Readers of this weblog know that there have been comments on the warm bias that we have identified, as reported in Matsui and Pielke, GRL, 2005, with respect to the global analysis of surface temperature trends. This is an important issue as this climate metric is used as an icon to communicate the concept of global warming to policymakers. The abstract of the Parker 2004 Nature paper , for example, stated that the
“Controversy has persisted over the influence of urban warming on reported large-scale surface-air temperature trends. Urban heat islands occur mainly at night and are reduced in windy conditions. Here we show that, globally, temperatures over land have risen as much on windy nights as on calm nights, indicating that the observed overall warming is not a consequence of urban development.�
Parker 2004 has been used as evidence to argue that the global surface temperature trends are robust (e.g. CCSP, 2006). In the Matsui and Pielke paper, we show, however, that trends of surface air temperature should not be expected to have the same values for the different sets of days used in the Parker paper. Based on well understood concepts of boundary level meteorology, because Parker found similar trends, there necessarily must be some error in Parker’s analysis. For those unfamiliar with boundary layer meteorology, the reason for this is that minimum temperatures on calm nights should in fact show a larger warming trend than on windy nights (explained below), and not the identical trends reported by Parker. We were motivated to look at this subject because of the obvious inconsistency in the Parker results, and what we found has much broader implications for the long-term surface temperature record.
Studies of the lower levels of the atmosphere (lowest tens of meters) show that it cools at night when winds do not move warm air into the area. This cooling occurs as heat is lost to space. For this reason, minimum daily temperatures typically occur near sunrise, due to cooling overnight. The nighttime cooling varies with height. With light winds, the cooling is greater near the surface and less aloft, while with stronger winds, which are associated with greater mixing of the air above a particular location, the cooling rate is more uniform with height. Light and strong winds can be documented at a particular location from observed wind data.
The rate of heat loss to space is dependent on several factors, including cloudiness and the local atmospheric concentrations of carbon dioxide and of water vapor. Under cloudy conditions, the cooling is much less. Similarly, an atmosphere with higher concentrations of the greenhouse gases, CO2 and H2O, also reduces the cooling at night. Consequently, if there is a long-term trend in greenhouse gas concentrations or cloudiness it will introduce a bias in the observational record of minimum temperatures that will necessarily result in a bias in the long-term surface temperature record.
Because of changes to the atmosphere over the past century, there are several reasons why we should expect the nighttime cooling in the lower atmosphere to have been reduced. One reason for this is that carbon dioxide concentrations have increased, such that the local effect of greenhouse gas concentrations on temperature measurements is larger. Also, an increase of cloudiness has been reported which has the effect of reducing nighttime cooling. An increase in water vapor content in the lower atmosphere would also reduce the cooling rate at night.
Our paper shows that in such circumstances where nighttime cooling is reduced systematically over time, i.e., under trends of greater atmospheric greenhouse gases or an increase in cloudiness, the resulting effect will be to increase minimum temperatures from what they would have been absent the reduced nighttime cooling. This increase in minimum temperatures is greater on nights with light winds than nights with strong winds, due to the mixing of air, and can be on the order of 1 degree C in the lowest 10m above the ground. Minimum daily temperatures are of course important because they are used as input to calculate the daily temperatures that comprise the long-term surface temperature record.
When there is a long-term trend of a reduction in nighttime cooling, then when temperature data are collected, the combination of all of the minimum temperatures on light and strong wind nights will result in an overstatement of warming trends by tenths of a degree. (Note that this assumes that the overall reduction of nighttime cooling such as due to more cloudiness over time and/or increases in the atmospheric concentration of carbon dioxide and/or water vapor is on the order of 1 watt per meter squared. Based on the IPCC, 2001 findings, this is a reasonable estimate of the change over the recent decades in the atmospheric radiative forcing).
What this means is that because (a) the land surface temperature record does in fact combine temperature measurements of light wind and windy nights and (b) there has been a reduction in nighttime cooling, the long-term temperature record may be contaminated by a warm bias that accentuates the observed trend of warmer temperatures. Such a bias would be of similar or larger magnitude to those biases recently discussed in the context of global satellite measurements of temperature. The reduction in nighttime cooling that leads to this bias may indeed be the result of human interference in the climate system (i.e., local effects of increasing greenhouse gases or human effects on cloud cover), but through a causal mechanism different than that typically assumed.
This effect results from a systemic microclimate effect in temperature data which are present in the global temperature record, but are unaccounted for in current analyses. This raises the possibility that those GCMs that appear to accurately represent global average temperature trends over recent decades may be obtaining results that look right when compared to data, but for the wrong physical reasons. If so, this would call into question their ability to accurately predict the future evolution of the climate system.
