3.1 Representativeness
One
of the most important decisions in preparing for an air quality modeling
analysis involves the selection of the
meteorological data base; this is the case whether one is selecting a site
for monitoring, or selecting an existing data base. These decisions almost
always lead to similar questions: “Is the site (are the data)
representative?” Examples eliciting a negative response abound; e.g.,
meteorological data collected at a coastal location affected by a land/sea
breeze circulation would generally not be appropriate for modeling air
quality at an inland site located beyond the penetration of the sea breeze.
One would hope that such examples could be used in formulating objective
criteria for use in evaluating representativeness in general. Though this
remains a possibility, it is not a straight forward task - this is due in
part to the fact that representativeness is an exact condition; a
meteorological observation, data base, or monitoring site, either is, or is
not representative within the context of whatever criteria are prescribed.
It follows that, a quantitative method does not exist for determining
representativeness absolutely. Given the above, it should not be surprising
that there are no generally accepted analytical or statistical techniques to
determine representativeness of meteorological data or monitoring sites.
3. SITING AND EXPOSURE
3.1 Representativeness
3.1.1 Objectives for Siting
3.1.2 Factors to Consider
3.2 Simple Terrain Locations
3.2.1 Speed and Wind Direction
3.2.2 Temperature, Temperature
Difference, and Humidity
3.2.3 Precipitation
3.2.4 Pressure
3.2.5 Radiation
3.3 Complex Terrain Locations
3.3.1 Wind Speed
3.3.2 Wind Direction
3.3.3 Temperature Difference
3.4 Coastal Locations
3.5 Urban Locations
3.6 Recommendations