Note: clearly satellites can see urban heat, as demonstrated by this recent paper unveiled at the 2010 AGU meeting by NASA. See: Satellites Image the Urban Heat Islands in the Northeast. It can also be demonstrated that the UHI biases the thermometers upwards. As cities grow, so does the increased bias. In that paper NASA says:
The compact city of Providence, R.I., for example, has surface temperatures that are about 12.2 °C (21.9 °F) warmer than the surrounding countryside…
So when you see images like this one above, where the satellites can clearly see the UHI, wouldn’t it make sense to then just look at the biggest low pass filter heat sink on the planet, the oceans, to see what the difference might be? After all, we don’t have urban heat islands in the oceans. Frank Lansner thinks it is worth exploring in this guest post. – Anthony
UAH reveals Urban Heat
Guest post by Frank Lansner
How UAH (University of Alabama, Huntsville) satellite temperature data supports Urban Heat (UHI) as a real and significant factor when estimating global temperatures.
Northern Hemisphere temperatures in recent years:
Fig1. UAH global temperatures trend equals global sea surface temperatures: The black temperature graph – average RSS+UAH satellite NH (Land + Sea) – has a smaller warming trend than the other (brown) land data series – but in fact resembles the cooler Sea Surface Temperature trend. (The blue graph “CSST” is an average of the rather similar SST´s: MOHSST6, HADSST1, HASSST2, ERSST.v3b, HADISST1and Kaplan SST 98.)
The satellite data represents both land and ocean temperatures – and yet they resemble only the SST´s. Why ?
Satellite temperatures and SST do have one thing in common: They are for sure without the UHI warming error from the cities and airports – they are excluding UHI:
Fig2. Now we split the UAH data up in a land fraction and an ocean fraction. Both still seems to yield considerably lower temperature trends than the land data (brown) measured from mostly cities and airports on the ground.
So UAH land temperatures have colder temperature trend than the ground based land temperatures. Are the land-data deviations due to general issues with the satellite data then? Perhaps the satellite data happens to show colder trends for some “known” reasons etc?
Not likely: There is a good resemblance between the UAH ocean temperature trends and then the directly measured ocean data, SST (“CSST”). This shows that satellite data (and thus also satellite land data) are indeed useful and likely to be correct.
So, unless the satellites always starts to fail just when flying over land, the deviation between land data measured on the ground (mostly from cities and airports) vs. satellite land data is likely to originate mostly from the ground based land measurements. This “extra heat trend” seen in the ground based land temperature data may be explained by UHI + possibly faulty adjustments of data and siting problems.
– One more result might also support the correctness of UAH data:
Systems will always seek equilibrium.
On fig 2 we see a pattern of gabs between the UAH land and ocean data. However, after the gabs the UAH land and ocean data these data unite again and thus despite the temporary deviations, they still seem to produce a common trend.
Is it surprising that the temperatures over land and sea will seek equilibrium? Or would it rather be surprising if they did not? What force should maintain a still bigger difference in temperatures between land and see trends?
Fig 3. Lets focus on the temporary gabs between satellite land and ocean temperatures. The green curve represents a de-trended version, just the difference between the land and ocean temperature data from satellite. From fig 3 it appears to some degree that land and sea temperatures align or reaches equilibrium mostly when temperature do not change fast.
Lets take a look at the same phenomenon in the decades just before the satellite age – I use original temperature data published en around 1974-84 for this:
Fig 4. On this illustration we have confirmed, that the land-AIR temperatures are fastest to reach a temperature change “100%”, then the Marine-AIR temperatures comes soon after “80%” and finally the sea water surface temperatures reaches the new temperature level. Again it seems, that after a given time ocean temeperatures and land temperatures tends to find equilibrium. The bac-to-equilibrium-between-land-and-sea-surface-temperatures seems to happen whithin few years, escpecially if general warming/cooling pauses or reverses.
With a reasonable argumentation that also the Land fraction of satellite data is a good indicator of land temperatures, lets look at the “extra heat” seen in the ground based land temperature measurements (mostly from cities and airports). How much “extra heat” do the ground based land data contain?
