Sensors seek out lightning throughout world


POSTED: Monday, December 21, 2009

A global network of sensors to detect lightning has been developed based on research by University of Hawaii meteorologist Steven Businger and his team.

The data potentially could be used to identify thunderstorms, forecast hurricanes and other weather phenomena and aid climate change research, the scientists say.

Jim Weyman, meteorologist-in-charge of the National Weather Service's Honolulu Forecast Office and director of the Central Pacific Hurricane Center, said it's a valuable system because it provides information from a great distance on severe weather systems with lightning. Aircraft and ships can be warned to avoid those areas, he said.

Businger, recently elected as a fellow of the American Meteorological Society for his contributions to the atmospheric sciences, said he became aware of the potential of long-range lightning detection about nine years ago with the advent of global positioning systems and other technology.

He approached the Navy with the idea in 2001 and the Office of Naval Research funded building of a lightning network covering Hawaii and the Central Pacific.

He chose Vaisala, a global leader in environmental and industrial measurement products, as a partner for the Pacific Lightning Detection Network—PACNET.

Detectors leased from Vaisala “;had to be developed according to our needs,”; he said. “;Vaisala, together with my group and some scientists at Stanford, calibrated and developed these sensors in a way that they surprisingly had very, very vast range.”;

A detector essentially measures the noise in the electromagnetic spectrum created by lighting strikes and can see or detect lightning up to 6,200 miles away, Businger explained.

Vaisala recognized it wouldn't take many sensors to create a global network and did so after building PACNET.

But just detecting lightning wasn't enough, said Businger, whose collaborators included Antti Pessi, a former UH doctoral student and now a postdoctoral researcher.

Calibrating the network was a critical step toward making the data useful, Businger said, explaining they needed to know how accurately the network could locate lightning.

He said they used three data sets for the calibration—a NASA satellite with a lightning detector, the National Lightning Detection Network over the continental United States managed by Vaisala and a high-resolution network in Puerto Rico.

Comparing the long-range lightning detectors to data collected from national and Puerto Rico sensors, special new long-range detectors were developed for open ocean use, Businger said.

Four detectors were placed in the Pacific during the first year of the project and four more were installed last year in the Western Pacific—in Guam, Okinawa, the Philippines, Pago Pago, Kona and Lihue.

“;Once we had a feeling for how much lightning we were detecting, we started relating the lightning to precipitation (radar) data.”;

Businger said his team is continuing to work with Vaisala and the Navy “;to make use of data for weather forecasting because, you can imagine, if you know where lightning is occurring, you know where thunderstorms are.”;