: I just looked at the Navy website. The red color shows ice AT LEAST 5 meters thick. Much of that ice was 10 or more meters thick (some was over 30 meters thick)in past years. You cannot integrate it as 5 meters thick. This results in underestimating the ice volume in past years. This alone is probably enough to explain the difference between you and PIOMAS.
  6. michael sweet at 04:16 AM on 31 May 2010
    Websites to monitor the Arctic Sea Ice
    WUWT has integrated the colors of other peoples ice data unsuccessfully in the past (note here that BP got a lower value than WUWT). While BP has done an interesting analysis, I would not say that the US Navy has said what they think the ice volume is. BP has said what HE thinks the ice volume is based on the Navy graph. This type of analysis has many hidden errors since the Navy graph is not intended for this use. I agree with Riccardo, PIOMAS is intended for this use and will have lower error. PIOMAS undoubtedly has a high resolution map of the Navy graph that they consider in their analysis (unless the Navy gets their data from PIOMAS).
  7. Websites to monitor the Arctic Sea Ice
    Marcel Bökstedt, sometimes happens that critical thinking efficiency drops to zero. A post on WUWT is enough to spread the(ir) "truth". I do not have the answer to your question, obviously, but it should be noticed that PIPS is designed to predict ice concentration essentially near the ice edge and it is tested against this field (see for example here and here). On the contrary, PIOMAS is designed and tested to calculate volume. I'm not that surprised that the two do not match.
  8. Volcanoes emit more CO2 than humans
    JSFarmer, apart of Ian Plimer, (professor of mining geology and director of a few mining companies in Australia) and Mark Durkin (director of the infamous "The Great Global Warming Swindle") I don't think you can find many others disagreeing with your question #1. As for question #2, i've never heard criticism on the numbers.
  9. Marcel Bökstedt at 02:12 AM on 31 May 2010
    Websites to monitor the Arctic Sea Ice
    The difference between the navy data and PIOMAS is striking, even if the graph above of navy data only covers one particular date (is that correct BP?) According to PIOMAS, there has been a loss of around 9000 km^3 of ice in this period 1999-2010. The navy data shows almost no loss of ice, certainly much less than 9000 km^3. Does anyone have any idea about what is going on here?
  10. On temperature and CO2 in the past
    In #16, Mr. Camel states: "could not find any declaration that the CO2 concentration was driving the temperature changes" However, Riccardo stated this: "... starting about a couple of centuries ago, the system has been suddenly pushed out of its shell and moved to a completely different domain. The slope of the [temp-CO2] curve is hugely different, indeed almost flat, which suggests that the driver of the climate is different from anything seen in half a million years." (Italics added). Perhaps if one drops back a bit and asks "What has driven this hugely different behavior of the temp-CO2 system?" See the following graph: Notes: 1. De-seasoned atmospheric CO2 from 3 widely-spaced sample stations (Mauna Loa, Barrow and Palmer, Antarctica) 2. Composite Law Dome Ice Core (3 sample locations) Ice core air age used as time axis. 3. Carbon emission data Trailing 5 years (residence time?) summed and expressed in gigatons. Looks like a trend to me (pardon the shameless extrapolation into the future). So let's turn the question back on the reader: What explains the relationship between increased burning of fossil fuels and increased atmospheric CO2? And what else do you offer for Riccardo's hugely different driver?
  11. It's the sun
    JSFarmer, look yourself. The picture is from a NASA site.
  12. Volcanoes emit more CO2 than humans
    Sorry to ask such a basic question, but the threads get too complicated for me. The rebuttal argument was very concise for this topic and I'm curious if there is any dispute. I took a quick look aound and didn't find one. Regardless of the other effects of volcanoes, or what happens to the gasses, does anyone dispute the numbers stated in the response that: 1. Volcanoes emit around 0.3 billion tonnes of CO2 per year. 2. Human CO2 emissions are around 29 billion tonnes per year. ? Thanks
  13. michael sweet at 01:06 AM on 31 May 2010
    Why Greenland's ice loss matters
    FerdiEgb, The surface summer temperatures in Greenland are limited in their rise by the phase change of ice to water. The massive ice sheet creates it's own temperature. That does not mean that melt is less, only that there is not a large temperature response. Other measures are required to obtain an accurate picture of the situation. The rising melt line shows the situation more clearly.