Fig5. The extra heat in CRUTEM3 land data compared to UAH on NH is 0,103 K per decade.
Fig6. On global scale, the extra heat in CRUTEM3 land data compared to UAH on NH is 0,088 K per decade. (0,23K over 26 years from 1981 to 2007).
If the extra heat in data measured on land is applied to a period 1900-2010 – just to get a rough idea of the possible impact – using 35-40% land area as hadcrut does – we get global extra heat of +0,34 to +0,39 K added to the overall warming of the Earth related to the extra heat occurring when measuring from cities, Airports etc.
0,34-0,39 K is roughly half the supposed global warming 1900 – 2010 , but in this context we cannot claim to have quantitative precision, obviously. But the rough estimate of 0,34-0,39 K suggests that the impact of “extra heat” that cannot be detected by satellites plays an important role when trying to estimate global temperature trends.
The problem of “extra heat” in land temperatures (likely to be UHI and more) is escalated by GISS because they extrapolate the ground based land temperature measurements over the oceans in stead of using real ocean data:
Fig7. In the case of Hadcrut temperature series they use around 35-40% land data when calculating global data, but GISS have a temperature product using roughly twice this fraction for land area as fig 7 shows.
Fig 8 until around 2008 this illustration of land vs ocean temperatures was online at the NASA/GISS website. As we have seen, satellite data indicates that land temperatures from ground has trend around twice the trend of land data from satellite data – and as almost twice the warming trend of SST, ocean data. This tendency is confirmed on fig 8. From 1880 to 2007 we have an ocean warming trend around 0,6K and for land its around 1,2 K – twice.
Again, we saw from 30 years of satellite temperatures that global satellite data matches ocean temperatures rather closely. If valid, then the fig 8 indicates a 0,6 K faulty extra heat, UHI etc from 1880 to 2007.
****
Article from which most graphics where taken:
Review and feedback of the above article by E.M.Smith, Musings from the Chiefio:
“The rewritten past”: http://chiefio.wordpress.com/2010/12/13/the-rewritten-past
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Like I posted earlier. When (in summer) I leave the city, drive home, passing by the airport, then into the country side, the temperature drops 9-10 degrees (courtesy of fancy new car gadgets that just happen to be accurate to at least .5 degrees F). True it is hotter at UHI, however; the total global area of UHI is??? And the rest of the globe is???.
Why attempt to massage UHI when just a few miles away there is data more likely to be accurate. I find the whole scenario a waste of time and energy, meanwhile those with I.Q.s greater than two digits ponderously argue this ongoing insanity.
Sense Seeker says:
December 16, 2010 at 8:09 pm
I’m really keen to hear your explanation as to how warmer water (by definition less dense) disappears to the depth.
The peer review meme yet again. This is an analysis by an amateur submitted to WUWT for discussion. Did you read Franks comments at 3:06pm?
I guess if Frank was sitting around in a GISS office getting paid 6 figure sum plus benefits plus grants for research all the while playing blog games I’m sure he’d refine and tighten up his conjectures and submit to a journal where he had some mates who could peer review it for him. His name is Frank, not Gavin or James.
You know it makes sense.
I’m really keen to hear your explanation as to how warmer water (by definition less dense) disappears to the depth.
Via ocean currents, perhaps?
And I still think that this should be submitted to peer review. There’s all kinds of valid excuses, but I am afraid that outside this blog few people will take it seriously if it isn’t.
Baa Humbug said:
Sense Seeker says:
December 16, 2010 at 8:09 pm
Fresh water from lower layers surfaces, heated water disappears to the depth where it no longer heats up the air
“I’m really keen to hear your explanation as to how warmer water (by definition less dense) disappears to the depth.”
————————————————————————–
That struck me too, Baa. I have an ocean swimmer in the family who is a keen student of sea temperatures and weather conditions around the coast. She assures me that cold water does rise up from the depths in certain wind conditions, which push aside and cool warmer water on the surface. Time to don the wetsuit. But, for obvious reasons, the reverse does not apply.
Now, look at the Southern hemisphere, just to complete the picture.
