The Abundance and Seasonal Variability of Tropospheric Ozone and Its Precursors Over China

Harvard University, Cambridge MA

Investigators

Abstract

The goals of this project include an improved understanding of factors regulating the abundance and seasonal variability of tropospheric ozone and its precursors (in particular NOx, nitrogen oxides, NO + NO2) over China. Multi-year observations of NO2 from space will be employed to develop improved information on seasonal and spatial variations in combustion and biological sources of NOx over China. New constraints on emissions of CO and CO2 (carbon monoxide and dioxide) associated with Chinese fossil fuel consumption will be developed using the first continuous, long-term, simultaneous measurements of CO2 and CO at a surface station in north China. Improvements in understanding of emissions will be incorporated in a 3-dimensional nested grid chemical model (GEOS-Chem) to analyze surface and aircraft observations of ozone for different seasons over Asia. Specific objectives of the work are: (1) to develop 'top-down' estimates for the seasonal variation of combustion and microbial sources of NOx over China based on a reanalysis of multi-year observations of NO2 columns inferred from GOME and other satellite instruments; (2) to determine factors responsible for the seasonal variability of tropospheric ozone and the outflow of ozone from the Asian landmass using a 3-D nested-grid model to analyze aircraft and a year long record of surface observations; and (3) to improve the understanding of emissions of CO2 associated with Chinese fossil fuel consumption and the role of the biosphere for the regional budget of CO2 over China. This research is expected to improve our understanding of combustion and biological sources of NOx on a global scale with particular emphasis on sources from rapidly developing China. This will be helpful for policy makers by providing input into understanding the complex impacts of ozone pollution on public health and agricultural productivity in China. Results of this work will also be integrated into the teaching of undergraduate (science and non-science) and graduate students at Harvard.