Modeling Tip – July 2011
Run AERMINUTE Using AERMET View
One of the model updates made by the U.S. EPA earlier this year was the release of the new AERMINUTE executable. AERMINUTE processes 1-minute ASOS wind data to generate hourly wind speed and wind direction averages to supplement data within standard hourly surface data files. Meteorological stations throughout the United States have gradually replaced manned observations with Automated Surface Observing Stations (ASOS). This led to a marked increase in missing or calm hours in the hourly observations which degrades the quality of air dispersion modeling analyses. AERMINUTE provides much higher wind data quality by processing the raw 1-minute data logged by the automated station.
The input to AERMINUTE is limited to a data format from the U.S. National Climatic Data Center (NCDC) known as DS-6405. Presently, these data files are only available for ASOS stations in the U.S.
When processing data for U.S. projects, AERMINUTE can be run easily in AERMET View Version 7. Follow these simple steps:
Step 1: Start a new project in AERMET View. Select the ASOS 1-Minute tab from the Surface display. Select Yes to include a 1-Minute ASOS Wind Data File. Press the AERMINUTE button on the right side of the window.
The input to AERMINUTE is limited to a data format from the U.S. National Climatic Data Center (NCDC) known as DS-6405. Presently, these data files are only available for ASOS stations in the U.S.
When processing data for U.S. projects, AERMINUTE can be run easily in AERMET View Version 7. Follow these simple steps:
Step 1: Start a new project in AERMET View. Select the ASOS 1-Minute tab from the Surface display. Select Yes to include a 1-Minute ASOS Wind Data File. Press the AERMINUTE button on the right side of the window.
Step 2: AERMINUTE uses 1-minute ASOS wind data in TD-6405 format from the NCDC. AERMET View includes a link to NCDC’s data archive to retrieve the necessary files. Press the Download Files button to open the link to NCDC’s FTP site.
Step 3: Download the files needed for your project. Folders are named based on the year of data (e.g., “6405-2010” for data from 2010) and files are named by station callsign, 4-digit year, and 2-digit month. This example uses data from Pittsburgh, PA (KPIT) for the full year 2000 (200001 – 200012).
Step 4: After downloading the files, select the Specify File button to locate and add the files to your project.
Step 4: After downloading the files, select the Specify File button to locate and add the files to your project.
Step 5: AERMINUTE can compare its calculated hourly wind averages to those identified in TD-3505 hourly surface data. If your project will run TD-3505 data, select the Copy Hourly Surface File button.
Step 6: You’re ready to run! Click Process to run AERMINUTE.