The broader implications of Matsui and Pielke (2005), which will be well understood by anyone with an understanding of the physics of the lower atmosphere, should cause consternation among anyone who uses the global temperature trend record for scientific or policy purposes. As we have emphasized here (as have others, such as Hansen, Levitus, Barnett, Willis) a more meaningful metric than global average temperature to assess global warming is ocean heat content.
Hi,
Being a child of the forties, I remember what a photochemical soup cities were, especially where there was industry, and this extended to any number of factory towns. Coal was the heating fuel of choice up to ~ 1955 and contributed greatly to the gray dawn. Given that, one might expect that if you are correct, the strongest urban heating effect would have been from ~1910 - 1960.
I think it unlikely that the current decade is cloudier (or better said, that there are lower aerosol concentrations) then in the early half of the twentieth century.
Comment by Eli Rabett — January 23, 2006 @ 7:44 pm
This is really quite amusing. You’ve proposed some simple model of how you think temperatures should behave, and on finding absolutely no support for this in the data, you repeatedly insist the data must be wrong!
Comment by James Annan — January 24, 2006 @ 4:42 am
James- the “simple” model is based on many boundary layer studies of how the nighttime temperature profile behaves in the real world. The model applied in our study is based on data.
I recommend that you read Stull (1988), Oke (1987) and other excellent texts to better understand the observational and theoretical basis for our conclusion.
Oke, T.R., 1987: Boundary Layer Climates, 2nd ed., 435 pp., John Wiley.
Stull, R., 1988: An Introduction to Boundary Layer Meterology. 666 pp., Springer.
Comment by Roger Pielke Sr. — January 24, 2006 @ 7:27 am
Is there such a thing as average global temperature?
Prof John Brignall’s view:
http://www.numberwatch.co.uk/Temperatures.htm
Comment by Paul Biggs — January 24, 2006 @ 10:33 am
Very interesting.
I am new to this area of interest, but I have some small experience in statistical analysis, so……
If the daily minimum temps are showing increases (less cooling), are we seeing similar increases in the daily maximum temps? Or, is the difference of temps between daily min and max temps staying stable, or is it being compressed from the low (and/or the high) end?
Finally, heat (energy) being what it is……if the atmosphere is losing less of it at night, what is the long term impact of the system having more “energy” available?
jdr
Comment by JD Rudman — January 24, 2006 @ 5:04 pm
#5 by JDR is what I wanted to ask. It would be interesting to see the temperature trends by time of day. And the time at which the daily peak have been recorded over the decades.
Even so, it appears that more record high temperatures are being recorded around the world.
Comment by K — January 24, 2006 @ 7:45 pm
JD Rudman- thank your thoughtful feedback on the weblog.
The website http://www.ucsusa.org/global_warming/science/early-warning-signs-of-global-warming-heat-waves.html states
“There has also been a general trend toward reduced diurnal temperature range, mostly because nights have warmed more than days. Since 1950, minimum temperatures on land have increased about twice as fast as maximum temperatures (Easterling et al., 1997).”
This means diurnal temperature, according to their analysis, has decreased.
On the reduction of cooling at night, this would cause an accumulation of heat if it were not compensated by other components in the atmospheric heat budget and/or transfers of heat to the other heat reservoirs in the climate system (the oceans including sea ice, continental ice sheets, and the ground). The assessment of the ocean heat storage changes is the metric that we have proposed to monitor the integrated effect of climate system heat changes (see
Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335.
http://blue.atmos.colostate.edu/publications/pdf/R-247.pdf
Comment by Roger Pielke Sr. — January 24, 2006 @ 8:31 pm
Brignall needs to update his website. Currently the surface records and the satellite record agree within their uncertainties. Moreover, Brignall ignores all but one of the satellite records, one that, although it was the first, has had to be constantly corrected over the years, including a rather embarrassing arithmetic error recently spotted. For the current state of play see http://www.realclimate.org/index.php?p=170 and http://www.realclimate.org/index.php?p=179 which has links to the various studies.
Comment by Eli Rabett — January 24, 2006 @ 9:05 pm
Brignall does need to update his website, but his points about ‘global average temperature’ are very well made. If you are referring to decaying satellite orbit, this was subsequently corrected by Christy and Spencer, and made no difference, if my memory serves me correctly.
Comment by Paul Biggs — January 25, 2006 @ 1:45 am
Re #8: I disagree with the tone in Rabett’s posting. To call the latest error discovered in the Christy/Spencer record “embarrassing” is not correct. It is in line with the thinking at RealClimate, though, where they believe that their status and pride is hurt if someone tells them they have been wrong at some point.
