An examination of convective moistening of the lower stratosphere using satellite data

摘要

In this paper, we use satellite data to test the hypothesis that deep convection moistens the lower stratosphere. Water vapor measurements from Earth Observing System-Microwave Limb Sounder and Atmospheric Chemistry Experiment-Fourier Transform Spectrometer over North America are binned according to the International Satellite Cloud Climatology Project deep convection indices. The results show that in the North American region (50–112°W, 10–50°N) the convection-impacted samples are significantly moister than the nonimpact samples in the lowermost stratospheric layer right above the tropopause, and a drier tendency is also noticed right above this moistened layer. Trajectory modeling is used to aid the identification of deep convection-impacted water vapor samples. However, we find that a substantial fraction of high-concentration (>8 ppmv) samples at 100 hPa cannot be attributed to nearby deep convections.