From the we told you so department and The Hockey Schtick: It is all about nighttime influence on minimum temperatures, mostly due to the heat sink effect of urbanization and nearby structures and paving.
New paper finds “surprisingly, there are many US weather stations that show cooling” over the past century
A paper published today in the Journal of Climate finds, contrary to popular belief, that US “monthly maximum temperatures are not often greatly changing — perhaps surprisingly, there are many stations that show some cooling [over the past century].
In contrast, the minimum temperatures show significant warming. Overall, the Southeastern United States shows the least warming (even some cooling), and the Western United States, Northern Midwest, and New England have experienced the most warming.”
In essence, this paper is saying the weather/climate has become less extreme, with little to no change in maximum temperatures “and even some cooling” of maximum temperatures in some stations, and warming of minimum temperatures. Thus the temperature range between minimum and maximum temperatures has decreased, a less extreme, more benign climate.
According to the paper, the warming in minimum temperatures is regional, with the SE US showing “the least warming (even some cooling),” suggesting that other processes such as ocean and atmospheric oscillations are responsible, rather than a uniform warming from AGW.
Note these results are after the huge up-justments made to the US temperature data and urban heat island [UHI] artificial warming, which could account for all or most of the warming of minimum temperatures.
Trends in Extreme United States Temperatures
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From our 2012 draft paper: Acceptably placed thermometers away from common urban influences read much cooler nationwide:
A reanalysis of U.S. surface station temperatures has been performed using the recently WMO-approved Siting Classification System devised by METEO-France’s Michel Leroy. The new siting classification more accurately characterizes the quality of the location in terms of monitoring long-term spatially representative surface temperature trends. The new analysis demonstrates that reported 1979-2008 U.S. temperature trends are spuriously doubled, with 92% of that over-estimation resulting from erroneous NOAA adjustments of well-sited stations upward. The paper is the first to use the updated siting system which addresses USHCN siting issues and data adjustments.
The new improved assessment, for the years 1979 to 2008, yields a trend of +0.155C per decade from the high quality sites, a +0.248 C per decade trend for poorly sited locations, and a trend of +0.309 C per decade after NOAA adjusts the data. This issue of station siting quality is expected to be an issue with respect to the monitoring of land surface temperature throughout the Global Historical Climate Network and in the BEST network.
That US 5-year temperature graph is interesting. Looking at the measured temperatures, it appears to be cooling from 1930-1998 then upward jump in 2000 then cooling again 2000-present. If we were to believe that graph, US has been cooling most of the time since 1930.
That brings us to one of the unexplored causes of the “pause”. During the past decade it is becoming increasingly difficult to adjust past temperatures down and recent ones up, because too many people are watching and there are numerous unofficial archives of temperature dataset versions out there. With less opportunity for biased meddling, current trends are becoming flat, that is, activist-scientists have shot themselves in the foot.
davidmhoffer says:
“So regardless of what the net forcing actually is from (CO2, sunspots, butterflies on Mars, whatever) it is certainly more pronounced at high latitudes and winter.”
David, I am not so sure that what you say is not an artifact of GISS “adjustements” to the raw data. As I wrote in a response to Ed Carlye at NoTricksZone:
The GISS, Hadcrut4 and other series show a significant warming during the 20th century that is greatest in the Arctic region, in line with the claims of Arrhenius that a doubling of atmospheric carbon dioxide would result in warming mainly in this area, at night and in the winter. However, an analysis of long run raw temperature records from around the Arctic Rim in the database of John Daly (http://www.john-daly.com/stations/stations.htm#Europe ) shows that in most cases of those with a 100 year record show warming in the 1930’s to 1940’s as equal to or greater than the end of the century when atmospheric carbon dioxide levels were much higher, or no trend. Looking at the recent BEST data shows that they use the same raw data for these stations but by data manipulation change the overall trends to one of +0.7C or greater. , Karlén, a Swedish scientist made a plot of 25 data series from the NordKlim database and found similar results that contradicted the IPCC data:
http://hidethedecline.eu/pages/posts/scandinavian-temperatures-ipccacutes–scandinavia-gate–127.php
http://geoclimate.se/articles/20131107_GISS_Wibjorn_Karlen.pdf
His studies are detailed in the post at WUWT (http://wattsupwiththat.com/2009/11/29/when-results-go-bad/) in which he states
” In attempts to reconstruct the temperature I find an increase from the early 1900s to ca 1935, a trend down until the mid 1970s and so another increase to about the same temperature level as in the late 1930s. … In my letter to Klass V I included diagram showing the mean annual temperature of the Nordic countries (1890-ca 2001) presented on the net by the database NORDKLIM, a joint project between the meteorological institutes in the Nordic countries. Except for Denmark, the data sets show an increase after the 1970s to the same level as in the late 1930s or lower. None demonstrates the distinct increase IPCC indicates. The trends of these 6 areas are very similar except for a few interesting details. … I have in my studies of temperatures also checked a number of areas using data from NASA. One, in my mind interesting study, includes all the 13 stations with long and decent continuously records north of 65 deg N.
