Organic Halogen and Hydrocarbon Distributions During SEAC4RS Measured from the ER-2 and DC-8.

Abstract:

Organic halogens and hydrocarbons are important contributors to chemical processes in the upper troposphere/lower stratosphere (UTLS) region and hydrocarbons are well known contributors to chemical processes throughout the troposphere. Whole Air Sampler systems (WAS) were deployed during Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS) on the NASA ER-2 (Univ. of Miami WAS) and the NASA DC-8 (Univ. of California, Irvine WAS). Both systems measured a wide variety of organic halogen and hydrocarbon species in the samples collected. For this presentation we show the vertical distributions of select chemical species from the surface to the lower stratosphere and compare those distributions to the Community Atmosphere Model with Chemistry (CAM-Chem) in order to evaluate their representation in the global model. We also show a comparison of measurements taken during SEAC4RS (2013) with those taken in the same region during the Stratosphere-Troposphere Analysis of Regional Transport 2008 (START08) campaign. The Univ. of Miami WAS system was flown on the NSF/NCAR GV during START08. The two campaigns were conducted in different seasons and different stratosphere/troposphere exchange regimes, allowing evaluation of how the North American Monsoon convection influences the transport time scale in the UTLS (during SEAC4RS) relative to the pre-monsoon regime observed during START08.