SO 2 and NO 2 of 1.14 ppb and 4.58 ppb, respectively. The slightly higher NO 2 is attributed to re-location of the monitoring station. Similar seasonal trends are evident as at Dauphin. SO 2 maximums are clearly associated with northerly winds, while NO 2 maximums are more distributed but mostly seen with southerly winds. SO 2 maximums were most often recorded under Continental High synoptic conditions, while NO 2 maximums were primarily seen with the Gulf Return pattern.
Unstable conditions prevail over the area throughout the year.
A relationship between the mixed height, or lifting condensation level, under unstable conditions and the surface dewpoint depression shows mean mixed heights over the area to range from 250 m to 750 m. Much lower heights can occur under stable conditions. Methods for determining the proper values of drag coefficient, stability parameter, mixed height, turbulence intensity, and vertical eddy diffusivity from routine measurements are provided and demonstrated, and recommended for use in offshore modeling efforts. Long-term measurements of SO 2 and NO 2 concentrations and related meteorological conditions in the northeastern Gulf of Mexico region. OCS Study MMS 98-0020.