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Unforced variations: Dec 2014

Filed under: — group @ 3 December 2014

This month’s open thread. Think history, Lima, and upcoming additions of a single data point to timeseries based on arbitrary calendrical boundaries.

265 Responses to “Unforced variations: Dec 2014”

  1. 101
    patrick says:

    @91 John Atkeison: Thank you. Thank you Dr. Donald Wilhite and associates in climatology.

    “How quickly…will plants and animals…adapt to projected changes?” (1:27:45)

    Clint Rowe: “In terms of adaptation of both plants and animals, probably not fast enough…if there is even adaptation space available to certain ecosystems. For example, if you’re a little rodent living in the high alpine environment and the climate warms up and you keep moving up the mountain,there’s a top to that mountain, and you can’t go any higher. So your ecosystem space disappears. And so do you.” (1:29:40)

  2. 102
    Ragnaar says:

    Tisdale has a post over at WUWT about CO2 and OHC that links to: I see that thread is closed. I think that more CO2 does warm the oceans but the question is how much? A chart which I think is from the IPCC AR5: I estimate as saying that the oceans gained 250 ZJs over the last 40 years while the atmosphere gained 2.5 ZJs. Granting that the CO2 caused all the atmospheric warming, is there an explanation of why the effect real close to or on the ocean surfaces seems to be 100 times as effective at trapping heat?

  3. 103
    MARodger says:

    [edit – please try and stay substantive]

  4. 104
    Zachary says:

    So with the recent article released about methane is this the catastrophic release Dr. Box was referring to?

  5. 105

    “…with its clearly misleading trend line. And as far as 2001 is concerned, yes that data point is an outlier because it’s clearly NOT a part of any trend, as is clearly evident from simply looking at the graph.”

    – See more at:

    No, and no. The trend line is not ‘clearly misleading,’ and the 2001 data could very well be part of a trend.

    The first is true because we do not have statistical evidence that the trend changes (i.e., change point analysis or something similar). Eyeball Mark I has manifestly failed to produce anything objectively valid (otherwise we wouldn’t all be banging on about this still.)

    The second is true because we have no evidence that the large change isn’t due to normal variability. (I.e., as has been repeatedly observed, this data set is noisy.) The graphed observations have a couple of other outliers that are just about as far from the calculated trend line in (I think) 1971 and 1982, so it’s not all that remarkable in the data.

    Victor, you are putting on quite a clinic in what confirmation bias really looks like–which is, a lot like argument from incredulity.

  6. 106
    Hank Roberts says:

    > why the effect real close to or on the ocean surfaces
    > seems to be 100 times as effective at trapping heat?

    Warmth spreads slowly through dirt and rock, by conduction.
    Warmth spreads quickly through water, because water is a fluid, by circulation.
    About 70 percent of this planet’s surface is water.

    Put a bucket of water in the sun.
    Put a bucket of dirt in the sun.
    Check the temperature at the bottom through the day.

  7. 107
    Harvey Moseley says:

    I have been a physicist for 35 years, and I am convinced that if one wants a particular result more than they want to get a correct and robust answer, it is time to get out of the business. No scientist should have a stake in any position other than a commitment to get the right answer. The whole public climate discussion is so strange to follow. Large numbers of people talking as if the have a priori knowledge, when we all know that the analysis of large global data bases is the only path to answering questions about changes in global climate. No anecdotal observation can be of much use in this discussion. The question as to where to start the analysis of a time series is similarly strange. There are statistical tools for assessing the reliability of fits if the analysis if defined a priori. However, if one selects starting and ending points after having seen the data, his ability to make statistical statements is much reduced. This goes for numerical and eyeball fits. You have to make decisions like this before you see the data. If not, you have to do the hard work of understanding statistical biases caused by not selecting the analysis process ahead of time. Not what you want to do if your goal is to get the best answer possible given the data, which should be the goal of any scientist. I am similarly amazed that among nonprofessionals, there is a feeling that a young scientist must “go along” to make it in the field. In fact, if a scientist could develop a scientifically sound position explaining climate change without requiring human forcings, he would quickly become the most famous climate scientist in the world and his career would be made. The search errors in the current understanding of scientific problems is central to the endeavor. Saying “it looks pretty good to me” does not do much to advance ones career.

