We’ve talked a lot about record cold and snow, now more from the “weather is not climate department”, and this time there’s a warm side to the story. I’d planned to write something about this, since several people left the UAH numbers in Tips and Notes, but Luboš Motl beat me to it, so I’ll give him the honor here. It will be interesting to see what some pundits do with this number, especially if they compare it to the longer 100+ year instrumental surface temperature record. – Anthony
From his post:
Global UAH: warmest January day on record
Source for this graph is here
Many people think that the globe must be terribly cold these days. We’ve seen huge cold snaps and snowfalls in Britain, Eastern parts of the U.S., Western Europe, Central Europe, China, Korea, and India where hundreds of people have frozen.
So these are almost all the important places, right? (At this moment, the speaker forgets that there are places such as Latin America, Australia or the Balkans which have been warm.) So the globe must be cool – cooler than average, people could think.
However, the daily UAH global mean temperature shows a different story. The early January 2010 was warm. And on January 13th, which is the latest day whose temperature is known, we have seen the warmest January day on their record. The brightness global temperature near the surface was
T = -16.36 °C
which may not look excessively warm 🙂 but it is actually 0.11 °C warmer than the warmest January temperature recorded by UAH so far – which was on January 5th, 2007 (-16.47 °C). Of course, some alarmists might feel happy for a while. They’ve been afraid that the worries about a new ice age could escalate. And they’ve been saved: the global weather is warm again. The strong El Nino episode could have helped them – or someone else. It’s important that they’re saved. 😉
However, there is another, more important consequence of these numbers. And it is the following: the global mean temperature is irrelevant for you and for everyone else, too. It didn’t help the hundreds of frozen people in India, the passengers whose flights were canceled, and millions of other people in the European, Asian, and American civilization centers.
If you actually draw the monthly data from 1979 to 2009 – the global ones and those in e.g. Prague – you will find out that the correlation coefficient is just 0.17 – well below the maximum possible value of 1.00. It won’t be much higher outside Prague, either. 🙂
The Pythagorean average monthly anomaly in Prague has been something like 1.95 °C. Imagine that you want to use the global temperature in order to improve the estimate of the temperature in Prague for a given month. If you add the global anomaly and the expected local average temperature in Prague for the month, you will reduce the typical fluctuation from 1.95 °C to 1.92 °C or so – almost no change. The swings in the global temperature won’t visibly help you to improve the predictions of the local temperature.
So while it may be fun to watch the global temperature – a meaningless game that many people began to play in recent years because of the AGW fad (and yes, your humble correspondent only plays these games because others do, not because it is scientifically important) – it is very important to realize that the changes of the global mean temperature are irrelevant for every single place on the globe. They only emerge when things are averaged over the globe – but no one is directly affected by such an average.
Even if you accumulate a whole century of changes, the relevance of the global temperature will be essentially non-existent. A 1.5 °C warming of the global mean temperature is still less than one standard deviation of the monthly average at a given place. And the “local” climate may also shift – the January 2100-2150 average may be warmer than the January 1950-2000 average in Prague by much more than those 1.5 °C. Different regional climates change differently and most of these changes have nothing to do with the changes of the global mean temperature!
By the way, it’s almost certain by now that January 2010 will also be the globally warmest January on the UAH record – the anomaly will likely surpass 0.70 °C. It may even see the highest (or at least 2nd highest) monthly UAH anomaly since December 1978. I will print more exact predictions in a week or so.
Gary (14:13:47) :
You wrote:
“The UAH daily data is brightness temperature ie the calculated temperature of a black body emitting the same radiation as measured. The true temperature can only be calculated if the emissivity is known. As long as emissivity is constant a trend of brightness temperature will follow the true temperature with a constant displacement. When emissivity varies problems arise. If the emissivity is rising with constant true temperature the UAH data will show an increasing brightness temp and warming. This is possibly what is happening at the moment with all the snow and ice around.”
I think you’ll find that the satellite data seeks to measure and then invert the radiances across the entire measurable spectrum. The method for extracting temperature should not and does not assume a constant emissivity. For example, if Earth’s albedo increases because of snow cover (or increased cloud reflection) with zero change in average temperature then one expects a disproportionate increase in outgoing SW radiation with little change in LW emission. A temperature change with no change in albedo should increase radiance across the spectrum with a (predictable) shift in peak radiance.
Thus, while the temperature interpretation is indirect and will always be prone to some error, I have not read anything in the literature that would suggest a systematic warm bias in the event of increasing albedo. If anyone else has, I would appreciate a reference.
