Volume 1 - The Atmospheric Studies Group at TRC

Table 4-6 lists meteorological data used in the SEA.DAT file after the adjustments
are made. The lateral turbulence intensity (I y ) is used in the CALPUFF turbulence
profile file.
The UP.DAT (upper-air) input file is designed to provide CALMET with vertical
profiles of wind and temperature representative of the onshore flow at 00Z (mid to
late afternoon) during the tracer sampling. Both 00Z and 12Z vertical profiles of
wind and temperature are developed for four levels: surface, 10m, overwater mixing
height, and model-top (3000m). The 00Z wind speed at 7m is extended to levels up to
the mixing height using a stability-class-dependent power-law profile (A,B=0.07;
C=0.10; D,E,F=0.15) and the speed at the model-top is set to that at the mixing
height. The surface wind speed is set to that at 10m, which has been adjusted from
the anemometer height to 10m. Wind direction at all levels equals the release wind
direction. Temperature at the surface equals the air temperature in the SEA.DAT file,
and temperature aloft is computed from this using the temperature gradient dT/dz (in
the SEA.DAT file) up to the overwater mixing height. The default CALMET
temperature gradient -0.0045 ºK/m is used above the mixing height. Pressure is
assumed to be 1013 mb at the surface, and decreases with height at 0.1 mb/m.
Ventura, California
Description
The tracer dispersion study in the Ventura, California area was conducted along the
California coast during four test days in September 1980 and four test days in
January 1981 (Areovironment, 1980 and 1981, Zanetti et al., 1981, and Schacher et
al., 1982). Data from all four of the test days in September and three of the four test
days in January are in the dataset. SF 6 tracer was released about 8m above the water
from a boat located 6 to 8 km from shore, and sampled along two arcs about 10 to 12
km long. The first arc is ½ km to 1 km from the shoreline and the second arc is about
7 km from the shoreline. Evaluation of OCD4 with this dataset focused on the onehour
average concentrations measured close the shoreline in Arc 1.
Meteorological data used in the OCD4 evaluation dataset includes wind at 20.5m,
temperature at 7m, and air-sea temperature difference measured at the release
location, and vertical temperature gradient measured over the water by an aircraft.
Final Report Vol.1 42