Ocean Surface Winds

Ocean Surface Winds  thumbnail


The SeaWinds scatterometer, carried aboard NASA's QuikSCAT satellite, is a microwave radar designed to measure the backscatter related to near-surface wind speed and direction over the oceans. A rougher ocean surface returns a stronger signal because the waves reflect more of the radar energy back toward the scatterometer antenna (backscatter), and a smoother ocean surface returns a weaker signal because less of the energy is reflected. Given the known relationship between the roughness of the surface and the strength of the wind, it is possible to compute the wind speed and direction - the wind vector - from multiple observations of the signal returned from a given area on the ocean surface.

Measurements of the global sea-surface wind speed and direction, observed by QuikSCAT, are important to meteorologists and oceanographers in the preparation of marine weather forecasts and the issuance of warnings for the high seas. These include forecasts of the strength and track of hurricanes and winter storms, forecasts that are important to emergency response, offshore oil production and commercial shipping. Wind information is also used in forecasts of waves and ocean currents. The measurements are also important in observing and understanding the global manifestation of phenomena like El Niño Southern Oscillation (ENSO). Winds are related to key processes in the hydrological cycle (evaporation and precipitation), to the energy cycle (through evaporation and other energy fluxes), and the CO2 budget.

NASA's QuikSCAT mission carrying the SeaWinds scatterometer was launched in June 1999 and has been operating ever since.

For more information click here; information about other scatterometers and scatterometer products and animations can be found here. More information about near realtime operational products can be found here.

Notable Features

  • Tropical cyclones can be seen ( the eye structure is not resolved, so the maximum speed of hurricanes are lower than the actualy speeds)
  • High latitude storms are bigger in area than the tropical cyclones and the speeds are better resolved. There some some big and powerful storms that move from the North Pacific into the US and Canada, and others that form in teh North Atlantic and slam into Europe.
  • Fronts are very easy to see moving to the East off of non-tropical land masses. Relatively rough weather is associated with fronts, particularly cold fronts.
  • The large areas of high wind speeds in the Southern Ocean is quite exciting, particularly for people interested in boat races.
  • The arrows are three day trajectories of surface winds. Where they converge there is likely to be rising air, which is associated with rain. Where they diverge, the air is sinking, and associated with clear sky.
  • This dataset runs from 2004 through 2006