Description: In connection with the authors work on the apparent Iris Effect, they have acquired 2 years of additional data, and are redoing their analysis with the larger amount of data. So far, the results duplicate earlier results with greater statistical significance. They have also responded (successfully) to a number of criticisms of the initial publication. In particular, while differing estimates of cloudy and clear emissivity may be correct, they have shown that they reduce feedback factors by no more than 20%. The resulting feedback factors remain negative and large. Moreover, current data analyses suggest that the earlier estimates may be low for other reasons. They have also shown that all cloudy regions in the region covered by the GMS satellite are convective in origin. They are, however, continuing their work on an improved measure of cumulus activity. In particular, they are using TRMM data to determine thresholds in the T11 channel of GMS that are functions of time, position and SST. They have confirmed that the previous results had a very high statistical significance. However, they expect that the use of the improved measure of cumulus will improve this still further. They have completed their study of the possible reconciliation of temperature records for the troposphere and the surface. They have shown that the two time series can be reconciled by assuming that the surface temperature is responding to a jump in atmospheric temperature which occurred rapidly in 1976 associated with an observed regime change. The suddenness of the change observed in 1976 seems inconsistent with a greenhouse origin. Moreover, the relative rapidity with which the surface responded (a delay time of about ten years) is most consistent with low climate sensitivity. They have completed a simple study in which they show that rough agreement of observed and model predicted …
Date: April 12, 2002
Creator: Lindzen, Richard S.
Partner: UNT Libraries Government Documents Department