CO2 - how much

And more evidence of the CO2 fudging

"Raveninghorde" schreef in bericht news: snipped-for-privacy@4ax.com...

You've no idea how dodgy the 19th century CO2 measurments were, and the early modern measurements were not much better - it took a while before the chemists involved worked out how to get stabe and consistent measurements, and instrumental methods are lot tidier than wet chemical analysis.

Anybody who makes a fuss about the 19th century measurments not agreeing with modern results has never had to do the measurments the way they did, or thought about the consequences of measuring atmospheric CO2 in towns where everything was coal-fired.

--
Bill Sloman, Nijmegen

The latter link leads to a link that has one to this, the paper used:

As noted in "page 263" (5th page after the title page), nearly all air samples selected were taken from 2 meters above the ground in rural areas or at the peripheries of towns.

Although the author did note confidence of lack of contamination from industry, it appears to me there were still local sources of CO2 affecting the readings. I suspect that is why the curve for chemical determination has all those bumps that Mauna Loa determinations lack.

Meanwhile, Mauna Loa managed to find a seasonal cycle in atmospheric CO2, indicating accuracy beyond the 1-3% that the paper mentions for the chemical analysis methods.

Another thing to look for if it can be found: Time of day and weather conditions when the air was sampled for chemical determination of CO2 content. When time of day and weather conditions favor convection between surface-level air and middle or upper tropospheric air, then the sample should represent global level of atmospheric CO2 content fairly well. If the sample was taken with lack of sunshine and lack of convection, then the plants in the area are not removing much CO2 from the local air while animals (including insects), bacteria, molds, yeasts and fungi are adding it, and lack of convection is allowing it to build up. And at

1-1.5 hours after sunrise on a sunny day it will probably not have come much back down to the general atmospheric concentration. Air samples taken on cloudy days are probably often not much better than ones taken at night.

- Don Klipstein ( snipped-for-privacy@misty.com)

That one makes the tall claim that liquid water exists in Antarctica ice as cold as -73 C, and that explains how the figures from ice core data can be incorrect. (Ice formed in the last thousand or two years would certainly not be subject to the pressure resulting from depth that would lower the freezing point of older ice that can be 3 kilometers below the surface).

And the cited support for that claim was a paper I could not find with a web search. It is titled "Sulpfuric acid at grain goundaries in Antarctic ice". That appears to me to be a cause of a few parts per million of liquid.

Also, we now have about 5 decades where both ice core samples and Mauna Loa data are available, so I would think that the determinations from ice core samples have fairly good correction factors.

- Don Klipstein ( snipped-for-privacy@misty.com)

Send some of that CO2 to the northeast, brrrrrr we could use it.

Cheers

Also note the journal -- famed, by the way, for publication of McIntyre and McKitrick, some years back. Energy & Environment is not a peer reviewed scientific journal. It's a policy journal.

Jon

How do they seperate the responses for different gases using infrared absorption at Mauna Loa?

5&...

I don't know exactly. I image that the use a device called an infra- red spectrometer to look at infra-red absorbtion lines that are specifc to C02, and don't overlap with infra-red absorbtion lies from the other gases present.

Gas phase infra-red absorbtion lines are pretty narrow - you need a pretty high resolution spectrometer to be able see the actual line width rather than the spectrometer's resolution limit - and it isn't difficult to pick lines where there is very little interference.

If you need to get really picky you can measure the apparent concentration of the interfering species at a wavelength where its absorbtion is dominant, then subtract a correction from the intial estimate of the CO2 level.

This generalises, so you can measure absorbtions at a number of wavelengths (at least as many as the number of gas species for which you want concentrations), write out a series of simultaneous for absorbtion at each wavelength as function of the concentrations of all of the absorbing gases, and solves the equations for the concentrations.

You have to take care to choose the right wavelenghts at which to measure the absorbtions, and the right path length over which to measure the absorbtion at any particular wavelength (which isn't going to be the same for different wavelenghts, and will change with gas concentration) in order to make sure that the system of simultaneous equations is "well-conditioned" so that it can be inverted to produce accurate estimates of all the gas concentrations, but this usually isn't difficult.

-- Bill Sloman, Nijmegen

The terms to google are "non-dispersive infrared" and/or "NDIR", I think. But to add to your comment, there's both a sample cell and a reference cell in the system, each with their own inlets and outlets, a shared infrared source, optical filter and detector, if I recall -- for in situ calibration on every sample taken. I could be wrong about that frequency, though. It's used instead of gas chromatography because the absolute levels in the atmosphere are large enough.

I think NOAA and Scripps each operate various sites. If there is a question about the details of operation, calibration, etc., I'd recommend contacting one or both of them about the specifics. The measurements are accurate but there's obviously limited spatial coverage, which are also made close to the planetary boundary layer. There are proposals and test sites for measuring column CO2 levels (using eddy covariance?)

Jon

As you say they use NDIR with a Siemens Ultramat 3 but I haven't found the spec of the equipment yet. I also haven't found a paper I can access that describes the process.