  8. 108
    Ragnaar says:

    Hank Roberts:
    “Warmth spreads slowly through dirt and rock, by conduction.
    Warmth spreads quickly through water, because water is a fluid, by circulation.”
    I understand water is good at gaining energy. Earth soil can be more like insulation. A bucket of water would respond faster assuming equal weights. Trying to add all this up, we have plus 250 ZJs in the oceans. No possible outcome could be plus 250 ZJs in the atmosphere as it would be quite warm. So in the roughly 40 year time frame, there were some possible outcomes. 250 ZJs in the oceans or exiting the TOA, or some combination of both. So this large block of 250 ZJs can go into the oceans, but if it does not, it better not hang in the atmosphere for too long. 250/40 years = 6.25 additional ZJs that the atmosphere would have to shed at the TOA each year. Thank you for replying Hank Roberts. Perhaps this is some low level insubstantial question, but I think a 3 bin diagram divided at the TOA and oceans surface showing ZJ flows under different scenarios would be helpful.

  9. 109
    Anonymous Coward says:


    Keeping things simplistic, -> and (– being averaged net energy flows at TOA or the surface of the oceans (ugly, round arrow-heads ’cause RC’s software may otherwise be seeing HTML backets) and the longer arrow being the larger flow…
    greenhouse-driven warming: –> atmosphere -> oceans
    circulation-driven cooling: -> atmosphere –> oceans
    circulation-driven warming: (- atmosphere (– oceans
    aerosols-driven cooling: (– atmosphere (- oceans

    About your original query, it’s important to understand that the larger energy flow is going to be only slightly larger if you average over a long period. There are large short-lived (and often cyclical) imbalances between the net energy flows at TOA on the one hand and the surface of the oceans on the other. But as you noted, the heat capacity of the atmosphere is comparatively tiny. So one way or another, these two flows have to balance in the long run. In the very, very long run such flows are unsustainable of course. But the oceans are so huge that on a human scale, their capacity to balance energy flows at TOA seems inexhaustible. The thing is, that capacity isn’t infinite.

  10. 110
    Hank Roberts says:

    Worth quoting from a

    New comment on Fractal Planet
    SJ (the blog host) commented on General Climate Discussion (1).
    in response to Will: Haven’t really seen this covered.. Does this finding represent any kind of breakthrough vis a vis understanding how marine methane will react, or is it a relatively minor detail?

    Details. It’s like quantifying the things we’ve been thinking about in broad strokes. Lots of work like this to be done, though, mapping out various areas, as factors like bottom water warming and fate of released methane will vary a lot from place to place.

    For context, their “up to 0.4 million metric tons of methane” (of which none may reach the atmosphere) would be about 0.07% of the estimated annual global methane release.

  11. 111
    Victor says:

    #105 Kevin

    “Victor, you are putting on quite a clinic in what confirmation bias really looks like–which is, a lot like argument from incredulity.”

    If you are accusing ME of confirmation bias, you would be wrong. I could care less about whether or not lake effect snowfall increased between 1971 and 2001. Actually an increase in snowfall for any reason during the period covered in that graph could also count as evidence against global warming, consistent with a cooling trend and less snow, not more. The same goes for the accompanying graph, showing no trend in non-lake effect snowfall during that same period. Under a global warming regime, we’d expect snowfall to decrease, not remain steady.

