Post by Dr. Ryan N. Maue
December global surface temperatures cratered after the Cancun climate confab, which ended a string of above-average months. However, until the government temperature keepers put out their 2010 autopsy and bubble plot with the appropriate fanfare and press release, I am going to use the tools at my disposal to come up with a reasonable estimate of the recent global temperature.
From operational and reanalysis numerical weather prediction best-estimates of the atmosphere-ocean state, the global mean temperature for December 2010 [image link] was actually below the previous 30-year mean pushing 2010 down the list of the hottest ever. Europe, North America, and Australia saw much below average December temperatures, while the Arctic saw much above average temperatures (but that’s relative, it’s still really cold)
You must look at the weather — weather is part of the climate — and understand the high-frequency redistribution of heat, moisture, and momentum on the order of days and weeks. I will show you now why the weather matters.
Temperature Fluctuates Wildly on Short Time Scales: Weather
Here is a daily trace of the JRA-25 reanalysis near-surface temperature anomalies for 2009 and 2010 based upon a climatology of 1980-2009, a 30-year chunk of climate. Reanalysis datasets do have their issues, but also advantages, which are beyond the scope of this simple show-and-tell. There’s nothing sketchy going on here; no hiding of any declines; just showing you the data!
The blue-line is the zero-line corresponding to the 30-year mean. Blow it up and you see, what people can observe is the weather, and weather is not climate — except when it is. This plot shows you how temperature changes due to the global weather flow-regimes, which are modulated by all of the natural climate actors like El Nino, La Nina, the NAO, AO, AAO, etc. The daily temperature time series is extremely noisy and fluctuates wildly, but there appears to be a rhythm to the madness. I’ll leave that as homework exercise to explain the ups-and-downs (hint it’s weather). I find it rather discouraging that the entire time series I plot up is boiled down to one annual number, and an AGW signal is somehow sucked out — with a blizzard attributed to it no less! Even the IPCC AR4 models say we have many decades to go before seeing such visible changes.
Since we are using the previous 30-years as the baseline, the anomalies have course decreased in magnitude in the recent 1980-2009 period. The usage of 1961-1990 or 1971-2000 will provide the same qualitative picture, but there will be some important differences (future post). The Earth didn’t warm uniformly between the separate “climate normals”, and it isn’t expected to. That’s part of the point of my message here.
Temperature Fluctuates Spatially: Weather
Spatially, you can see the action of the temperature anomalies from the plot at the beginning of the post:
This is a great way to visualize all of that global warming going on. The image at the top is the most recent 14-day average ending December 30, 2010 showing the extreme Arctic warmth of +15 to +20C, and of course the northern Eurasian chill. If you mouse over the plot, you can watch the course of the past year go by. The development of the La Nina in the Pacific is apparent as the summer wanes. You can find the Russian Heat Wave pretty easily in July, even though 2010 ended up pretty much average there. If you desire, you can change the URL in your browser to see similar animations for the past 30-years: 1979 … 1989 … 1999 … 2009. Have fun with the weekly animations of temperature — all of the major cold blasts are in there for the USA…
What’s the Temperature Right Now?
But, what is the actual temperature: if it is 15 degrees C above normal in the Arctic, what does that mean: well, here is a global temperature analysis and 7-day forecast from my Florida State Weather Map page. Also, below this image, is the departure from normal, so you can see in real-time just how hot the planet is — and watch as 2011 starts off as just an average year. You’ll hear a lot about the historically warm Arctic, but who cares at this point, no one lives there and it is still plenty cold. Is that a global warming signal in winter up there? I doubt it, how about storm tracks, blocks, the NAO, and some natural climate variability manifested in the weather?
We are talking hundredths here? Really?