The pattern is the same as for the Nordic countries. This diagram only shows 11-yr means of individual stations. A few stations such as Verhojans and Svalbard indicate a recent mean 11-year temperature increase up to 0.5 deg C above the late 1930s. Verhojansk, shows this increase but the temperature has after the peak temperature decreased with about 0.3 deg C during the last few years. The majority of the stations show that the recent temperatures are similar to the one in the late 1930s.
In preparation of some talks I have been invited to give, I have expanded the Nordic area both west and east. The area of similar change in climate is vast. Only a few stations near Bering Strait deviates (e.g. St Paul, Kodiak, Nome, located south of 65 deg. N).
One example of published data not supporting a major temperature increase during recent time is: Polyakov, I.V., Bekryaev, R.V., Alekseev, G.H., Bhatt,U.S., Colony, R.L., Johnson, M.A., Maskshtas, A.P. and Walsh, D., 2003: Variability and Trends of Air Temperature and Pressure in the Maritime Arctic, 1875-2000. Journal of Climate: Vol. 16 (12): 2067ñ2077.
He included many more stations than I did in my calculation of temperatures N 65 N, but the result is similar. It is hard to find evidence of a drastic warming of the Arctic.”
“Note these results are after the huge up-justments made to the US temperature data and urban heat island [UHI] artificial warming, which could account for all or most of the warming of minimum temperatures”
So the real results would be no warming at all and probably cooling.
davidmhoffer,
What was the time frame you analyzed. I could easily interpret greater poleward changes in LW as a result of periodic cycles of heated water being transported to the poles. The tropic wouldnt change much, but elsewhere would. Mode waters rise to the surface in the winter.After Arctic oscillation blows thick ice from the Arctic, thinner ice will vent more heat.
herkimer says:
March 25, 2014 at 4:30 pm
8 months are declining, 1 month is flat, and 3 months are rising
On closer inspection, the warming is mostly due to March and June.
WUWT?
This is what I’ve been seeing in my analysis of global temp data, but on a world wide basis. Max temp day over day change is flat. And its Minimum temps that changed, but what I think is happening to min temps is its being influenced by SST’s, for instance when the PDO switched, the amount and location of warm pacific air entering the US changes, the same looks to be happening in Eurasia and Africa.
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jim Steele says:
March 25, 2014 at 9:20 pm
Gil Dewart says: “Note that merely on the basis of atmospheric long-wave absorption bands any temperature increase would likely occur in the minimum temperatures (night, winter, etc.).”
I stronglydisagree. Longwave absorption from uniformly mixed greenhouse gases like CO2 should be acting equally night and day. That is basic physics!!!
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Initially I thought as Gil Dewart does, but upon further study, the “atmospheric windows” and the CO2 & other GHG absorption bands are present regardless of day or night. So I agree w/you.
@davidmhoffer and Jim Steele
I disagree, you just have to look at it as a measure of rate of change, because that’s what it really is, the Sun goes down, and temps drop. It’s also data we have, as opposed to data we wished we had.
What I was most interested in was how has night time cooling changed over time, and is there a trend. I think the answer is it wiggles around a little, and there is no trend.
Something else I’m looking at is how much do daily temps change as the year progresses, and there is a slight trend in the slope of this, But it has a hint of being the top of a cycle, as it looks like it changed direction in the early 2000’s, when the PDO switched.
jim steele;
What was the time frame you analyzed. I could easily interpret greater poleward changes in LW as a result of periodic cycles of heated water being transported to the poles.
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1880 to about 2008. Just a guess as it was about 5 years ago and am going from memory on that. GISS only breaks the data down into very large zones, so I did it with other data sets that let me break it down into 10 degree increments, but I no longer recall which ones. The pattern held for all but the highest lats (about 80 to 90). That said, keep in mind that ALL the warming was minor, just the tropics/summer least minor. And while the pattern was clear, you’re correct that it was potentially more indicative of poleward shifts of periodic cycles, the root cause of which is probably multiple effects with no way to sort out which ones are which.
