Study: Many US weather stations show cooling, maximum temperatures flat

US_station_trends_Jones

Image: Verity Jones plotted from GHCN data

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.

NCDC_adjustments_vs_measured


 

Journal of Climate 2014 ; e-View

Trends in Extreme United States Temperatures

Jaechoul Lee Department of Mathematics, Boise State University, Boise, Idaho Shanghong Li and Robert Lund

Department of Mathematical Sciences, Clemson University, Clemson, South Carolina
Abstract
This paper develops trend estimation techniques for monthly maximum and minimum temperature time series observed in the conterminous 48 United States over the last century. While most scientists concur that this region has warmed on aggregate, there is no a priori reason to believe that temporal trends in extremes and averages will exhibit the same patterns. Indeed, under minor regularity conditions, the sample partial sum and maximum of stationary time series are asymptotically independent (statistically). Previous authors have suggested that minimum temperatures are warming faster than maximum temperatures in the United States; such an aspect can be investigated via our methods. Here, statistical models with extreme value and changepoint features are used to estimate trends and their standard errors. A spatial smoothing is then done to extract general structure. The results show that monthly maximum temperatures are not often greatly changing — perhaps surprisingly, there are many stations that show some cooling. 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.

 

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.

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Gunga Din

,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.

==================================================================
Love that.
“Up-justments”.
“I was colder than I thought!”

Dave N

Cue the predictable alarmists quote of “the US is just 2% of the Earth’s surface”, then cue the “you’re missing the point” replies.

Gil Dewart

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.).

Carnwennan

Careful not to over egg the UHI effect, Surfacestation irregularities notwithstanding. The reason for this discrepancy is mostly the greenhouse effect which limits the rate at which heat leaves the atmosphere at night. We are all aware of the way high humidity and cloud cover leads to warm nights. The point we should be making is that greenhouse warming is not harmful as it mostly effects night time temperatures and minimums, not potentially dangerous daytime maximum temperatures.

JimS

It takes a lot of effort on the part of many bureaucracies to keep that hockey stick from getting limp.

Gunga Din

Gil Dewart says:
March 25, 2014 at 4:07 pm
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.).

===================================================================
Where I live roughly 60°F overall have been added to the record lows between 2002 and 2012.

Gunga Din

JimS says:
March 25, 2014 at 4:11 pm
It takes a lot of effort on the part of many bureaucracies to keep that hockey stick from getting limp.

===========================
I think it’s gone beyond Viagra.

Peter Miller

Are there any ‘proofs’ for global warming that do not involve the use of manipulated statistics or dodgy computer models?

Gary Pearse

“suggesting that other processes such as ocean and atmospheric oscillations are responsible, rather than a uniform warming from AGW.” (re nighttime warming)
I guess the obvious heat urban heat sink phenomenon warming the nights wasn’t suggesting itself to these fellows. I remember an uncle of mine getting married in Yonkers in 1950 – he was warned that it would be a lot hotter and muggier in downtown NY in July and better in Yonkers. Sheesh, ordinary folk were aware of this over 60 years ago.

Dave N says:
March 25, 2014 at 3:54 pm
Cue the predictable alarmists quote of “the US is just 2% of the Earth’s surface”, then cue the “you’re missing the point” replies.

Yeah, but…
supposedly the US monitoring sites were/are the best in the world.
So, if the US sites have such a debatable level of reliability, how bad must the rest of the world’s information be?
I doubt if there is anyone who calls himself/herself a “climate scientist” disagrees that the planet’s climate has warmed since the end of the LIA, but I suspect beyond that there isn’t so much agreement on how much it has warmed, especially when one analyzes the siting and accuracy problems.

