Photochemical Ozone Budget of the Eastern North Pacific Atmosphere (PHOBEA)

点击翻译按钮获取中文摘要

9529604 Jaffe This project addresses the formation of tropospheric ozone and the abundance and origin of ozone precursors. Observations of surface and free tropospheric ozone in the northern hemisphere show a spring maximum. Previous measurements in Alaska and model simulations indicate that some of this peak can be explained by photochemical production from winter accumulated, anthropogenic, ozone precursors. In this regard, the most important ozone precursor is peroxyacetyl nitrate (PAN). Measurements also show an important role for vertical transport in warming of air masses and causing thermal decomposition of PAN in the boundary layer. This anthropogenically caused ozone production may contribute to the long-term increases in ozone which have been observed at several northern hemispheric locations during spring and summer. In this project, ground-based measurements of ozone, nitrogen oxides, total reactive nitrogen, PAN, carbon monoxide, radiation, radon, and reactive radical species, as well as aerosol properties, ultraviolet radiation, and meteorological parameters will be measured by the PI in collaboration with other researchers at the Cheeka Peak research site in Washington. In addition, aircraft-borne measurements of the abundance of ozone, nitric oxide, PAN, and carbon monoxide will be performed in the spring of 1997 in conjunction with the ground-based measurements. 0- and 1-dimensional models will be employed. The data will provide answers to questions including: (1) What is the ozone budget in this region; (2) What are the conditions that give rise to air mass warming and PAN composition, leading to enhanced ozone formation; (3) What is the influence of Asian emissions on air masses which arrive at the West Coast of the US; and (4) What is the influence of cloud types and heights on the ozone/nitrogen oxide photochemistry.