Weather models, online comments shape NOAA's drought forecast

Weather models, online comments shape NOAA's drought forecast

By Tony Lee Orr

GCN Staff

National Oceanic and Atmospheric Administration scientists are using supercomputer models and the Internet to help predict spring drought conditions.

The new technology let the service issue its first spring drought forecast, which predicted that dry weather would persist and, in some areas, intensify. Several states experienced their driest February on record, officials said.

Basic information assesses how serious the situation can become, said Ants Leetmaa, director of NOAA's Climate Prediction Center at the National Weather Service.

Scientists track deficits in rainfall and soil moisture, then use the information to create a drought model, he said.

The information is sent to other experts nationwide via the Internet for comment. The regional experts compare the information against data and circumstances in their areas.

'The Internet is a critical element. It lets us form a consensus,' Leetmaa said.

Other factors are also considered.

'The La Nin' pattern, which has dominated the United States for the past two years, has created a serious moisture deficit in many areas,' NOAA administrator D. James Baker said.

Once the background forecast is created, scientists figure in La Nin's effect and enter all the information into the weather service's supercomputer, Leetmaa said.

The IBM RS/6000 Scalable Parallel system processes data at 690 billion instructions per second. Last year, it ranked as the world's 26th-fastest supercomputer [GCN, Nov. 22, 1999, Page 1].

When upgraded in September with even more advanced technology and additional processors, the supercomputer will process weather data at 2.5 trillion instructions per second.

The final upgrade will make the IBM supercomputer 28 times faster than the Cray C-90 it replaced earlier this year, NOAA said [GCN, Feb. 21, Page 33].

After crunching the data, the supercomputer spits out its rainfall prediction for the next season, taking La Nin' into consideration, Leetmaa said.

'It indicates that the drought will reinforce the signal from La Nin',' he said, meaning the drought could foster drier conditions, feeding on itself, and become worse.

The predictions have an impact that reaches far beyond the nation's farmers. Drought can cause economic and social losses comparable to that of major hurricanes, officials said.

Loss of land

Wildfires this year have claimed 208,000 acres'nearly four times the losses for the same period last year, officials said. The areas affected by the 2000 drought, NOAA officials said, parallel those caught of the 1988 drought, which was the most costly weather disaster in history with an estimated $40 billion in losses.

The average annual cost associated with droughts is more than $6 billion.

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