QuikSCAT Satellites








hurricane rita windspeeds over gulf of mexico september 21, 2005

Hurricane Rita is shown above as observed by NASA’s QuikSCAT satellite on September 20, 2005, at 10:29 UTC (6:29 a.m. Eastern Daylight Time). At this time, the hurricane had 195-kilometer-per-hour (120 mile-per-hour; 105- knot) sustained winds. Within the next 24 hours, Rita would surge in power, packing winds near 280 km/hr (175 mph; 150 knots), reaching the very top of the hurricane-strength categories and becoming the fourth most powerful storm ever recorded.

The image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, shown in purple, surround the center of the storm. caption credit

Science Objectives

  • Acquire all-weather, high-resolution measurements of near-surface winds over global oceans.
  • Determine atmospheric forcing, ocean response, and air-sea interaction mechanisms on various spatial and temporal scales.
  • Combine wind data with measurements from scientific instruments in other disciplines to help us better understand the mechanisms of global climate change and weather patterns.
  • Study both annual and semi-annual rain forest vegetation changes.
  • Study daily/seasonal sea ice edge movement and Arctic/Antarctic ice pack changes.

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The QuikSCAT mission is intended to record sea-surface wind speed and direction data under all weather and cloud conditions over Earth's oceans. QuikSCAT was initiated as a "quick recovery" mission to help reduce the ocean-wind vector data gap created by the loss of the NASA Scatterometer (NSCAT) on the Japanese Advanced Earth Observing Satellite (ADEOS), which ceased functioning when ADEOS failed on June 30, 1997. QuikSCAT was launched from Vandenberg Air Force Base, Calif., aboard a Titan II vehicle, reducing the data gap by about one-half.

QuikSCAT operates in a near polar orbit. It flies in a circular orbit at an altitude of approximately 800 km (500 miles) above Earth's surface. It completes a full orbit in about 101 minutes, which translates to a little more than 14 orbits per day.

SeaWinds is the main instrument on the QuikSCAT satellite. SeaWinds is an active radar scatterometer. This scatterometer operates by transmitting high-frequency microwave pulses to the ocean surface and measuring the echoed radar pulses bounced back to the satellite.

QuikSCAT satellite QuikSCAT

The scatterometer estimates wind speed and direction over the Earth's oceans at 10 m above the surface of the water. The instrument collects data over ocean, land, and ice in a continuous, 1,800-kilometer-wide band, making approximately 400,000 measurements and covering 90% of Earth's surface in one day. QuikSCAT can acquire hundreds of times more observations of surface wind velocity each day than can ships and buoys, and can provide continuous, accurate and high-resolution measurements of both wind speeds and direction regardless of weather conditions. This data is vital for global climate research, operational weather forecasting, and storm warning.

The SeaWinds scatterometer is providing unprecedented, frequent surface wind speed and direction measurements over the global oceans. Coupled with other satellite measurements of cloud patterns, water vapor and rain, the data are contributing to scientists' ability to predict the intensity, location and movements of hurricanes and other severe marine weather patterns.