Diagnosing Stratospheric Water Vapor Relationships to the Tropical Cold Point Tropopause (Invited Presentation)

Dehydration at the tropical cold point tropopause primarily controls stratospheric water vapor, with additional (uncertain) contributions from subtropical monsoonal circulations and extreme deep convection. We quantify the links of stratospheric water with near-equatorial cold-point temperature (Tcp) using satellite measurements from Aura MLS and GPS radio occultation, focusing on interannual changes over the period 2004-2018. Water vapor anomalies can be traced away from the tropical tropopause to quantify transport in the Brewer-Dobson circulation, including diagnosing seasonal variations. Moreover, correlations with Tcp can be used to reconstruct water vapor changes tied to the cold point. Differences from observed water vapor suggest where additional processes may contribute to water vapor entry to the stratosphere.