Major chemical, steel, and fabrication industries generally 3-5 story buildings, flat roofs Light-moderate industrial
Rail yards, truck depots, warehouse, industrial parks, minor fabrications; generally 1-3 story buildings, flat roofs Commercial
Office and apartment buildings, hotels; >10
story heights, flat roofs Common residential
Single-family dwelling with normal easements; generally one story, pitched roof structures; frequent driveways Compact residential
Single-, some multiple-, family dwellings with close spacing; generally <2 story height, pitched roof structures; garages (via alley), no driveways Compact residential
Old multifamily dwellings with close (<2m)
lateral separation; generally 2 story height, flat roof structures; garages (via alley) and ash pits, no driveways Estate residential
Expansive family dwelling on multiacre tracts Metropolitan natural
Major municipal, state, or federal parks, golf courses, cemeteries, campuses; occasional single-story structures Agricultural rural Undeveloped Uncultivated, wasteland
Undeveloped rural Water surfaces Rivers, lakes
Grass and tree growth extremely rare; <5% vegetation
Very limited grass, trees almost totally absent; <5% vegetation
Limited grass and trees; < 15% vegetation
Abundant grass lawns and light-moderately wooded; >70% vegetation
Limited lawn sizes and shade trees; <30% vegetation
Limited lawn sizes, old established shade trees; <35% vegetation
Abundant grass lawns and light wooded; >80% vegetation
Nearly total grass and light wooded; >95% vegetation
Local crops (e.g., corn, soybean); 95% vegetation
Mostly wild grasses and weeds, lightly wooded; >90% vegetation Heavy wooded; 95% vegetation
Source: A.H. Auer, 1978, Correlation of land use and cover with meteorological anomalies, Journal of Applied Meteorology 17.
consistency, the EPA has a protocol to follow when data are substituted for missing observations.
Both short- and long-term models also require mixing height data to define the upper limit of the area where effluent mixing occurs (the ground being the lower limit). Holzworth (1972) developed a set of figures and tables for seasonal and annual mixing heights, which are typically used in long-term modeling. For short-term applications, model users can interpolate hourly mixing height values (using the EPA's RAMMET preprocessor) based on twice-a-day upper air data collected by radiosonde measurements at numerous sites throughout the country and available through the National Climatic Center (NCC).
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