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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It is a pity that the old [and current if they still keep them] records from coastal lighthouses could not be used exclusively to get a true UHI-free temperature sample of the earth. This would still show any true background warming.
Even Lady in Red’s Ohio lighthouse above would still show a trend [but may not “play along” as quickly as GISS would like].
Just musing here, but wouldn’t UHI being real and measurable just shift some portion of the A part of AGW from CO2 to UHI?
Stefan, could you link to the satellite picture you mention?
Talbloke and many others, thanks for reading and commenting!
K.R. Frank
As Bob Tisdale I’d like to see the global picture. Given NH is land and SH is ocean you may be missing so detail here. Having said that Fig6 is illuminating.
Has this sort of analysis made it into the peer-reviewed literature?
OT – but ironic
The “Gore effect” shows little respect for Gore’s hometown.
“Coldest December since 1942 grips Nashville”
http://www.tennessean.com/article/20101213/NEWS01/12130320/Coldest-December-since-1942-grips-Nashville
Great! And yet our esteeemed Huhne and Cameron have just previewed UK energy policies (electricity generation) that is so dedicated to expensive and unreliable (in the sense of not always on) Renewables, mainly wind, that I can’t even laugh so I should not weep. “Carbon” this and “carbon” that littered the speech, so I read. Sob.
Sorry mods, bit off thread, but the UHI fiasco is at the root of the over estimation of CO2 effect in the real world…
Good summary, thank you.
But, WWAD?
(What Would the AGU Do?) Would they accept this logical a presentation – that “removes” half of their vaunted funding and importance?
Frank, thank you for a stimulating article.
Eyeballing Fig 8 and assuming a land/ocean anomaly temperature coincidence at 1960 (this may be reasonable given the population growth and urbanisation since that date) gives gives an anomaly difference of 0.5Deg C to 2008.
The IPCC 2007 4th assessment report 3.2.2.2 Urban Heat Islands and Land use effects works very hard at downplaying UHI, a quote……
Hmmm,
I seem to remember a series of papers some time ago that discussed how the satellites were calibrated. If I remember correctly the raw data from the satellites has be processed by an algorithm that was created to get the output to match readings taken directly from “Known” temperatures. I wonder if UHI has been incorporated into this creating an AlGoreithm that shows warming where there is none.
If I am reading this correctly – and please correct me if I have misunderstood any of this ….
UAH from their satellite data are suggesting that this is a more accurate record than the global temperature records because of UHI not being properly allowed for in urban weather stations records (supported by NASA 3 yr research on UHI).
UAH suggest that the satellite data points to an actual global temperature anomaly / rise since 1880 of 0.6 k (celcius) rather than the 1.2k (celcius) claimed by NASA/GISS.
From my reading of them: the Manley CET (central england temperature records) show a mean CET temperature from 1659 to 1973 of 9.6 degrees C. The ‘corrected’ CET now used by CRU / HADCRUT includes stations in warmer areas and shows slightly different temperatures but with a mean average from 1971 to 2010 of 9.9 degrees C.
Comparing the Manley figures with CRU in sequence :
1971 (M) 9.7 (CRU) 9.68
1972 (M) 9.2 (CRU) 9.19
1973 (M) 9.5 (CRU) 9.54
I do not understand why CRU reduce the first 2 years and elevate the 3rd as I have understood they were both working with the same raw data.
The start date of the global temperatures used to show global warming is 1880 ( a short but very cold period); I think December 1880 was the start of the period used. The mean of Dec 1880 – Nov 1881 from Manley was 8.6 degrees C with a long term mean from 1659 to 1973 of 9.6 degrees showing the year of 1881 as 1 degree below the long term average mean.
The current mean produced from the shorter period of 1971 to 2010 from CRU / HADCRUT is, as above, 9.9 degrees C. That suggests a rise in temperature of 1.3 degrees C or thereabouts from 1880/81 according to CRU/HADCRUT.
Assuming that UAH are correct, and from the NASA data it looks pretty certain that that are, then the actual anomaly/increase since December 1880 is around 0.6 degrees rather than the 1.2 degrees or therabouts suggested by NASA / GISS (and similarly CRU/HADCRUT at 1.3)
CRU/HADCRUT do not seem treat 1880 as a below the long term mean temperature hence their stating the rise in temperature is around 1.3 degrees C.
