Measurements of Mixing and Stable Isotope Ratios of Atmospheric CH4 from Air Samples Collected from a Transect of Pacific Ocean Between Los Angeles and NZ

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This project was submitted for consideration under the NSF Program, "Career Advancement Awards for Minority Scientists and Engineers". The research consists of a series of atmospheric methane measurements that will provide a North-South Pacific Ocean transect distribution for methane abundance and stable carbon isotopic composition (13C and 12C). The main scientific objectives of the measurements are to determine the latitudinal mixing ratios of atmospheric methane in order to understand the dominant sources that might be contributing to its increasing global concentration levels. Surface clean air samples will be analyzed for 13C/12C, D/H and mixing ratios at different latitudes and longitudes from shipboard collections. The collections will be made from a transect of the Pacific Ocean between Los Angeles, CA and Auckland, New Zealand. The air samples (collected using pressurized cylinders) will be analyzed using GC/FID (methane concentration) and for 13C/12C and D/H abundances using a isotope ratio mass spectrometer (IRMS, Finnigan MAT). Data will be incorporated into an existing database for a global distribution of atmospheric methane abundance and isotopic composition. Overall, the study will help to develop global information on atmospheric methane that can be incorporated into models which assess the secular trends, source strengths, and influence of this important greenhouse on global climate.