What about people removing snow? that’s also urban activity that seems natural but it really isn’t…?
Here and there on the globe, there seems to be a necking together of global temperatures around and just after 1990. Not always, just often.
Two things happened then. The WMO marshalled the troops, who seem to have cleaned up their data for international comparisons. Second, the Hg thermometer was widely replaced by thermistors etc and (probably) new ways to determine average temperatures.
Then, after about 1995, the adjusters thought it was time to start working their particular brands of magic again.
What a mess. How many proxy papers should be written again because they were calibrated against a faulty temperature series?
“… cold water does rise up from the depths in certain wind conditions, which push aside and cool warmer water on the surface. […] But, for obvious reasons, the reverse does not apply.”
Johanna, maybe I misunderstand you, but I am a bit mystified by your last sentence. What what are those obvious reasons? And if cold water is added to the surface, other (probably warmer) water must disappear to the deep. That, or the total ocean surface expands?
John F. Hultquist says:
Go here and read what Dr. Roy S. has to say:
http://www.drroyspencer.com/latest-global-temperatures/
Thanks John, I had not seen that page before…
Pertinent text…
Contrary to some reports, the satellite measurements are not calibrated in any way with the global surface-based thermometer record
I guess the reports I read were in error… I hate it when bad data gets stuck in my brain. 🙂
Sense Seeker says:
December 16, 2010 at 9:29 pm
Well yes, currents do allow cool waters to rise to the surface (see for example upwelling zones) but this doesn’t explain how warm water could possibly sink.
Deep ocean water is remarkably uniformly cool, be it at the tropics or higher latitudes.
If warm water could sink, deep water would be much warmer by now especially since it’s been 11,000yrs since the last ice age.
There is a natural thermal decoupling between warm surface water and cool deep water, the warmer the surface water, the more it will resist mixing with deep water.
On a related issue, the above is opposite to how the atmosphere behaves. The atmosphere warms from the bottom up creating thermals etc and rapid mixing. Oceans warm from the top, thermal decoupling prevents the ocean from behaving like the atmosphere.
That’s my humble opinion and am open to changing my mind if shown to be wrong.
Dr. Phil says:
December 16, 2010 at 8:18 pm
“Great article, but really I don’t understand the basic premise behind correcting for UHI affects. Aren’t the urban temperature measurements real measurements? Urban areas are warmer than non-urban, so what?”
Hi Dr. Phil!
basically all cities in the world have grown massively from their 1900 size to their 2010 size. Therefore, all temperature stations in or around these urban areas does not just have a warm urban temperature, no theyve gotten a lot warmer during 1900-2010.
This we can measure by simply comparing the temperature trends of true rural areas with urban areas.
read: http://hidethedecline.eu/pages/posts/urban-heat-island-uhi-city-heat-in-global-temperatures-85.php
and exaples of UHI from all over the world:
http://hidethedecline.eu/pages/posts/urban-heat-island—world-tour-155.php
K.R. Frank
So the problem here is really the extrapolation of measurements taken from warmer urban heat islands to non urban (and cooler) areas and also to sea areas. Proabably due to the paucity of actual temperature data from enough non UHI areas? But with satellite data, that shouldn’t be the case, should it? Notwithstanding the limitations of satellite based methods of inferring ground and air temperatures.
Cities are a part of the world. So if a component of (or all of) “global warming” is the UHI effect, it does not mean that it is not real. It only means that it is caused by urbanisation, not atmospheric CO2.
This is about the best approach I have seen to estimate the effect of UHI and the local effect of land use change on global temperature.
(I added land use change, because it has a local effect on ground based temperature leading to a warming bias, in addition to its global effect).
Frank showed that ground based and satellite based temperatures over sea are very similar, while ground based measurements have a significantly higher trend over land. It is hard to explain this discrepancy by anything else but UHI / land use change contaminated data and perhaps flaws in data processing.
He also demonstrated, that satellite measured trends over sea and land tend to converge on longer timescales, while they do not converge for ground measurements. Pretty hard to explain the latter as well with anything else but UHI / land use change contaminated data, especially during multi year periods of temperature decrease.