    What my analysis reveals is the confirmation bias of the paper’s authors, whose intention was to associate lake effect snow with climate change, via a correlation with Great Lakes warming. If the alleged warming trend could be associated with a trend toward increased lake effect snow that would bolster their hypothesis. So they carefully chose two datasets that appeared to substantiate their theory. And since they are “real scientists” they focused only on the overall trend indicated by linear regression, conveniently ignoring the fact that there is no trend at all for the last 30 years of the survey. Now THAT is what I would call “confirmation bias.” But I’m not a “real scientist,” so what do I know?

  12. 112
    Victor says:

    Oops again. The sentence in my last comment should read: “Actually an increase in snowfall for any reason during the period covered in that graph could also count as evidence against global warming, since warming would be consistent with less snow, not more.”

  13. 113
    Hank Roberts says:

    Here’s the temperature anomaly vs. CO2 level, year by year.
    Interesting way to see when both of those started to change and where it’s heading:

    That’s from:

    Hat tip to:
    for the lead.

  14. 114
    Hank Roberts says:

    > Victor
    > warming would be consistent with less snow, not more

    It’s so easy to look this kind of thing up. If you’d just write your opinions into a search before pontificating, you’d post fewer mistakes.

    Doou think this kind of mistake attracts readers to your blog? Do you want credulous people who’ll believe what you say without bothering to check your ideas?

    If so, you’re fishing in the wrong pond here I suspect.

    Lake effect snow – Science Daily

    In order for lake effect rain or snow to form the temperature difference between the water temperature between the surface and 850 mb should be at least 13 degrees Celsius. Lake effect of extremely cold air over still warm water in early winter can produce thundersnow, snow showers accompanied by lightning and thunder.

    … large amounts of snow that the lake effect (so called because the lake provides the moisture that fuels the snow) can bring ….

    “This is definitely one of the strongest lake bands that we’ve experienced,” Judy Levan, the warning coordination meteorologist with the National Weather Service office in Buffalo, said….

    And it’s something Buffalo could face more often in a warming world. Rising global temperatures are also warming the Great Lakes and keeping them ice-free longer during the cold season.

    Forecast by measuring the water temperature vs. the air temperature. Easy.

  15. 115
    MartinJB says:


    I am SO very glad to have your insight. You see, I wouldn’t have known that the researchers had the intent of associating lake effect snow with climate change. I also wouldn’t have known that they “carefully’ selected the two datasets that would support their hypothesis. I also wouldn’t have known that “real scientists”, by their nature, focus on the overall trend and ignore evidence that contradicts what they’re trying to prove. If you could now let us know how you KNOW these things, I’m sure we’d all be grateful.

    Of course, it could just be a case of confirmation bias… insomuch as it confirms your idea that climate science is populated by a bunch of folks who blindly follow their numbers without exercising their obviously lacking critical thinking skills. Skills with which you are blessed in truly epic quantities.

  16. 116

    Victor again:

    “If you are accusing ME of confirmation bias, you would be wrong. I could care less about whether or not lake effect snowfall increased between 1971 and 2001.”

    But you quite self-evidently care deeply about proving that climate scientists are wrong, and that you are smarter than all those terrible ‘warmists’ at RC. In this case, that means insisting that what you–or should I write, “YOU”?–see must be correct. Those calculated trends and significance values are just meaningless formalities, and that pesky 2001 data point is clearly an outlier–the Victorian Eye is master of all data that it surveys!

    So yes, I’m accusing you of confirmation bias. Or rather, I would be, if I thought it were a matter of ‘accusation’, rather than a simple human tendency that we all need to guard against if we wish to arrive at something like the truth.

    “Actually an increase in snowfall for any reason during the period covered in that graph could also count as evidence against global warming, consistent with a cooling trend and less snow, not more.”

    Hank already dealt with that one, but since you seem to value personal judgment more than objective science, I’ll offer my own experience growing up in “Snow Ste. Marie,” another place famous for lake effect snow. Back in the 1960s, there was already awareness on the ‘folk wisdom’ level that once Lake Superior froze–and it used to do that fairly regularly, whereas it’s become pretty rare now–snowfalls tended to decrease markedly.