  14. Websites to monitor the Arctic Sea Ice
    Its been noted elsewhere that summer arctic ice loss is accelerating. Has anyone noticed a systematic asymmetry between the summer minimum and winter maximum ice extents? Both are decreasing, but the accelerating rate of decrease in the summer outpaces the somewhat linear decrease in the winter ice extent.
    Here's a graph:

    Notes: Ice extent from month-by-month data files for the years 1979-2009; expressed as a percentage of 1979 values, hence 1979=0. "Summer min" is the average of the 3 months of least extent (which are Aug-Sep-Oct), while winter max is the average of the corresponding three months (Feb-Mar-Apr) for each year in the dataset. Rather than plot these data as a time series, I've found it far more interesting to plot such data vs. a relevant independent variable on the 'x-axis'. In this case, I've used temperature: LOTI for latitude N64-N90, adjusting those temperature index values so that 0 falls at 1979. Note that this index is in hundredths of deg C.
    Hope that explanation of relatively minor data manipulation and presentation was vaguely comprehensible!
    The best-fit functions for each season (the central curves in each set of three) are shown with +/- 1 stdev, as labeled. The two seasonals intersect at 1979, which is (0,0) as explained above. I couldn't resist the forward projection, but its only 2 years. I suppose this is a symptom of the formation of short-lived "new ice" each winter and the loss of longer-lived "old ice". So don't buy the claim that ice area is recovering based on a couple of cold winters.
  15. Berényi Péter at 22:49 PM on 30 May 2010
    Websites to monitor the Arctic Sea Ice
    #13 tobyjoyce at 18:57 PM on 30 May, 2010 After dipping into WUWT, a lot is been spouted about the U.S.Navy monitoring of Arctic Ice I have checked it. The claim May arctic ice volume inside 70N has grown by 25% since 2008 is bogus. The actual growth is only 13.6%. Here is the US Navy Polar Ice Prediction System. As it makes forecasts only for the next 24 hours, I suppose it can not be too far from reality and they must have some means to check it. Submarines, perhaps? Ice over the Arctic having some strategic military relevance, they must not be badly off the mark I suppose. Except if it were classified and public version is only for confusing the enemy :) Anyway. They do not publish tabular data, just pictures like this one: [img src="http://www7320.nrlssc.navy.mil/pips2/archive/pips2_thick/2010/pips2_thick.2010053000.gif">
    Moderator Response: [Sph] Bad images removed
  16. There's no empirical evidence
    PaulK, it's not clear to me what you mean by "the assumptions in your version of the heat balance equation". Which assumptions did "I" make? Did you find something wrong? I understand we're back to the beginning but I'm a bit lost with this discussion.
  17. It's the sun
    Thanks.. I clicked on the link. It was a little more difficult for me to undestand- lots of acronyms. But I will try. It talks about TSI (Total Solar Irradiance) and a debate over how to measure it. I tried to gleen sunspot info from it. It appears to use sunspot activity to reconstruct TSI. TSI corrolates to sunspots. The argument is complicated for me- trying to focus on sunspot activity, the skeptic claim is that it is increasing. The science response says it is decreasing. (confirmed by corrolating TSI in the other link) Is that correct- sunspot activity is decreasing?
  18. There's no empirical evidence
    Riccardo #95, Erratum. I should have written ALSO equal to -F*exp(-t/tau). (A Taylor expansion of this form and then curtailment of the higher order terms yields your form of the heat equation.)
  19. Websites to monitor the Arctic Sea Ice
    After dipping into WUWT, a lot is been spouted about the U.S.Navy monitoring of Arctic Ice. Where does the Navy monitoring fit in with the civilian monitoring?