herkimer

“There are many stattions that show cooling” Even NCDC/NOAA records show cooling .
The following are monthly temperature trends for Contiguous US or 48 states as calculated by the NCDC/NOAA Climate at a Glance web page for the last 16 years [1998-2014]. The figure reflect the linear trend in Fahrenheit degrees per decade per NCDC/NOAA web page data t o March20,2014 using base period of 1998-2013
WINTER (-1.78 F/DECADE) – DECLINING
DEC -1.21 F/decade (declining)
JAN -1.52 (declining)
FEB -2.77 (declining)
SPRING (+0.21 F/DECADE)- RISING
MAR +1.4 (rising)
APR -0, 21 (declining)
MAY -0.56 (declining)
SUMMER (+0.48 F/ DECADE-RISING
JUN +1.19 (rising)
JUL +0.25 (rising)
AUG -0.01 (declining)
FALL( -0.44 F/DECADE-DECLINING
SEPT +0.06 (flat)
OCT -0.61 (declining)
NOV -0.76 (declining)
ANNUAL(-0.38 F/DECADE-DECLINING
Summary
8 months are declining, 1 month is flat, and 3 months are rising
WINTER AND FALL have DECLINING TEMPERATURES
SPRING AND SUMMER have RISING TEMPERATURES [Spring is almost declining with 2months out of three declining]

jdej

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
Dr Christy provides real data for temperatures in the troposphere and compares with the models. Same effect off models running hot. Well worth reading the whole transcript. Dr Christy’s section begins on page 300

JimS

This statement is most interesting:
“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.”
A more benign climate is a prelude to an episode of long-term glaciation.

aaron

UHI is a poor term. Economic Heat Island is a little better, but not very good because of financial distortions. Agriculture and civil engineering/land use changes are probably huge contributors to land surface temperatures.

Having stumbled upon many stations with cooling trends a good while ago (http://diggingintheclay.wordpress.com/2010/09/01/in-search-of-cooling-trends/), speculated on the many possible reasons for this (http://diggingintheclay.wordpress.com/2011/10/30/how-best-to-deal-with-cooling-cities/ http://diggingintheclay.wordpress.com/2012/05/13/examining-urban-heat-islands-part-2/), it’s good to see such studies appearing in the literature.
US stations with cooling trends were also fairly obvious when mapping station trends:
US map of station trends by colour

Jimbo

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.

The Climastrology adjustments are objective, unbiased and based on rigorous methods. We can calculate to within very, very small changes in temperature. That’s how we do things, just listen to the ‘necessary’ upward adjustments voodoo science.

Jimbo

Adjust for this!
http://youtu.be/t-sXHl3l-rM

The siting classifications clearly nails what’s going on – there is no other explanation of significance except UHI for the data. All the other would-be causes would affect all the sites
equally, which is clearly not the case.

LadyLifeGrows

Yeah, we’ve known about the alarmists fiddling the weather data for years. But they are called “the Church of Global Warming” because they act like young-Earth Creationists in that there is absolutely no falsifying their hypothesis. This isn’t going to do the trick, either.
We need to upgrade their ability to face reality. That means searching intently for where they are RIGHT. And they are fundamentally right in Keeling’s CO2 graph. An alarmist site I looked at this week referred to a society for the preservation of the Keeling graph. But I first saw it here.
That graph is not natural–not with that timing. Modern civilization caused that graph. But what does it mean?
The little annual wiggles provide a clue. Carbon dioxide goes up in the winter when plants and animals are dying. It falls in the summer when plants are photosynthesizing. So that graph means either–the Earth’s carrying capacity is rising due to burning fossil fuels (as suggested by leaf area indices) or that we are looking at a Great Dying due to soil-destroying modern agriculture.
I believe it is both.
So how do we make the liars right? By thanking them for pointing out the Keeling graph and directing the Environmentalist movement toward truth. They want to heal the world–which DOES need a great deal of healing. And they can only really heal it if the tell the truth and deal with the truth.

