One of NASA’s newest Earth-observing instruments, the SeaWinds
scatterometer aboard Japan’s Advanced Earth Observing Satellite
(ADEOS) 2—now renamed Midori 2—has successfully transmitted its first
radar data to our home planet, generating its first high-quality images.
From its orbiting perch high above Earth, SeaWinds on Midori 2
(‘midori’ is Japanese for the color green, symbolizing the
environment) will provide the world’s most accurate, highest
resolution and broadest geographic coverage of ocean wind speed and
direction, sea ice extent and properties of Earth’s land surfaces.
It will complement and eventually replace an identical instrument
orbiting since June 1999 on NASA’s Quick Scatterometer (QuikScat)
satellite. Its three- to five-year mission will augment a long-term
ocean surface wind data series that began in 1996 with launch of the
NASA Scatterometer on Japan’s first ADEOS spacecraft.
Climatologists, meteorologists and oceanographers will soon routinely
use data from SeaWinds on Midori 2 to understand and predict severe
weather patterns, climate change and global weather abnormalities like
El Niño. The data are expected to improve global and regional weather
forecasts, ship routing and marine hazard avoidance, measurements of sea
ice extent and the tracking of icebergs, among other uses.
“Midori 2, its SeaWinds instrument and associated ground
processing systems are functioning very smoothly,” said Moshe
Pniel, scatterometer projects manager at NASA’s Jet Propulsion
Laboratory, Pasadena, Calif. “Following initial checkout and
calibration, we look forward to continuous operations, providing vital
data to scientists and weather forecasters around the world.”
“These first images show remarkable detail over land, ice and
oceans,” said Dr. Michael Freilich, Ocean Vector Winds Science
Team Leader, Oregon State University, Corvallis, Ore. “The
combination of SeaWinds data and measurements from other instruments on
Midori 2 with data from other international satellites will enable
detailed studies of ocean circulation, air-sea interaction and climate
variation simply not possible until now.”
The released image, obtained from data collected January 28-29,
depicts Earth’s continents in green, polar glacial ice-covered
regions in blue-red and sea ice in gray. Color and intensity changes
over ice and land are related to ice melting, variations in land surface
roughness and vegetation cover. Ocean surface wind speeds, measured
during a 12-hour period on January 28, are shown by colors, with blues
corresponding to low wind speeds and reds to wind speeds up to 15 meters
per second (30 knots). Black arrows denote wind direction. White gaps
over the oceans represent unmeasured areas between SeaWinds swaths (the
instrument measures winds over about 90 percent of the oceans each day).
SeaWinds transmits high-frequency microwave pulses to Earth’s
land masses, ice cover and ocean surface and measures the strength of
the radar pulses that bounce back to the instrument. It takes millions
of radar measurements covering about 93 percent of Earth’s surface
every day, operating under all weather conditions, day and night. Over
the oceans, SeaWinds senses ripples caused by the winds, from which
scientists can compute wind speed and direction. These ocean surface
winds drive Earth’s oceans and control the exchange of heat,
moisture and gases between the atmosphere and the sea.
Launched December 14, 2002, from Japan, the instrument was first
activated on January 10 and transitioned to its normal science mode on
January 28. A four-day dedicated checkout period was completed on
January 31. A six-month calibration/validation phase will begin in
April, with regular science operations scheduled to begin this October.