  20. There's no empirical evidence
    Riccardo #95, Effectively, yes. Or at least it would be the same if one were to accept the assumptions in your version of the heat balance equation (and change the sign convention on the perturbation). With these assumptions, it is ALSO equal to -F*exp(t/tau) - the perturbation from a single impulse forcing.
  21. Latest GRACE data on Greenland ice mass
    John, what's the baseline for the ice mass anomalies? I looked for this in Velicogna 2009 but maybe missed it. Meanwhile AMSU-A is still looking scary. I was rash enough to blog about it in April and it's still not disappointing. The thing is, we aren't meant to obsess about short-term changes because natural variability will overwhelm the long-term trend if we look at too short a period, but natural variability should be pushing temperatures down not up over this period. I'm expecting someone to steal Spencer's email any day now.
  22. Working out climate sensitivity from satellite measurements
    MikeCoombes, on a yearly bases you would need to account for the internal movements of heat, someone (inappropriately, in my opinion) calls them "internal forcings". For example, think about downwelling and upwelling and mixing of ocean waters. These movements are not well know and may produce a large unaccounted variability in the short run but tend to average out over longer periods.
  23. On temperature and CO2 in the past
    jyyh, this is a good point, the distribution of the density of points is not uniform. It's higher at the two extremes, expecially in the cold phase region. This means that the climate system "prefers" to stay in the cold phase and sometimes switched to the warm phase, the two more stable phases. They are called stable attractors.
  24. Skeptical Science now a Nokia app
    Well done, the more of this sort of thing the better.
  25. Robust warming of the global upper ocean
    Ken #67 The one thing you always ignore in raising this argument is the importance of measurement error, although you will always report the bottom end of the uncertainty to try and support an "AGW isn't terribly important" position. An explicit acknowledgment of the size of error terms, and accounting for the full range of possible values (not cherry picking the range at which you will consider) is important. The other area your argument is deficient, which we've been through before is that you will only consider data at very short time durations. In order to improve the validity of your argument you need to consider longer time durations which would fit the definition of "climate". At the moment, you're really looking at "weather" and claiming that it's climate.
  26. On temperature and CO2 in the past
    Great presentation. I see there's a more thinly dotted area in the domain occupied for 420000 years, at about a quarter down from the oval top. Would this be the transitional times between glacials and interglacials?
  27. Skeptical Science now a Nokia app
    cool, now i need to update my phone. doug, lol, but this is a climate site, maybe somewhere else?
  28. Latest GRACE data on Greenland ice mass
    Wes, the myth that you're repeating is this idea that-because it might have been warmer in one region of the world than global temperatures today-that this means we have nothing to worry about. There is evidence that Greenland was-at the *peak* of the MWP-as warm as temperatures are today (based on 18-O isotope levels in the ice), but this says nothing about the temperature in the rest of the Northern Hemisphere. What also needs to be remembered is that all the evidence suggests that the warm period that gave rise to the Greenland colony occurred over the space to more than 4 centuries-wheras the warming of the late 20th century has occurred in the space of barely 4 decades. Its highly probable that a more rapid *rate* of warming might have different impacts on Greenland's ice than all previous examples of relatively slow warming in the past.
  29. Doug Bostrom at 13:13 PM on 30 May 2010
    Skeptical Science now a Nokia app
    Amazing how fragmented the phone market is. How about we start an OS flame war? Something we can all disagree on!
  30. mothincarnate at 11:18 AM on 30 May 2010
    Skeptical Science now a Nokia app
    Awesome! I never actually checked up if you answered about my question regarding the Nokia app, but I'm happy to hear it's available. Thanks John!
  31. Skeptical Science now a Nokia app
    Palm Pre Plus app? Now that Palm is about to be part of HP and is on Verizon, AT&T, and Sprint? Pretty please? With your sweetener-of-choice on top?
