Unsettling new AGU study of climate models, effect of water vapor varies up to 96% among codes, 'highlights uncertainty,' study published 7/3/12

.
7/3/12, "Stratospheric water vapor and climate: Sensitivity to the representation in radiation codes," Journal of Geophysical Research, AGU

"Key points:

• Stratospheric water vapor is poorly represented in many broadband radiaton codes
• Spectral sampling rate is important for LBL calculations for strat. water vapor
• Radiation code errors for stratospheric water vapor may cause temperature biases

There has been considerable interest in the climate impact of trends in stratospheric water vapor (SWV). However, the representation of the radiative properties of water vapor under stratospheric conditions remains poorly constrained across different radiation codes....

The stratosphere-adjusted radiative forcing differs by up to 96% across the less detailed codes. The results highlight an important source of uncertainty in quantifying and modeling the links between SWV trends and climate."...

--------------------------------------------

7/2/12, "Settled science update: Effect of water vapor varies up to 96% in different computer models," HockeySchtick

"A paper published today in the Journal of Geophysical Research reports that the computer-modeled effect of stratospheric water vapor upon the climate ["radiative forcing"] varies by up to 96% between various computer model codes.

Regardless of this remarkable divergence, the "radiative forcing" from "greenhouse gases" coded into all computer climate models is based upon fallacious thermodynamics.

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117, D13102, 9 PP., 2012
doi:10.1029/2012JD017484

Stratospheric water vapor and climate: Sensitivity to the representation in radiation codes"

via Tom Nelson