Meteorological Data

The latest available representative five year meteorological data sets are required for refined dispersion modeling, using AERMOD.  See Section 4.2.2 of the Ambient Impact Analysis Guideline for a detailed discussion of the meteorological data analyses and processing that are required for AERMOD.

AERMOD-ready five year meteorological data sets were generated from National Weather Service (NWS) Automated Surface Observing System (ASOS) stations across Connecticut.  The raw hourly surface data format is Integrated Surface Hourly Data (ISHD), and the upper air data format is the Forecast Systems Laboratory (FSL) that are used and processed by the latest version of AERMET.  EPA has developed a pre-processor program (AERMINUTE) and users guide that reads one and five minute wind data to calculate hourly average wind speed and wind direction.  This approach has reduced the number of calm hours produced from the technique outlined in Section 6 of the Meteorological Monitoring Guideline (EPA 2000) to calculate average wind speed and direction.  CTDEEP has incorporated Adjust U* as a regulatory option (EPA 2017) in the AERMOD processed ready met data for all the ASOS sites in Connecticut.  The table below displays the surface station, WBAN ID #, paired with upper air station WBAN ID # and the processed AERMOD modeled-ready five year meteorological data zip files.

Please use this link (Air Quality Dispersion Modeling) to retrieve the latest AERMOD ready processed meteorology data sets. 
The Oxford/Waterbury and Chester Airports' ASOS sites were deemed to have insufficient hourly meteorological data for use in AERMOD modeling.
Content Last Updated on August 21, 2026