Frances, Ivan Contribute to NASA’s Hurricane Studies

Seen through the eyes of the Multi-angle Imaging SpectroRadiometer
aboard NASA’s Terra satellite, the menacing clouds of Hurricanes
Frances and Ivan provide a wealth of information that can help improve
hurricane forecasts.

The ability of forecasters to predict the intensity and amount of
rainfall associated with hurricanes still requires improvement,
particularly on the 24- to 48-hour timescales vital for disaster
planning. Scientists need to better understand the complex
interactions that lead to hurricane intensification and dissipation,
and the various physical processes that affect hurricane intensity and
rainfall distributions. Because uncertainties in representing
hurricane cloud processes still exist, it is vital that model findings
be evaluated against actual hurricane observations whenever
possible. Two-dimensional maps of cloud heights such as those
provided by the Multi-angle Imaging SpectroRadiometer offer an
unprecedented opportunity for comparing simulated cloud fields against
actual hurricane observations.

The newly released images of Hurricanes Frances and Ivan were acquired
Sept. 4 and Sept. 5, 2004, respectively, when Frances’ eye sat just
off the coast of eastern Florida and Ivan was heading toward the
central and western Caribbean. They are available at:
http://photojournal.jpl.nasa.gov/catalog/PIA04367 .

The left-hand panel in each image pair is a natural-color view from
the instrument’s nadir camera. The right-hand panels are
computer-generated cloud-top height retrievals produced by comparing
the features of images acquired at different view angles. When
these images were acquired, clouds within Frances and Ivan had
attained altitudes of 15 and 16 kilometers (9.3 and 9.9 miles) above
sea level, respectively.

The instrument is one of several Earth-observing experiments aboard
Terra, launched in December 1999. The instrument acquires images
of Earth at nine angles simultaneously, using nine separate cameras
pointed forward, downward and backward along its flight path. It
observes the daylit Earth continuously and every 9 days views the
entire globe between 82 degrees north and 82 degrees south
latitude. It was built and is managed by NASA’s Jet Propulsion
Laboratory, Pasadena, Calif. JPL is a division of the California
Institute of Technology in Pasadena.

More information about the Multi-angle Imaging SpectroRadiometer is
available at: http://www-misr.jpl.nasa.gov/ .