    So, no, the correlation between snowfall and temperature is not simple and linear, though a lot of folks tend to assume it is.

  17. 117
    Chuck Hughes says:

    For Dr. Eric Steig:

    I personally don’t see how this is not an irreversible situation given the fact that CO2 levels continue to rise. Of course, what do I know? I’m looking forward to getting your take on it. This is dated December 2, 2014 so I assume this is the latest information.

    The total amount of loss averaged 83 gigatons per year (91.5 billion U.S. tons). By comparison, Mt. Everest weighs about 161 gigatons (177 billion U.S. tons), meaning the Antarctic glaciers lost an amount of water weight equivalent to Mt. Everest every two years over the last 21 years.

    The rate of loss accelerated an average of 6.1 gigatons (6.7 billion U.S. tons) per year since 1992.

    During the period when the four observational techniques overlapped, the melt rate increased an average of 16.3 gigatons (18.0 billion U.S. tons) per year — almost three times the rate of increase for the full 21-year period. The total amount of loss was close to the average at 84 gigatons (93 billion U.S. tons).
    The Amundsen Sea Embayment in West Antarctica. Credit: NASA

    The Amundsen Sea Embayment in West Antarctica.
    Credit: NASA

    The four sets of observations include NASA’s Gravity Recovery and Climate Experiment satellites, laser altimetry from NASA’s Operation IceBridge airborne campaign and the earlier ICESat satellite, radar altimetry from the European Space Agency’s Envisat satellite, and mass budget analyses using radars and the University of Utrecht’s Regional Atmospheric Climate Model.

  18. 118
    Victor says:


    “But you quite self-evidently care deeply about proving that climate scientists are wrong, and that you are smarter than all those terrible ‘warmists’ at RC.”

    No, I’m not interested in proving climate scientists wrong (except when they actually are, natch). But I, like many others, am skeptical regarding the strenuous efforts by alarmists to attribute any and all unusual weather events to “climate change.” Extraordinary claims require extraordinary evidence — and attributing a cold weather event like snowfall to warming is an extraordinary claim. If in fact warm weather produced cold weather, as was also claimed recently, then there would be nothing to be alarmed about, would there? The two would simply cancel one another out.

    So no, I’m not smarter than any of you guys. I just have more sense. :-)

  19. 119
  20. 120
    MARodger says:

    I think we have had enough of this borehole-fodder from Victor the Troll.
    @118 we are told his beef does not concern the work of “climate scientists”. Rather, his target is “alarmists”, these being in this particular case the authors of Burnett et al (2003) who include a climate scientist and a climate scientist (with odd photo) and a geologist with work in climatology and another climate scientist. So while the alleged target may be “alarmists” (although such an assertion has not be yet justified), the actual chosen targets are all “climate scientists”.
    #118 continues telling us that it is “extraordinary” to attribute a “cold weather event” to “warming”. I was unaware that there was any threshold temperature below which any event is rated “cold weather” and that, however less cold it may have become, however much it is transformed by a globally warming climate, such “cold weather” requires extra proof to be attributed to AGW. Scrub those winter temperature records, those polar ice balances; they are nothing to do with AGW because thay are “cold weather”, apparently. And this is beacuse “warm” is effectively ‘anti-cold”, a position not so difficult to defend, but that also it seems “warm” = “warming”, according to clever Victor.
    I do not feel it is worth giving the commenter @118 (Victor the Troll) further room here. He assures us he possesses “more sense” but, if so, he evidently keeps it locked away and is wholly unwilling to utilise it.

  21. 121
    Dan S. says:

    re: 118. Actually you have shown you have little sense. Your critical thinking skills are clearly abysmal re: climate change as you simply regurgitate what others have told you and what you want to believe (definitive, classic intellectual laziness) as opposed to actually reading the peer-reviewed science. BTW, please cite one, just one, climate scientist who claims “to attribute any and all unusual weather events to “climate change””.

