This view of Earth comes from NASA's Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite.
This view of Earth comes from NASA's Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite.

Ten years ago, on Aug. 24, 1992, Hurricane Andrew developed in the Atlantic Ocean and became one of the costliest hurricanes in U.S. history as it caused massive damage in South Florida. Since then, NASA has launched three satellites, including two with instruments developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., that will help improve forecasting of tropical cyclones.

NASA's Tropical Rainfall Measuring Mission; the JPL-developed and managed Quick Scatterometer, or Quikscat; and the Aqua satellite, with its JPL-managed Atmospheric Infrared Sounder system, each look at different factors of tropical cyclones to help generate better forecasts. The Tropical Rainfall Measuring Mission focuses on the intensity of tropical rainfall, which is indicative of whether a cyclone is weakening or strengthening. Quikscat collects wind data, and Aqua records ocean and air temperatures and humidity. These factors are primary in the strengthening of a hurricane, and NASA researchers, working with forecasters from the National Hurricane Center, hope data from these satellites will improve hurricane predictions. These efforts may help lessen damages when another hurricane like Andrew strikes our coasts.

"Andrew's wind data was recently re-analyzed and found to have reached maximum sustained wind speeds of 266 kilometers per hour (165 mph) at landfall in South Florida, making the hurricane a Category 5 on the Saffir-Simpson hurricane scale," said Max Mayfield, director of the National Hurricane Center. Category 5 storms have winds over 249 kilometers per hour (155 mph) and storm surges generally over 5.5 meters (18 feet) above normal sea level. This makes Andrew one of only three Category 5 hurricanes known to have struck the United States.

On August 24, Andrew cut its destructive swath through South Florida and entered the Gulf of Mexico. On August 26, Andrew made landfall 161 kilometers (100 miles) southwest of New Orleans, and was downgraded to a tropical depression the next day, northeast of Jackson, Miss.

South Florida was declared a federal disaster area, as entire neighborhoods were destroyed. Andrew caused more than $25 billion in damages (1992 dollars). The enormity of the damage created a new awareness of hurricanes and further prompted scientists to study these deadly storms in an effort to predict and mitigate future similar catastrophic events.

Toward this goal, the National Hurricane Center, part of the National Oceanic and Atmospheric Administration, together with NASA and other federal agencies, work together to provide the public with the best information possible. The Center uses several computer models to help forecast and track the intensity of tropical cyclones. Each computer model includes air temperature and pressure, sea surface temperature, wind speed and humidity as recorded from hurricane hunter aircraft that fly above tropical cyclones and drop sensors into them to get this data. The National Hurricane Center also verifies storm locations with the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite.

"NASA's Tropical Rainfall Measuring Mission satellite has been very valuable in determining hurricane or tropical cyclone intensity and in improving hurricane track forecasting through the use of rainfall data into hurricane forecast computer models," said Dr. Bob Adler, Tropical Rainfall Measuring Mission project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. Data from the mission have been combined with data from other satellites to detect heavy rain events and the associated flood potential due to tropical cyclones in areas where there is limited ground-based information.

The SeaWinds instrument on Quickscat is a specialized microwave radar that measures the speed and direction of winds near the ocean surface. It is being used by many marine weather prediction centers to improve monitoring and forecasting of tropical cyclones. In January 2002, the United States and Europe incorporated wind speed and direction data from Quikscat into their operational global weather analysis and forecast systems. Significant improvement has been demonstrated. JPL manages Quikscat for NASA's Office of Earth Science, Washington. D.C.

The Aqua satellite, launched this past May, carries the Atmospheric Infrared Sounder instrument developed by JPL. It is the central part of the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit/Humidity Sounder for Brazil instrument group that will obtain global temperatures and humidity records throughout the atmosphere. NASA hopes these data will lead to improved weather forecasts and improved determination of cyclone intensity, location and tracks. "The improved data from Aqua will not make weather forecasting perfect, but should make it better," said Dr. Claire Parkinson, Aqua project scientist at Goddard.

"People should be watchful and remember that it only took one hurricane named Andrew during 1992 to change the lives of hundreds of thousands in South Florida," said Dr. Scott Curtis, researcher at Goddard and the University of Maryland Baltimore County, Baltimore, Md.

More information and images are online at

JPL is a division of the California Institute of Technology in Pasadena.

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