WIND FARMS SHOW UP ON LIVE DOPPLER 18…………
July 1st, 2009 at 4:16 pm by Chad Evans under Chad's WLFI Weather Blog
I have had numerous questions recently as to why it seems to always be raining near Fowler, or why there continues to be a red blob over Benton County on Live Doppler 18:
These are the wind farms showing on our Live Doppler.
National Weather Service radars & other television station radars are having the same issues as more & more wind farms are built.
This is what causes this pollution of the data (this graphic via the National Weather Service Forecast Office in Milwaukee, Wisconsin):
There are 3 ways to combat this:
1. Decrease radar sensitivity, so the blob shows up less. However, this would mean that rainfall echoes would not be as detailed & would even be inaccurate. A heavy storm that should show up as red, could be only yellow on the radar. A pink spot indicating large hail might only be red or yellow, if sensitivity is decreased.
2. Tilt the radar beam upward to overshoot the wind farms. The Live Doppler beam is at the correct, standard height & a shift in the beam upward could overshoot any low-topped showers or t’storms near the radar or cause the data to be inaccurate by reflecting rain & hail data well up in the storm, not toward the surface. What is reflected toward the surface is what is likely reaching the ground.
3. Set up an “Exclusion Zone”. This would be built into the radar to basically skip northwest Tippecanoe, Benton & even far southwestern Newton counties so NO data shows up there. However, this would mean that these locations would have no coverage from our Live Doppler. Thus, that would never be a solution.
Obviously, there is no clear-cut remedy for this.
However, we do have a Doppler 18 Network of 4 other radars that are far enough away from that wind farm to prevent this data pollution from occurring.
Thus, I normally compare our data with Live Doppler 18 to our 4 other radars at National Weather Service Offices in Lincoln & Chicago, Illinois & North Webster & Indianapolis, Indiana. With these radars, I am able to determine whether wind farm interference is occurring or an actual t’storm is over central Benton County.
As more wind farms are constructed, potentially more blobs will develop on Live Doppler 18 over the next few years…………stay tuned………….
Here are other cool links that explain this phenomena:
http://www.meteorologynews.com/2009/04/13/windmills-interference-causing-problems-for-doppler-radar-signals/
http://www.erh.noaa.gov/buf/windfarm.htm
http://www.watertowndailytimes.com/article/20090624/NEWS03/306249964
Excellent post on the causes and possible solutions to this false echo. We are going to see more and more wind farms setting up shop across this part of the country. Chad…doppler radar is excellent and most tv stations have exceptional radars. What do you believe is the next generation of radar? Will this problem be eliminated with that? Thanks!
Now I know why the “storm” near Fowler that I saw on doppler 18 wasn’t appearing on the Indianapolis radar last week. LOL!
Very interesting on the wind farms. The first time I saw that on your radar it scared the bejeebers out of me knowing that red blob was close to my location.
That explanation is not correct. There is a huge cluster of windmills from Oxford to Otterbein, yet the radar does not show rain there?!?!?!
Explain that!
The radar beam gets higher as you go northwest & lower as you get closer to the station.
Thus, it does not show up near Otterbein because the beam is too low below the turbulence to show up. Additionally, the beam is too high for any farms northwest of Fowler.
The beam is at “the sweet spot” or height near Fowler for maximum turbulence & maximum echo pollution.
Are the windmills to blame for the dissolution of rain everytime it nears the state line? We are very dry in white ,cass,and carroll county’s
The radar beam is at precisely the right height at Fowler to be bent & re-reflected back to the radar transmitter at the television station.
The beam gets higher as you move northeast of the radar site, since Earth is curved. At Brookston, the beam is lower than it is at Fowler. Thus, it is too low to be at the optimum height for the beam to be radically affected.
Northwest of Fowler, the radar beam is too high to be affected by wind farms.
All this said, the outer periphery of a circle 30 miles around the radar is fair game for any large turbine 150′ high.
to pollute the radar data.
I hope this helps & thanks for the email!
Brookston is 14 miles from the radar & thus too close………Fowler is about 30 miles away from the radar.