Mi Cro;
I disagree, you just have to look at it as a measure of rate of change, because that’s what it really is, the Sun goes down, and temps drop.
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The sun goes down gradually, and during that process everything from evaporation to convection to hadley cell circulation to cloud formation and position and enough other factors to fill a text book change gradually too. Plus large processes like AMO, PDO, ENSO and more are superimposed on everything else. So how do you sort out what portion of the measured change was due to changes in those processes versus radiative processes? Unlikely that you can in my books.
To be honest, they don’t matter.
Pick a period or location where the skies are clear for 3-4-10 days, and the underlying pattern comes through, clear skies cool radiatively, and even with weather superimposed on this, you can see this when looking at large numbers of station reading.
Follow the url in my name and go look at the half dozen blogs there on this data.
The only thing that does seem to matter are the large processes, and they are regional, and the data shows this.
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jdej says:
March 25, 2014 at 4:41 pm
The night time bias is discussed very nicely by Dr John Christy in the APS transcript at about page 374. Transcript at http://www.aps.org/policy/statements/upload/climate-seminar-transcript.pdf
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Thanks — very interesting transcript. Recommend it to everyone.
jim Steele says:
March 26, 2014 at 6:03 am
Sir your idea that warm water rises is in direct contradiction to the now known hiding place of the missing heat i.e. it is in the deep ocean. Please conform your thoughts to the correct meme.
Sarc needed?
The reason why the maximum should be used is because it is better correlated between the different stations. July has a high correlation in many places that I have seen.
March is something else, I live at around 45° of latitude in North America, and this year I could see snow melting on the pavement and the top of houses at -12°C on sunny days. The effect of urban development on March temperature is huge. But this year, new snow was constantly falling so the UHI was not as powerful.
I have come to think that the variation of temperature from January to March might be a good indicator of the level of UHI in mid-latitudes. The reason is that March is probably more affected by the UHI than January, not that January is not affected at all. In January, the ratio of sun forcing to air temperature is low, so surfaces without snow cover are not absorbing too much heat from the sun. Also, the amount of accumulated heat in the pavement during the summer is mostly gone. And March is highly affected by the UHI because the snow is melting on the pavement and the top of houses under a sun that is intense in relation to air temperature. So the change in temperature from January to March would be biased toward a warming when urbanization is increasing. And effectively, at many stations it is now nearly impossible to have a March that is cooler than January.
Some people have pointed out to an increase in temperature at the end of Spring and the start of the summer. Maybe the ground is better irrigated. June is often cold because there is a lot of water to evaporate. Remove that water and it is summer. Again, the top of houses and the streets are very well irrigated, Spring is gone very fast on those surfaces.
I have also come to believe that some of the night warming could be due to an increase in the greenhouse effect. I think that more greenhouse gases in the atmosphere means that the atmosphere and the ground exchange more heat. So the temperature of both are more tightly correlated. This leads to an increase in diurnal temperature range in the atmosphere as it follows more closely the daily variation at ground level. Because the daily variation in heat content occurs over a greater volume of the atmosphere, it is lower near the ground. The lowering of the DTR actually cools the max and warms the min, it could explain why so many stations have seen a reduction in the number of very warms days. The lower DTR at ground level would increase the mean temperature a little bit. The higher DTR higher in the atmosphere would also decrease the average temperature a little bit. The cooler nights in the atmosphere could also limit the amount of water vapor that travels to the top of the atmosphere. A drier top of the atmosphere would have a higher adiabatic lapse rate that would lead to a cooling of the stratosphere. The energy budget of the planet would be affected in two ways. First, the increase in CO2 would increase the height of emission to space from CO2 molecules. Second, the drying of the top of the atmosphere would lower the height of emission to space from H2O molecules. I don’t know which would be the strongest, they could annihilate entirely. It is interesting to note that even if sea surface temperatures where high in the last 20 years, the amount of water vapor has only increased near the ground. See climate4you.com in the greenhouse gases section.
richard says:
March 26, 2014 at 4:26 am
“Note these results are after the huge up-justments made to the US temperature data and urban heat island [UHI] artificial warming, which could account for all or most of the warming of minimum temperatures”
So the real results would be no warming at all and probably cooling.