CRU/HADCRUT use data which I suspect (?) is contaminated by UHI. If that is so and a correction by lowering of 0.6 degrees is in order then that suggests an actual anomaly / rise from 1880 of 0.7 degrees would be correct. Taking 1880 from Manley as 1 degree below the long term mean and adjusting current CRU/HADCRUT figures by -0.6 degrees to correct as suggested by the UAH data / study that brings the CRU/HADCRUT corrected rise / anomaly down to just 0.7 degrees. That is below the long term average by 0.3 degrees and suggests that since 2005 – when temperatures are shown as ‘static’ that we have actually been experiencing a slight drop in temperature since 2005.
As I say at the outset I may be misunderstanding one or more parts of this – so please put me right if I am wrong.
Thanks
“jorgekafkazar says:
December 16, 2010 at 1:11 pm
I always enjoy Frank’s posts, and his little linguistic quirks make me smile. “Gabs” obviously means “gaps,” here. In German context, they sound identical. Great work, Frank. Your English is far better than my Deutsch. Someday I’ll tell you about a conversation I had while waiting for a streetcar in Stuttgart…
But what is GISS’s pretext for extrapolating the ground based land temperature measurements over the oceans instead of using real data? I’m boggled.”
As can be understood from some of Frank Lansner’s comments above he is actually Danish rather than German as suggested in above post. Gap is probably more like őffnung in German.
We Sunny People will be vindicated!!!
They [non-Suns] will find that El Nino and La Nina are coupled to the Sun’s output.
The PO and AO are coupled to the Sun’s output.
The Poles lose heat faster that the Equator due to EUV. The thickness of the Stratosphere, Troposphere [therefore, the insulating effect] is coupled to the Sun’s EUV.
Remember the Sunspot peak predictions?? How they were 1 year, then 2 years, now 3 years late. Since 2005, “Quiet Sun”; maybe we are in a Maunder Minimum…
Again, my simple Solar/Earth Model [based purely on the 10.7 cm Flux] shows cooling at the rate of ~0.1 C/2.5 years [conservative value]. We have already lost 0.2C since 2005. The “Quiet Sun” has the average Flux values at ~85 [lowest value is ~67]; this is a little short of 250 during a Sunspot peak.
So UHI mis-measurement or not, the Earth is cooling; and cooling rapidly.
The melting of the Martian Poles can’t be due to CO2; could it be due to the Sun?? Measured from 1980 until 2000.
From 1670 until now, we have been in an active [ramp up] Sun. Now the sudden decade change [cooling] is upon us; and we aren’t prepared.
CO2, Cosmic Rays, Geothermal Heating, Volcanoes, etc., does one really think that these have a bigger effect than the Variable Sun. Under an Eclipse, the temperature drops 10 to 20C in a matter of minutes.
The Sun Rules, and it has been Quiet. We will be cold, very very cold.
Just reminds me of the climate gate email that is not often discussed where someone (I dont recall who off hand) notes its good that the skeptics at least have not yet made a point yet about the discrepancy between land and ocean temps, as the land should follow the sea and cannot warm at a faster rate for any physical reason. I have noticed this before, as it make no sense to have the land warm faster than the sea, unless there is a UHI influence in the data.
I greatly appreciate Frank Lansner’s wonderful posts and graphs. I also noted Bob Tisdale’s comments(corrections) and hope that Bob can assist Frank with something more complete according to the “raw” data. Thanks to both.
Hey this web site has become a major outlet of information for projects of mine. It’s very informitive.
Robert M says: at 4:59 pm
Go here and read what Dr. Roy S. has to say:
http://www.drroyspencer.com/latest-global-temperatures/
Under Kramer above,
“Anthony, why can’t somebody just calculate the earth’s temperature using data from stations unaffected by UHI? I’d be more trusting of what this data says even if it showed an increase (and I suspect it would). REPLY: Easier said than done- the problem is that only a handful have been identified in the USA that are free from UHI and siting biases, and we haven’t even begun to look at the entire world. – Anthony”
Agreed. Here is a set of plots for about 16 truly rural Australian BOM stations, mostly free of siting biases. The inland ones (which are at slightly higher altitude as well) do no follow the same pattern as the coastal ones. The coastal ones are generally flat over the last 40 years, the inland ones usually show a moderate temp increase. The increase must be from another cause, which I have not identified. The cause must be fairly local to the last 40 years, because if you project back or forwards a few decades you run into implausible numbers.
http://www.geoffstuff.com/SI%20GRAPHS%20AND%20STATS.doc
There’s a lot more explanation of this in draft at
http://www.geoffstuff.com/Final%20draft.doc
I got tired of looking for real effects when there was so much noise. BTW, the airports are not major fire-breating monsters – it’s unlikely that asphalt or engine heat are significant, as a personal view, except maybe at Broome.