    (crickets chirping)

    Thought so. You are simply shooting from the hip.

  22. 122

    #118–“I just have more sense.”

    Ah, that’s what the kids are calling it these days?

  23. 123
    Radge Havers says:

    “I just have more sense.” @~118

    That’s trolling if ever I heard it.

  24. 124
    Chuck Hughes says:

    So no, I’m not smarter than any of you guys. I just have more sense. :-)

    Comment by Victor — 12 Dec 2014

    Concern Troll –

    A person who posts on a blog thread, in the guise of “concern,” to disrupt dialogue or undermine morale by pointing out that posters and/or the site may be getting themselves in trouble, usually with an authority or power. They point out problems that don’t really exist. The intent is to derail, stifle, control, the dialogue. It is viewed as insincere and condescending.

    That be you Victor.

  25. 125
    Hank Roberts says:

    For Steve Harris, further replies to his offtopic question, further on this:

    If the air mass is at least 13 ° C colder than the lake, heavy lake-effect snow can occur. …. producing bands of heavy snow down wind from the lakes Erie and Ontario.
    – See more at:

    and for Victor, some measurements:

    historical lake temperatures

    Buffalo Lake-Effect Snow: 4 Things to Know –

    Published Nov 20 2014 12:00 AM EST … Nov. 18, the 7 a.m. weather balloon released from Buffalo measured an air temperature of just 0.1 degree … Lake Erie’s average water temperature was 47.8 degrees on November 18.

    Now, what more do you need? I think you can assume the temperatures from Nov. 20 are reported in F not C, so you can figure out if that roughly 47F temperature difference means the lake was more than 13C warmer than the air.

    Can y’all do that and let us know whether you agree on the answer?
    You know how to look this stuff up.

  26. 126
    Steve Fish says:

    Re- Comment by Victor — 12 Dec 2014 @ 5:12 PM, ~# 118

    Victor, your statement- “attributing a cold weather event like snowfall to warming is an extraordinary claim” -is actually what is extraordinary. Atmospheric physics is pretty complicated, but for this situation there is a couple of very basic (high school level) facts that apply generally.

    The world is warmer so more water evaporates. The atmosphere, thereby, contains more water. Have you got that? What happens to atmospheric water vapor? It doesn’t just keep increasing does it? No, in fact it rains and snows out of the atmosphere. What would cause this? Hint- look up dew point and lapse rate. So, when the moist air gets cold there is more precipitation in a warmer world. I know that this is tough, but….


  27. 127
    SecularAnimist says:

    So, everybody gets the virtuous satisfaction of whacking the tired old boilerplate denialist talking points, falsehoods, distortions, irrelevancies, fallacies and outright nonsense in Victor’s blatantly bad-faith trollery over and over again, while Victor gets the trollish satisfaction of being the center of attention while ignoring or dismissing those rebuttals and repeating the aformentioned talking points over and over again, and so it goes, on and on.

    Has arguing with deniers — which is, really, so easy to do — become a sort of “comfort zone” for climate advocates?

  28. 128
  29. 129

    Question to experts:
    On the website I could not find the file GLB.Ts+dSST.txt updated for November, but only the updated file When I use this file to calculate the global temperature anomaly I get 0.64 °C for November 2014. Is this correct?

  30. 130
  31. 131
    Edward Greisch says:

    118 Victor: As far as I am concerned, it only snows when it is warm. “Warm” and “cold” are relative terms. They are relative to the person who is talking. 28 degrees F is warm if you are me. 40 below is cold if you are me. But 40 below is warm if you live above the Arctic Circle or in Antarctica. I agree with everybody except Victor. I think Victor is phishing for a quote to use against RC. So be careful what you say.

  32. 132

    #130–Ah, the monthly update. Still warmer than any November before 2001, but cooler than several since.

