Results from Aura MLS and the in situ hygrometers during the Costa Rica AVE campaign on the annual cycles of tropical UTLS H2O and CO

The MLS instrument on board the Aura satellite launched on 15 July 2004 is providing daily near H2O and CO profile data in the upper troposphere and lower stratosphere (UTLS). H2O measurements from the 2006 Costa Rica AVE campaign and the cryogenic frost point hygrometer are compared to MLS. Tropical tape recorder signatures are present in both CO and H2O. The H2O tape recorder signature is the imprint of the annual cycle in the tropical tropopause temperature. The CO tape recorder is the imprint of biomass burning events brought up to the UTLS by tropical deep convection. The CO and H2O measurements can be used to understand the roles of convection and in situ freeze-drying processes in the tropical tropopause layer. The MLS CO and H2O from MLS and the in situ hygrometers are compared to results from a convective cold trap model.