@Dave N – they are becoming predictably boring. Well done.

pat

this goes on and on with MSM coverage of scary CAGW stories; nary a sceptical mind on show:
26 March: Business Spectator: Roz Pidcock: How the media’s preparing for IPCC impact
Ahead of its official launch on Monday, parts of the media have been previewing the second part of the report on climate change impacts, after it was leaked online a few months ago.
Here’s our rundown of which of what’s been making the pages of our newspapers;
‘Immediate and very human’ risks
Seth Borenstein for Associated Press gives a succinct rundown of the “immediate and very human” nature of climate change impacts. On the report’s key messages, Borenstein says:
“The big risks and overall effects of global warming are far more immediate and local than scientists once thought. It’s not just about melting ice, threatened animals and plants. It’s about the human problems of hunger, disease, drought, flooding, refugees and war, becoming worse.”
Alister Doyle for Reuters describes how climate change impacts are already being felt across the world, putting pressure on governments to act. Growing risks include food and water security, violence and conflict, health risks, species losses, extreme weather and slowed economic growth…
***Primed and ready
The scale of climate change impacts is huge – from heatwaves, to crop production, to sea level rise. And the range of topics covered in our newspapers so far would seem to bear this out. The media is primed – get ready for a more detailed look at some of these issues as delegates in Japan thrash out the exact wording of the Summary for Policymakers – ahead of its official release next Monday.
Originally published on Carbon Brief.
http://www.businessspectator.com.au/article/2014/3/26/policy-politics/how-medias-preparing-ipcc-impact

Theo Goodwin

Doesn’t the “US Temperature Five Year Mean” chart show the NCDC reported as cooler than the actual readings? Is the chart labeled correctly? What am I missing?

pat

what pecision!
26 March: Salon.com: Lindsay Abrams: 10,853 out of 10,855 scientists agree: Global warming is happening, and humans are to blame
Virtually all of the scientific papers published in 2013 accept climate change
As geochemist James Lawrence Powell continues to prove, the only people still debating whether or not climate change is “real,” and caused by human activity, are the ones who aren’t doing the actual research. In an update to his ongoing project of reviewing the literature on global warming, Powell went through every scientific study published in a peer-review journal during the calendar year 2013, finding 10,855 in total (more on his methodology here). Of those, a mere two rejected anthropogenic global warming. The consensus, as he defines it, looks like this…
http://www.salon.com/2014/03/25/10853_out_of_10855_scientists_agree_man_made_global_warming_is_happening/

stas peterson

Am I the only one that questions taking the average of the good sites +.155, and the bad ones +.248 and getting +.3 something, instead of +.202? What the hell kind of average is that?

Theo Goodwin

Verity,
From your map I get the impression that “no change” and “cooling” far exceed “warming.” Am I reading that correctly?

DR

I’m sure glad I don’t have to to present data to A2LA auditors like is done to temperature records; our 17025 accreditation would be laughed off the wall.
Scientists should be required to have not only a statistician accompany all their research, but a metrologist as well. The creative data manipulation climate “scientists” is jaw dropping.
.

This seems to confirm what we’ve been saying for awhile about the discrepancy between rising “average” temperatures and the almost complete absence of new state maximum records.
http://en.wikipedia.org/wiki/U.S._state_temperature_extremes
I love the word “surprisingly” in that abstract… Only surprising for certain biases, I suppose…

Verity Jones says: March 25, 2014 at 5:02 pm
Verity, I was curious as to the trend period in your plot? Also the data source?

Theo Goodwin says: March 25, 2014 at 5:34 pm
Doesn’t the “US Temperature Five Year Mean” chart show the NCDC reported as cooler than the actual readings? Is the chart labeled correctly? What am I missing?

NCDC cooled the past temperatures and left the recent temperatures unchanged, therefore making the supposed warming look much greater than it actually was, if indeed there was any warming at all in the raw data.

D. Cohen

This article suggests that global warming as originally put forth by the alarmists — not much change in the daytime highs but higher lows overnight — is a good thing, calling the result a more benign climate. In fact that is what has been driving me nuts over the last decade, the assumption by both skeptics and alarmists that global warming would be bad for us rather than good. Everyone is eager to debate the science rather than this premise — the premise that global warming would be bad — instead of whether or not the premise itself is true. Personally, I would like warmer winter nights, longer growing seasons, and both greenland and antarctica ice-free and ready for human settlement.