And finally, he makes estimates of the overstatement of ground based global temperature measurements.
These are extraordinary results. I would really like to hear, if Bob Tisdale has any objections against the data used, and I would really like to see a statistician like McKitrick weigh in and transport this approach and these results into a statistical framework.
Thanks manfred, and yes, from hereof the heavy artillery are welcome to investigate 🙂
I will between Christmas and new year make a “global-edition” though since this has been asked for. However, fig 6 is truly global and tells it all (!)
phlogiston says:
December 17, 2010 at 12:45 am
“Cities are a part of the world. So if a component of (or all of) “global warming” is the UHI effect, it does not mean that it is not real. It only means that it is caused by urbanisation, not atmospheric CO2.”
Dear Phlogiston, the city area is just a tiny fraction of the Earths surface and should only count in the global temperatures as a tiny fraction. The problem is, that in the old days, temperature station where ment to tell peoble temperatures where they lived. Temperature stations rarely had a climate science purpose. Therefore when we just use an average of all these urben and near urban temperature stations we make the grave error that we treat the tiny urban area as if it covered a lot of the Earth. If 50% of temperature stations has urban or near urban sitings, we get urban data for half the land area and not just the tiny fraction we should.
K.R. Frank
Well, your graph plotting “with UHI” and ‘excluding UHI’ is absolute nonsense!
The trajectories diverge only because you somehow decided arbitrarily that the temperature sets coincided in 1981. Why would they be similar that year? If one had decided to do so in 1992 for example, we would be at the same temperature rightnow. This is more or less what happens when one simply CORRECTLY shifts the curves wrt to their basis line.
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1900/offset:-0.15/mean:24/plot/gistemp/from:1900/offset:-0.24/mean:24/plot/uah/from:1900/mean:24/plot/rss/from:1900/mean:24
Er, it really would be a good idea to look at the southern hemisphere data as well, as Steven Mosher suggests, before you all jump to too many conclusions. You can do it if you go to woodfortrees.org, and it will take about 10 minutes with the software there to see that NH and SH do not behave the same way.
Frank, what did NOAA do wrong that they did not find this urban heat effect when comparing good and bad measurement sites in the US, as established by the surfacestations.org project? http://www1.ncdc.noaa.gov/pub/data/ushcn/v2/monthly/menne-etal2010.pdf
Re. phlogiston says:
December 17, 2010 at 12:45 am
“Cities are a part of the world. So if a component of (or all of) “global warming” is the UHI effect, it does not mean that it is not real. It only means that it is caused by urbanisation, not atmospheric CO2.”
It also means you cannot extrapolate it 1200 K, or miles, especially into the oceans. And quite obviously you should not base CO2 CAGW policy on this.
Sense Seeker says: December 16, 2010 at 8:09 pm
“You attribute all that [to] the urban heat effect, but couldn’t it just be that the capacity of the ocean to absorb heat is so much greater than that of land?”
Seems like a reasonable question. Just burnt my feet on the sand before cooling them in the ocean.
Oh, those inconvenient Reasonableness Tests!
My gut reaction to the multipliers applied to human “contributions” to the atmosphere and climate initially was, “That’s just goofy!” But then I always do mental rough order-of-magnitude (or better) guesstimates of anything I’m about to entrust to a calculator or computer. A seriously discrepant result sets off alarm bells.
Apparently Warmists lack this “trick”.
Frank Lansner says: “Bob, the “CSST” is taken as a raw average of these datra illustrated here:
http://hidethedecline.eu/media/PERPLEX/fig25small.jpg”
And you continued, “As you can see, the black CSST is pretty much smack on top of all the CSST I used and I allowed to make this “rough” CSST to work with simply because all the different variations of SST mostly are very similar. Yes, the kaplan ends before the others, and stick out a little but this single outlier in no way makes the CSST move far away from the others as you can see. “
As noted in my earlier comment, Frank, you’ve included datasets in your average that have no reason to be included in an average. And it’s not only the Kaplan data that ends early. The HADISST and HADSST1 data in your graph end in the late 1990s. The MOHSST ends in the early 1990s. Do you think your average would be impacted by the fact that these datasets are incomplete?