Concerning this From Dr Spencer, “While this sounds like a good way to measure surface temperature, it turns out that the microwave ‘emissivity’ of the surface (it’s ability to emit microwave energy) is so variable that it is difficult to accurately measure surface temperatures using such measurements. The variable emissivity problem is the smallest for well-vegetated surfaces, and largest for snow-covered surfaces. While the microwave emissivity of the ocean surfaces around 50 GHz is more stable, it just happens to have a temperature dependence which almost exactly cancels out any sensitivity to surface temperature”
I asked about the snow and recieved one response. Gary (14:13:47) :
… The true temperature can only be calculated if the emissivity is known. As long as emissivity is constant a trend of brightness temperature will follow the true temperature with a constant displacement. When emissivity varies problems arise. If the emissivity is rising with constant true temperature the UAH data will show an increasing brightness temp and warming. This is possibly what is happening at the moment with all the snow and ice around.
From this one would estimate that the data would show a false high reading due to the increase of snow on the ground. ??? Is this quantified. How much does this affect the margin of error? Other posts indicate the amount and reflectivity of the clouds can effect the readings. Can or does? and again how much?
And I guess no one here knows what the effect of this is ???…While the microwave emissivity of the ocean surfaces around 50 GHz is more stable, it just happens to have a temperature dependence which almost exactly cancels out any sensitivity to surface temperature”
Thanks, just trying to learn
“Formation of snow requires removal of heat from water vapor in cold air. That heat remains in the air. The snow drops to the ground. The atmosphere where the snow fell now holds the snow’s latent heat of freezing and, though it is still cold, it is “warmer” than it would be if there had been no snow. Got it?”
Got it. But… when the snow melts in the spring it takes the same amount of heat to melt it as it gave up when it turned to snow? Result being “cooler” than it would be if there had been no snow and netting to zero? Unless the snow lands some place far enough north or south that it never melts? my head hurts from thinking about this?
davidmhoffer (16:50:23) : “…Got it. But… when the snow melts in the spring it takes the same amount of heat to melt it as it gave up when it turned to snow? Result being “cooler” than it would be if there had been no snow and netting to zero? Unless the snow lands some place far enough north or south that it never melts? my head hurts from thinking about this?”
Yes, the spring will be the reverse situation (except the snow may run off as it melts, instead of requiring heat to evaporate it locally.) The net will not be zero, though, since the winter albedo during heavy snow accumulation was raised, thus cutting the heat input to the system. Remember, too, that flow of heat from the NH to the pole, as has occurred this winter, also increased heat output to space. Less heat in, more heat out -> global cooling, net.
Global temperature is not very meaningful. The ocean is almost 1200 times as large a heatsink as the atmosphere. Think of that! That’s a pound of air for every half a metric ton of ocean. Air temperature changes are transient and insignificant in comparison.
This really doesn’t matter because the idea of a “global average temperature” is a complete fiction.
Nobody believes any more in kool-aid powered satellites, launched from Hollywood launch pad.
Or is it because of “positive feedbacks” from the GISS office in NY?
Luboš wrote:
“A 1.5 °C warming of the global mean temperature is still less than one standard deviation of the monthly average at a given place.”
This is surely true (maybe even understated), but does it really refute the relevance or significance of a global mean temperature? The global mean has its own standard deviation, and that ought to be the basis for determining whether or not it is changing significantly over time, not the standard deviation at a given place, which will always be much higher.
I think a perfectly good analogy here is to the stock market. The standard deviation of a market index, say the DJIA, will always be much less than the standard deviation of an individual stock price. So? That doesn’t make the market index meaningless as a measure of aggregate market activity. So why does the higher standard deviation of temperature at a given place make meaningless the global temperature as a measure of aggregate, world wide, climate change? There may well be good reasons, from a physical point of view, for questioning the meaning of a global temperature as a metric for monitoring climate change. But not from a statistical point of view.
The real bottom line here is that we happen to be in a “warm phase” globally in the decadal oscillation of global temperatures, with the rate of change in global temperatures rising since the latter part of 2007 (after the last La Nina). Think, then, what this means when the rising phase ends in the next year or two, and we enter the next decadal downturn. I’m making no predictions on how significant the downturn will be, but the current increase in rate of change will reverse (it cannot increase much longer), and we’ll get a period of “global” cooling. I don’t know if the cold this winter is the start of this downturn, or not. We’ll know soon enough, though.
