Upper tropospheric water vapor and clouds: new evidence from EOS MLS satellite observations

Upper-tropospheric water vapor distribution and its relationship with tropical deep convection are important topics for climate research. Previous studies suggest that tropical deep convection tends to moisten upper-troposphere on a variety of spatial and temporal scales. However, due to lack of observations on vertical profiles of water vapor and clouds above 300 hPa, past investigations were restricted to vertical integrated quantities, for example, average relative humidity above 500 hPa. Recent satellite observations from EOS Microwave Limb Sounder (MLS) provide unprecedented information on the vertical structure of water vapor and clouds, including ice water content and cloud fraction, from 300 hPa and above. Analysis is performed to reveal the interplay of tropical deep convection with upper-tropospheric water vapor and the implications for global climate change.