Image-processing scientists at the Jet Propulsion Laboratory, Pasadena, Calif., have used digital animation techniques to produce three-dimensional, whirlwind tour of Earth, flying the viewer over, under and through the cloudtops in the atmosphere of our planet.

The production, called "Earth: The Movie," was constructed from satellite data and digital elevation maps of Earth to show how clouds form and influence weather as they move across the planet's surface. From vantage point made possible only by computer, "Earth: The Movie" also allows the viewer to see Earth's cloudtops in three dimensions -- all over the world.

The data visualization techniques developed to produce "Earth: The Movie" represent powerful new tools that scientists will use to study the complex relationships between Earth's topography, atmosphere, ocean, and biosphere.

"Earth: The Movie" was created by Jeffrey R. Hall, Kevin J. Hussey and Robert A. Mortensen of the Digital Image Animation Lab (DIAL) of JPL's Image Processing Laboratory, in cooperation with atmospheric scientists Dr. Moustafa Chahine of JPL and Dr. Joel Susskind of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The data displayed in the production were derived from the High-Resolution Infrared Sounder-2 and Microwave Sounding Unit on NASA's Nimbus 7, an Earth-observing satellite launched on Oct. 24, 1978. The data show the monthly average cloud cover for December 1978 and the daily cloud cover from Dec. 31, 1978 to Feb. 4, 1979.

The production represents 9 gigabytes (9 billion bytes) of information. Cyber 205 supercomputer at the Goddard Space Flight Center was used to preprocess the data. The data were then processed at JPL by two mainframe computers executing 4 million instructions per second over 18.4 days.

"Earth: The Movie" was produced by JPL for the Office of Space Science and Applications.



A study of the Earth's climate must take into account the crucial role played by clouds. Besides delivering life-giving rain to the land, clouds help maintain proper balance in the global climate. The following digital animation combines satellite cloud data and Earth elevation data from maps to demonstrate how atmospheric scientists and visualization specialists team up to perform climatic research. The clouds were derived from infrared and microwave satellite instrument data using supercomputer. Part One: Rectangular projection of Earth's surface and clouds.

At first glance, clouds may appear chaotic, but closer observation reveals semblance of order. Recognizable patterns show how air moves up and down while circulating around the globe. The varied features of the Earth's surface (portrayed here by color) as well as prevailing winds, have distinct effects on the formation and distribution of clouds. Computer animation to visualize clouds provides unique insight into the structure and dynamics of global weather systems. Part Two: Three-dimensional flight over the world.

Now, as we add the third dimension to both the Earth's surface and the clouds, we can see the relationship between cloud-tops and the Earth's topography. The cloudtop elevations were also derived from satellite data. The vertical dimensions have been exaggerated twenty times to enhance comparison. - Our flight takes us along the west coast of Africa. - Flying north of Scandinavia, we see Europe, then quickly cross the North Atlantic and drop below the cloud-tops off the eastern United States. - We look west into the Amazon basin of South America. - We circle Cape Horn and view the Andes mountains up close. - Central America passes below as we view North America. - Diving below the clouds in the mid-Atlantic, we fly over the Mediterranean. - Turkey passes to our right as we fly across the Caspian Sea into the southern Soviet Union. - China, and now Japan, are below us. - Southeast Asia and Australia are seen as we head for the Himalayas and Indian subcontinent. - The Middle East and Africa complete our journey. Part Three: Spherical projection of Earth showing daily cloud activity over the Pacific Ocean.

The atmosphere can be considered gigantic solar powered engine which controls our daily weather. The Pacific Ocean, shown here, covers nearly half the Earth. It is the major storehouse of energy and source of water vapor for the planet.

This is the winter season in the northern hemisphere and we can observe the course of numerous storms, one after the other, approaching North America from the Gulf of Alaska. Part Four: Spherical projection of Earth showing daily cloud activity over the Atlantic Ocean.

Note the belt of clouds near the equator as we rotate the Earth to observe the opposite hemisphere. This belt provides the moisture necessary to sustain the equatorial rain forests of the Congo basin in Central Africa and the Amazon in South America.

North Africa, dominated by the Sahara, is characterized by its lack of clouds. Near the top of this hemisphere we can also observe winter storms move with regularity across the North Atlantic and Europe. Conclusion

The data visualization techniques developed to produce "Earth: The Movie" represent powerful new tools that scientists will use to study our complex global environment.

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