Comparing POSIDON and ATTREX Observations of Water Vapor to MLS Measurements

POSIDON and ATTREX observations of water vapor with MLS interpolated onto aircraft altitudes show some important differences. The aircraft relative humidity (RH) fields show higher values at lower altitudes compared to MLS, and there are more frequent observed occurrences of super saturated air in the observations than in MLS data. Back trajectories are used to analyze the dehydration process. The existence of the super-saturated layer seems to depend on how recently air parcels saw convection. These results suggest that convection has a role in both hydration and dehydration of air near the tropical tropopause.