I would combine all the readings from UHI and airports into group “CAGW” and the remaining into group “REALITY.” Then see if there is a growing differentiation over time between the two groups. I suspect UHI has a limit on how warm the UHI effect is and while UHI can grow geographically. Why not use Antarctica and the Arctic with no urban affect as a control??
Mi Cro says:
March 26, 2014 at 7:47 am
To be honest, they don’t matter.
Pick a period or location where the skies are clear for 3-4-10 days, and the underlying pattern comes through, clear skies cool radiatively, and even with weather superimposed on this, you can see this when looking at large numbers of station reading.
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Well yes of course. But that doesn’t tell you exactly how much cooling (or lack of) to attribute to CO2 vs water vapour and all the other radiatively active components of the atmosphere, nor does it tell you CO2’s effects on on the global system where they are mixed in with non clear sky effects to the point where we’ve got no idea at all. I just don’t think you can take the clear sky case and extrapolate it to the whole system. Al the clear sky case tells you is what happens under clear sky conditions.
True, but at low temps you can eliminate most of the effects of water vapor, then that leaves any change in cooling due to changes in GHG’s and aerosols.
And if there’s no evidence of any change, what ever the cause of modern warming is, it isn’t an increase in Co2.
Marc77 says:
March 26, 2014 at 8:37 am
Thanks Marc77 for your thoughts about March and June, and the influence of urban development. You make a lot of sense.
On the effect of greenhouse gases, recent research shows that it is mostly about water. Extensive analysis of radiosonde data shows little effect from CO2 upon the temperature profile in the atmosphere up to mid Stratophere.
“The fits for the barometric temperature profiles did not require any consideration of the composition of atmospheric trace gases, such as carbon dioxide, oxone or methane. This contradicts the predictions of current atmospheric models, which assume the temperature profiles are strongly influenced by greenhouse gas concentrations.”
http://oprj.net/articles/atmospheric-science/19
If we look at the data from the Southpole’s winter, there is a slight cooling since the 1950s. To me that suggests no CO2 sensitivity. Due to the extreme cold water vapor is no factor and it is far enough from the oceans to minimize effects from ocean heat ventilation. There is virtually no landscape or urbanization effect, and during the long Antarctic night the only driver of temperatures trends would be CO2 concentrations. Yet no warming trend.
The most important is probably that the daily max has not changed much in the last 60 years. July is not getting warmer. And we should wait to see what happens when the North Atlantic goes cold. The amount of water vapor over Eurasia might be affected.
A question based on the following below, I know this is the thermosphere and therefor not relevant to the lower atmosphere but how come we cannot make the same observations on co2 in the lower atmosphere either looking up or down with the same equipment. They seem to make precise observations, how come we cannot lower down.
Carbon dioxide and nitric oxide are natural thermostats,” explains James Russell of Hampton University, SABER’s principal investigator. “When the upper atmosphere (or ‘thermosphere’) heats up, these molecules try as hard as they can to shed that heat back into space.”
“The thermosphere lit up like a Christmas tree,” says Russell. “It began to glow intensely at infrared wavelengths as the thermostat effect kicked in.”
“For the three day period, March 8th through 10th, the thermosphere absorbed 26 billion kWh of energy. Infrared radiation from CO2 and NO, the two most efficient coolants in the thermosphere, re-radiated 95% of that total back into space”
But what you don’t understand is that all of this upsets manbearpig.
What is the point of setting standards for weather stations and then continuing to include those that are “non-compliant” with the required standard?
With respect to the increase of minimum temperatures, see
McNider, R.T., G.J. Steeneveld, B. Holtslag, R. Pielke Sr, S. Mackaro, A. Pour Biazar, J.T. Walters, U.S. Nair, and J.R. Christy, 2012: Response and sensitivity of the nocturnal boundary layer over land to added longwave radiative forcing. J. Geophys. Res., 117, D14106, doi:10.1029/2012JD017578. Copyright (2012) American Geophysical Union. http://pielkeclimatesci.files.wordpress.com/2013/02/r-371.pdf
Among our conclusions, we wrote
“it is likely that part of the observed long-term increase in minimum temperature is
reflecting a redistribution of heat by changes in turbulence and not by an accumulation of
heat in the boundary layer.”
In other words, this part of the temperature increase is not a result of warming, just a change in the vertical structure of the temperature,.
Nice discussion, guys. Don’t forget that “etc.” in my post. How about bringing in some geography here – relation of the atmospheric absorption spectrum to “polar warming”(?).
CFACT reports today that the winter of October 2013-March 2014 has been the coldest since 1912.