The mixing height data offered here present twice daily (derived) values and are obtained from the National Climatic Data Center (NCDC), Asheville, North Carolina. All data/station files for a state are in TXT format and have been compressed into a single ZIP file for that state. A description of the mixing height data format (TXT)(4 K, 07-07-1992) is provided. All mixing height meteorological data files have missing data filled as prescribed in the Procedures for Substituting Values for Missing NWS Meteorological Data for Use in Regulatory Air Quality Models (TXT)(8 K, 07-07-1992), except where the guidelines could not be followed due to an excessive number of repetitive missing values. Please read the Missing Meteorological Data Report (TXT)(3 K, 07-07-1992) to identify the station/years that are not complete. A list of mixing height data stations (TXT)(6 K, 07-07-1992) are provided.

The data offered here are used in concert with the surface meteorological data for air quality modeling. The twice daily mixing height values are to be combined with hourly surface data using the PCRAMMET preprocessor program to obtain hourly interpolated mixing height values.

Read Me (TXT)(1 K, 10-02-2020) - File listing for FTP Download Directory
State mixing height data files - FTP Download Directory