This award will support the coordination of the continued planning for the Tropical Tropopause Layer Chemistry Experiment (TTL-Chem), planned for 2007 using the HIAPER (High Altitude Platform for Environmental Research) aircraft. TTL-Chem addresses the photochemistry of the Upper Troposphere/Lower Stratosphere (UT/LS) region. Specifically, the experiment will investigate the chemistry of the tropical middle and upper troposphere near and "down-wind" of the region of maximum convection. Science questions include: (1) What is the chemical nature of the outflow from the convective region of the Western Pacific? (2) What are the chemical fates of short-lived compounds transported from the tropical boundary layer into the TTL? (3) What are the mechanisms that control ozone within and below the TTL?
The TTL-Chem project is expected to provide novel information about a region of the atmosphere that is important for understanding both the budget of stratospheric ozone, but also the climate system.