  32. Working out climate sensitivity from satellite measurements
    I was wondering if it might be possible to estimate climate sensitivity from yearly temperature changes in each hemisphere. The forcing would be from the changes in the amount of sunlight, not CO2, but I understand that the sensitivity should be the same to at least first order. Also the heat transport from one hemisphere to the other should not be as great an effect as just using the tropics. There could also be interesting hemispheric differences because of the differing land to ocean ratios and the amount of surface snow affecting albedo. Am I totally off base? Thanks.
  33. Websites to monitor the Arctic Sea Ice
    One more to add to the robust list. NPEO North Pole Environmental Observatory http://psc.apl.washington.edu/northpole/index.html Two automated observatories are placed, and tracked, pn the central Arctic ice-flow. Excellent meteorological support, and live pictures daily.
  34. There's no empirical evidence
    PaulK, maybe I didn't understand your notation. Is your f(t) the same as what people usually call F(t)−λΔT? In other words, did you include both the forcing and the response to the forcing into f(t) so that it's not not just f(t) but f(t,ΔT(t))?
  35. On temperature and CO2 in the past
    Jeff the data are from the Dome C but it does not change much. Definitely to compare those data with the global average there is an amplification factor to take into account. In a comment above I quoted the value of 2 from Masson-Delmotte 2010. It would translate to about 5-6 °C, not unthinkable but on the high end side of the accepted range. Anyway, I think that a quantitative prediction of the expected temperature rise from just these GHG data is a bit implausible. Masson-Delmotte and co-workers expanded the analysis beyond just GHG and found a climate sensitivity varying between 0.76 °C/Wm-2 for the period 400-800 Kyrs and 0.86 °C/Wm-2 for 0 400 Kyrs, both near the central IPCC estimate. What may be a cause of concern is its increase over time and over forcing (the parabola in fig. 3 here).
  36. There's no empirical evidence
    Hi Riccardo, Your first paragraph (#91) raises a profound question, which I believe requires a separate post to deal with. Before I can get to it, however, your second paragraph suggests to me that we still have a gulf of understanding to bridge. You wrote: “But then you confuse the forcing with the OLR and never in you analysis does the net balance appear. Indeed you write dH/dt=-f(t); here f(t) should be the net energy (im)balance but then it cannot be equal to the OLR. You need to have both the forcing and the thermal radiation. I'd suggest to first write and solve the heat balance equation for ΔT (sorry if i keep using variations, why bother with the equilibrium values?). After that we can try to see who's that guy we call OLR.” Let me deal with this sentence by sentence to see if we can bridge the gap:- “You confuse forcing with OLR”. I don’t believe that I do anywhere. Can you be more specific about where this confusion occurs and I will try to address it. “...never in your analysis does the net imbalance occur. Indeed you write dH/dt= -f(t);...” The net imbalance IN FLUX is the basis for the analysis. I wrote dH/dt = Q(t) – E(t) = absorbed SW (flux) – Outgoing LW(flux) at TOA This IS the net imbalance at TOA. I also wrote:- Assume that at time t = 0, the system is in steady-state equilibrium: Q(0) = E(0). Now, keeping everything else unchanged, consider a positive impulse forcing F1 = constant which results in a perturbation, f(t), of the OLR. We can write: OLR(t) = Q(0) + f(t) ; Q(t) = Q(0) = constant ; dH/dt = -f(t) The net imbalance here is Q(t)-E(t), but Q(t) = Q(0) and E(t) after the forcing is equal to Q(0) + f(t). Hence the net imbalance is equal to Q(t)-E(t) = Q(0) – (Q(0)+f(t)) = -f(t). This is also by definition equal to the rate of change of energy entering or leaving the system, so we also have:- dH/dt = -f(t). “Here f(t) should be equal to the net energy imbalance.” No. It should not. The perturbation f(t) has the dimensions of FLUX. The negative form –f(t) is equal to the net FLUX imbalance for this boundary condition of constant input flux. This function represents a perturbation of OLR for a single pulse of CO2. It would have to be integrated w.r.t. time to give a net energy imbalance. “...but then it [f(t)] cannot