Volume 1 - The Atmospheric Studies Group at TRC

A two-station radiosonde program provided high-resolution wind and temperature
soundings on each side of the strait at three-hour intervals. These data are
interpolated to hourly periods and placed into the UP.DAT file format. Sub-hourly
SODAR wind data were successfully obtained at three locations (the tracer release
location in Gladsaxe, Denmark, an island about 2 km from the western edge of the
strait, and a site about 10 km inland in Sweden), and sub-hourly wind and
temperature data were obtained at the 95 m tower from which tracer releases were
made in Barseback, Sweden. These SODAR and tower profiles are averaged to
hourly periods and merged with the nearest radiosonde UP.DAT data to produce
hourly UP.DAT files at 4 more locations.
Meteorological data obtained from instrumented masts at eight locations and hourly
weather observations at one location are reformatted and placed in a SURF.DAT file.
Cloud cover observations are provided at two locations, and are inferred from
shortwave radiation measurements at three locations using the conversion
relationships between cloud cover and shortwave radiation that are in CALMET.
A SEA.DAT file is created from wind, air temperature, and sea temperature data at
one location in the strait, at the Oskarsgrundet NE lighthouse denoted as SEA in
Figure 2-6. Relative humidity data for SEA.DAT are taken from a mast located at
the downwind shore of the strait. That is, the relative humidity in the onshore flow is
used to characterize the relative humidity over the strait. The mixing height over the
strait and the vertical temperature gradient below and above the mixing height for
SEA.DAT are estimated from occasional minisonde profiles obtained from a boat in
the strait. Typically two good profiles are available during all but one experiment,
May 22. This experiment has an air-sea temperature difference of 5C to 6C which is
similar to that on May16 and June 4 and 5, so we assume that the overwater surface
layer can be represented by measurements on May16 and June 4 and 5.
Table 4-10 lists meteorological data used in the SEA.DAT file for those hours in
which SF 6 was released.
4.2 Model Application & Evaluation Methods
CALMET Configuration
Cameron, Carpinteria, Pismo Beach, Ventura
CALMET is applied to each of the OCD4 datasets in the same way, emphasizing the
near-surface overwater meteorological structure. CALMET is configured to
extrapolate the surface observations in the SURF.DAT and SEA.DAT files in the
vertical using Monin-Obukhov similarity relations and the local values of the
roughness length (z 0 ), Monin-Obukhov length (L), and friction velocity (u * ).
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