The Christy/Spencer record has been corrected several times as is quite normal in the course of sincere and true science. When an error is spotted and the arguments are solid, changes are made. Rabett should know that there are two major satellite records, one by Christy/Spencer and one by RSS. Both of these contained the recently spotted error, and both have been corrected. There is still a dispute over the statistics applied to the raw data, which leads to a difference between the computed decadal temperature rates. The Christy/Spencer rate is currently at +0.123°C/ decade, while I believe the RSS is closer to 0.20°C/decade.
To aknowledge that your critics have a point and that your methods and/or results should be changed accordingly is one of the key points to true science. It shows strength, rather than weakness. The mentioned weblog would be all the better for it if they understood this.
Comment by Anders Valland — January 25, 2006 @ 2:17 am
Good point Anders - which brings me to this extract from a letter from David Henderson to a UK environment minister:
‘I am sure you will be aware that an important adjustment has just been made to the temperature record derived from satellites as a result of independent replication made possible by the full availability of all data and code. The originator of the satellite record has publicly thanked the researchers that discovered the error. Contrast this with what our own Prof. Phil Jones told Warwick Hughes when he asked for access to the unadjusted raw data from which CRU derive its surface temperature record. “Even if WMO agrees, I will still not pass on the data. We have 25 or so years invested in the work. Why should I make the data available to you, when your aim is to try and find something wrong with it.” (source http://www.ukweatherworld.co.uk/forum/forums/thread-view.asp?tid=24950&posts=18).’
Comment by Paul Biggs — January 25, 2006 @ 9:31 am
Re #10: “Both of these contained the recently spotted error, and both have been corrected.” Really? RSS of course spotted the problem with the UAH data to begin with. I don’t recall that the RSS data ever had this error. Do you have a link to the contrary? Your point about the scientific process is well-taken, but of course S+C would be getting cut a lot more slack were it not for their public role as skeptics. (I should hasten to note that Spencer has gone much farther out on that limb than Christy.) Roger stands as an example of how to go about being critical of the details of climate science without getting in that kind of trouble.
Re #11: Since for some reason it’s not apparent to you, Phil is unwilling to give Warwick his data because Warwick is interested in it only for purposes of attack. This is abundantly clear from a quick glance at Warwick’s site.
Comment by Steve Bloom — January 25, 2006 @ 1:27 pm
Roger, why can’t you just go out and add a second temp sensor to an existing weather station, placing it at a sufficiently different height so as to get some kind of empirical backing for your hypothesis? This seems like it ought to be cheap and easy, and as the CO state climatologist you should be in a perfect position to make it happen. It also seems that the necessary data could be obtained very quickly, since all you need is a rather short period of variable winds.
Comment by Steve Bloom — January 25, 2006 @ 1:34 pm
Re#12 If the data is sound, then it will withstand any ‘attack.’ Whether Warwick’s site is non-believer’s site, or a believer’s site like ‘realclimate’ is irrelavant. Data that is hidden from scientific criticism can’t be trusted, for obvious reasons.
Comment by Paul Biggs — January 25, 2006 @ 3:48 pm
Steve- This is a very good suggestion; we need this capability in the global surface temperature climate observation network. However, the concept that the lapse rates will be different as a function of wind speeds at night is well known. What we need are observations over several decades to quantify the warm bias that we have identified. I am not aware that any such data over this time period exists.
If concurrent measurements were made of the cooling rate in the nighttime boundary layer, however, we could bin the data by wind speed and cooling rate in order to address the magnitude of this issue. The results, though, would be for the particular location where the observations are made.
As State Climatologist of Colorado, unfortunately, we do not have a budget to do this. The National Climate Data Center, as part of their climate reference network, would be an appropriate agency in the United States to undertake this evaluation. The Regional Climate Centers also could perform this analysis (Ken Hubbard, Director of the High Plains Regional Climate Center is an internationally recognized scientist who would be ideal, as he has worked with surface temperature data observations). I will contact Professor Hubbard on this subject.
Comment by Roger Pielke Sr. — January 25, 2006 @ 3:49 pm
Re.#12, I do not have any such links. i have re-checked my information and you are correct that the RSS was not corrected. Thus that part of my post should be disregarded.
I do wonder a bit about your statement that “but of course S+C would be getting cut a lot more slack were it not for their public role as skeptics. ” Do you imply that you would believe their dataset more if they did not publicly express their concerns?
I do agree that Roger sets a very good example for all, and from what I have read of John Christy he seems to take the same approach. As for Roy Spencer he is a quite vocal skeptic, and there are a few issues where I disagree with him. However, on the issues regarding the UAH-dataset I find his argumentation to be solid. He is also quite open on the fact that there is an honest difference of opinion between the UAH and RSS teams.