I’ve been watching AMSU daily temp all month. This is looking to be a record or near record warm January. I don’t know *where* the hell its warm, but it ceratinly is nowhere in the northern hemisphere, that’s for sure…
The answer probably resides in the tropical West Pacific, where the tropical rainfall is currently widespread. Those thunderstorms move energy from the sea surface into the troposphere, warming it. The storms will subside in a week or two and the temperature spike will drop.
An interesting comment from James Hansen on Lateline (ABC in Australia 7 Dec 09), available here:
http://www.abc.net.au/lateline/content/2008/s2764523.htm
“JAMES HANSEN: You know, if you look at this global temperature curve
and smooth it over a few years you’ll see that it’s continued to increase
over the last decade. And in fact, it’s not true that 1998 was the warmest
year. 2005 was the warmest year.
The British analysis shows 1998 as the warmest year because they exclude
polar regions, because there are no weather stations there or very few. But
there are other ways to estimate the temperature in the polar regions and
in fact, because of the decreased sea ice in the Arctic it has been warmer
and warmer in the Arctic.
And when you include these polar regions, it turns out that 2005 was the
warmest year. And when you average over a few years you’ll find that the
temperature curve has continued up. And besides, you don’t expect the
temperature to go up every year.
There’s a lot of natural variability in the system primarily due to the
tropical El Nino/La Nina cycle. And now we are moving into the El Nino
phase, so it’s a pretty good bet that, first of all, this year is going to be
one of the warmest years, 2009, and 2010 will probably be the warmest
year on the record.”
At first I dismissed this as more alarmism, but since he is the guy who runs GISS I guess he had some inside information on what was happening. I still wonder though, how valid the Arctic sea ice adjustments are, and whether these are being incorporated into the January 2010 measurement.
January heat wave, sorry but this is BS. USA also had a shity cool summer which NOAA somehow painted as warmer than normal summer. Orwellian double speak again. They are outright lying. Didn’t Hansen promise from 2010 onwards would be the warmest decade?
Big interest are invested in carbon trading. It is obvious they will make a go for it, they have nothing to lose but lose. If the public buys such ridiculous “observed data” the slave tax will go through.
If the warmistas actively publish that this has been the warmest January ever then it will surely do more to destroy faith in their alarmism. Even if they happen to be right.
If global “warming” doesn’t affect the places people live, then what’s the problem?
jorgekafkazar
thanks for the explanation re snow melting. already had the rise in radiation from the poles figured out, been harping on it myself for a while, nice to see someone else mention it. Seems to me it is a pretty big negative feedback that the models don’t account for.
TerrySkinner (15:41:19) – good points.
Another issue that may be affecting satellite measurements is that I have read that the infrared blocking of CO2 is mainly in the 12 to 20 micron wavelength. This corresponds to the ‘hot body’ radiation at temperatures near freezing. So CO2 has a greater greenhouse effect (I assume in the upper troposphere) when there is a lot of ice and snow on the ground. This may be a source of distortion in the satellite measurement.
I think the initial post was poorly argued and the commentary hasn’t been very helpful either. If, and this is a big IF as the data is very uncertain, this proves to be the hottest January on record, then it quite strongly suggest factor(s) that need to be quantified. CO2 and methane being two of them.
With weak solar activity and strongly negative NAO I don’t think anyone in the sceptic camp was predicting the possiblity of an unusually hot January. Quite the contrary. Lubos Motl’s Non sequitur that “even if it is warming, it doesn’t matter” is simply a weak and faulty argument and strikes as ideological and not a scientific postulation.
A 2C warmer world would have a clearly different climate compared to what we have today. The difference between medieval warm period and little ice age in Europe was possibly less than that. And it didn’t matter in the overal picture that during the medieval warm period you had a number of cold anomalies and during the little ice age there were warm anomalies. They were two distinctly different climates in Europe.
In that perspective a 2C warmer world would be a very different place indeed. Whether for better or worse, I don’t think that is an argument we can answer with any comfortability due to huge uncertainties in how the warming would average coupled with huge global variation in how the weather patterns would change.
So you can’t count out the possibility that a 2C warmer world could make for a lot worse living conditions for humanity. I don’t say it is likely but to entirely to dismiss the possibility is not rational at all. With this I’m merely saying that while it still seems logical to remain firmly in the skeptic camp, I think that at the same time the scientific position is to remain open to new information and to be ready to change your mind if the strenght of the measurements and arguments start switching to the other side.
So this potential warm anomaly in a time of strongly negative NAO and weak solar activity is something we skeptics need to quanity and not to dismiss.
These posts are not helping. I don’t care about the technical argument, stop being cute with the titles that have nothing to do with the point of the post.
