Wind farms interfering with Doppler radar

Maple Ridge Wind Farm is one of several farms in the state causing problems for the National Weather Service Forecast Office in Buffalo.

Maple Ridge in Martinsburg, Harrisburg and Lowville has created interference for the service's Doppler radar in Montague.

"It does pose a problem for the immediate Tug Hill area," said David A. Zaff, meteorologist for the service. "The biggest problem is during a severe weather event."

The service has a Web page about Doppler radar interference. It shows how wind projects in Sheldon, Wethersfield, Eagle and Bliss create the interference with a station in Cheektowaga. The wind projects are about 20 to 35 miles southwest of the radar. Maple Ridge is less than 10 miles from the Montague station.

The turbines cause problems because they are in the radar's line of sight to the sky. They reflect some of the radar's signal, which is then interpreted as wind or precipitation.

Moving the radars is not an option. Turbines would not be a problem if they were placed out of the line of sight — farther away or lower — from the radar.

"We site the radar at the highest location possible to give us a clear view of the sky," Mr. Zaff said. "The problem with that is that people like to site wind turbines in the same place."

Mr. Zaff said adding other wind farms in the Tug Hill area, such as Roaring Brook in Martinsburg, will increase the interference.

"It's not like radar can magically pass through it; you're essentially putting a wall there," he said.

The service cannot force developers to change their plans for turbine placement. But he said that over the past decade, awareness of the problem has grown and the service has talked to towns and developers.

Mr. Zaff said the interference or clutter is noticeable both to meteorologists and to those who look at radar on television or online.

"It's a little difficult to separate the clutter from the wind farm from an actual severe weather event," Mr. Zaff said. "It's usually pretty temporary — five or 10 minutes."

But, he said, the service sometimes has only a few minutes of lead time to put out warnings on severe weather.

ON THE NET

National Weather Service Forecast Office in Buffalo: www.erh.noaa.gov/buf/wind
farm.htm