WestHighlander

Surely, Mr. Powell understands that literature searches and meta studies are not doing “Actual Research”
“As geochemist James Lawrence Powell continues to prove, the only people still debating whether or not climate change is “real,” and caused by human activity, are the ones who aren’t doing the actual research. In an update to his ongoing project of reviewing the literature on global warming, Powell went through every scientific study published in a peer-review journal during the calendar year 2013, finding 10,855 in total (more on his methodology here). Of those, a mere two rejected anthropogenic global warming. The consensus, as he defines it, looks like this”…

rogerknights

pat says:
March 25, 2014 at 5:36 pm
what pecision!
26 March: Salon.com: Lindsay Abrams: 10,853 out of 10,855 scientists agree: Global warming is happening, and humans are to blame
Virtually all of the scientific papers published in 2013 accept climate change
As geochemist James Lawrence Powell continues to prove, the only people still debating whether or not climate change is “real,” and caused by human activity, are the ones who aren’t doing the actual research. In an update to his ongoing project of reviewing the literature on global warming, Powell went through every scientific study published in a peer-review journal during the calendar year 2013, finding 10,855 in total (more on his methodology here). Of those, a mere two rejected anthropogenic global warming. The consensus, as he defines it, looks like this…
http://www.salon.com/2014/03/25/10853_out_of_10855_scientists_agree_man_made_global_warming_is_happening/

But here’s what I’ve posted on various websites that reported on Powell’s Puffery earlier:

The article states:

“To be classified as rejecting, an article had to clearly and explicitly state that the theory of global warming is false or, as happened in a few cases, that some other process better explains the observed warming. Articles that merely claimed to have found some discrepancy, some minor flaw, some reason for doubt, I did not classify as rejecting global warming.”

How many papers that “explicitly state that the theory of global warming is false” would get by peer review with that phrase intact? How many would even be submitted to peer review if they included that phrase? They therefore tend to be more circumspect and merely cite a discrepancy, some flaw (minor perhaps only in the author of this article’s opinion), etc.
Here’s a link to 1100+ peer-reviewed papers supporting skeptical arguments critical of ACC/AGW alarmism:
http://www.populartechnology.net/2009/10/peer-reviewed-papers-supporting.html
========

The article states:
“Global warming deniers often claim that bias prevents them from publishing in peer-reviewed journals. But 24 articles in 18 different journals, collectively making several different arguments against global warming, expose that claim as false. Articles rejecting global warming can be published, . . . .”

Strawman. The claim is not that skeptics are 100% “prevented” from being published, but that that it is difficult (and hence rare) to get them published, or to get them published without being watered down, as I hinted above.
==========

The article states:
“If there is disagreement among scientists, based not on opinion but on hard evidence, it will be found in the peer-reviewed literature.”
AND:
“A few deniers have become well known from newspaper interviews, Congressional hearings, conferences of climate change critics, books, lectures, websites and the like. Their names are conspicuously rare among the authors of the rejecting articles. Like those authors, the prominent deniers must have no evidence that falsifies global warming.”

IOW, an article will be classified as skeptical only if it presents hard evidence. BUT an article will be counted accepting/endorsing even if it presents no hard evidence, but merely implicit opinion:

“Articles about methods, paleoclimatology, mitigation, adaptation, and effects at least implicitly accept human-caused global warming and were usually obvious from the title alone.”

Denial must be explicit, but acceptance may be implicit. This double standard biases the results of this article. By how much is unknown. For that, the author should have indicated how many fall into the “implicitly accepting” category.
==========

The article states:
“If there is disagreement among scientists, based not on opinion but on hard evidence, it will be found in the peer-reviewed literature.”

