http://www.sciencemag.org/content/327/59...
http://ruby.fgcu.edu/courses/twimberley/...
About 99% of water vapor is contained in the troposphere. Studies have suggested that stratospheric water vapor may contribute significantly to climate change.
Increased stratospheric water vapor cools the stratosphere but it warms the troposphere.
Decreasing stratospheric water vapor warms the stratosphere but temperatures near the Earth's surface cool.
“The comparison of these radiative forcings,” the author's state, “suggests that the decadal changes in stratospheric water vapor have the potential to affect recent climate.”
“This work highlights the importance of stratospheric water vapor for decadal rates of warming based directly upon observations, illuminating the need for further observations and a closer examination of the representation of stratospheric water vapor changes in climate models aimed at interpreting decadal changes and for future projections.”
My personal answer is that we don't know. If you go back in time past the 1990s, you have to rely primarily on radiosonde data. While people sift through that data and do the best job they can with it, it is notoriously unreliable for humidity measurements. The hygristors that are used in the radiosondes have been changed multiple times, and are subject to errors due to things like wetting when the sonde passes through a cloud layer, or failure of the person launching the balloon the get the sonde out of its package early enough before launch to let the sensor equilibrate to the ambient atmosphere. These sensors were never intended for long-term climate change measurements, and I think it's really risky to use them for that.
GPS and Millimeter Wave Radar measurements of precipitable water (integrated water vapor) are much more reliable ways to measure the water vapor content of the atmosphere. The problem is that they don't go very far back in time. I have my own data set of precipitable water that covers the time period from 2003-2009, and if anyone wanted to fund me I could extend it through the present, but even that would only be an 11 year record, and that's too short a time to draw any conclusions. There are a few GPS measurements going back into the mid-1990s, but not very many. I think in a couple of decades we'll have a definitive answer to this question, but right now I don't think we know.
On the other hand, there is very little reason to expect that water vapor won't scale with the Clausius-Clapeyron value.
Water vapor is only in the atmosphere @ 2 days after it forms. AGW warms the air which increases evaporation which would add more water vapor. It is still short lived
Jeff has made so many claims that were later proven untrue that I refuse to follow his babble any further. He is a mental misfit who refuses to acknowledge that his pals once touted an impending Ice Age.
Even though his pal Lamb once touted the Ice Age. High Priest did, H H Lamb, the man who invented this AGW rubbish:
"In 1971 Lamb decided to base his pioneering research at a university, and he became the first Director of the Climatic Research Unit established in 1972 in the School of Environmental Sciences at the University of East Anglia.[1] In 1973 and 1975 he arranged for two international conferences which were hosted in Norwich. At first his view was that global cooling would lead within 10,000 years to a future ice age and he was known as “the ice man”, but over a period including the UK's exceptional drought and heat wave of 1975–76 he changed to predicting that global warming could have serious effects within a century. "
So it bothers me that anyone would give an ounce of serious thought to anything Jeff M has to say. It is like walking from the sterility of an operation room to the nastiness of a hog pen.
That is definitely a negative. At 300 millibars however, water vapor has been decreasing.
http://www.climate4you.com/images/NOAA%2...
http://www.earthlyissues.com/watervapor....
In a warming world, relative humidity can go down while the partial pressure of water vapor goes up, if the partial pressure goes up less than the vapor pressure.
I guess if cyclops knew where the stratosphere is, compared to where the troposphere is he might see his mistake.
Tropospheric water vapor has made a small but constant increase as Co2 has warmed the atmosphere.
http://web.a.ebscohost.com/abstract?dire...
There are quite a few papers on it just as there are on stratospheric water vapor changes
Those measures are for relative humidity: http://science.howstuffworks.com/diction...
Definitions of terms:
http://disc.sci.gsfc.nasa.gov/data-holdi...
Here is a graphic from the 2007 IPCC report showing precipitable water vapour:
http://www.ipcc.ch/publications_and_data...
This was from a journal article that has been updated from 2005:
http://envsci.rutgers.edu/~toine379/extr...
You can view the data via the mynasadata page here:
Lower Troposphere - http://mynasadata.larc.nasa.gov/las/UI.v...
Upper troposphere - http://mynasadata.larc.nasa.gov/las/UI.v...
Over the same time period cloud concentration has shown little change.
http://mynasadata.larc.nasa.gov/las/UI.v...
Overall water vapour concentration appears to be controlled by the ENSO/PDO over short time scales. There are, however, problems with historical data dependent on the measuring technique.
http://images.remss.com/papers/mears_GRL...
Sagebrush: I'm not even going to bother with you.
Jeff M. says it has but I searched online to find a source but couldn't find anything except this chart from the university of Oslo. http://www.climate4you.com/images/NOAA%20ESRL%20AtmospericRelativeHumidity%20GlobalMonthlyTempSince1948%20With37monthRunningAverage.gif
What do you think does it look like an increase?