be equal to the OLR. “ You are right. It is not equal to the OLR. It represents a perturbation of the OLR for a single impulse forcing . The OLR for this forcing (and a boundary condition of constant absorbed SW) = Q(0) +f(t) as stated. “You need to have both the forcing and the thermal radiation.” Agreed. They are both built into the perturbation. “I'd suggest to first write and solve the heat balance equation for ΔT.” Well as perhaps we will eventually get to, I am not sure what this should be in the real world. On the other hand if you want a solution for ΔT based on Schwartz-like assumptions, then you immediately have one from the solution I proposed by writing CdT/dt = C dΔT/dt = dH/dt. Since we know dH/dt, we can trivially calculate ΔT. This post is already too long, so I will answer the more difficult question that you posed in your first paragraph (Why use this new numerical solution when there is one already available?) in a separate post, when I get a little more time. But one thing which you said did strike me. I may be wrong, but I get the impression that you think I backed out the solution for OLR from Schwartz. I did not. I solved the superposition equation from the generalised definition, and then set all of the perturbations equal to each other for equal superposition timesteps. A “Chinese box” proof then demonstrates that the superposition solution is analytic for this boundary condition of F=bt. I then applied this solution to the more restrictive assumptions of Schwartz. It is possible that you are getting confused over the dimensionality of the solution I offered. Because the term for OLR involves an integral of flux, it may appear like there is confusion between energy and flux. There is no such confusion. The integral term is here effectively divided by time, but the superposition timestep equals 1 year. Hence the integral term here has the dimensionality of a flux. More later when I have a minute.
  37. On temperature and CO2 in the past
    Marcel Bökstedt at 20:57 PM regarding your comments on C reservoirs, particularly "Historically, the amount of carbon available in the atmosphere plus the carbon in the reservoir is a constant C', because at that time presumably no carbon was added to the system" Given that the amount of C that is released into the atmosphere through combustion of fossil fuels is relatively small compared to what is in constant exchange between the atmosphere and (1) the plants and soil and (2) the oceans, then very minor changes in the ratio of the exchange could be a significant factor in what is sequestered or released from the reservoirs being referred to. For the soil reservoir, plant growth is the key factor that apart from the obvious inputs, relies on C as the most basic foundation of them all, it being the energy source for soil biology and thus the most basic driver of all plant growth. Over the time spans examined in this discussion, CO2 levels have changed from plant starvation levels to still less than desirable levels of today. If the 6.5Gt of carbon being released annually by burning fossil fuels today is an important factor, than anything that has, or can vary the estimated 200Gt of C in constant exchange between the plants, soil and atmosphere today has to be allowed for. Are there any studies out there that estimate just how much C was being exchanged through biological means when CO2 levels were about 200ppm, because it is not enough just to measure what amounts of CO2 were present in the past, but to allow for the what all other changes it was causing when trying to make the connection with any of the other indicators also measured in order to close the loop. A very small change in any of the natural processes could have yielded greater changes than the simple combustion of fossil fuels today.
  38. Jeff Freymueller at 04:05 AM on 30 May 2010
    On temperature and CO2 in the past
    Riccardo, the T anomaly for Figure 1 is the T anomaly for Lake Vostok, right? If that is correct, and if the temperature changes are amplified at high latitudes, might that not explain why the temperature changes globally are smaller? Present evidence suggests that the Arctic is warming ~3 times faster than global average, if that holds for the past data and for Antarctica then rather than 11C, the present CO2 might be predicted to raise global temps by 3-4C. Or am I wrong ahout the temp record used?
