Typhoon Odessa
Western Pacific Ocean, Earth

Hurricanes (which are called typhoons when they occur in the western Pacific) are among the most powerful and most organized atmospheric systems on Earth. They form in tropical regions, where warm ocean waters trigger local thunderstorm activity. Under the right circumstances, regional wind currents and the Earth's rotation can organize these storm systems (called waves) into large spiral systems. When sustained winds reach 119 kilometers per hour, a hurricane is born.

When observed by shuttle astronauts in August 1985, Typhoon Odessa was a mature and powerful storm with a tightly formed eye wall. Hurricane circulation (counterclockwise in the northern hemisphere) forms a cylindrical wall of thunderstorms up to 100 kilometers wide near the center called the eye wall, which is the site of the most damaging winds. These storms create powerful updrafts that pull warm surface air into the hurricane, further feeding storm activity.

When the rising thunderclouds of the eye wall encounter the tropopause (at 13,500 meters) they are no longer buoyant and spread laterally. Some air flows downward into the center, dissipating clouds and forming the eye (seen in a close-up image). Most of the air flows outward, however, forming a circular cloud deck over the hurricane called the cirroform anvil.

Hurricanes can affect an area 600 kilometers wide. The general circulation in a hurricane is part of the mechanism that redistributes tropical heat from the ocean to the atmosphere and from the equator to the poles.

DATA SHEET (Top)

Location:
     26 N, 135 E
Mission:
     STS 51I
Image Numbers:
     51-35-76, 51-35-77
Vertical Exaggeration:
     1.5 × Normal
Spacecraft Altitude:
     323 kilometers
Stereo Baseline:
     97 kilometers