Yesterday, Climate Audit announced the submission of a paper on tropospheric temperature trends (see).
We have also submitted a paper which relates to his study. It is
Pielke Sr., R.A., T.N. Chase, J.R. Christy, B. Herman, and J.J. Hnilo, 2009: Assessment of temperature trends in the troposphere deduced from thermal winds. Int. J. Climatol., submitted
“Recent work has concluded that there has been significant warming in the tropical upper troposphere using the thermal wind equation to diagnose temperature trends from observed winds; a result which diverges from all other observational data. In our paper we examine evidence for this conclusion from a variety of directions and find that evidence for a significant tropical tropospheric warming is weak. In support of this
conclusion we provide evidence that, for the period 1979-2007, except for the highest latitudes in the Northern Hemisphere, both the thermal wind, as estimated by the zonal averaged 200 hPa wind and the tropospheric layer-averaged temperature, are consistent with each other, and show no statistically significant trends.”
Our conclusion reads
“Our paper demonstrates that there are significant uncertainties in using the TWE [thermal wind equation] to diagnose tropical temperature trends. Results using the TWE in the deep tropics are in significant disagreement with all other observational data. We have also provided evidence that the TWE is less robust and subject to higher variability and error than other available data. Use of the TWE is not physically appropriate in deep tropical latitudes and near the tropopause it can be affected by the reversal of temperature gradients should the tropopause be crossed. For these reasons we conclude that the diagnosis of an upper tropospheric warming in the tropics using the thermal wind is not likely to be accurate.”
We weblogged on this issue in response to two Nature articles last year; see