Volume 1 - The Atmospheric Studies Group at TRC
Volume 1 - The Atmospheric Studies Group at TRC
Volume 1 - The Atmospheric Studies Group at TRC
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Chevron Pl<strong>at</strong>form 28A served as the SF 6 tracer release site on seven of the test days,<br />
and a 20m bo<strong>at</strong> was used on two of the days due to the prevailing wind direction.<br />
Pl<strong>at</strong>form 28A is loc<strong>at</strong>ed 6.75 km from shore, and the tracer was released 13m above<br />
mean low w<strong>at</strong>er. <strong>The</strong> bo<strong>at</strong> loc<strong>at</strong>ions used are about four km from shore, and the<br />
tracer release was from a mast 13m above the w<strong>at</strong>er. Thirty-five (35) samplers<br />
placed in a single arc along the coast over a span of about 17 km provide sequential<br />
hour-averaged concentr<strong>at</strong>ions.<br />
Meteorological d<strong>at</strong>a were obtained <strong>at</strong> Pl<strong>at</strong>form 28A, <strong>at</strong> a 10m mast installed on the<br />
shore 5m to 20m from the w<strong>at</strong>er, and <strong>at</strong> a 25m tower loc<strong>at</strong>ed 2 km inland. Horizontal<br />
and vertical profiles of temper<strong>at</strong>ure, dew-point temper<strong>at</strong>ure and turbulence were<br />
obtained by aircraft. <strong>The</strong> OCD4 evalu<strong>at</strong>ion d<strong>at</strong>aset (DiCristofaro and Hanna, 1989)<br />
uses meteorological d<strong>at</strong>a from these sources in the following way:<br />
Aircraft<br />
Pl<strong>at</strong>form 28A<br />
estim<strong>at</strong>ed mixing height and overw<strong>at</strong>er dT/dz<br />
w<strong>at</strong>er temper<strong>at</strong>ure, wind speed (18m), air temper<strong>at</strong>ure (18m)<br />
10 m Mast σ θ (10m), RH(10m), wind speed (10m), air temper<strong>at</strong>ure (10m)<br />
Wind speed and temper<strong>at</strong>ure measurements <strong>at</strong> the 10m mast are used only to replace<br />
missing values <strong>at</strong> Pl<strong>at</strong>form 28A. No air temper<strong>at</strong>ures were measured <strong>at</strong> Pl<strong>at</strong>form 28A<br />
during the July 1981 experiments, so the air temper<strong>at</strong>ure measured <strong>at</strong> the shoreline<br />
10m mast is used for the air-sea temper<strong>at</strong>ure difference in July.<br />
Geophysical Processing<br />
Gridded land use and terrain elev<strong>at</strong>ion d<strong>at</strong>a for the CALMET geophysical file are<br />
obtained from the United St<strong>at</strong>es Geological Survey (USGS). <strong>The</strong> terrain d<strong>at</strong>a are<br />
from the one-degree 1:250,000-scale DEM d<strong>at</strong>aset, with an approxim<strong>at</strong>e resolution of<br />
90m. Land use d<strong>at</strong>a are from the 1:250,000-scale Composite Grid <strong>The</strong>me (CTG)<br />
d<strong>at</strong>aset, with a resolution of 200m. Because the sp<strong>at</strong>ial vari<strong>at</strong>ion in land use is the<br />
primary geophysical property for this applic<strong>at</strong>ion, a modeling grid is chosen th<strong>at</strong><br />
places each land use d<strong>at</strong>apoint in the center of a model grid cell. <strong>The</strong> modeling grid<br />
chosen to cover the area is defined by:<br />
Map Projection: UTM (Zone 15N)<br />
D<strong>at</strong>um: NAS-C (North American 1927)<br />
SW Corner Coordin<strong>at</strong>es (km): (464.9,3285.7)<br />
Number of cells (nx,ny): (135,65)<br />
Cell Size (km): 0.200<br />
Final Report Vol.1 26