## Advanced / Special Topics / Verification Statistics

See the DATEM (Data Archive of Tracer Experiments and Meteorology) web page for more detailed information on each of these tracer experiments. The model verification statistics are presented for the un-averaged data, where each measured and calculated concentration is paired in space and time. Zero-zero pairs are always excluded. Results are also presented after temporally averaging the measured and calculated values over the duration of each experiment. These latter results are paired in space but not time and hence represent the calculation's spatial performance. Statistics presented are the correlation coefficient (R), the fractional bias (FB), the figure-of-merit in space (FMS), the KS parameter representing the departure of the measured and calculated cumulative distributions from each other, and the normalized rank (0 to 4) which is computed from the sum of the previous four parameters.

Unless otherwise noted, all calculations used the NCAR/NCEP 2.5 degree reanalysis meteorological data for the dispersion calculations. The main characteristics of each experimental data set are summarized as follows:

ACURATE - Semi-continuous Kr-85 emissions from South Carolina and 12/24-hour sampling along the US east coast at five locations from 100 to 800 km from the source for a duration of 18 months.

ANATEX - A three month duration experiment with simultaneous 3-h duration releases of perfluorocarbon tracer from Glasgow, MT (GGW) and St. Cloud, MN (STC). Twenty-four hour averaged samples were collected at about 70 locations over the US east coast (500 to 3000 km downwind) for the duration of the experiment.

CAPTEX - Six 3-h duration perfluorcarbon releases from Dayton, OH or Sudbury, CA and 6-h sampling for about three days after each tracer release.

INEL74 - Semi-continuous Kr-85 releases from Idaho for a two month period and 12-h averaged samples collected at 12 stations along a north to south line in the midwest US about 1500 km downwind.

OKC80 - Single 3-h perfluorocarbon release from Norman, OK with 3-h samples collected for about 2 days along an arc 600 km downwind from the source.

ETEX - Single 12-h perfluorcarbon release from eastern France and 3-h samples collected throughout western Europe. Calculations used the ECMWF analysis data.

Verification Statistics Summary

Model performance by rank for time mean (spatial correlation) and individual sample paired concentrations. The rank is computed from the sum of the correlation, fractional bias, figure-of-merit in space, and the Kolmogorov-Smirnov parameter.

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