Climate Files
GeoSWMM can use an external climate file that contains daily air temperature, evaporation and wind speed data. The program currently recognizes the following formats:
- Global Historical Climatology Network - Daily (GHCN-D) files (TEXT output format) available from NOAA's National Climatic Data Center (NCDC) Climate Data Online service at Climate Data Online (CDO) - The National Climatic Data Center's (NCDC) Climate Data Online (CDO) provides free access to NCDC's archive of historical weather and climate data in addition to station history information. | National Climatic Data Center (NCDC) (noaa.gov).
- Older NCDC DS-3200 or DS-3210 files.
- Canadian climate files available from Environment Canada at Données climatiques historiques - Climat - Environnement et Changement climatique Canada (meteo.gc.ca).
- A user-prepared climate file where each line contains a recording station name, the year, month, day, maximum temperature, minimum temperature, and optionally, evaporation rate, and wind speed. If no data are available for any of these items on a given date, then an asterisk should be entered as its value.
When a climate file has days with missing values, GeoSWMM will use the value from the most recent previous day with a recorded value.
For a user-prepared climate file, the data must be in the same units as the project being analyzed. For US units, temperature is in degrees F, evaporation is in inches/day and wind speed is in miles/hour. For metric units, temperature is in degrees C, evaporation is in mm/day and wind speed is in km/hour.