Hydrocarbon ratios during PEM‐WEST A: A model perspective

作者：S. A. McKeen, S. C. Liu, E.‐Y. Hsie, X. Lin, John D. Bradshaw, S. Smyth, G. L. Gregory, Donald Ray Blake · 发表于：Journal of Geophysical Research Atmospheres · 年份：1996 · DOI：10.1029/95jd02733 · 被引用次数：180 · 研究领域：Atmospheric and Environmental Gas Dynamics、Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate

A useful application of the hydrocarbon measurements collected during the Pacific Exploratory Mission (PEM‐West A) is as markers or indices of atmospheric processing. Traditionally, ratios of particular hydrocarbons have been interpreted as photochemical indices, since much of the effect due to atmospheric transport is assumed to cancel by using ratios. However, an ever increasing body of observatonial and theoretical evidence suggests that turbulent mixing associated with atmospheric transport influences certain hydrocarbon ratios significantly. In this study a three‐dimensional mesoscale photochemical model is used to study the interaction of photochemistry and atmospheric mixing on select hydrocarbons. In terms of correlations and functional relationships between various alkanes, the model results and PEM‐West A hydrocarbon observations share many similar characteristics as well as explainable differences. When the three‐dimensional model is applied to inert tracers, hydrocarbon ratios andother relationships exactly follow those expected by simple dilution with model‐imposed “background air,” and the three‐dimensional results for reactive hydrocarbons are quite consistent with a combined influence of photochemistry and simple dilution. Analogous to these model results, relationships between various hydrocarbons collected during the PEM‐West A experiment appear to be consistent with this simplified picture of photochemistry and dilution affecting individual air masses. When...