  33. 133
    MARodger says:

    SecularAnimist @127.
    I think the expected way of things is that a denialist who is shown to be so obviously wrong will take heed and, like a normal human being, amend their thinking accordingly. Of course this will be difficult when there is denial involved. And it could be considered to be doubly so when the intention is troll-like and is intended to be contrary. But trolls are more thoughtful and thus less deniaist, so the two conditions are not entirely additive.
    Yet there are two conditions when shaming a denialist/troll for holding nonsensical views is less effective. The first is psycopathy, something a true troll could well have in spades. The second is stupidity, something a denialist will very likely be well endowed with.
    Our present infestation is probably primarily a denialist rather than a troll, here getting a couple more hits for his grubby little website from folk who may be curious of where such an idiot could be coming from. That the level of nonsense is unabated on that website perhaps demonstrates that trolling is not the primary aim and the level of stupidity is genuine.

    And the response to such nonsense will always be to rebut it, with egregious nonsense getting the full broadside. While a true troll would revel in such attention, how much of a sad idiot would a denialist have to be to gain the “satisfaction of being the center of attention”?

  34. 134
  35. 135

    #130 Meow

    Thank you!

  36. 136
    Victor says:

    Lake Erie’s water temps were 10 degrees below average last June.

    And here’s a map of November temps for Lake Erie since the 1920’s ( Sierra Rayne ( couldn’t see a warming trend. Neither can I.

    Now as far as lake effect snow is concerned, it takes two to tango: warmth from the water, cold from the air. The cold from the air during the snowstorm in question was part of a blanket of extreme cold that covered almost the entirety of the US. Without that exceptionally cold air the unexceptionally warm water in Lake Erie would not have produced snow of anywhere near that magnitude.

    [edit – strawman arguments just to provoke responses are getting quite boring. Either engage with substantive discussion or play games somewhere else.]

  37. 137
    MARodger says:

    Of course, the lake-effect snow does seem to follow as a result of winter ice conditions on the lakes and the maximum freeze is getting less. Despite all the interannual variability, the downward trend of the Great Lakes Annual Max Ice Cover 1973-2013 is actually statistically significant (-8.3% loss per decade +/-5.5%). So, scratch my head, what’s causing that reduced ice? Shape-shifting aliens? It’s got to be!!

  38. 138

    Victor, you may be interested in this abstract on lake temperatures. They found a trend of 0.4°C per decade for the period between 1985 and 2009.

    For more information, see also the homepage of the Global Lake Temperature Collaboration (GLTC).

  39. 139
    Radge Havers says:


    Websites are easy to set up, and can easily be used as a base for baiting.

    Re: Sad Idiots. You can see he’s not interested in either thoughtful comments or making his case as much as he is in self-promotion:
    “In my latest blog post I cite two other reports in which essentially the same conclusion regarding the California drought is reached. I know you’d rather not go there, Hank, but for any lurkers who might be interested, here’s the link…”

    There was something similar going on recently at Greg Laden’s blog with a troll who also had a trap site set up. In fact I wouldn’t be surprised if they were the same troll.

    In any case, if they’re sucking the air out of a thread, they sould be dumped, IMO.

  40. 140
    Victor says:

    #50 Meow

    I’ve been studying Tamino’s post on Trend and Noise, one of the two linked to by Meow earlier on this thread. (See The distinction he draws between a long term trend and what might appear to be a short term trend, but is really just noise, makes sense for sure. And on general principles I would tend to agree.

    However, there’s an element in the graph that he doesn’t discuss: pattern. And I’m wondering whether the patterning of data, as revealed in such a graph, is taken into account when assessing trends. The GISS graph he displays at the end, starting with 1975, reveals a fairly consistent, wavelike pattern — and that pattern continues into the last segment of the graph as well, from 2002 on. On the other hand, the short-term, one-year, graph he uses as an example of noise displays a completely different pattern, clearly not a continuation of what’s come before. And since Goddard’s 2002-2012 graph looks very much like a continuation of the earlier pattern, it would seem harder to dismiss as mere noise.