You continued, “(there ARE big differences between the various SST trends but this mostly occurs before 1960. Thats why I only use it after 1960. Before 1960 i find the SST trends hopelessly in disagreement).”
I showed you in my earlier graph that there are BIG differences in the trends of UAH Ocean TLT and the HADISST, HADSST2, and ERSST.v3b SST anomalies AFTER 1979. Here it is again:
http://i54.tinypic.com/2edcpix.jpg
You continued, “Bob, except for Kaplan I can use any of the other SST´s in stead of the “CSST” in this article and in wont change the point in the present article. besides, remember i use 5 yr avg.”
A 5-year average does not help smooth out the differences between the SST datasets. There are still significant differences:
http://i53.tinypic.com/o9mmjd.jpg
Also, I’d check the source of your Kaplan SST data. As you can see in the next graph, it does not diverge from the others as your graph portrays:
http://i51.tinypic.com/3090j1i.jpg
I notice you failed to respond to the rest of my comment here:
http://wattsupwiththat.com/2010/12/16/uah-and-uhi/#comment-551893
So let me use another method to show that most of the differences between TLT anomalies and Surface Temperature anomalies are not a result of UHI effect. The following gif animations include two maps. Each represents the temperature anomalies in 2009 compared to a base period of 1979-1980. In effect, they are showing the change from the 1979-1980 average temperature to the 2009 temperature. The first compares UAH TLT anomalies and GISTEMP LOTI. As you can see, there are significant differences between the two datasets in Africa, South America, and in parts of Southern Asia that should not have significant UHI components:
http://i51.tinypic.com/15gcne9.jpg
The same thing holds true if we compare RSS TLT anomalies and NCDC surface temperature anomalies:
http://i56.tinypic.com/oqaybm.jpg
And here’s a comparison of RSS TLT anomalies and HADCRUT surface temperature anomalies. Since the Hadley Centre data is not infilled (actually portrays where readings are taken), it’s tough to determine the differences:
http://i56.tinypic.com/66hfd4.jpg
Returning to the comparison of UAH TLT anomalies and GISTEMP LOTI, I’ve widened the range of the contours to help show the differences at high latitudes in the Northern Hemisphere. As is widely known, the change in the GISTEMP LOTI Arctic data is much higher than the UAH TLT anomaly data for the Arctic:
http://i51.tinypic.com/rif28g.jpg
Again, I will end this comment with the same statement. Basically, any conclusion you’ve reached that UHI is responsible for the difference between TLT and land surface anomalies is based on your assumptions from an incomplete analysis.
@Baa Humbug
“I’m really keen to hear your explanation as to how warmer water (by definition less dense) disappears to the depth.”
You mean that cold water, being slightly denser, must always sink to the bottom?
Totally correct, old chap. This also explains why CO2, being 50% more dense than O and N, always sinks to the lowest levels of the atmosphere and is never found more than a few hundred meters above the ground. Also explains why we are all dead because the CO2 concentration near the ground is almost 100%. Stout fellow, Humbug!
/sarc off
pyromancer76 says: December 16, 2010 at 5:53 pm
Yes. Haha. Was just thinking, we need a paper submitted for peer-review and publication, authors Lansner, Tisdale and McKitrick. Then Manfred (12:48 am) beats me to suggesting it.
Seriously. This looks like being potentially a damn good and important paper. We really need to quantify UHI plus station loss plus siting probs plus sensor biases. And benchmark the crucial input of amateur scientists into regaining integrity – and the potential for cooperation.
One thing I’ve pondered about is why folk talk about anomalies as though there is a standard to be deviated from? Isn’t that the reason we have the AGW farce? If the World’s temperature was zeroed during a cold period of a natural cycle then surely it would appear that over the last thirty years that is has been warming. Likewise before then we had seen science zero the World’s temperature during and warm period and then panicked when it cooled into the 1970s. What is needed are measurements of actual temperatures, not proxies or extrapolations, especially when we are only dealing with a degree here or there. Or do folk really think that there is a standard temperature that the Earth is set at?