These issues, which are either not recognized at all in the assessments or are understated, include: - the identification of a warm bias in nighttime minimum temperatures - poor siting of the instrumentation to measure temperatures - the influence of trends in surface air
water vapor content on temperature trends - the quantification of uncertainties in the homogenization of surface temperature data, and the influence of land use / land cover change on surface temperature trends.
Not exact matches
But
on a plane, the low
water vapor content and air pressure combined with more rapid breathing equals a need for more
water.
Most climatologists expect that
on average the atmospheres
water vapor content will increase in response to surface warming caused by the long - lived greenhouse gases, further accelerating the overall warming trend.
Alternatively, more direct observations of that radiative imbalance would be nice, or better theoretical and observational understanding of the
water vapor and cloud feedbacks, or more paleoclimate data which can give us constraints
on historical feedbacks, but my guess is that ocean heat
content measurements would be the best near term bet for improving our understanding of this issue.
Rearranaging the winds and
water vapor distribution strikes me as a good candidate for effecting a flip
on the time scale of a few years, with
water vapor content resetting the thermostat.
Ray, let's plot the distribution
on the vertical axis for some metric related to RP's
water vapor content (isn't there something called «hurricane energy» or the like?)
The second nonlinearity is that the
water vapor feedback depends
on the moisture
content of the air, which via the Clausius - Clapeyron relation is a nonlinear function of temperature.
Climate projections, such as those used by the Intergovernmental Panel
on Climate Change, rely
on models that simulate physical properties that affect climate, including clouds and
water vapor content.
Water vapor on the other hand is a much more potent climate driver since there is a much larger
content with a large variation, from under one percent (10,000 ppm) to close to 10 percent (100,000 ppm).
To name one relevent initial condition that has changed......... atmospheric
water vapor content has changed
on every spatial level.
States that other feedbacks likely to emerge are those in which key processes include surface fluxes of trace gases, changes in the distribution of vegetation, changes in surface soil moisture, changes in atmospheric
water vapor arising from higher temperatures and greater areas of open ocean, impacts of Arctic freshwater fluxes
on the meridional overturning circulation of the ocean, and changes in Arctic clouds resulting from changes in
water vapor content
Back to your post
on observed versus modeled atmospheric
water vapor content trends with warming
Elliott et al. conclude, based
on the selected data below 500 hPa only that SH (moisture
content) increased slightly with warming, but not at a rate sufficiently strong to maintain constant RH, as is assumed by the IPCC models in estimating
water vapor feedback.
1) The Perry curves in this posting are based
on NASA measurements taken in the Arctic, where the
water vapor content of the Atmosphere is less than in regions closer to the Tropics.
Wild et al. (2001) proposed that 344 W m − 2 is a best estimate from models but noted that considerable uncertainties exist and especially that there were problems in accurate simulation of thermal emission from a cold, dry, cloud - free atmosphere, and a dependence
on water vapor content.