On Sept. 5, 2019 at about noon EDT, the Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard NASA's Terra satellite passed over the eye of Hurricane Dorian as the storm tracked northeast along the Atlantic coast, about 50 miles from Charleston, South Carolina. During this time, Dorian was weakening from Category 3 to Category 2 following a second period of intensification.
MISR carries nine cameras fixed at different angles, each of which viewed Dorian over a period of about seven minutes. The multi-camera views are used to calculate the heights of the cloud tops, and the motion of the clouds between the views provides information on wind speed and direction. The left side of the image shows the view from the downward-pointing (nadir) camera, with wind velocity vectors superimposed over it. The derived cloud-top heights are shown at the right, along with the color scale.
The length of the wind arrows is proportional to wind speed and their colors show the altitude of the cloud tops in kilometers. MISR observed cyclonic (counterclockwise) wind speeds up to 35 meters per second (78 miles per hour) at altitudes of 3-4 kilometers (1.9 to 2.5 miles), consistent with maximal wind gusts reported by the National Hurricane Center based on data from local weather stations and buoys.
At higher altitudes of 11-12 kms (6.8-7.5 miles), MISR observed anti-cyclonic (clockwise) wind speeds up to 55 meters per second (123 mph). The eye, spiral rainbands, and reversal of wind direction between low and high altitudes are typical features of a hurricane's anatomy.
These data were captured during orbit 104869. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, California, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, Greenbelt, Maryland. The MISR data were obtained from the NASA Langley Research Center Atmospheric Science Data Center, Hampton, Virginia. JPL is a division of the California Institute of Technology in Pasadena.