MODIS
Wind Observations Improve Weather Forecasts
 The
different colors show the observation tracks of three consecutive orbits of the
MODIS
instrument, about 11/2 hours apart, with the white area representing the overlap area
of all three orbits. Tests at the Joint Center for Satellite Data Assimilation show
that wind observations, obtained from tracking cloud or water vapor features in the
images of 2 or 3 overlapping orbits, improve medium range weather predictions. The
NOAA -
NASA -
DoD
Joint Center for Satellite Data Assimilation (JCSDA)
has shown that winds derived from NASA's
MODIS
observations improve the accuracy of medium
range weather predictions. Based on these results, the
NWS will start to assimilate
these observations in the next upgrade to its global forecast model. The winds are
derived using an innovative technique developed by NESDIS researchers. For many years,
atmospheric winds have been measured by tracking the movement of cloud and water
vapor features in consecutive images of GOES
satellites. Hovering over the equator,
GOES
does not see polar areas. The new technique exploits the capability of the
polar orbiting MODIS
to take snapshots of polar areas only one to two hours apart,
and from these images to track cloud and water vapor features. Unlike geostationary
satellites at lower latitudes, it is not be possible to obtain complete polar coverage
at a snapshot in time with one or two polar-orbiters. Instead, winds must be derived
for areas that are covered by two or three successive orbits, an example of which is
shown here. The whitish area is the overlap between three orbits. MODIS
is the first of a new generation of visible and infrared imagers that is a pre-curser of the
NPOESS
VIIRS and the
GOES-R imager.
NESDIS
provides the base funding for the JCSDA,
with the other partners contributing additional resources.
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