  39. Working out climate sensitivity from satellite measurements
    Chris, "ONE: However Spencer and Braswell state explicitly in their paper that their analysis doesn't have anything neccesarily to do with climate sensitivity at all. So you are basing your conjecture on a dismissal of S&B's assessment. Why do you consider that they are wrong?" I don't consider them wrong they aren't making the point that you are making. S&B (and I)are not talking about the long-term feedback response(ie climate sensitivity), they are talking about short-term feedback response. S&B doesn't *necessarily* say that long-term sensitivity must be negative because it doesn't measure that. However, for a given set of long-term feedbacks S&B predict a less sensitive climate than if short term variations are governed by noise(in S&B's terms). "THREE: You don't like my response to your question "What processes do you think governs the climate *on the timeframe* Spencer is dealing with?". I suspect that the reason is that you meant something other than what you asked. Clearly it's only noise and massive virtually instantaneous changes in forcing (volcanoes; extraterrestrial impacts) that can impact climate in such short timescales. I wonder if you really meant to ask "what processes do you think governs net TOA radiation transfer on the "timeframe" Spencer is dealing with"? If that's what you meant (please let me know) then I could answer that question. " In S&B's context clearly "noise" random perturbations in the relationship btw forcing and temperature. EArlier you quoted this from S&B "These striations are significantly different from a similar plot of two time series of random numbers, shown in Fig. 3b, suggesting that the striations are due to some underlying physical process.". FYI, the plot of random numbers would be noise per S&B. "FIVE: Another way of thinking of this is that the climate system has inertia to change and thus has a memory. Under the general case of persistent TOA radiative imbalance, the excess energy that accumulates in the climate system as a result of the imbalance isn’t radiated away. It’s only energy (positive or negative) that rises or falls above the energy compatible with the TOA forcing and climate inertia or “memory” that is rapidly dissipated, since the system will always tend towards the background state around which these internal fluctuations are “dancing”. Lin et al have just published a a couple of papers [**] in which they have taken Spencer and Braswell’s “striations” at face value, assigned S&B’s value to the coefficient f(s) and used this in a model that is more realistic than S&B’s by adding a term for the climate “memory”. When they do this, S&B’s purported value for what might be f(s) is entirely compatible with rather well-established estimates of the real climate sensitivity." Yes, Lin's approach is quite interesting. You'll note that they had to "add" something to make sense of what Spencer found. They did not call him names or try to say that everyone who disagreed with them did not "read the paper". No, they set out to actually try and explain the behavior of the real world. My brief reading of Lin's paper here doesn't allow me enough understanding of how the memory is supposed to work to comment much on it. i will read bit more and see what I think. Here it is for anyone who is interested. http://www.atmos-chem-phys.net/10/1923/2010/acp-10-1923-2010.pdf Cheers, :)
  40. Doug Bostrom at 03:26 AM on 30 May 2010
    Robust warming of the global upper ocean
    PaulK, It seems we all share Trenberth's frustrations. Poor Trenberth has been scrutinizing this matter for decades now, always struggling with the sort of problems you detail. The thing I find most astonishing about his 2010 review are the enduringly paltry choices he has for obtaining primary data, choices that have problems known for 20 years or more and have gone largely unaddressed, or at least have not enjoyed concerted attention on the part of folks assembling mission objectives. We've ignored the requirement for better instrumentation, the price of which is vanishingly small compared to what we collectively spend on really important things, such as hair gel for us guys and eyeliner for the ladies. We can't just throw money into instrumentation randomly, but in fact we do have a reasonably good idea of what we want to measure. Venus has a dedicated climate orbiter on the way with the primary mission of taking a close look at various aspects of radiation there. Back here-- where we live-- we mostly use instruments glued onto orbiters as afterthoughts. As I mentioned earlier there are plans to intensify deep ocean measurements, good, but it's still a puzzle to me as to why we're -planning- data collection now as opposed to -analyzing- data we've already collected. Really, our thinking about money and opportunity costs is quite incoherent.
  41. Doug Bostrom at 03:12 AM on 30 May 2010
    Latest GRACE data on Greenland ice mass
    Riccardo good point and how amazing that I can blather so around the target without mentioning it...
  42. Latest GRACE data on Greenland ice mass
    Since the mass balance of a glacier is recorded on an annual basis, monthly or more frequent updates just do not make sense. Given the rapid snow melt off and well above average temperatures for Western Greenland this year, expect more losses.
