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Fall 2001

Science Bits

Scripps wildfire forecast is on target

As of September, the fire season of 2001 across the western U.S. was considerably less destructive than that of 2000. Using a statistical technique based on available fuel rather than seasonal weather conditions, scientists at the Scripps Institution of Oceanography correctly pegged this downturn. The 2001 Western Wildfire Season Forecast, issued through the Scripps-based California Applications Program, was based on data from January and March 2001; January, March, May, and August 2000; and May 1999. It spanned the entire region from the West Coast through the Rocky Mountains. The Scripps outlook keyed on two years of dry conditions that, ironically, limited the growth of fire-friendly fuel. In its first operational year, 2000, the outlook correctly predicted a much more active fire season.

Constructed by a team led by Anthony Westerling, the forecasts are based on 20 years of data from the U.S. Forest Service, the Bureau of Land Management, and the National Park Service. The Scripps outlook infers the amount of available fuel—vegetation that will readily burn during the fire season—from values of the Palmer Drought Severity Index. Then the fuel supply is used to estimate the acreage at risk during an approaching fire season. While the PDSI has been employed for years to study fire risk, this study used PDSI values at seven different intervals over the preceding two years. The statistical technique, principal components regression, appears to have some skill at detecting not only local risk but regional relationships of fuel to acres burned.

In the Mediterranean climate of California, where vegetation growth concentrates in the winter, warm-season fires are more likely when the preceding winter was dry but the winter before that was wet. In this scenario, fuel builds up during the wet winter and dries out during the following year's drought. In contrast, the Great Basin of the intermountain West dries out more quickly, so only a year's lag after a wet winter and spring produces peak fire risk.

The experimental forecast does not include details on how a specific fire might behave or how much it would burn. The forecast team is now exploring how the outlook might be narrowed to specific time frames in the fire season and whether the lead time might be increased. Along with Westerling, the researchers include Timothy Brown (Desert Research Institute), Dan Cayan (Scripps/U.S. Geological Survey), Michael Dettinger (USGS), and Alexander Gershunov (Scripps).

On the Web:
Scripps/California Applications Program

U.S. Geological Survey
Scripps Institution of Oceanography at the University of California, San Diego
Desert Research Institute, University and Community

Roads and waterways linked in state monitoring system

A team of ocean engineers led by a University of Rhode Island (URI) researcher has pooled information on highways and waterways into a single environmental monitoring and forecasting system. Using a variety of strategically placed devices and sensors, the TRANSMAP system identifies road-pavement and meteorological conditions throughout Rhode Island and marine conditions in adjacent Narragansett Bay. TRANSMAP is expected to be available on line in October.

"Some of the data in TRANSMAP [have] been collected for several years, but getting access—even for professionals—has always been a problem. There has also never been a single system that combines both land and marine information," says Malcolm Spaulding, professor and chair of the URI Department of Ocean Engineering. "For coastal states especially, the water has a dramatic impact on weather conditions and the environment, so it makes sense to combine the land and marine databases."

Designed to help transportation professionals determine when roads need plowing or salting and to aid commercial ships transporting people or cargo, TRANSMAP may also serve officials responding to hazardous waste spills, road designers, competitive sailors, fishers, scientists, and the traveling public. Real-time data is combined with numerical weather prediction models to anticipate future conditions. The roadway system consists of eight pavement- based sensors installed by the Rhode Island Department of Transportation five years ago. The seven marine data collection points were installed by the Rhode Island Department of Environmental Management with funds collected from a legal settlement following a 1996 oil spill at North Cape, Rhode Island.

One version of TRANSMAP is aimed at nontransportation professionals and the general public, while another is tailored for specialists. Both versions allow users to view current and historic data from each of the collection points and to overlay a wide variety of maps from the state's Geographic Information System. TRANSMAP's generic design makes applications possible for regions beyond Rhode Island.

University of Rhode Island

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Edited by Bob Henson, bhenson@ucar.edu
Prepared for the Web by Jacque Marshall
Last revised: Tue Oct 23 11:26:05 MDT 2001