I do believe that the main point stands, that both Christy and Spencer find it rewarding to have competent people reviewing and correcting their work. The data and methods are out in the open and can be debated. I believe the rest of climate science would benefit greatly from such openness. Sadly, it does not seem to be heading that way.
Comment by Anders Valland — January 26, 2006 @ 5:27 am
Anders, my point was that following years of S+C’s active promotion in non-scientific circles of their data as likely more correct than the (then) conflicting surface temp data, some of the folks on the other side of the debate understandably succumbed to the temptation to wax snarky. Similarly, with regard to the remaining differences, I think that many are tempted to not give S+C the benefit of the doubt to the extent that might otherwise have been the case. To my knowledge, none of this had or has any affect on the scientific aspect of the debate. Finally, I don’t think it’s the case that all of S+C’s data and methods are public.
Comment by Steve Bloom — January 26, 2006 @ 4:01 pm
There are at least three current reconstructions of the MSU data. The first is, of course Spencer and Christy, followed by RSS and then the University of Washington group. You can see them all at http://www.ncdc.noaa.gov/oa/climate/research/2005/ann/global.html.
In addition there was a one time reconstruction of the nadir views in 2000 by Prabhakara and various analyses by Grody and co-workers. S+C shows the smallest trends of all of them.
Brignall ONLY refers to the S+C data set, which he comments on in the following way:
*************************************
Fortunately there is an alternative, which is satellite surveillance. Microwave radiation from oxygen in the atmosphere is temperature dependent and therefore provides a convenient remote thermometer. Because the satellite orbit is continuously scanning the Earth’s surface like a television raster, it is equivalent to a very large number of well-distributed thermometers. As a result it produces a credible estimate of a global average temperature. The results cross calibrate well with data collected by balloons.
Less fortunately, the satellite record is relatively short, as the technology has not been around for very long. It shows a slight cooling trend, but all finite data sets show trends that are not necessarily properties of the parent distribution. All the satellite data tell us at the moment is that there are no dramatic changes of temperature occurring.
***************************
Now this was written previous to the last recomputation of the S+C trends, which now show a positive change within the error limits of the surface trends and the GCMs. Moreover there is no reference to the other reconstructions which were available at the time that Brignall wrote his piece, so he is clearly out of date and should correct his statments.
Moreover, if the previous S+C reconstructions agreed so well with the sondes, what is the current agreement now that the S+C reconstruction has changed?
Comment by Eli Rabett — January 26, 2006 @ 9:41 pm
Ok, now that the science is out of the way, let us look at this correspondence. First I stand by my statement that the last correction to S+C was embarassing. Having published something with a significant sign error is always embarassing. Having the error pointed out by a competitor whose analysis you have been contesting is doubly embarassing. Having that error move your analysis into a range where it is consistent with the analysis of your competitor that you have been claiming is inferior is triply embarassing. Misspelling embarassing is only singly embarrassing.
Second, look at the claims here. Paul Biggs points us to a site that depends on an analysis (S+C pre latest correction) with serious errors in it to support its conclusion. When this is pointed out he falsely claims that the correction of the errors made no difference.
Anders Valland falsely claims that the same error was found in the RSS data set. He states that the S+C trend is currently 0.123 oC/decade and adds that the RSS trend is closer to 0.20 oC/decade. Actually it is 0.14 oC/decade. That is at best technically true but clearly misleading. When the adjustments of the University of Washington group (Fu) are made S+C drops to 0.10 and the RSS trend rises to 0.20.
We will now cue the violins while we hear about “major analyses” “if my memory serves me correctly” “while I believe” and the other magic incantations that confer implausible deniability. You got google guys, maybe even some books.
Comment by Eli Rabett — January 26, 2006 @ 10:11 pm
The point about ‘global average temperature’ is that, however measured, it is inaccurate and is meaningless as a climate change metric.
Comment by Paul Biggs — January 27, 2006 @ 2:32 am
Steve Bloom says in #12 “Phil is unwilling to give Warwick his data because Warwick is interested in it only for purposes of attack. This is abundantly clear from a quick glance at Warwick’s site.”
Steve, The core of my work as it relates to the Jones et al papers, consists of my City Reviews, 5 Degree Grid Cell reviews and the USSR High Magnitude Climate Warming Anomalies 1901-1996, pages. I simply point out how Jones et al use of urban data inserts UHI warming into their trends and contrast this with trends from more rural data often ignored by Jones et al.
Much of this material was posted in 2000 and 2001 and since then nobody has written in and rebutted any of the above material.
Last month I wrote my Open Letter Number 1 to all the Jones et al 1986 authors asking if they had second thoughts about their inclusion of Atlanta. Phil’s reply started, “The Atlanta station you refer to is one of 22 sites within the grid box (30-35N, 80-85W) where Atlanta is located. So even if the data have become more urban affected through time, the effect on the grid-box average would be minor.”
