All meteorologists, but especially Air Quality Meteorologists, are interested in wind direction information at a given location. One tool that meteorologists use to provide a visual depiction of wind direction frequency at a given location is called a windrose because it displays wind information and sometimes it looks like a rose.
Windroses from Maine DEP:
- Display the direction the wind came from.
- Present the data for 36 directions to reduce bias created within windrose creation software.
- Provides information about wind speed for each 10 degree sector.
- Depict 5 years of data. During the course of 5 years a wide range of weather will occur. So 5 years of weather data has long been used for air quality analyses. So while the windroses are not all from the same 5 years, each should be representative of winds at that location.
- Are site specific. Topography and land sea breezes all impact winds near the surface. There is a great difference between winds in a river valley and winds just a few miles away.
It is advisable to consult a meteorologist before deciding whether or not a windrose from one location would be an accurate representation of winds at another location.
Maine DEP maintains a number of monitoring stations around the state collecting air pollution data and some also collect meteorological data (DEP MET), mainly wind direction and speed. At DEP MET sites, wind data is collected continuously and a minute average is tabulated. An hourly average is calculated from that hour's 60 one minute averages*.
In addition, during the 1980's and 1990's, there were a number of locations around the state where various industries were required to collect quality meteorological data using the same procedure as described above. QA'd data from both DEP and industry sites was prepared for input into software which creates the windroses presented here.
Please contact us to request one or more windroses.
* Important Note About Wind Data Collection Methods: The way the National Weather Service (NWS) reports winds is different from the way DEP reports winds. Wind direction information on NWS sites is a snapshot' of a moment in time rather than an hourly average. You can view the NWS current winds by following these steps:
- Go to either Gray NWS or Caribou NWS depending on which part of the state concerns you.
- Click on the map for the location you are interested in.
- The resulting page displays the forecast for that location. On the right, part-way down the page, you will see the most current hour of weather data from the nearest NWS monitor to that location.
- Links to view data from other nearby NWS monitors or a 3 day history of hourly weather from that monitor are displayed under the current weather data.