NEW Ozone/Wind Rose Interface! Click Here
Instead of plotting wind speed as a function of wind direction, we can plot ozone concentration as a function of wind direction. These are sometimes called a "pollution rose." The pollution rose below shows the same June 2015 period at Hawthorne. During the month of June, Hawthorne most frequently experienced unhealthy ozone concentrations when with winds were from the northwest. Air quality was generally good when winds blew from between south and east.
Figures like this can be created using the interface here: http://meso2.chpc.utah.edu/gslso3s/cgi-bin/ozone_rose.cgi
- Station ID: Select one in-situ station from the list of IDs
- Rose Type: Select rose type. Ozone and Wind Speed have been discussed. (The clock roses will be discussed later.)
- Time Option: UTC or Local time
- Hour Interval: Default is "All Day" which shows all ozone observations between the dates. You can change the hour interval to look at 3 hour chunks of the day. This is useful to see ozone concentrations for different times of the day. For example, at Hawthorne pollution roses between 6:00-9:00 AM looks very different than at 3:00-6:00 PM
- Pot Range: This allows you to zoom in and out of the polar plot. The number selected will be the outermost percentage displayed.
- Begin Time: The beginning month, day, year, and hour.
- End Time: The ending month, day, year, and hour.
---- Some examples ----This tool allows you to look at ozone concentrations and wind for different days at any station. Pollution roses for Hawthorne on each day of IOP 1 were quite different. On Wednesday, the air was clean when air blew from the south, and was dirty when it blew from the north-northwest. Thursday, however, had much more frequent winds from the south and south east with cleaner air.
---- Another View Point ----Rather than plotting ozone concentration or wind speed frequency as a function of wind direction, another way to look at ozone concentration is as a function of time of day. I call this an "ozone clock." Imagine looking at a 24-hour clock with midnight at the top and noon at the bottom. Below shows the MTMET "ozone clock" for the month of June. As expected, ozone concentrations are most healthy (green) in the morning hours. The afternoon, especially 15:00, most frequently has the most polluted air because ozone is produced in the presence of sunlight.
NOTE: When creating plots like this for other stations, it is best to look at long periods of time (weeks to months), otherwise it may look as if a big bite has been taken out of the clock. The bit is caused when some hours have no wind direction reported. Ideally, the "clock" should roughly look like a circle because there are the same amount of each hour in a day (i.e. 3:00 AM occurs seven times in a week, as does 8:00 PM. In other words, each hour should occur 4.2% of the time). A wavy circle is caused when there are different amounts of observations for each hour during the period.
Send suggestions or comments about the interface to firstname.lastname@example.org