The roles of deep convection and extratropical mixing in the tropical tropopause layer: An in situ measurement perspective

摘要: The majority of air which enters the stratosphere passes through tropical tropopause layer (TTL), where temperature profile and amount deep convection set entry level for stratospheric water vapor. We use simultaneous in situ measurements ozone, carbon monoxide, dioxide, vapor, heavy vapor (HDO) from 2006 Costa Rica Aura Validation Experiment 2007 Tropical Composition, Cloud, Climate Coupling campaigns a one-dimensional mixing model to investigate how different transport pathways TTL impact stratosphere. focused on four main pathways: (1) slow upward ascent, (2) isentropic midlatitude lowermost stratosphere, (3) convective injection, (4) descent within coupled convection. Each pathway brings into with specific chemical signature, such that anomalies simultaneously measured tracer concentrations can be used identify source mass. found accounted 20–60% lower 20–40% above tropopause, bringing elevated ozone radiatively warm TTL, impacting dehydration takes place. Convective input average ~30% below 370 K potential temperature, ~10% both summer winter, increasing by 0.3 ppmv up 1.6 some masses.