But the weakness of the warmist case isn’t in the “hard evidence” so much as in the inferences drawn from that evidence, the selectivity applied in deciding which evidence is the most relevant, the inferences drawn from those relevant bits of evidence, the assumptions made, etc. It is at those matters where the main thrust of skepticism has been directed.
But journals want to publish “findings.” This biases them against publishing wide-ranging, argumentative critiques. (To be fair, they rarely publish similar argumentative essays from the warmist side either.) They have a just-the-facts attitude. But the facts don’t speak for themselves. Argumentation has therefore moved to other venues.
What’s needed is an online venue where viewpoints can be argued among credentialed scientists, with the peanut gallery roped off into a separate section where their comments won’t disrupt the discussion, but can be drawn upon by the participants if desired. (Seen but not heard, IOW.) This is what has finally gotten underway with the establishment this month of the Climate Dialogue site, at http://www.climatedialogue.org/
==========

The article concludes:
“Scientists do not disagree about human-caused global warming. It is the ruling paradigm of climate science, in the same way that plate tectonics is the ruling paradigm of geology. We know that continents move. We know that the earth is warming and that human emissions of greenhouse gases are the primary cause. These are known facts about which virtually all publishing scientists agree.”

So what? (Irrelevant thesis.) Skeptics don’t deny that. What they deny is that this warming will continue at its current pace; that it would be very harmful if it did so—or even harmful on balance at all; and that there are amplifying factors that will accelerate the current trend. The alarmists’ case rests on the assumptions of strong positive feedbacks and the absence or weakness of negative feedbacks. That’s where their case is weakest.

The article states:
“By my definition, 24 of the 13,950 articles, 0.17 percent or 1 in 581, clearly reject global warming or endorse a cause other than CO2 emissions for observed warming. The list of articles that reject global warming is here.”
[i.e., at http://jamespowell.org/styled/index.html ]

Hmm . . . There’s nothing in that list by the following skeptical scientists, at least half of whom have presumably published papers properly classified as skeptical:
Syun-Ichi Akasofu, Claude Allègre, John Christy, David Douglass, Don Easterbrook, William M. Gray, Richard Lindzen, Nils-Axel Mörner, Fred Singer, and Roy Spencer.
I took their names from Wikipedia’s “List of [35] scientists opposing the mainstream scientific assessment of global warming” at http://en.wikipedia.org/wiki/List_of_scientists_opposing_the_mainstream_scientific_assessment_of_global_warming
Here are four other names, half of whom I presume wrote articles that were missed: Zbigniew Jaworowski, Augusto Mangini, Nathan Paldor, and Richard Tol.

Steve from Rockwood

You might want to update that “US stations” to “US and Canadian stations” so that I can feel comfortable knowing the American climate scientists haven’t invaded the Great White North.
It’s interesting how poor the coverage across Canada is (compared to the US).

Kenny

Just saw an article from Live science stating CO2 levels were 5 times higher during the dinosaur days. How’d they ever survive?

Steve from Rockwood

And you took over Mexico too.

Anthony Watts says:
March 25, 2014 at 5:25 pm
Verity, I’ve added your map to the head post
===============
good to see that tiny cross on the map at James Bay labelled Canada. Whole lotta ‘mericans probably couldn’t locate it otherwise.

Jeff F

Its amazing how when you examine a paper that was published by a department of Mathematics, you get completely different results from publications from a department of “Climatology”. The sad thing is that most of the climate scientists aren’t even hiding their bias anymore. They are just churning out garbage year upon year.

chris y

Mosher says we only need 5 stations to nail the US temperature trend. Now have a glance at Verity Jones’ map, and make your ‘pick-5’ choices for 5 stations that are dispersed across the country. My guess is that the nailed trend can vary from -5 C/century to +5 C/century.
Dead. Certain.

KenB

I guess it’s damn, we needed better fudging factors, why didn’t we adjust all the old temperature data ranges to anticipate that someone might look when we had the opportunity and the world media at our beck and call. Too many eyes looking now to get away with that sort of thing, but double talk and confusion might work in the short term!! I also noted the “surprisingly” but then we are not surprised at all.

