Sunday, July 27, 2008

Hurricane and tsunami warnings from satellites

Science Daily: For humans in the path of destructive hurricanes and tsunamis, an accurate warning of the pending event is critical for damage control and survival. Such warnings, however, require a solid base of scientific observations, and a new satellite is ready for the job.

The Ocean Surface Topography Mission (OSTM)/Jason 2 adds to the number of eyes in the sky measuring sea surface and wave heights across Earth's oceans. The increased coverage will help researchers improve current models for practical use in predicting hurricane intensity, while providing valuable data that can be used to improve tsunami warning models.

"When it comes to predicting hurricane intensity, the curve in the last 40 years has been somewhat flat, with little advance in how to reduce error in predicted intensity," said Gustavo Goni, of the National Oceanic and Atmospheric Administration (NOAA) in Miami. Maps of sea surface height created from satellites, however, could help change the curve.

Satellites that measure sea surface height have been running operationally nonstop since November 1992. But more than one is needed to fly at the same time in order to identify all the features that could be responsible for intensification of tropical cyclones all over Earth. The OSTM/Jason 2 mission will help make the additional coverage possible.

…While sea surface height may not necessarily be the most significant parameter for hurricane intensity forecasts, researchers now know that if sea surface height is accounted for in current forecast models, errors in forecasts for the most intense storms are reduced. For weak storms, the reduction in error is not very significant. However, for storms in the strongest category 5 range, the heat content in the upper ocean derived from sea surface height becomes increasingly important. "This is a good thing, because these are the storms that produce the most damage," Goni said.

This is what it looked like on the ground: Inside the Astrotech processing facility at Vandenberg Air Force Base, the OSTM/Jason-2 spacecraft is viewed from another angle after being lifted to a vertical position on the tilt dolly. The OSTM, or Ocean Topography Mission, on the Jason-2 satellite is a follow-on to Jason-1. It will take oceanographic studies of sea surface height into an operational mode for continued climate forecasting research and science and industrial applications. NASA, Wikimedia Commons

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