Wednesday, June 13, 2007

Story of the day-Hurricane-warning satellite could fail

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Key hurricane-warning satellite could fail: scientists
An aging weather satellite crucial to accurate predictions on the intensity and path of hurricanes could fail at any moment, but plans to launch a replacement have been pushed back seven years to 2016.
In a letter obtained by the Associated Press, the U.S. National Oceanic and Atmospheric Administration's chief said the failure of NASA's Quick Scatterometer (QuickScat) satellite could bring more uncertainty to forecasts and widen the areas that are placed under hurricane watches and warnings.
If the satellite falters, experts estimate that the accuracy of two-day forecasts could suffer by 10 per cent and three-day forecasts by 16 per cent. That could translate into large tracts of coastline and the difference between a city being evacuated or not.
"We would go blind. It would be significantly hazardous," said Wayne Sallade, emergency manager in Charlotte County, which was hit hard by Hurricane Charley in 2004.
A NOAA spokesman disputed that, saying alternatives such as using data from other satellites would help diminish any increased uncertainty coming from the loss of QuikScat
But scientists said that if QuikScat failed, they may have to rely on less accurate satellites. Bill Proenza, director of the National Hurricane Center in Miami, also said authorities "may have to err on the side of caution" in future forecasts.
'We would go blind. It would be significantly hazardous.'—Wayne Sallade, Charlotte County emergency managerThat means "more people disrupted, and more impact on the economy," Proenza said. "We have to err on the side of the protection of life. And that's how we would handle it."
Transmitter failureQuikScat, launched in 1999, provides key data on wind speed and direction over the ocean. Weather aircraft and buoys can also obtain similar measurements near a storm, but they do not provide a constant flow of data as QuikScat does.
Last year, the satellite suffered a major setback — the failure of a transmitter used to send data to Earth about every 90 minutes. Now the satellite is limping along on a backup transmitter and has other problems. The backup transmitter could last years, but there will be no warning when it is about to fail, said Robert Gaston, who works with the satellite at NASA's Jet Propulsion Laboratory.
Emergency managers like Sallade have been briefed on the satellite's problems. They said if they cannot rely on forecasts, they may have to make crucial decisions earlier, such as evacuating patients from hospitals or moving around emergency equipment. Emergency managers estimate that the total costs of evacuations are up to $1 million US per 1.6 km of coastline, meaning wider evacuations could be expensive.
A replacement for QuikScat was originally scheduled to launch in 2009, but U.S. officials have said it is now scheduled to launch in 2016. In a letter to a Florida congressman, NOAA administrator Conrad Lautenbacher blamed the delay for launching a replacement satellite on technical and budget problems.
Even if money were immediately available, a replacement satellite is estimated to take at least four years and cost approximately $400 million to build.
Fallback plansIf the satellite fails, the options are few. Other satellites have instruments to measure wind speed and direction over water, but they are less accurate.
A European satellite called ASCAT is available, but it does not give scientists as clear a picture as QuikScat because the distance between the readings it takes is larger. Using ASCAT would be like a person who wears glasses taking them off, seeing a once-sharp world blurred, said National Hurricane Center senior hurricane specialist Rick Knabb.
A NASA and Department of Defence satellite called WINDSAT also measures wind speed and direction, but it too is beyond its expected lifespan, and scientists have had trouble using it to observe tropical weather systems

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