I'd like to know if it is measuring the total green house gas content and fudging the CO2 result based on a theoretical mix of methane, ozone, CO2 etc or if they are doing something more complex.

It looks as if this was the device used for many years. Siemens don't give away much about the operating principles, but it does seem to be non-dispersive. Be warmed, its a 2.15MB file.

pdf

this link tells you quite a bit more about ore aout the way the system works

http://74.125.77.132/search?q=3Dcache:

eng/ultramat_5e.htm

I don't think that you've got this quite right. Gas chromatorgraphy is all about separating gases.

A gas chromatograph will include some kind of detector at the end of the chromatographic column to identify various compoenets as they are eluted out of the column, and estimate how much of each component is present, but that wouldn't make much sense in this application.

I'd be interested to hear what they are using now. You seem to be able to design a very cute NDIR gas analyser around a tunable dode laser source.

-- Bill Sloman, Nijmegen

The technique should be measuring the various greenhouse gases separately; there may be some minor interference between some of the greenhouse gases, but as long as you are measuring all of them it isn't difficult to correct for any cross-sensitivity in the detector.

The Siemens Ultramat 3 is a multi-channel device, and should be able to measure different gases in separate channels.

-- Bill Sloman, Nijmegen

It is used for CH4, which is around 1.8ppm or something like that. The gas is separated into individual chemical components, which can then pass through a detector -- I believe this is what is called a chromatogram. Measuring the height of each peak in a chromatogram, the amount of a component can be calculated. As I gather it, anyway.

Jon

So it's reasonably probable that there is no longterm CO2 increase, no global warming, no positive correlation between CO2 and temperature, and no sea level rise, and that carbon taxes are just more taxes.

John

Two names to look for -- Charles Keeling (whom I assume must have written a paper or two on the details since late 1957 when it was first placed into service on Manoa Loa) or more modernly Dr. Denning, who figures on a lot of papers I've looked at concerning atmospheric CO2 and various problems and solutions regarding its measurement for climate research use. I haven't collected a paper that provides the details, yet.

If I were doing this, I'd contact Dr. Denning and a few other scientists working the area and ask them for a reference to the seminal papers describing the details sufficiently to develop an informed opinion about the digested data you see published. You might suggest that Dr. Keeling (before he died) must have written some piece about his design and how it is calibrated and used, back in the day when there might have been more questions about his methods, to jog memory. Or contact Scripps as an interested engineer who is looking to understand the details of operation so as to come to an independent opinion and to consider it in the context of some papers you've been reading about the need for developing column CO2 measurements (that should convince them you at least have some idea and are truly curious.)

If you do find such a paper, I'd like to get a copy and save it in my folder on climate science. So let me know, please.

Jon

Just as it's reasonably probable to assume that the U.S. economy will recover quickly, on its own.

Here are a few more like-minded assumptions:

1/ Peace in the middle east is just around the corner. 2/ N. Korea will soon abandon its nuclear program. 3/ Pakistan will stop exporting nuclear technology to nations that hate the U.S. and Israel 4/ The price of oil will never again reach +$100/barrel. 5/ Obama will get a line-item veto to curb pork. 6/ Bin Laden will be captured next week and his org. shut down. 7/ GM, etal, will suddenly become profitable, after the bail-out. 8/ Po-folk will soon be able to afford health care and homes. 9/ Retirees will be able to cash in their investments to live decently. 10/ EEs will go back to designing circuits, full-time.

In article , snipped-for-privacy@comcast.net says...>

The rest of that stuff is easy, but no more meetings? Get real!

In fact a sample of gas is passed through a long thin pipe, which is packed with or coated with an absorbing medium.

You push the sample through with an gas that doesn't absorb on the medium - I can't remember what is normally used, but it would probably be nitrogen in this application - and the various components in the sample move through the pipe, spending some of their time stuck to the lining or the packing material and some of the time as vapour, moving along with the carrier gas.

Different components in the sample interact more or less strongly with the stationary phase, move through the column at different rates, and emerge separated as a function of their different retention times.

Change the stationary phase and you can get different retention times and separate the components on the basis of different properties - and optical active stationary phase can (sometimes) even separate optical isomers

You can use all sorts of detectors at the output to pick up these peaks and find out how big they are. The flame ionisation detector is cheap and popular and would work fine with methane.

For some small molecule applications people use quadrapole mass spectrometers as detectors, and there's nothing - excpet the cost - stopping you from using a tandem mass spectrometer to detect big molecules and measure their molecular weight - in the first section - before bashing them with electrons or photons and looking at the masses of the fragmentation products in the second stage.

Remarkably cute stuff. I'm sorry that I never got to work on it - though I once spent a couple of months helping to get a tandem mass spectrometer working.

-- Bill Sloman, Nijmegen

I thought Mauna Loa Observartory's job was to measure atmospheric CO2 from air samples taken from the air around the observatory.

I would think that they use equipment properly calibrated by testing on already-known gas mixtures. There are infrared wavelengths at which there is not much atmospheric absorption by anything except CO2 and at which CO2 absorbs greatly.

- Don Klipstein ( snipped-for-privacy@misty.com)