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 normalized sum of the previous four parameters. The URL includes links to download the measurement data, meteorological data, statistical programs, and HYSPLIT configuration files.
Unless otherwise noted, all HYSPLIT calculations used the NCEP North American Regional Reanalysis (3 hr; 32 km) meteorological data for the dispersion calculations. The main characteristics of each experimental data set are summarized as follows:
ACURATE - consisted of measuring the Kr 85 air concentrations from emissions of the Savannah River Plant, SC. Twelve and 24 hour average air concentrations were collected for 19 months (March 1982 - September 1983) at 5 locations along the United States east coast from 300 to 1000 km from the plant (Fayetteville, NC to Murray Hill, NJ).
INEL74 - consisted of a little over two months of Kr-85 releases (February 27th to May 5th, 1974) from Idaho and continuous 12 h sampling (February 27th to May 4th, 1974) at 11 locations in a line about 1500 km downwind (Oklahoma City, OK to Minneapolis, MN).
ANATEX - consisted of 66 PerFluorocarbon Tracer (PFT) releases (33 each from two different locations - January 5th to March 26th, 1987) every two and one half days. Air samples were collected for 3 months (January 5th to March 29th, 1987) over 24 h periods at 75 sites covering most of the eastern US and southeastern Canada. PTCH (perfluro-trimethylcyclohexane) was released from Glasgow, Montana (GGW), and PDCH (perfluro-dimethylcyclohexane) and PMCH (perfluro-monomethylcyclohexane) from St. Cloud, Minnesota (STC).
CAPTEX - during September and October of 1983, consisted of six 3 h PFT releases (September 18th to October 29th, 1983), four from Dayton, Ohio and two from Sudbury, Ontario, Canada with samples collected at 84 sites, 300 to 800 km from the source, at 3 h and 6 h averages for about a 48 hour duration after each release (September 18th to October 30th, 1983).
OKC80 - consisted of single release of two different PFT tracers (July 8th, 1980) over a 3 hour duration with samples of 3 hour duration collected at 10 sites 100 km and 35 sites 600 km downwind from the Oklahoma City release point from July 8th to July 11th, 1980.
ETEX - although there were two releases, the primary evaluation data set is from the first release on October 23, 1994 from western France. Three hour duration sampling was conducted in western europe from October 23 through October 27th.
METREX - consisted of 6 hour emissions of perfluorocarbons simultaneously, from two different locations, every 36 hours. The tracer release locations were in suburban Washington, D.C, while 8 hour air samples were collected at three locations within the urban area. The experiment ran for one full year. In addition monthly air concentration samples were collected at about 60 locations throughout the region.
SRP76 - consisted of continuous emissions of Krypton-85 from the Savannah River Plant near Aiken, SC. About 15 sampling locations were placed around the plant at varying distances (15 - 150 km) and directions. Weekly samples were collected between September 1975 and August 1977. Twice-daily samples were collected over four months (November 1976, February, April, July of 1977).
Verification Statistics Summary
The HYSPLIT model performance by rank for the time mean (spatial correlation) and individual sample paired concentrations for the most recent version of HYSPLIT is given. The rank is computed from the sum of the correlation, fractional bias, figure-of-merit in space, and the Kolmogorov-Smirnov parameter. In addition, all required data are provided with the HYSPLIT distribution to run CAPTEX release #2 and compute the resulting performance statistics through the GUI.
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