The Tribune

By RASHAD ROLLE

Tribune Staff Reporter

rrolle@tribunemedia.net

AS debate rages about whether the Department of Meteorology’s Doppler radar system worked during Hurricane Joaquin, one American expert said yesterday that for the tool to be effective this country needs at least two more radars.

Bob Dreisewerd, a meteorologist for 25 years and the chief development officer for Baron, a weather intelligence firm, also told The Tribune yesterday that it is wise, though not necessary, for institutions to continually upgrade their radar technology.

The Bahamas’ current radar located at the Lynden Pindling International Airport (LPIA) was first attained in 2005.

“The weather radar is useful during a tropical storm or hurricane event when the event gets within the range of the radar,” Mr Dreisewerd said. “I would say the effective range of the radar when you are using a S band radar, of which I believe there is one in The Bahamas, is about 250 kilometers. “Once the storm is within 250 km of the weather radar, that radar is useful for the tracking of the event in the short-term. It’s not a long-term tool but it is a short-term tool for tracking the tropical event and what the event is causing. One of the limitations in The Bahamas today is currently there is I believe one S band radar and I believe it is Nassau.

“...One radar is not really effective enough to cover the entire range of islands. So the radar is nearly centrally located but ideally if the island chain had three radars it could be effectively covered more than it is today.”

He explained that a typical Doppler radar could determine rainfall intensity and wind motion and that more recent technology could “discern the shape and size of hydrometeors” within rainfall.

Like meteorological officials here in The Bahamas, Mr Dreisewerd emphasised that radars are incapable of long-term analysis of weather systems.

Such analysis is done by incorporating “satellite imagery” and “numerical weather prediction models,” he said.

“As you are outside of the short-term radar range, it’s typically information gained from satellite imagery and observations available from buoy observations or ship report observations or flight level observations that feed into these numerical weather prediction models,” he said, noting that buoys are located all around the globe.

“The existing satellite information in my opinion is sufficient for use by The Bahamas as well. The footprint of coverage is large enough. It’s a sophisticated satellite network and is used by the (US) National Hurricane Centre and is sufficient for The Bahamas,” he said.

However, he noted that data from radars are important even during long-term analysis of weather systems. Such data is used as input into computer models in order to improve the predictive nature of such weather models.

This week, a local daily published a series of articles that claimed the radar was not working during parts of Hurricane Joaquin. After the claims were published, forecaster Wayne Neely also maintained the radar was not operational for a period of time as Joaquin churned through the country.

However, officials from the Department of Meteorology and Minister of Transport and Aviation Glenys Hanna Martin have strongly denied the allegations.