    So the question arises: could what distinguishes trend from noise be related to pattern as well as time-span? And is there any means of measuring that?

  41. 141
    MARodger says:

    Radge Havers @139.
    I’m still far from convinced that he is clever enough to be a full-on troll, but am in full agreement that he is ‘sucking air out of the thread’. He certainly brings nothing of interest.

    His latest contribution @136 kicks off pointing to a cherry-picked June temperature report. This year Lake Erie was cold in May rather than June (the link given talks of early June and is dated the 7th), but while May 2014 was the coldest for 30-odd years, this wasn’t so exceptional for that 30-odd year period. And the “10 degrees below average” claim isn’t reflected in the May average (surface) temperatures. June 2014 itself was normal by recent standards, and the average year-to-date has been cool rather than cold, again by recent standards. (NOAA monthly data tables here)
    And the rest of his input @136 that’s substantive is only repeating things he has served up before, although back then he did manage to warn us that he was trawling on a denialist website to get it (presumably informing us for arse-cover reasons). The lack of trend in Lake Erie November temperatures (and October as well) is a lack of statistical trend rather than no trend. Why November? Again a cherry-pick. December/January allow a trend to be seen before the temperature bottoms out at 32ºF in March/April and December/January shows a +0.015ºF/yr trend that is significant (but still only just +/-0.0146ºF over 1927-2014. The data is that noisy).

  42. 142
  43. 143

    #140–Yes, Victor, there are analytic procedures for “patterning.” Recurrent ones can be analyzed via mathematical tools provided by Joseph Fourier.

    [digression]Coincidentally, the guy who first spotted what we now call the ‘greenhouse effect.’


    If you’ve a mind to read up on it a bit, Wikipedia has this to say:

    Tamino has also done a number of posts using Fourier transforms to look at temperature trends (and related phenomena).

  44. 144
    Ray Ladbury says:

    OK, Victor, here’s some data in which to look for a pattern. I will give you 10 ordered pairs. You tell me if there is an oscillatory or wave-like behavior:


    Is there a wave-like pattern. If so, predict the next ordered pair in the data series.

  45. 145
  46. 146
    Matthew R Marler says:

    According to Romps et al, (1) an increase of 1C in global mean surface temperature is calculated to increase the rate of cloud-to-ground lightning discharges in the US East of the Rocky Mountains by 12%, +/- 5%. They model the rate of lightning strikes by multiplying the energy available (CAPE) times the rainfall rate, and multiplying that by a proportionality constant. Their model for lightning strike rate has a good fit, R^2 = 0.77 between modeled lightning ground stroke rate and actual ground stroke rate for a year of data, measured twice per day. They then obtain changes in CAPE times rainfall rate from CMIP5 model runs, and calculate the relative change in lightning rate from the relative change in CAPE times rainfall rate.

    Why is that a reasonable approach to modeling lightning strikes, and why does the model fit well? CAPE, for “convective available potential energy”, is the potential energy in cold, dry air at altitude (units are Joules/kilogram) that is available to be converted to kinetic energy, air that originated as warm moist air at the surface and rose by convection and dried as it cooled. The air cools by at least three processes: expansion, as the air rises through progressively less dense air; advection and mixing at the surface of the rising column; radiation to space by the water vapor and carbon dioxide. CAPE as defined is proportional to the integral across the vertical rise of the air of the difference between the temperature of the rising air and the temperature of the surrounding air (2, pp181-183.) Romps note that this is the maximum amount of energy available to power lightning, and that the exact details of the creation of lightning and its powering by CAPE are not settled. But CAPE is an instantaneous energy density, not a rate of energy flow. A model of a rate of production of lightning strikes requires an energy flow, or power. The natural rate would be proportional to the rate at which energy is carried upward in convection, but that is unavailable; since the water of the process is conserved, Romps et al chose the simultaneous precipitation rate (in kg/m^2/sec ). Their model is accurate if each kilogram of water carries approximately the same amount of energy from surface to lightning height, and if each Joule of CAPE contributes the same amount to lightning. That’s something that I wrote.

