Five-year climatology of tropical dry air intrusions as viewed by AIRS/Aqua

Low-level moist conditions are prevalent throughout much of the tropical oceans. However, previous studies have noted the occurrence of dry air intrusions, defined here as anomalously dry air events through the depth of the troposphere. These events may have important local effects on convective strength and the maximum cloud-top heights of convective cells. In this study, we will analyze five years (September 2002-August 2007) of water vapor values as viewed by the Atmospheric Infrared Sounder (AIRS) instrument onboard the Aqua satellite. Anomalously dry local events will be analyzed through their lifetimes in the tropics with regards to size, location, and duration. Seasonality and regional differences in the nature of the dry air intrusions will be discussed. Back-trajectories will be used to track the origins of dry air events with respect to subtropical and/or midlatitude weather conditions.