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Plotting Temperature

The standard mode of plotting temperature these days seems to be plotting temperature anomalies. This has irked me regularly because my professors in college so routinely slapped me for doing this.

Apparently, it is okay, because everyone is doing it, but I am still troubled. How far off is the following thought process.


Temperature is a function of latitude, longitude, altitude, axial tilt, time of day, time of year, precision of instrument and accuracy of instrument. You could combine axial tile, time of day and time of year into one variable and the accuracy and precision are really the error bars that should be tagged to any plot. That leaves us with with a 4D equation for temperature, which we then reduce to 2 variables in any of the "standard" charting done in the discussion.

Even Dr. Spencer seems to use this mode for analysis.

Isn't a 2D representation (monthly average temperature aka time and temp) obfuscating the data too much.

Wouldn't a better way of representing the data be plotting the average temperature plus the standard deviation of the temperature plus an error bar on top of that?

On any given day the range of temperatures on this planet will include 200K to 320K.

Am I crazy to suggest that the standard deviation be plotted. I suspect that such a plot done on a temperature anomaly would make the changes into a flat line? If you filled in the area covered by the standard deviation, you would get a solid graph at least as big as the charts currently use to show the Global Temperature Anomaly.

Putting the standard deviation into the chart will at least get you a little bit closer to a 3D representation of 4D data. Maybe someone will wake up and say -- "WTF are we doing reducing global average temperature down to a single point?"

Re: Plotting Temperature

I think the clue is in the word "Plotting". Oooh, er, or am I starting to get a bit paranoid

Re: Plotting Temperature

brad.tittle


Temperature is a function of latitude, longitude, altitude, axial tilt, time of day, time of year, precision of instrument and accuracy of instrument.


Foster is so right Brad. What your teachers did not tell you, (because the academic world had not been suborned then), was that now, you need to wrestle with four more additional variables:-

1, The influence of the site's position.

2, The influence of which sites are included or excluded.

3, The influence of Urbanisation.

4, The interpretation (Massaging) of these influences.

From all this Brad, I conclude that the instrument itself is now redundant!

Regards, David

Re: Plotting Temperature

I fail to see why any observations are necessary. Our modern Aristotelian science can predict these observations from the theory. Since the theory is perfect, there is no point in grubbing around with thermometers or suchlike. Observations are imperfect and only lead to apparent anomalies. Important scientists then have to waste time explaining these 'anomalies' whilst heretics stir up dissent and confusion amongst the ignorant.

Always remember, we can conceive the idea of a 'most perfect' theory of climate change. Is such a theory true? Well, if it were not, one could conceive of a more perfect theory - one that was true. Thus, one arrives at a contradiction. Therefore our most perfect theory of climate change must be true. Q.E.D.

Re: Plotting Temperature

The original intention of wetaher stations was not to determine climate change but to adress purely local concerns.
If one were to start with a planet bereft of any temperature measurement stations and one wanted to study climate change I suspect that one would have to design a network of stations that doesn't even come close to what they are actually using and one woul have to also be sure to understand what one is measuring.
AT the moment, the main concern seems to be with UHI effects.
The problem is that even small station changes seem to introduce significant temperature changes.
The problem is that when one locates a station in a particular area all it reports is the teemperature of the temperature sensor. It is hoped this represents the local environment. Local? how local? it would seem that local means very local if a station move of a few hundred yards can introduce a significant change in the data. That suggests that there is no way to know, whatever the station chosen, just how representative that measured temperature is of the region it represents.
Nor can one be sure that if there are climatic changes in the region that these changes will be faithfully recorded by the temperature station.
Some better understanding is needed to determine not only that the stations is free from the influences of landing planes, car parks and A/C units but also that the station location is able to represent the region as a whole.
STill, the real purpose of AGW isn't climate change prevention/remedy, it is a new world order and access to all that tax money.
In such circumstances I can quite understand the teempetation to scrap actual temperature measurements and infer them instead. It seems this is what is actually happening. The great death of temperature stations - the majority of the victms are northern hemisphere high altitude sensors, and where large areas of ocean have their temperature determined from proxies, stations somewhere on land.
The great advantage of all this is that the grant money is not actually spent on weather stations or even on computer programming (to judge by the UEA programs) ... this is what really troubles me, what has Prof Phil Jones spent his £23million in grant money on?
Does any one actually ask for and get an accounting? or is it his to dspose of as he sees fit?