    Here is their model: F = (h/E)x(PxCAPE)

    where F is the lightning flash rate per area (m−2 s−1),
    P is the precipitation rate (kgm−2 s−1), and CAPE
    is in J kg−1. Using an adiabatic definition of CAPE,
    the product of CAPE and P is the theoretical maximum
    rate at which kinetic energy is imparted to
    ascending water condensates, in units of W m−2.
    The constant of proportionality, h/E, contains
    the dimensionless conversion efficiency h and
    the energy discharge per flash E (in joules). The
    efficiency h is the ratio of power per area dissipated
    by lightning to the CAPE per area per time available to condensates.We do not propose here a specific charging mechanism, but we note that most charging mechanisms are consistent with the notion that higher updraft speeds and water contents should yield higher flash rates.
    That is a quote from their paper, “eta” converted to “h”. That last statement is about rank orders.

    My question is: Why does it make sense to multiply the CAPE times the rainfall rate? Water is conserved, so the rainfall rate is approximately proportional to the rate at which moist thermals carry warm water from the surface to the layer at which lightning is occurring; does this not implicitly assume that, of each amount of warm moist mass leaving the surface, the same fraction of the energy (latent plus sensible)is converted to CAPE? (that is, constant across the range of temperatures, humidities, rainfall rates and lightning rates encountered in their study? ) Why does their comment about the rank orders translate into this particular proportionality and fit the data well.

  47. 147
    Victor says:


    Yes, Kevin, I know about Fourier analysis. What I was wondering was whether such methods were being used to quantitatively distinguish noise from trend in climate science. If Tamino has already done that then I guess the answer is “yes.” Now I’m wondering whether it’s possible to apply similar methods to the topic of this post.

  48. 148
    Hank Roberts says:

    A tidbit — read it from the top

    I can let you in on a little secret. Michael Mann is embroiled in an intense debate with other climate scientists about an important issue that is totally unsettled. It is a true debate. They are arguing over the data, its interpretation, and what it means. The debate is about the important question of what happens to tree growth shortly following major volcanic eruptions. Mann says it is likely that some trees are so badly affected by the short term climate change caused by the volcanic eruptions that they essentially stop growing, which messes up a small part of the long term record the tree rings from these plants are normally used for to track climate change over time. Others say this doesn’t happen and the record is fine the way it is, but rather, what some think about the effects of volcanic eruptions on climate, and indirectly, on trees, is not exactly right.

    That, ladies and gentlemen, is a debate. A scientific debate. The outcome of that debate will not affect the overall picture of climate change, but it will have an important influence, possibly, on how we calculate the rate at which increasing greenhouse gas will warm the surface of the Earth. (Long term the same outcome will probably happen, but if volcanic effects are stronger, there may be more periods of slightly less rapid warming.) Esoteric, detailed, important, not paradigm changing, not an inconvenient truth, and to most people, mind numbingly boring if you get into the details. But it is an example of the kinds of debate that are real in climate science….

  49. 149
    mrlee says:

    What do you guys think of the lowered oil prices? Good or bad? One one hand, a lot of investment in marginally profitable projects may be canceled. On the other hand I’m afraid the same will be true for renewables. What do you guys believe?

  50. 150
    MARodger says:

    Somebody with a tad more wits about them may come to notice that some websites are equiped with a Search facility. But to come out with an eye-popping “clearly not a continuation of what’s come before” demonstrates the level of witlessness.
    There is a difference between attributing signal (which should be familiar) and plotting some underlying signal one, two, three. I’m not sure that Fourier transforms are particularly useful for either and even in a prelimenary investigative role require use with extreme caution.
    (By the way, 2014 probably won’t be the hottest on record in Australia but a lacklustre third hottest.)