  43. On temperature and CO2 in the past
    Thank you gallopingcamel. The understanding of current climate is like a puzzle, this post addresses just one piece, better, a tiny part of a piece. Although I may know what the final image will be I cannot tell from the tiny piece. I've been careful to avoid this trap which would cause the discussion to derail.
  44. Robust warming of the global upper ocean
    Doug #65 Chris #66 Similar information is repeated in Dr Trenberth's Aug09 paper: http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/EnergyDiagnostics09final2.pdf which I have oft quoted in these blogs. The relevant Fig 4 of this paper shown how the TOA imbalance of 0.9W/sq.m is derived. Note that the main warming components are CO2, about 1.66W/sq.m and other GHG (1.0 W/sq.m) and the main cooling effects are surface, direct and cloud albedo. Solar is minimized at 0.12W/sq.m giving an overall net AG forcing imbalance of 1.6W/sq.m. Dr Trenberth then shows the Net Responses of the Earth system as -2.8W/sq.m (radiative feedback) and WV and ice albedo as +2.1W/sq.m giving a net response of -(minus)0.7W/sq.m. (The -2.8W/sq.m is calculated from S-B for a temperature rise of 0.75degC at a radiating temperature of 255degK. This is proportional to T^4.) The TOA imbalance is net AG (+1.6) and net response (-0.7) to give 0.9W/sq.m total net imbalance. Chris, the Solar forcing is only 0.12W/sq.m and we know that the 11 year cycle gives an incoming variation of about 0.25W/sq.m from top to bottom - therefore this is nowhere near enough to offset the postulated 0.9W/sq.m of net positive imbalance. If you look at the CERES satellite data there is a +6.4 W/sq.m TOA imbalance - which is impossible; so again we have an offset error and BP's low accuracy but high precision. In fact if you look at Doug's reference: http://content.imamu.edu.sa/Scholars/it/net/trenbert.pdf the absolute values of the components are all over the place - so only year to year differences make sense. If you go back to BP's post #30 or #36 (I think) he gives the last 10 years satellite chart and there are no significant year to year trends showing anything near negating the 0.9W/sq.m imbalance at TOA. Clouds and aerosols could be the most poorly understood, modelled and measured, however Dr Trenberth claims that HIRS is measuring to +/-1% which is +/-0.5W/sq.m and again - no big differences year to year. And of course the OHC seems flat since 2004 by Argo analysis. Conclusion: The 0.9W/sq.m imbalance might be much less over the last 6 years at least and the major culprits are Log CO2, Log 'other GHG', WV+Ice albedo feedbacks, or Surface, Direct and Cloud albedo. Clearly less warming, or more cooling or combinations of both.
  45. gallopingcamel at 00:09 AM on 30 May 2010
    On temperature and CO2 in the past
    Congratulations Riccardo! I read your guest post several times but could not find any declaration that the CO2 concentration was driving the temperature changes over the Vostok timescales. Then I checked the comments and most of them referred to correlation rather than causation. Nothing for me to disagree with here.
  46. Latest GRACE data on Greenland ice mass
    #15, Daisym, Land rise around Greenland (local relative sea level fall) will actually increase sea level rise at distant points. The land rise decreases the volume of the ocean.
  47. Working out climate sensitivity from satellite measurements
    Thanks Riccardo....linking to that paper just wouldn't work for me!
  48. Working out climate sensitivity from satellite measurements
    BC, you need to use forcing instead of CO2 concentration. For example, between 1970 and today CO2 went from 325 ppm to 390 ppm. The forcing is F = 5.35*lnC2/c1 ~ 1 W/m^2; temperature increase has been about 0.5 °C and the sensitivity λ would be λ = 0.5/1 = 0.5 °C/Wm^-2. Double CO2 means 3.7 W/m^2 which translates to about 1.85 °C per doubling CO2, lower than the most probable value of 3 °C.
  49. Working out climate sensitivity from satellite measurements
    here's the link to Lin et al. 2010 paper cited by chris.
