BREEZE processes this data in accordance with U.S. EPA guidance, adapting the EPA methodology as needed in cases where a local regulatory agency prefers to deviate from EPA guidance, or for international locations where U.S.-specific guidance does not apply. In such cases, the Data Team's Certified Consulting Meteorologists (CCM) make expert decisions on the most credible scientific approach to use.

Meteorological Data for ISC and CAL3DHCR

The ISCST3 model, the predecessor to AERMOD, uses an .ASC or .BIN meteorological file that incorporates wind speed and direction, temperature, and atmospheric stability data. This file format is also used by the CAL3QHCR road emission model (the most-used dispersion model in the BREEZE ROADS software package), and by a variety of specialty modeling tools (such as some plume visibility modeling techniques). 

Terrain Data for ISC

Terrain data for ISC and related models is similar to that needed for AERMOD: 

NED Data (U.S.) 

NED data is currently considered the “gold standard” for U.S. terrain data. This dataset is constantly refined and improved. Recent changes to the NED format have made it difficult to find NED data that is compatible with the ISCST3 models. The BREEZE Data Team can provide NED data for the entire U.S. at 30 meter resolution and for select areas at 10 meter resolution. 

DEM Data (U.S.) 

For some applications such as the FAA's EDMS dispersion modeling utility, DEM-format terrain data is required. These data can also be used for many other purposes such as adding 3-D visualization of terrain in graphics programs. BREEZE provides 7.5 minute DEM tiles for the United States. Each tile covers an area that is 7.5 minutes of latitude by 7.5 minutes of longitude (approximately 10 miles by 10 miles). Coordinates are in Universal Transverse Mercator (UTM) format and the resolution is 30 meters. The 7.5 Minute Digital Elevation Model (DEM) is a widely supported format produced by the United States Geophysical Survey (USGS). 

DEM Data (Worldwide) 

You can purchase 1 Degree DEM tiles for nearly anywhere in the world. Each tile covers a block of land that is 1 degree of latitude by 1 degree of longitude (approximately 100 km by 100 km in most locations) and is centered at the location of your choice. Coordinates are in arc seconds with a resolution of approximately 90 meters. Custom sized DEM tiles with 90 meter resolution are also available.

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