Quite apart from the fact that some of Phil’s other 21 stations in that grid box, for example Savannah, Jacksonville, Macon and Thomasville, are UHI affected, in my opinion we can not approach truth and reality in science by leaving errors in data on the basis that more valid data dilutes them.
Rather than throwing around pejorative terms like “attack” Steve, it would be more constructive for your case to show where any of the many dozens of examples I refer to of Jones et al use of UHI affected data, might be wrong. Finally, you or anyone will need more than a “quick glance”.
Comment by Warwick Hughes — January 29, 2006 @ 2:51 pm
I still find it very strange to think that embarrassment should be a primary reaction. According to what I have read from both Christy and Mears it seems they are not really after embarrasing one another. They are trying to do things right. If the error was so obvious as to make it embarrassing, why did it take so long to be spotted? After all, the S+C dataset has been under attack for a very long time now. If things were as simple as Rabett claims I believe there are a lot of other swho should feel embarrassed for not pointing out the error a long time ago.
Anyways, this is going nowhere. As Paul Biggs pointed out, global average is not a good measure of these things.
Comment by Anders Valland — January 29, 2006 @ 2:57 pm
Gee, Anders, sign errors are not embarrassing? Wooo.
More seriously, a lot of folks don’t appear to recognize that energy content in the atmosphere is pretty much proportional to temperature and thus temperature is a useful index of energy content (and a lot easier to measure).
Comment by Eli Rabett — January 29, 2006 @ 10:29 pm
Eli- one comment here. The energy content of the atmosphere also requires the inclusion of water vapor.as we discuss in:
Pielke Sr., R.A., C. Davey, and J. Morgan, 2004: Assessing “global warming” with surface heat content. Eos, 85, No. 21, 210-211. http://blue.atmos.colostate.edu/publications/pdf/R-290.pdf
Davey, C.A., R.A. Pielke Sr., and K.P. Gallo, 2005: Differences between near-surface equivalent temperature and temperature trends for the eastern United States - Equivalent temperature as an alternative measure of heat content. Global and Planetary Change, accepted.
http://blue.atmos.colostate.edu/publications/pdf/R-268.pdf
In these paers, we evaluate heat in terms of the moist enthalpy in the surface air.
The moist enthalpy is also the metric of heat that should be computed throughout the troposphere (particularly the lower troposphere where the amount of water vapor present can be quite large).
Comment by Roger Pielke Sr. — January 30, 2006 @ 8:47 am
I see Brignall has added a footnote:
Footnote (Jan 06): According to revisionists, the satellite data now show a slight warming trend. This does not affect the argument, besides the fact that apparent trends in random data are never zero, variables in the real physical world are never constant.
The reason I originally posted the link:
“In a well-behaved system an estimate of a global average can be obtained by sampling. As we see in the discussion of averages, the variance of the estimate will be inversely proportional to the size of the sample, and the standard deviation proportional to the square root of this.”
“The global average temperature exists as a theoretical concept. If we were able to place a large number of sensors around the world at regular spacings, we would be able to establish a meaningful estimate of the instantaneous average, which could then in turn be averaged over a year to produce a number that is a reasonable representation of the thermal state of the surface of the planet. Unfortunately, such a ground station network does not exist. Not only are the existing sensors poorly distributed, many are placed in thermally atypical sites such as cities and airports, others are in primitive rural areas where they are poorly maintained. Ironically though, it is over the oceans that the most discrepant surface measurements occur. Thus surface weather stations provide a very poor basis for determining average global temperature.”
Comment by Paul Biggs — January 30, 2006 @ 10:39 am
How, exactly, does one “correct for UHI”? How is it “determined” how far off a history is? It seems that the only way to accurately correct for UHI is eliminate records within, say, 100 km of cities. Has anyone done that and what is the result?
Comment by Steve Hemphill — January 30, 2006 @ 11:14 am
Re #21: Warwick, the quick glance refers to the following statement that is clearly intended to be the first thing that catches one’s eye upon accessing your site: “Exposing situations where unsound science is used to prop up fashionable and expensive policy notions, usually policy coloured a shade of Green.” Why in the world would Phil Jones or anyone else want to hand over their data to someone with such an obvious axe to grind?
BTW, those unfamiliar with Australian politics should know that numerous references farther done the page make clear that the capital G reference to Green refers to the Australian Green Party; i.e., Warwick’s site not only has a bias, but is overtly partisan. All of which is fine, but it’s not exactly indicative of a scientific approach.
Re #25: I can only stand back and admire the logic of that footnote. Paraphrasing, “The data upon which I based my argument is no longer valid, but my argument is unaffected since all data is variable.”
