AS TYPHOONS Violet and Tom raged over the western Pacific this autumn,
they were being watched by a new instrument on board Japan鈥檚 Advanced Earth
Observing Satellite. The instrument, a scatterometer provided by NASA, monitors
ocean winds by measuring the frequencies of radar signals reflected from the sea
surface.
These frequencies are dependent on sea conditions, says Johnny Chan of Hong
Kong鈥檚 City University, allowing researchers to map wind directions and
strengths over large swathes of ocean. The above image was produced by Tim Liu
and Wendy Tang of NASA鈥檚 Jet Propulsion Laboratory in Pasadena, California. The
arrows show wind directions, blue denotes areas with calm air and the various
shades of red indicate regions with moderate to high winds.
In addition to its main job of studying ocean winds, the scatterometer is
also being used to monitor ice sheets and rainforests. David Long of Brigham
Young University in Utah has developed a method to enhance radar images
reflected from the ground.
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