Meteorology

Meteorological data collected by the National Weather Service and the U.S. military can readily obtained from several sources at little or no cost. This page lists some of these sources. Often, the biggest problem is dealing with the miriad of formats that the data comes in. The meteorological preprocessors to AERMOD and ISCST3 have been designed to read several of these formats. However, the formats seem to have multiplied faster than the features to read them could be added to the models. The instructions and software available from this page tell you how to convert meteorological data in any of several formats to the SAMSON format, which all the models can use.

Where to get meteorological data for models.

WEBMET.COM contains a large amount of FREE surface and upper air meteorological data.

EPA Support Center for Regulatory Air Models (SCRAM) website contains several years of FREE surface meteorological data and mixing height data. These data have been included in the WEBMET.COM site given above.

National Climatic Data Center (NCDC) Online Store: Click on "CD-ROM Products" (under "Data & Products") to order meteorological data on CD-ROM, such as SAMSON or HUSWO CDROMS.
For more recent meteorological data, I now recommend going to the Integrated Surface Database page. Click on "CDO (web-based)". If you don't find it, search the NCDC site for "Integrated Surface Database". When you receive the data, use the ASCII text file. Note that the entire period of record you select will be contained in this one file.
There is a nominal fee for most data from NCDC.

What to do when your data set has missing data or is in the wrong format.

"Procedures for Substituting Values for Missing NWS Meteorological Data for Use in Regulatory Air Quality Models" by Dennis Atkinson and Russell F. Lee, 1992. This document describes the EPA-recommended procedures for filling missing data for use in such air quality models as ISCST3 and AERMOD. It is identical to the text file "missdata.txt" available from the EPA SCRAM website, except that formatting has been applied to the text.

NCDC_CNV is a program written by Russell Lee which can convert the abbreviated hourly surface meteorological data provided online by NCDC in comma-separated ASCII format, and the Integrated Surface Hourly Weather Observations (ISHWO, aka ISH, ISHD) to the SAMSON format. The file is a zipped file containing the program, instructions, and a sample input file. This is being made available "as is" without charge by the developer, and may be freely distributed as long as the instruction file is included intact. Updated 12/18/2007.