Comparison of Modelled and Measured Tracer Gas Concentrations during the Across North America Tracer Experiment (ANATEX)

摘要

The 24-hour surface concentrations of several perfluorocarbon tracer gases measured during the 1987 Across North America Tracer Experiment (ANATEX) provided a unique continental-scale data set with which to evaluate long-range transport and diffusion models. One such model, a multilayer Lagrangian model, was evaluated in the ANATEX Model Evaluation Study (AMES) by comparing distributions and time series of calculated and measured tracer concentrations at bands of sampling sites nearly equidistant from one of the two tracer release sites and by computing spatial differences in the concentration-weighted centroids of 20, 24-hour tracer 'footprints' or composite plumes. The results for this model indicated that it overemphasized the effects of the stronger upper-level winds. In spite of the bias in transport speed, the distributions of the calculated and measured concentrations were quite similar.