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Hurricane Season 2008: Hurricane Hernan (Eastern Pacific Ocean)
 
Aug. 11, 2008

NASA Satellites Provide Two Views of Hurricane Hernan

Satellite image of Hurricane Hernan Credit: NASA/JPL
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NASA's earth-viewing satellites can see hurricanes in many different ways. NASA's CloudSat captured a sideways view of Hurricane Hernan while QuikSCAT peered into the storm and provided in "under the hood" look at the winds inside.

On Monday, August 11, Hernan was in the open waters of the eastern Pacific Ocean, east of Hawaii. It's expected to weaken from a Category One hurricane to a depression by Saturday, Aug 16, in the waters far east of the big island.

This image from NASA's QuikSCAT satellite was taken at 2:40 UTC, Aug. 10, (10:40 p.m. EDT Aug. 9). It depicts Hernan's wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, are shown in purple, which indicate winds over 40 knots (46 mph).

At 11:00 a.m. EDT on August 11, the center of Hurricane Hernan was located near latitude 19.0 north and longitude 130.2 west or about 1,335 miles west of the southern tip of Baja California.

Hernan is moving toward the west-northwest near 10 mph and a turn toward the west and west-southwest is expected during the next day or two. Maximum sustained winds are near 80 mph with higher gusts. Slow weakening is forecast during the next 48 hours. Estimated minimum central pressure is 983 millibars.

Satellite image of Hurricane Hernan Credit: NASA/JPL/Colorado State University/Naval Research Laboratory-Monterey
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NASA's CloudSat satellite's Cloud Profiling Radar captured a sideways look across Hurricane Hernan. This is a combination of the CloudSat image (on the bottom) and an image from NASA's Aqua satellite (top).

The top image from NASA's Aqua satellite was supplied through the U.S. Naval Research Laboratory. It was created using data from the Advanced Microwave Scanning Radiometer- EOS (AMSR-E). Over the ocean, AMSR-E microwave frequencies probe through smaller cloud particles to measure the microwave emissions from larger raindrops. AMSR-E provides improved measurements of rainfall rates.

The image on the bottom is from NASA's CloudSat satellite. The red line through the Aqua satellite image shows the vertical cross section of radar, basically what Hernan's clouds looked like sideways. The colors indicate the intensity of the reflected radar energy. The top of Hernan's clouds reach almost to 14 kilometers, or approximately 8.7 miles high.

The blue areas along the top of the clouds indicates cloud ice, while the wavy blue lines on the bottom center of the image indicate intense rainfall. Notice that the solid line along the bottom of the panel, which is the ground, disappears in this area of intense precipitation. It is likely that in the area the precipitation rate exceeds 30mm/hr (1.18 inches/hour) based on previous studies.