Comment by Steve Bloom — January 30, 2006 @ 2:33 pm
Steve- there is a correction for “urban bias” as reported, for example, in http://www.ncdc.noaa.gov/oa/climate/research/ushcn/ushcn.html
The extract from that summary states,
“The final adjustment is for an urban warming bias which uses the regression approach outlined in Karl, et al. (1988). The result of this adjustment is the final version of the data. Details on the urban warming adjustment are available in Urbanization: Its Detection and Effect in the United States Climate Record? by Karl. T.R., et al., 1988, Journal of Climate 1:1099-1123.”
The new paper by González et al that is reported on in my weblog
http://climatesci.atmos.colostate.edu/2006/01/29/do-urban-areas-have-larger-long-term-temperature-trends-than-other-locations/,
however, indicates the urban bias correction, at least for tropical coastal cities is too small.
Comment by Roger Pielke Sr. — January 30, 2006 @ 7:04 pm
I see. It seems that to correct for UHI one needs to *know* what it is, or estimate it which is just introducing error. One would think the only way to truly eliminate urban bias would be to eliminate urban readings. That’s why I was wondering if anyone looked at strictly non-urban site trends, which would appear to be the most accurate way of checking temperature change.
Thanks,
Steve
Comment by Steve Hemphill — January 30, 2006 @ 8:46 pm
Steve- Thank you for your comment. From our paper
Pielke Sr., R.A., and T. Matsui, 2005: Should light wind and windy nights have the same temperature trends at individual levels even if the boundary layer averaged heat content change is the same? Geophys. Res. Letts., 32, No. 21, L21813, 10.1029/2005GL024407.
http://blue.atmos.colostate.edu/publications/pdf/R-302.pdf
which has been discussed on the weblog, there is a warm bias even with pristine rural locations, when there is any warming in the lower atmosphere at night. The urban bias cannot be corrected this way, and, moreover, the urban effect is different in different parts of the world. This complexity has not been considered by the groups that diagnose surface temperature trends.
Comment by Roger Pielke Sr. — January 30, 2006 @ 10:08 pm
Actually Paul, you might want to send Brignall an Email. Spencer and Christy now agree that the mid-troposphere is warming, and the warming is consistent with measured surface warming. Have not heard anyone sensible call them revisionists. You might also point out to him that the temperature measurements are actually temperature anomaly measurements, that is measurements of changes at different locations, not the absolute temperature.
Brignall’s statement that “According to revisionists, the satellite data now show a slight warming trend.” pretty much labels what follows as twaddle.
Comment by Eli Rabett — January 30, 2006 @ 10:37 pm
Hmm, we must have an odd character in that string.
The contribution of water vaport to the specific heat of air is less than 0.5 per cent. Entropy is not energy. See comment 235 at http://timlambert.org/2005/06/barton/comment-page-5/
Comment by Eli Rabett — January 30, 2006 @ 10:47 pm
Eli- Energy is measured in units of Joules. Moist enthalpy, as we have shown, for example, in
Pielke Sr., R.A., C. Davey, and J. Morgan, 2004: Assessing “global warming” with surface heat content. Eos, 85, No. 21, 210-211. http://blue.atmos.colostate.edu/publications/pdf/R-290.pdf
and
Pielke, R.A. Sr., K. Wolter, O. Bliss, N. Doesken, and B. McNoldy, 2005: July 2005 heat wave: How unusual was it. National Weather Digest, submitted.http://blue.atmos.colostate.edu/publications/pdf/R-313.pdf (see Section VI).
is the appropriate metric of heat for surface air.
As an example, if the ground surface is wet, solar insolation is used mostly for evaporation which elevates the dew point temperature. The temperature does not rise much. However, if the ground is dry, the solar insolation results in a significant elevation of the air temperature.
Comment by Roger Pielke Sr. — January 31, 2006 @ 9:02 am
Re:#31, I wonder if it is a coincidence that John Brignall added his footnote after I posted the link to his site here? He has a mathematical view of ’science’ and has a ‘number of the month.’ For January it is ‘7′ for the number of metres sea level ‘will rise’ in the next 1,000 years. http://www.numberwatch.co.uk/2006%20January.htm
Water vapour? ‘The Climatic Effects of Water Vapour’ -
http://www.physicsweb.org/articles/world/16/5/7/1
Comment by Paul Biggs — February 1, 2006 @ 2:06 am
Re: #18,
The NOAA/NDCC site Eli linked states:
“In all cases these trends are positive. The increase in the UAH time series is 0.12°C/decade (0.22°F/decade), 0.14°C/decade (0.24°F/decade) for the RSS analysis and 0.10°C/decade (0.17°F/decade) for the University of Washington. Trends in UAH, RSS and UW data are less than the trend in global surface temperatures, which increased at a rate near 0.18°C/decade (0.32°F/decade) during the same 27 year period.”
