An assessment of the tropical humidity-temperature covariance using AIRS

We investigate the horizontal and vertical structure of variance between water vapor and temperature in the tropical troposphere, using satellite measurements from the Atmospheric InfraRed Sounder (AIRS). Our analysis reveals large spatial gradients in the local covariance between water vapor and temperature. Positive correlations dominate the tropical lower and upper troposphere, while regions of negative correlation are common in the tropical middle troposphere. While regressions of the tropical mean water vapor and temperature profiles reveal slopes of the same order of magnitude of the Clausius-Clapeyron regime, the regression of local values can be up to an order of magnitude larger than the Clausius-Clapeyron prediction. Results from the NOAA GFDL lobal circulation model are also shown for comparison.