Texas Commission on Environmental Quality
Emissions Banking Modeling Team (EBMT)
AERMET Meteorological Data
Reason for update: The EPA AERMOD program requires meteorological data
preprocessed with the AERMET program. Three additional variables are considered when
preprocessing the surface and meteorological data for a site. These variables are:
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Surface Roughness
Albedo
Bowen Ratio
The same periods of meteorological data that have been used in ISC3 for State and
Federal air dispersion modeling in support of Air Permits Division modeling have been reprocessed with the AERMET program. This will provide a degree of consistency during the
transition period from ISC3 to AERMOD. In addition, these data sets will provide a complete
standardized set of meteorological input data for use with AERMOD. Standardization of the input
data allows the staff to automate the review process thus reducing processing time.
If an applicant determines that special site or source characteristics should be
considered, then the applicant should discuss the methodology for preparing a unique set of
processed meteorological data for use in AERMOD. These parameters are developed on a caseby-case basis and should be approved for use by the EBMT before meteorological data sets are
processed.
File naming convention: File names have changed from those used in the past, but the
meteorological years for state permitting have not changed. The meteorological data for
AERMOD will have a file name consisting of eight characters followed by a file extension of either
*.SFC or *.PFL. The following example illustrates the file names:
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AUSV5YAM.SFC
The first three characters represent the surface station ID. In this case, “AUS” represents
Austin surface data. The fourth character “V” represents the first character of the upper air
station ID. In this case, the “V” represents Victoria upper air data. The “5Y” indicates this is a five
year data set. The seventh character “A” represents the Albedo/Bowen Ratio combination for the
surface/upper air meteorological combination. The eighth character “M” represents the choice of
surface roughness. In this case, the “M” represents the “medium” roughness category.
The five-year meteorological input files for federal permitting applications vary between
1983 and 1993. The exact five-year period for a county may not contain successive data
depending on the availability of representative surface and upper-air data used to develop the
five-year sets.
Source of data: Hourly surface data for the measurement sites were obtained from the
National Climatic Data Center (NCDC) Solar and Meteorological Surface Observation Network
(SAMSON) compact disk (CD) (years 1961-1990), the Hourly United States Weather
Observations (HUSWO) CD (years 1990-1995). Upper-air data were obtained from the
Radiosonde Data of North America CDs from the National Climatic Data Center for 1946-1994.
7/2006