Of the three MSU trends the UAH is in the middle. I find it interesting that all three MSU interpretations have trends smaller than the surface trend. In the associated graph it also looks like the MSU temperature increases lag the surface increases which suggests the surface is warming the atmosphere instead of the atmosphere warming the surface as you would expect from AGW caused by greenhouse gases.
For example, the 1997/98 el Nino transfered a vast quantity of heat from the ocean to the atmosphere. Yet this heat only shows up in the MSU data in 1998. Where did the heat come from and where did it all go?
And really, does 1.8, 1.4, 1.2 or 1.0°C per century seem all that bad compared to 3.0 or 5.4°C per century?
We really do need to get a better understanding of all the “other” causes of surface warming human induced (land use/abuse) and non-human induced so we can get a better understanding of the actual impacts of our greenhouse emissions. Thank you Roger.
Comment by Jeff Norman — February 1, 2006 @ 2:45 am
Roger, the snarky response is go read a text book on thermodynamics. The point is that enthalpy measures energy differences relative to standard states, whereas total energy is not enthalpy.
Comment by Eli Rabett — February 2, 2006 @ 9:49 pm
Eli- The defintion of enthalpy and moist enthalpy are given, for example, at http://amsglossary.allenpress.com/glossary/search?id=enthalpy1. The measure of dry and moist enthalpy is in Joules. It is an absolute measure of the heat in a parcel of air at a given height. I agree it is not total energy but it measures the heat content. In the context of surface global warming, surface air temperature is an incomplete metric as we show in our EOS paper. The contribution of water vapor (and liquid and solid water, if present) must also be included.
Comment by Roger Pielke Sr. — February 2, 2006 @ 10:48 pm
Re #23: Rabett says “Gee, Anders, sign errors are not embarrassing? Wooo.”
Wow, I didn’t realize that it was you who spotted the error. I thought it was the RSS team. It must have been really easy to spot as you think it so embarrasing for those who made it. After all, those I thought spotted the error made no mention og it being embarrassing…
As you are an avid supporter of the Hockey Team I can see why you are so obsessed with embarrassment.
That’s it for me. Eli will surely make another reasoned and well-tempered comment in line with the above, but for the sake of not polluting this otherwise fine discussion I will not reply.
Comment by Anders Valland — February 3, 2006 @ 4:02 am
Well, first I’ll send you all off to learn a little thermo http://www.nyanko.pwp.blueyonder.co.uk/fas/anotherhat_first.html and the mp3 is at http://www.haverford.edu/physics-astro/songs/links.html although you will have to search for it a bit down the page.
I expect everyone found it more interesting than a definition of something like internal energy http://amsglossary.allenpress.com/glossary/search?id=internal-energy1
There are several confusions in Prof. Pielke’s statements. First, while heat, work, internal energy, free energy and a lot of other things have units of J (or ergs or Hartree, or whatever you measure energy in) if we are talking about the energy of the system, then we should talk about the energy, not the heat, the work or the enthalpy, moist or dry.
I will remind everyone who ever took general physics or chemistry that heat is NOT a state function. It is a measure of a type of energy that can be put into or taken out of a system, just like work. Under special conditions (constant pressure) the heat put into (taken out of) a system is equivalent to a change in the enthalpy. We can argue about whether the atmosphere is a constant pressure sytem, but given the dance my barometer makes, it is not really.
Second, since work can be converted to heat with unit efficiency, heat content is at best an approximate and at worst a fairly meaningless measure of total energy since it excludes work. It also has a hard time with radiation.
Third, since the atmosphere can expand and contract as it gains energy both locally and globally, clearly work is being done.
Fourth, you can define, and actually measure the absolute energy of a system. So why not look at the energy of the system (which to good accuracy is characterized by the temperature)?
Comment by Eli Rabett — February 3, 2006 @ 9:43 pm
Anders dear, I never said that I was the one who spotted Christy and Spencer’s embarrassing mistake, I said the mistake was embarrassing. When you first responded, I explained why it was embarrassing.
Your refusal to respond to what is written, rather than what you would prefer to have been written makes any interchange with you tedious. On the other hand your continual practice of this sophomoric technique makes it necessary.
Notice how even and well tempered this response is. Not once did I resort to calling Anders Vallard a thief of fine pralines, someone who does not have a clue how to tie his own shoelaces or a practicioner of the black arts of non-equilibrium statistical thermodynamics. In fact I doubt he is any of these. Still….
