GENESIS AGCM Reveals Climate of Triassic and the cycling of greenhouse gases, marine produc- A new atmospheric general circulation model tivity and the movement of nutrients in the upper layer (AGCM), called GENESIS, may help researchers of the ocean, and the spread of pollutants. determine climates and climate changes of the past. The North Atlantic Tracer Release Experiment, The Pennsylvania State University's Eric Barron, funded by the National Science Foundation's division through a National Science Foundation-funded grant, of ocean sciences, is part of an international program has been using the GENESIS AGCM to explore the called the World Ocean Circulation Experiment climates of two time periods in the Triassic: the (WOCE). The goal of WOCE is to gather data from the Scythian and the Carnian. world's oceans in an effort to accurately predict cli- The GENESIS AGCM, developed by the National mate on scales of decades and longer. Center for Atmospheric Research and the University James Ledwell of the Woods Hole Oceanographic of Colorado, incorporates three types of cloud cover Institution led the tracer experiment team. The team and new models for vegetation effects, soil hydrology, mapped the distribution of a nontoxic chemical tracer snow cover, and sea-ice information and melting. It that they had released about 1000 feet below the also estimates paleotopography, solar insolation, at- ocean surface 700 miles off the Canary Islands' west mospheric C0 concentration, vegetation and soil coast. They found that the tracer spread quickly within types, and oceanic heat flux. the thermocline and confirmed previous inferences The results from the GENESIS AGCM suggested that mixing occurs slowly across this layer. that seasonal precipitation fell on major highland ar- After the tracer was released, its concentration was eas of the supercontinent Pangaea and the lowland measured. The scientists found that horizontal streaks interior experienced dry continental climates with large had formed a patch with a vertical width of about 60 seasonal temperature ranges. Both the Carnian and feet. Six months later the patch had spread vertically the Scythian periods experienced strong monsoons. only about 150 feet, but had formed streaks hundreds of miles long and approximately five miles wide. One year later, the patch had spread to a width of several Tracers Show Slow Mixing in the Thermocline hundred miles, but the tracer had diffused vertically A team of U.S. researchers has conducted the first less than 250 feet. direct measurement of how quickly ocean water mixes in the upper kilometer of the ocean. The team con- The team's next experiment will be to determine the cluded that mixing occurs slowly. These findings are rate of vertical mixing in deeper (depths up to 4000 m) crucial for the understanding of global climate patterns waters and in other locations. • Stratosphere Sickness Illnesses induced by flying at extremely high altitudes are not permanent, and only rarely are they serious, according to Dr. Martin G. Larrabee of the University of Pennsylvania Medical School, speaking over the Columbia Broadcasting System last August. Relief is almost immediate as soon as the man is returned to normal conditions. The laboratory "stratosphere chamber," which is hermetically sealed from the outside, reduces the air pressure and temperature at about the same rate as a fast plane climbing into the sky, explained John G. Bergdoll, Jr., chief engineer of the York Corporation, when interviewed during the same program. The York Corporation, credited with developing a modern stratosphere chamber which tests men and materials for altitude endurance, was responsible for engineering and installing the first one in Canada in 1939. Since then 30 have been built in the United States for use in aircraft plants, universities, and government laboratories. The chamber is a steel cylinder 22 feet long which resembles a submarine both inside and out. Within five minutes the temperature can be made to fall from 70°F to -70°F . Without even leaving the ground, the person within the chamber can experience all the sensations of both temperature and pressure which a stratosphere pilot must endure. The safe ceiling of human endurance is 38,000 feet, a little over seven miles. Stratosphere flying has touched off a life-and- death race between artillery and aircraft to see which can go the higher. An altitude of 35,000 feet, which earlier in the war was considered a safe level for bombers, according to the British, can now be reached by the latest German anti-aircraft guns. This means that flight ceilings must continually be pushed higher and higher but the problem is less one of machines than of human endurance.—S. S., Aug. 1943. Bull. Amer. Meteor. Soc., 24, 348. 2274 Vol. 74, Vol. 11, November 1993
Bulletin of the American Meteorological Society – American Meteorological Society
Published: Nov 1, 1993
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