1.State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences;2.Climate Change Research center,Chinese Academy of Sciences
The rapid transport by the overshooting deep convection is essential for summertime water vapor maxima in the lower stratosphere over the Asian monsoon region. However, the impacts of overshooting deep convection over subtropical Asian monsoon region on the lower stratospheric atmospheric composition distribution have not been fully addressed. In this study, we investigate the characters of overshooting deep convections during 2016 Wuhan rainstorm by using CloudSat and Aura Microwave Limb Sounder (MLS) satellite data. The concentrations of water vapor (H2O), ice water content (IWC), ozone (O3) in the upper troposphere/lower stratosphere during overshooting deep convections are analyzed. We find one overshooting deep convection case B which occurred at 5:00 a.m. on July 4. The overshooting convection considerably reduces the ozone mixing ratio near the tropopause. For example, it leads to 32.53% decreases of the climatological mean ozone mixing ratio. The overshooting convection is farther found to enhance the moisture at the lower subtropical stratosphere through the hydrating effect which has two different ways: moistening induced by ice particles evaporation and by the convective moisture flux itself. The overshooting convection results in a stronger moisture change (about 98.15% increase of climatology) when compared with ozone change. Our study implies that the local overshooting convections over subtropical Asian Monsoon region in boreal summer are important in transporting water vapor from the troposphere into the low stratosphere.