It’s a foregone conclusion that the official government data from whatever nation or agency will show that 2010 was the hottest year ever. It just has to be that way — please don’t look at that snow burying NYC or the bone-chilling historical cold throughout the UK and Europe, that’s just the weather. Instead, look at the articulate press releases with the bubble-plots from NOAA/NASA to see the real story of 2010, the hottest year ever by a few hundredths of a degree C. Yes, we are talking about hundredths and tenths of a degree during the past 10 to 30 years– that’s all. The Earth’s temperature varies a lot, from hour to hour, day to day, season to season, year to year for a bunch of reasons of which the sun is order 1, but even through all of that, you must know that the global temperature has changed only on the order of a 1-3 percent during the past 30-years. And, it isn’t a spatially homogeneous change, either. Not even close. AGW is built upon the premise of a slow, very slow upward trend that will eventually accelerate. But, that’s a long ways off — today, we are talking about hundredths of a degree C. How many trillions of dollars is that worth to you?
Thank you for the informative post which explains the drop in Arctic sea ice to a remarkably (possibly unheard of) low level for this time of year.
It will be interesting to see whether it recovers by the end of the freeze season or not
While I am sure GISS will come out with some impressively dire news, the satellite data which is actually scientifically usable has December at +0.18C. I have a little more at my website.
John Kehr
The Inconvenient Skeptic
Just for once will someone explain how these ‘averages’ are obtained?
Are these formed by:
* generating the mathematical mean of the maximum and minimum temperature observations (a meaningless figure!)”?
* Somehow using those ‘means’ to come up with an average temperature per square (cubic) kilometer of Earth’s surface (obviously skewed by the number and location of observation sites)?
* Averaging those means to come up with a ‘global average’ with a false level of precision?
And I must repeat while “weather is not climate” – “atmospheric temperature is not heat content”
As this number is used to guide governments into not making sufficient preparations for cold weather; they are literally life and death related. In any other business where figures are safety related there is considerable rigorous quality management, but ‘quality management’ is one thing that appears to be lacking in climatology.
[ryanm: the reanalysis dataset is gridded, and the temperatures are based upon 4 times daily instantaneous analysis of the near-surface temperature field. During the data assimilation process, all in-situ and satellite observations are used optimally to produce the best estimate of the true temperature, which is unknowable. Thanks for the reminder about temperature only being one metric]
There’s one more thing to notice here: As I’ve pointed out before: That big blob of positive anomaly up in the Canadian Arctic desert does not contain as much excess heat as an equally sized blob of positive anomaly in the tropics. The reason is that the total heat content (the enthalpy) of air depends not only on the temperature, but also the pressure and the water vapor content. And colder air is much, much drier than warmer air. In fact, even Sahara is moister than the Canadian desert, so a +10C anomaly in Sahara represents more excess heat than a +10C anomaly in Nunavut.
It would be even harder to collect good quality data, and it would be much harder to “sell” to the public, but if climate scientists really wanted to present a measure of excess heat in the atmosphere, they should measure enthalpy, not global mean temperature. But since the heat capacity of the atmosphere is so low compared to the ocean, ocean heat content is the only really reliable measure (if done right, of course…) of global warming anyway…
Dunno about the NH being cold (Which it clearly is and is receiving coverage in the Australian MSM. Really like watching drivers trying to drive on ice without proper “boots” on) but our “downunder summer” is looking to be cold and wet, 21c max in the Sydney today.
I appreciate your graphs and your explanation of the data.
I can only share that we here in South Australia have seen only 1 day
of 32C in the past 2 months of supposed ‘spring/’summer’ and each evening
has basically been much like tonight, here on the coast below the Coorong:
about 11-12C and while we’re NOT ‘stoking the fireplace’ ~ I’m getting
another ‘duna’/comforter for the bed tonight.
So much for our January ‘summer’ in the Southeast.
C.L. Thorpe
Wow, that red blot over the Arctic is impressive.
“AGW is built upon the premise of a slow, very slow upward trend that will eventually accelerate. But, that’s a long ways off — today, we are talking about hundredths of a degree C. How many trillions of dollars is that worth to you?”
This puts it all in perfect perspective – excellent post and Happy New Year!
Once more I would like to stress that averaging the anomalies is not the same as averaging temperatures. The whole game of averaging is to know the changes in energy content of the globe. It is the energy that makes the difference, not the anomaly on the temperature. The anomaly is a proxy for the temperature and the temperature is a proxy for the energy radiated.