  50. Working out climate sensitivity from satellite measurements
    shawnhet at 10:54 AM on 29 May, 2010 Shawnhet, I suspect you're doing what Spencer wants you to do - he's playing "fast and loose" with some numerological analyses of TOA radiation data and climate models and interpreting these (on his website, not in the paper) within an unrealistic simplified climate heat transfer model.....you're running with his insinuations with your extrapolated conjecture "If that relationship turns out to be robust, then the climate sensitivity will be less than, for instance, a system where the short-term response is governed by some other process." ONE: However Spencer and Braswell state explicitly in their paper that their analysis doesn't have anything neccesarily to do with climate sensitivity at all. So you are basing your conjecture on a dismissal of S&B's assessment. Why do you consider that they are wrong? TWO: This statement of yours is also incorrect: "It is pretty clear that they relate to coefficient of the short-term feedback process that seems to operate on changes in radiative forcing." Again it would help if you were to read the paper before making assumptions (even if Spencer does try to lead you to false interpretations). The "coefficient of the short term feedback process" [which I'll call f(s) for short a la Lin et al (2010) - see "FOUR:" and "FIVE:" below] isn't "operat(ing) on changes in radiative forcing". It's operating on changes in surface temperature (climate perturbations). THREE: You don't like my response to your question "What processes do you think governs the climate *on the timeframe* Spencer is dealing with?". I suspect that the reason is that you meant something other than what you asked. Clearly it's only noise and massive virtually instantaneous changes in forcing (volcanoes; extraterrestrial impacts) that can impact climate in such short timescales. I wonder if you really meant to ask "what processes do you think governs net TOA radiation transfer on the "timeframe" Spencer is dealing with"? If that's what you meant (please let me know) then I could answer that question. FOUR: Being careful with meaning is important in science. This is relevant to points TWO: and THREE: above. Let's take the situation that there is a change in sea surface temperature (SST) arising from an internal fluctuation in heat distribution (e.g. El Nino, so the SST temperature rises a bit). What happens to this excess heat? I would say that it will be radiated away, quite likely rather quickly. It's not going to be particularly affected by the radiative imbalance arising from the enhanced greenhouse effect. The latter sets the average background temperature which is the temperature that results from the greenhouse forcing and the particular state the the climate system has reached in response to the forcing at that particular time on its slowish trajectory towards a new climate equilibrium. So there's nothing really "opposing" the dissipation of the enhanced heat to space. On the very short term the climate system will always tend towards the state that the climate happens to be in, and so we aren't surprised if there's a very rapid dissipation of energy out of the system. That coefficient [f(s)] has got nothing whatsoever to do with the climate response to radiative forcing arising from a radiative imbalance at the top of the atmosphere (and to be fair to Spencer and Braswell, they say as much in their paper, even if you choose not to believe them). FIVE: Another way of thinking of this is that the climate system has inertia to change and thus has a memory. Under the general case of persistent TOA radiative imbalance, the excess energy that accumulates in the climate system as a result of the imbalance isn’t radiated away. It’s only energy (positive or negative) that rises or falls above the energy compatible with the TOA forcing and climate inertia or “memory” that is rapidly dissipated, since the system will always tend towards the background state around which these internal fluctuations are “dancing”. Lin et al have just published a a couple of papers [**] in which they have taken Spencer and Braswell’s “striations” at face value, assigned S&B’s value to the coefficient f(s) and used this in a model that is more realistic than S&B’s by adding a term for the climate “memory”. When they do this, S&B’s purported value for what might be f(s) is entirely compatible with rather well-established estimates of the real climate sensitivity. SIX: Apologies for the very long post (and I’ve answered the question I suspected you meant to ask anyway!). I might just add that once again the difficulties of estimating the true (Charney) climate sensitivity from contemporary real world measurements boil down to uncertainities of the true climate response times (inertia/memory etc.). Unfortunately, the system simply isn’t accessible to quick and easy answers…at least do far… [**] Lin, B. et al (2010) Can climate sensitivity be estimated from short-term relationships of top-of-atmosphere net radiation and surface temperature? J.Quant. Spec. Rad. Trans. in press (can’t seem to link to the abstract).

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