Comment by Eli Rabett — February 3, 2006 @ 9:58 pm
UHI… Roger has unaccountably overlooked “Thomas C. Peterson (2003). Assessment of Urban Versus Rural In Situ Surface Temperatures in the Contiguous United States: No Difference Found. Journal of Climate 16: 2941–2959″. You can find a ppt version: http://web.archive.org/web/*/http://www.ncdc.noaa.gov/oa/rural.urban.ppt. And apparently there was something published in Nature… oh yes, it was David E. Parker (2004). Climate: Large-scale warming is not urban. Nature 432: 290.
Jeff - the RSS trend is higher than the sfc trend; for up-to-date stuff the wiki page is usually the best: http://en.wikipedia.org/wiki/Satellite_temperature_measurements
Comment by William Connolley — February 5, 2006 @ 2:53 pm
Hi William- Please read my weblogs with respect to this topic:
e.g. “Why there is a Warm Bias in the Existing Analyses of the Global Average Surface Temperature”
http://climatesci.atmos.colostate.edu/2006/01/23/why-there-is-a-warm-bias-in-the-existing-analyses-of-the-global-average-surface-temperature/
and “Where are the Newly Recognized Uncertainties Assessed in the 2005 GISS Surface Temperature Record?”
http://climatesci.atmos.colostate.edu/2006/01/19/where-is-the-newly-recognized-uncertainty-in-the-global-surface-temperature-record-assessed-in-the-giss-surface-temperature-record/
Both the Parker and Peterson papers have fundamental issues with them. The Parker Nature paper, in particular has been refuted in the peer reviewd paper,
Pielke Sr., R.A., and T. Matsui, 2005: Should light wind and windy nights have the same temperature trends at individual levels even if the boundary layer averaged heat content change is the same? Geophys. Res. Letts., 32, No. 21, L21813, 10.1029/2005GL024407.
http://blue.atmos.colostate.edu/publications/pdf/R-302.pdf
I am looking forward to feedback on the issues that we have raised in the literature and on the Climate Science weblog.
Comment by Roger Pielke Sr. — February 5, 2006 @ 5:30 pm
Eli Wrote: So why not look at the energy of the system (which to good accuracy is characterized by the temperature)
Answer: Two critical factors are ignored. Heat for phase change dwafts changes in Cp values (note: in the example given Cp actually changes by 0.55% not 0.5% — an error of 10%). The second factor is temperature does not include volume change due to increased water vapor. Thus these two factors prevent using temperature alone to characterize the energy of the system to a good accuracy.
Comment by E. A . Stokes III — March 2, 2006 @ 4:17 pm
[...] ces have contributed little overall to the observed warming trends. (Roger Pielke Sr. has thought [...]
Pingback by jfleck at inkstain » Blog Archive » News of the Warm* — June 28, 2006 @ 3:11 pm
RE 8, etc…
Do you know how much scrutiny has been applied to S&C’s work over the years?
Conversely, how much scrutiny has been applied to RSS?
And as far as “rather embarrassing arithmetic error”…well, if that disaparaged their work in the field, do you know how many climate scientists should be similarly disparaged and how many of their studies should be minimized?
RE 12 - Your point about the scientific process is well-taken, but of course S+C would be getting cut a lot more slack were it not for their public role as skeptics?”
Wow, I can’t believe you actually owned up to the double-standard!
Comment by Michael Jankowski — January 24, 2007 @ 9:40 am
This got me thinking …. there has, for reasons of obvious profit motive, been lots and lots of science and engineering done in the realm of electronic equipment cooling that gets into the effects of laminar versus turbulant flow, optimal heat sink designs to obtain a sweet spot in terms of both radiative cooling and turbulance of fan / blower driven air, back pressure, etc. Here is multidisciplinary opportunity knocking, if only the current gulf between the worlds of electronic equipment R&D and manufacture, and, climate science, can be bridged.
Comment by Steve Sadlov — January 24, 2007 @ 10:42 am
When will Eli ever learn to be polite?
Comment by gmischol — March 14, 2007 @ 8:43 am
RE: #46 - shamelessly pinging to my own post … in light of Henrik’s 3 part series on climate models as engineering products …
Comment by Steve Sadlov — March 14, 2007 @ 11:04 am
Gmischol- Thank you for your comment. Everyone on this weblog should be polite.
Not being cordial distracts from the scientific discussion of the valuable contribution on issues in the Comments. One goal of Climate Science is to promote courteous scientific debate.
Comment by Roger Pielke Sr. — March 14, 2007 @ 2:37 pm
Dear Prof. Pielke
sorry for my comment. It was not my intention to distract from scientific discussion. It is especially the friendly tone for most of the time on this blog why I like to come back and read it (and learn a lot).
Comment by Gmischol — March 15, 2007 @ 10:49 am