This study confirms my own research of a few years ago, that not only do adjacent cities show inconsistent temperature trends, but states do, also. CO2 is an amazing molecule, to be able to decide which of two adjacent states to warm (e.g. New Mexico warming at 0.9 degrees F per century) and which to ignore (e.g. Texas, with zero degrees F per century). Also, Oklahoma is warming, while its neighbor, Arkansas, shows a cooling. Nice trick. CO2 is just amazing.
For NCDC data showing state-by-state comparisons, see http://sowellslawblog.blogspot.com/2011/09/us-long-term-temperature-trend-from.html
and for the Hadley-CRU data on more than 80 US cities, see http://sowellslawblog.blogspot.com/2010/02/usa-cities-hadcrut3-temperatures.html

Keith Minto

Minimum temperatures are meant reflect the lowest measured point of heat release, and as known from UHI, this is variable and not very important for climate studies. Sure, if you are city confined, knowing if you will need a cardigan at 3am may be important for you but not for long term record keeping purposes.
Maximum temperatures, with all of their problems in consistency across various geographies, are the closest approach we have to record what climate studies need : a reasonably accurate measure of daily insolation on the atmosphere at human level on the surface.
Heat release is just not that important.

Theo Goodwin

Hockey Schtick says:
March 25, 2014 at 5:49 pm
Thank You. By the way, you have an excellent website.

Jeef

JimS on March 25, 2014 at 4:11 pm
It takes a lot of effort on the part of many bureaucracies to keep that hockey stick from getting limp
——————
Why am I now thinking of hockey stick ‘fluffers’?!

Gunga Din

Gunga Din says:
March 25, 2014 at 4:12 pm
Gil Dewart says:
March 25, 2014 at 4:07 pm
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.).
===================================================================
Where I live roughly 60°F overall have been added to the record lows between 2002 and 2012.

====================================================================
I need to clarify that.
I didn’t mean that the record lows set between those dates have had 60°F added to them but that comparing the record lows listed in those years have have been “up-justed” about that amount.
I also meant 2007 and not 2002.

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!!!
However because daytime convection currents mix the air column all the way up to the tropopause and there is no night time convection, climate scientists have argued that we can detect greenhouse warming more easily at night.
Howeverif there is any “heat accumulation” due to CO2 trapping of heat, then we must see that signal in the maximum temperatures. However that is not the case. Most maximum temperatures in the USA have never exceeded the 1930 or 50s. If the maximums have not increased then ther can not be any heat accumulation.
Droughts also confound any interpretation of heat accumulation because temperatures rise more quickly when the surface is dry even when less heat has been absorbed due to lost heat capacity. Likewise the High pressure systems that create heat waves temporarily suppress convection that traps the heat in a very shallow layer near the surface for days, but once the High moves away the heat is carried back to the stratosphere. Averaging minimum temperatures or tempatures during droughts and heat waves are not a reliable measure of the green house effect.
Minimum temperatures measure a very shallow layer near the surface. At night and during the winter temperature inversions establish, trapping cold air at the surface while warmer temperatures stay aloft. The citrus and grape industries understand this and if there is a frost warning they deploy their huge fans to mix the warmer air down to the surface.
That night time and winter shallow surface layer is more prone to changes in the wind that bring warmer air to the surface. That shallow inversion layer is also prone to more warming from waste heat and surface changes that hold more heat, because the heat is not mixed throughout the air column like typical maximum temperatures. Likely due to such well established physical differences between daytime max and night time minimums, Karl did several studies in the 80s and 90s showing that higher populations created warmer minimums while maximums remained practically unchanged. All that suggests maximum temperatures are the best indicator of climate change while minimum temperatures are better indicators off landscape change.