Another piling-on rant isn’t necessary. The paucity of the global temperature records are nakedness themselves.
I’ve always been amazed by the observation that the most warming occurs in regions with fewest thermometers.
Old England says:
December 16, 2010 at 5:11 pm
===========================
I agree with everything you posted and think it needs no correction at all.
From a post on Irish temps awhile ago their land temps tend to be the same as the sea temp. Perhaps we should be extrapolating sea t 12000km over land rather than the reverse (Giss). That would get rid of all that unlikely hot orange color.
OT:
Madness at work courtesy of California…
“By JASON DEAREN, Associated Press Jason Dearen, Associated Press – 20 mins ago
SACRAMENTO, Calif. – California regulators on Thursday approved the first system in the nation to give polluting companies such as utilities and refineries financial incentives to emit fewer greenhouse gases.
The Air Resources Board voted 9-1 to pass the key piece of California’s 2006 climate law — called AB32 — with the hope that other states will follow the lead of the world’s eighth largest economy. State officials also are discussing plans to link the new system with similar ones under way or being planned in Canada, Europe and Asia.
California is launching into a “historic adventure,” said Mary Nichols, chairwoman of the state’s air quality board.
“We’re inventing this,” she said. “There is still going to be quite a bit of action needed before it becomes operational.”
California is trying to “fill the vacuum created by the failure of Congress to pass any kind of climate or energy legislation for many years now,” said Nichols.
A standing-room only board chambers featured testimony from more than 170 witnesses Thursday. Outside the chambers, a few climate change skeptics held signs reading “Global Warming: Science by Homer Simpson.” (…)”
+++
These people are crazy!
Looks like a very complex way of saying that the oceans warm up slower than the air over land.
You attribute all that the 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? Fresh water from lower layers surfaces, heated water disappears to the depth where it no longer heats up the air – which is what you measured in this exercise. On land, no such cooling mechanism.
Furthermore, the UHI effect is hardly a new issue. One previous study that also used satellite data found hardly any UHI effect, and a more recent study in Nature came to the same conclusion by comparing windy and calm nights.
And as always, one should be careful not to conclude too much from studies that have not been published in the peer-reviewed literature. Are you intending to submit your analysis?
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? How can you go in later and intentionally reduce the temperatures of urban areas, i.e. correcting for UHI. I thought the idea of measuring temperatures was to, well, measure temperatures. By doing UHI ‘corrections’ you’re now presently a false version of temperature. Sure, some urban areas are really warm, but their area is really small too, and I wouldn’t think when properly weighted over the whole earth it would make much difference at all. Bottom line, correcting raw data sounds bad and I just don’t get why it’s done.
Great article, but really I don’t understand the basic premise behind correcting for UHI affects. Aren’t the urban temperature measurements real measurements?
The problem is that c. 1% of the land is urban and 9% of the stations are urban. 17% of the stations are semi-urban and maybe c. 5% of the land is semi-urban. And that’s for just the U.S.
Foreign stations are likely to be much worse (with a disproportionate number in airports).
If you want to avoid bias, the same percentage of stations should be located in cities as there is urban landscape.
Bob, the “CSST” is taken as a raw average of these datra illustrated here:
http://hidethedecline.eu/media/PERPLEX/fig25small.jpg
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. (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).
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.
As i wrote in the article it can all be found discussed and more in the article here (which I asked you to review half a year ago):
http://hidethedecline.eu/pages/posts/part2-the-perplexing-temperature-data-published-1974-84-and-recent-temperature-data-183.php
goto part 2, fig 25.
And here is how close the CSST is to HADISST and Reynolds v2 SST, for example:
http://hidethedecline.eu/media/PERPLEX/fig81.jpg
I just use CSST not to chose one specific SST. And if you had read my original article you would know that im aware the differences.
K.R. Frank