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8
Mar
Are Changes in Water Vapor Consistent with the Models
Posted by David Stockwell in All

Table of contents for Upper Troposphere

Are Changes in Water Vapor Consistent with the Models
Douglass et al 2007 and Atmospheric Models

Recent conversations at ClimateAudit about the observations of a steady fall in water vapor in the upper atmosphere have been the subject of some controversy, as contrary to the climate models, they appear to show a strong negative feedback from water vapor as greenhouse gases increase. Climate liberals argue the data are so flawed they should not even be discussed. Climate conservatives argue that the whatever information is there should not be wasted simply because it does not agree with the models.

Andrew sends in a much more sensible approach, asking, along the lines of Douglass et al. 2007 and their study of upper tropical tropospheric temperatures:

“Are the models and data ‘consistent’.”

This is what one of Hansen’s models showed with regard to humidity changes for doubling CO2.

See here: http://icecap.us/images/uploads/GrayAppendix_PartA.doc
What do the observations show? I calculated their rates of change per Century from 1979 to 2008: Specific Humidity Changes, g/kg per Century -> Relative Humidity Changes, % per Century

See Here: http://www.cdc.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl
If the trends in the data are to be believed, the models are completely qualitatively wrong. Now, the humidity data have their problems, but that they could be so far off seems unlikely. Indeed, a recent paper, while noting the problems with the data, advised against hand-waving around the issue:

Paltridge, G., Arking, A., and M. Pook Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data, Theoretical and Applied Climatology DOI 10.1007/s00704-009-0117-x

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Andrew

BTW, "adjustments" to radiosonde data for discontinuity problems can be quite large. See:
http://www.climateaudit.org/?p=3062
I realize that I am playing devil's advocate here, but I want to be fair with my assessment.

Andrew

Pete-discontinuities in the original data due to changes in instrumentation etc. might alter the trend because some later instruments might consistently report lower values than the older ones would have. However, I see it as unlikely that the errors are so great and systematic to so radically change the "real trend"-the data are just so different from the model I looked at that I don't see how you could account for the differences with errors. But I am not familiar with the specific data issues, so I might be convinced to change my mind if I was presented with strong evidence to the contrary (and IMHO, the data from satellites that claim to somewhat contradict the radiosondes are not sufficient-like Paltridge et al. I don't think that modelers should handwave past the issue).

Andrew

Oh, and if you want to verify that, just rotate each graph 270 degrees clockwise and only the labels will look different from Gray's, in that they will be backwards.

Andrew

jae, I put those graphs together rather hastily- they are from Gray's paper and had an orientation which made it difficult to compare them to the graphs from the radiosonde data that I put together. Unfortunately, my attention to detail was not so great, and I didn't flip everything right. But other than that, I faithfully adapted the graphs from Gray's paper.

Pete Stroud

Gary P. I agree with you entirely. I cannot see any reason why humidity value accuracy should affect a trend. The sign of the feedback mechanism is so important that every effort should be put in to determining it, but unfortunately the IPCC are very unlikely to support such research.

Also Geoff Sherrington, a very pertinent comment.

kuhnkat

jae,

the mirror images are probably to get the pressure levels in the same direction as the following graphs for easier "eyeball" comparison.

jae

What's with the mirror images in Fig. 1?

jae

These data are certainly better than the "data" that comes from GCMs (but try to convince a thermophobe of this).

Geoff Sherrington

There must be a tremendous amount of commercial and military aircraft data that are left out of the compilations I have seen, especially over oceans. The sensors cannot be all that bad.

It gives one the feeling that there are "Datasets for Dummies" and datasets for the chosen.

cohenite

Gary P, good pertinent question but I would have thought Miskolczi's theory is sufficient in itself. The most pertinent question, however, is where is there one empirical validation of AGW?

Gary P

I keep seeing statements that the radiosonde data is flawed or has problems but I have not seen a reference to such problems.

Is the magnitude of the uncertainty in the humidity measurements from the radiosonde data so bad that there is uncertainty whether the trend is up or down? Miskolczi's solution to the radiation transport equations was validated by eliminating a temperature discontinuity between the air and the ground. Now his overall theory is being validated by the prediction that humidity would drop as CO2 went up. Is anybody putting together a new climate model that includes his advances? If not, why not?

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