Re: Plotting Temperature

It sounds like you're talking about temperature anomaly graphs which include uncertainty ranges Brad. I've occasionally seen graphs like that, but you don't tend to see them in newspapers. Here's a report which uses this sort of graph:

report

But even with the uncertainties in temperature included, the graph still indicates an increase in global temperature, at least when the uncertainties are estimated by climate scientists.

On the general issue of 'chartmanship' (the use of tricks with graphs to deceive the eye), I saw a pretty good attempt to present global warming data with the chartmanship heavily toned down on AGW sceptic Jonathan Drake's "Questioning Climate" website:

drake

The first thing Drake does is to plot data in degrees C with the Y axis starting at 0 deg C (and mentions in passing that it's quite tricky to find data given in anything other than the anomaly form). Then to give a sense of proportion to the warming data he brings in the fact that the swing in average global temperature over the course of a year is substantially bigger. But I suspect that his method of graphically presenting global temperature data is unlikely to be adopted by the AGWers.

Re: Plotting Temperature

Actually I am referring to the standard deviation of temperatures observed.

In any given day the temperature can range by 30F or more. (

If we plot the standard deviation of the temperatures we get an indication of the magnitude of the change. Adding the error information to the plot would also be useful.

I have the same problem with "Mean tide" data. They will show us what the "mean tide" is doing (increasing at a rather slow rate) but fail to show us what High and low tide are doing.

Re: Plotting Temperature

brad.tittle


In any given day the temperature can range by 30F or more.


Actually Brad, go out in the Nevada desert sometime, or even Death Valley. The temperature can vary by > 100ºF, from well below freezing to over 120ºF.

DaveE.

Re: Plotting Temperature

You just made my point all the more clear.

That also is an example of CO2 being such a wonder heat retainer...

Overcast skies in the desert, sort of warm.

Clear skies -- Get ready to freeze.

Re: Plotting Temperature

Another example of CO2 (not) being a wonder energy container.

In the Nevada & Arizona deserts there are many outcrops of rock.

Want to get cool? get in the shade.

It's often sub zero, even late afternoon.

In winter when some places never come out of shade, there are frozen rock pools that never melt, even though the temperature out of the shade is above 100ºF

DaveE.

Re: Plotting Temperature

Oh, I see what you're talking about Brad. Temperature anomaly graphs which take account of the diurnal range are even rarer than the ones with the uncertainty range estimates included. There are some graphs of global maximum temperature and minimum temperature from 1950 to the early 1990s in this 1997 paper which is available free to view on this link:

link1

If you look at Fig 1 of the paper you'll see why climate scientists prefer not to plot this sort of graph - the temperature rise per decade for the maximum temperature is half the rate of the rise of minimum temperature, suggesting that two thirds of global warming is occurring at night. If they plot mean temperature this detail is hidden.

I might as well include this link as well, criticism of the above paper by AGW sceptic Warwick Hughes:

link2

Re: Plotting Temperature

Even those don't show the absolute range of values. They seem to be focussed on just the low temp, high temps, average temps.

I would want to plot all of them on 1 chart. The mid line being the average. The upper line the average of the high temps and the lower the average of the low temps.

The only reason I think this chart is necessary is to get the idea of the forest back into the researchers heads.

The ability of scientist to focus on the 7th digit is admirable at some level. Recognizing that the 1 and 2nd digit don't care is much more important.