Energy flow=constant*T^4
Anomaly is Delta(T)
Here are some numbers: The arctic temperature is -20C
The Africa temperature is +20C
both show a 4C anomaly , setting parameters for the year 2010 .
In terms of anomaly there is the same change.
In terms of energy radiated (T arctic is -16C, T africa 24C)
257.15: 247.9 W/m2 Arctic
297.15: 442.1 W/m2 Africa
The radiation from Africa is 194.2 Watts/meter^2 more than the one from the Arctic, whereas the anomalies are the same.
Anomalies are bad proxies for energy and average anomalies worse for average energies.
[ryanm: the plots here are calculated from the actual data, not averaging together the global anomalies. I am well aware of the variability at each grid point in the domain.]
Ryan,
You say, ” … the global temperature has changed only on the order of a 1-3 percent during the past 30-years.”
How did you calculate that number? 1-3 percent of 293 degrees C is 2.9 to 8.7 degrees C. Expressing the change in the “departure from normal” as a percent varies depending on what you use for the “normal” or baseline value.
[ryanm: yes, true, and right]
Re Espen says:
January 3, 2011 at 2:28 am
Two excellent messages. I would add that changes in SWR have the dominant long term effect on OHC.
Yes, temperature is increasing slowly for humans, who often think of a decade as being a long time. However, the heating of the planet seems to be very fast compared to the past, where shifts in climate usually took 1000’s of years. A trend of 0.2 oC does not seem like a lot, but it’s really quite fast. The prediction of those pesky computer models is that warming should be strongest in the arctic, rather far from the UHI effect.
[ryanm: 0.2C over a period of a several decades seems quite reasonable to me in terms of natural variability considering the effects of the Pacific Decadal Oscillation are likely around that number…]
@Espen
I think we are both saying the same thing- atmospheric temperature is not heat content due to the differing enthalpy of dry and humid air.
As the polar vortices have both moved equatorwards this also mean that the drier polar airmasses are also extended equatorwards. This means that less heat has been needed to raise the atmospheric temperature.
I am sure that climate ‘scientists’ realize this and also know that politicians and the public do not understand enthalpy. Therefore, they continue using atmospheric temperature as their metric despite its invalidity for quantifying atmospheric heat content.
My concern is that this is hiding some really severe planetary heat energy loss and there will be total lack of preparedness for what that might cause.
Fantastic tools to be used again and again!
This really makes a difference.
If i should mention “something” that might be changed:
1) First of all, Denmark should be in the centre of this graphic, obviously:
http://www.coaps.fsu.edu/~maue/extreme/gfs/current/raw_temp.html
2) Ok, in the above anomaly map (superbe!) then i would have preferred if the colour scheme perhaps better showed cold vs warm. Many grey areas are in fact hot, and thus you have to take some more time to get an impression of the overall temperatures.
K.R. Frank Lansner
My ‘local’ weather station shows 2010 as -0.9C compared to the average since recording commenced in 2003 – granted only 7 years of data, but the year is cooler than previous years.
Here, Feb 2010 was quite a bit warmer (+5C) than normal, but Jan, Nov and Dec were all significantly cooler (-2 to -6), most other months average or slightly below. All of which I can remember quite well. There have certainly been quite a few low records set in the region generally.
I haven’t got round to checking this against the ‘official’ Met office data, they won’t verify (set? LOL) Dec temps until around late Jan 2011 probably.
I would like to make the point that we all ‘know’ our local weather – and, certainly in my experience, this never seems to tally with the officially published ‘view’, and certainly not since the AGW ‘global’ temp anomaly was quoted. I would suggest more people do the same and check their own local available data with the official stuff, just to see if they can ‘recognise’ their local weather is being properly represented and recorded! I think it would be interesting to note how the official ‘gridded’ data that encompasses my local area, and if it reflects our local weather after all the smoothing and adjustments, etc! Thats assuming one can get hold of said official data!
