Typhoon Nepartak, the first large typhoon in the northwest Pacific this season, is currently taking aim at the east coast of Taiwan. Over the past few days, Nepartak has rapidly gained strength, growing from a tropical storm to the equivalent of a Category 5 hurricane with sustained wind speeds of more than 160 miles (258 kilometers) per hour. Taiwan's Central Weather Bureau has issued a torrential rain warning, bracing for likely flooding as 5 to 15 inches (13 to 38 centimeters) of rain are expected to fall over Taiwan during the storm's passage. Waves of up to 40 feet (12 meters) are predicted on the coast as the typhoon approaches, and air and train travel have been severely impacted. The typhoon is currently moving at about 10 miles per hour (16 kilometers) to the west-northwest, and is predicted to pass over Taiwan within the next day and then hit the coast of mainland China. Central and eastern China are poorly situated to absorb the rainfall from Nepartak after suffering the effects of severe monsoon flooding, which has killed at least 140 people in the past week.
The Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard NASA's Terra satellite captured this view of Typhoon Nepartak on July 7, 2016, at 10:30 a.m. local time (2:30 a.m. UTC). On the left is an image from the nadir (vertical pointing) camera, which shows the central portion of Nepartak and the storm's eye. The image is about 235 miles (378 kilometers) across. The island of Manila in the Philippines, about 250 miles (400 kilometers) south of Taiwan, is visible to the southwest of the eye. The image shows that Nepartak's center is extremely compact, rather than broken up into spiral bands as is more typical of typhoons. This means that the storm may retain more of its strength as it passes over land.
MISR uses nine cameras to capture images of the typhoon from different angles. This provides a stereographic view, which can be used to determine the height of the storm's cloud tops. These heights are plotted in the middle panel, superimposed on the image. This shows that the cloud tops are relatively low, about 2.5 miles (4 kilometers), in the eye, but much higher, up to 12.5 miles (20 kilometers), just outside it.
By tracking the motion of clouds as they are viewed by each of the nine cameras over about seven minutes, it is possible to also derive how fast the clouds are moving due to wind. These wind vectors are superimposed on the image in the right panel. The length of each arrow shows the wind speed at that location (compare to the 45 miles per hour or 20 meters per second arrow in the legend), and the color shows the height at which the wind is being computed. The motion of the low-level winds (red and yellow arrows) is counterclockwise, while the motion of the high winds (blue and purple arrows) is mostly clockwise. This is because hurricanes draw in warm, moist air at low altitudes, which then flows upward around the eye, releases its moisture as rain, and moves outward at high altitudes. As is typical of these types of storm systems, the inflowing low winds and the outflowing high winds spin in different directions.
These data were captured during orbit 88041. 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.