norah4you

That’s US, correct or not correct presented data is irrelevant for the climate debate as long as the climate change belivers forgotten to present same type of weather stations for places in for example Indian Ocean……. How many local readings/day out in open sea is to be found in daily reports? Mind you – if there is area where all satelites missed a big plane – how is it possible to believe that same satelites made temperature readings available for let’s say each 20 meter in open sea. Approximation, in- or expolering of data assumtions and models never ever show correct situation. Let alone correct temperatures if there aren’t enough weatherstations on ships to give more figures than the satelites……

davidmhoffer

jim steele;
I stronglydisagree. Longwave absorption from uniformly mixed greenhouse gases like CO2 should be acting equally night and day. That is basic physics!!!
>>>>>>>>>>>>>>>>>
Jim, you’re one of the best contributors there is to this site in my opinion. But on this, I’m not so certain. Stefan-Boltzmann Law is:
P=5.67*10^-8*T^4
So, for a given increase in downward energy flux, the temperature increase would be expected to be smaller at higher temperatures. For example, at 20 degrees C, it takes 5.7 w/m2 to raise the temperature one degree, but at 40 C it takes 7.0 w/m2. To be fair of course, at 20 C there’s only 418 w/m2 going up from surface for Co2 to work on, while at 40 C there is 551. But the cooling cycle starts at the high temperature for the day, and so it is that higher upward LW flux that the ghe works with to slow the descent into night time lows. Hence I’d expect a more pronounced effect at night than during the day.
Of course it is way more complicated than that once you start considering lapse rate and emergent feed backs and all and sundry other factors. But from a simple radiative physics perspective, I would take a different view.

Mac the Knife

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.
Hooooo Boy – that’s going to leave a mark. Couldn’t happen to more deserving folks!

davidmhoffer says “Jim, you’re one of the best contributors there is to this site in my opinion. But on this, I’m not so certain. Stefan-Boltzmann Law is…”
David I agree “that for a given increase in downward energy flux, the temperature increase would be expected to be smaller at higher temperatures” so that radiative response must be considered along with the surface effects I mentioned. Radiative effects could explain a difference in trends with a greater rising trend trend in the minimum, but for the 80s and 90s minimum rose 3 times faster than maximum. That does not compute if we consider at most CO2 only added 2 w/m2.
Radiative dynamics do not explain why much of the eastern USA experienced a warming hole. Several studies show landscape changes and urbanization explain a large proportion of the observed warming over the past 50 to 100 years, and many studies show that the minimum is more sensitive to landscape changes and urbanization.
So how do you separate competing effects and attribute the cause to CO2?

davidmhoffer

jim steele;
So how do you separate competing effects and attribute the cause to CO2?
>>>>>>>>>>>>>>>
For that I have no answer. Nor does anyone else as far as I am concerned. If there WAS a way to accurately separate and quantify competing effects, the climate models would be reasonably accurate. The fact that they are not just inaccurate, but horridly so, shows that they have these things wrong in at least one if not many different ways. Given that the models use a wide array of aerosol forcings as fudge factors and STILL get it horridly wrong suggests the latter. Nor have I seen anyone with a strong physics background outside of the climate cabal itself even TRY to justify the notion that we have anywhere close to the amount of data over a sufficient time period to compute such a thing, in fact the opposite.
richardscourtney did attempt an experiment once involving a weather balloon with up and down sensors to measure LW flux at various altitudes with the intent of launching it and recording data during a solar eclipse. The idea was that this would be sorta like instantly (relative to a 24 hour day) turning the SW power source off and on again. Something went wrong and the experiment was never done. But THAT is the kind of experiment that needs to be done (in my opinion anyway) to measure data and begin (just begin) sorting out causes and effects of CO2 on LW. This business of measuring night time lows and day time highs and trying to make some sense out of them over a long term trend is doomed to failure for the precise reasons you just outlined (not to mention quite a few more that come to mind).
All that said, if you break down GISS/LOTI (for example) by latitude, you’ll find that the tropics show the least temperature change, temperate zones more, and arctic zones still more (though even that breaks down at, I forget, about 80 degrees or so). I also broke it down by season, with summer showing the least change, fall and spring more, and winter the most. 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. By extension, it ought to be more pronounced at night time lows rather than day time highs as well, and that is what the physics in its most simple form would suggest.
But separate and quantify all the components and render unto CO2 what is CO2’s? I don’t think all the data we have, even if properly analysed, can tell us that.