BillD,
Incorrect. Rapid shifts in temperature are not extraordinary, and they have nothing to do with CO2: click
BillD is correct. 0.2C per decade would be very fast. In just 100 years that’s 2C warming which is a lot for a global amount.
Smokey, that is an abrupt change triggered by an unstable climate, although in this case it’s regional. That’s precisely the kind of thing we have to worry about with a 0.2C per decade change. We could hit something abruptly on the way up.
In fact it’s possible we’ve already started hitting something…*points at the snow storms in the UK and US*
Since I started keeping Phila. PA temperature records going back to Jan 1 2011 we’ve had record high temps. Yesterday it was 51F! It’s unprecedented and worse than I thought. The trend is definitely predicting 200F temperatures this summer. Today it’s 23F but that’s just weather so it doesn’t count. I can hide that somehow with some sort of trick. I know, I’ll look at the latest tree rings in my woodpile before I burn them in my woodstove.. If they are large I’ll use that as a temp. proxy and throw out the actual readings. Next I’ll mount my thermometer on the chimney in direct sunlight for future readings.
Wasn’t the cold in europe supposed to be because of winds pulling cold air down from the arctic? Is that why the arctic is warmer?
anna v says:
January 3, 2011 at 3:18 am
Once more I would like to stress that averaging the anomalies is not the same as averaging temperatures. The whole game of averaging is to know the changes in energy content of the globe. It is the energy that makes the difference, not the anomaly on the temperature. The anomaly is a proxy for the temperature and the temperature is a proxy for the energy radiated.
Energy flow=constant*T^4
Anomaly is Delta(T)
Here are some numbers: The arctic temperature is -20C
The Africa temperature is +20C
both show a 4C anomaly , setting parameters for the year 2010 .
In terms of anomaly there is the same change.
In terms of energy radiated (T arctic is -16C, T africa 24C)
257.15: 247.9 W/m2 Arctic
297.15: 442.1 W/m2 Africa
The radiation from Africa is 194.2 Watts/meter^2 more than the one from the Arctic, whereas the anomalies are the same.
Anomalies are bad proxies for energy and average anomalies worse for average energies.
Sounds all very good except much of the energy radiated from the troposphere comes from latent heat of state change of water. This is does NOT follow Stefan Boltzmann’s equation.
Thank you Dr Ryan for an interesting piece. In your future article about the selection of baseline period, can you also explain why climate scientists use a 30 year instead of 60 year baseline? It seems to me that if you are not capturing a full 60-ish year cycle for the baseline then you risk showing too large or too small an anomally if your baseline is not peak to trough in a cycle, but perhaps capturing the cooler thirty year period. Use of a 60 year base should compensate for the selection of baseline period.
The map with the ‘hot’ arctic is the familiar distorting projection. As always it grossly exaggerates the most northerly and southerly areas and greatly compresses everything nearer the equator. For example Greenland (836,109 sq miles) appears several times larger than India (1,269,346 sq miles). The green area in mid-Pacific looks about the same size as the Arctic red-area but in reality it must be several times bigger.
Thanks Ryan, been using your weather model pages, they are great.
The big hotspot over north east North America is only 3.0% of the global surface area. Given at least half of it is not getting any sunlight at all right now, it would represent less than 0.5% of the total global solar energy budget. I guess the warm anomalies must be moving in from somewhere else. That is the question.
Another thing which might be going on right now with the global climate is that global water vapour levels are falling rapidly. After the El Nino’s impact peaked in April 10, total column water vapour levels were very high (in the NCEP reanalysis dataset).
Now that we are in a La Nina and global temperatures are falling, those water vapour levels are also falling rapidly – probably below normal already in December. Perhaps that is why there seems to be so much rain and snowfall right now. The atmosphere has been dumping water vapour. The total change could end up being 10% from peak in April 10 to trough in April 11.
http://img340.imageshack.us/img340/8490/ensotempsvstcwvnov10.png
http://img152.imageshack.us/img152/1485/ensovstcwvnov10.png
Q. Is this within the limits of natural climate variability?
I don’t understand the title of the piece. Surely Urban Heat Islands warm up the places where people live so why are these the cold areas?