You have just confused the average person. This is like skeptical suicide.
Basil (18:24:50) :
Here is a statistical beef. The temperature of a 10km^2 area can contain a standard deviation equal to 1.5C. How large is the finest resolution of grid box used in standard practice?
Can someone help me out here? i was thinking (hopefully that’s not a crime yet) that what we should be looking at ony any given day is not the maximum temp but the difference between the overnight minimum and the previous day’s maximum temperature. this will show tha daily variance. then we look at the cloud cover levels for the area and over time we should be able to plot a graph that would show how much of the heat loss each day was stopped from the cloud cover , then the remainder would be what’s trapped by GHG’s and particles. Is there something wrong with that theory?
It is interesting that the UAH global satellite data is so well insulated from the record cold here on the ground.
If that is in fact true and not the result of manipulation, then there is no reason why anyone should be concerned about UAH global satellite data.
With kind regards,
Oliver K. Manuel
It would be so much easier if our planet didn’t have any tilt, or any modulations thereof, and equal land mass placement. The Northern half would be the northern half and the southern the southern. Where do you draw the line on a tilted spacially imbalanced planet? Comparing Vostok and GISP2 the hemispheres DO NOT respond with the same amplitude or phasing to a given forcing (almost double in the NH)! That comparison implies that a global average WILL have a northern dominant component/trend. There is no average no? It would have to have a denominating line south of the equator.
Does this global mean temperature refers to the top surface layer of the Earth’s atmosphere? Well, since the unusually cold air currently present sinks, the warm air due to the El Nino is forced up the atmosphere, thus we are getting higher temperatures at the top layer of the atmosphere. Is it so??
Actually I just went to the site (link in the article) and provided that you have java installed you can look at the data any way you want. Pick the layer and the years you want to compare, and press redraw. Now there is no doubt from the data that an over all increase is being shown over the ten years. But jumping on a 1 degree (F) rise on one day in January is misleading. If you turn off most of the other years so you aren’t looking at spaghetti, the first 9 days of January 2007 were WARMER than the first 9 days of 2010, so don’t draw any conclusions yet, the data isn’t all in. 2007 started out WARMER than 2009 for the first six months, but was cooler for the last six. All of which is almost as meaningless as the original observation of a 1 degree F rise year over year on a single day. Climate responds to input change in decades, perhaps centuries. Trying to discern a clear cause and effect out of 10 years satellite data does not seem reasonable.
I blame Australia for it. It was rather hot there. There is also a large hot spot in the South Pacific nearly as large as Australia, with a temperature anomaly peaking at +4 degree C.
I agree, although my research involves Western Australia which is a long way from the South Pacific. November and December temperatures jumped sharply in most of Western Australia. January also has been above average so far. The same months in 2008/09 were below average.
Albeit somewhat meaningless, I like to compare and update recent combined and averaged temperatures over the previous 12 months with averages from around 1900 at the same 32 Bureau of Meteorology monitoring sites across the 2.5 million square kilometres of Western Australia (http://www.waclimate.net):
Nov 08 – Oct 09 min 0.39 C warmer max 0.60 C warmer than ~ 1900
Dec 08 – Nov 09 min 0.53 C warmer max 0.92 C warmer than ~ 1900
Jan 09 – Dec 09 min 0.59 C warmer max 1.09 C warmer than ~ 1900
Western Australia’s recent soaring temperatures may or may not be influenced by:
– the upward correction in November by the Australian Bureau of Meteorology of about 0.4 C for all its August 2009 temperature recordings
– the Copenhagen summit
– a hot spot in the South Pacific
– the Rudd Government’s intention to reintroduce emissions trading legislation in parliament next month
– the weather
I’ve created some graphs from the high quality (homogenized and corrected) data set for the 26 Western Australia locations monitored by the Bureau of Meteorology from 1910 to 2009 (updated by the BoM last week so all 12 months of data is available up to and including 2009 instead of 2008):
http://www.waclimate.net/1910-western-australia.html
I’ve also charted from 1979 to 2009:
http://www.waclimate.net/1979-2009.html
This is the official data (downloadable from the BoM site) charted via Excel.
snowguy (21:16:59) :
Does this global mean temperature refers to the top surface layer of the Earth’s atmosphere
Actually the satellite has multiple channels at different layers. The one shown in the article is ch04 “near surface”. The highest channel they record is 118,000 feet. If you look at that channel, 2010 is “warmer” than 2009 so far, but cooler than 1999, 2000, or 2001.