Walter Orr Roberts

Geomagnetic Storms and Wintertime 300-mb Trough Development in the North Pacific-North America Area

Abstract This study confirms, for seven additional winters, a relationship discovered earlier between geomagnetic storms and subsequent deepening of 300-mb troughs. For this study a trough which moves into or is formed within the Gulf of Alaska area on the second to the fourth day after a geomagnetic storm, is defined as a key trough; it is found that key troughs tend to undergo a greater degree of subsequent intensification than non-key troughs. A vorticity index is computed in addition to the trough index used in earlier studies, and both indices show the same tendency. In the final section we speculate on possible causes for the relationships discovered.

Influence of solar magnetic sector structure on terrestrial atmospheric vorticity

Abstract The solar magnetic sector structure has a sizable and reproducible influence on tropospheric and lower stratospheric vorticity. The average vorticity during winter in the Northern Hemisphere north of 2ON latitude reaches a minimum approximately one day after the passing of a sector boundary, and then increases during the following two or three days. The effect is found at all heights within the troposphere, but is not prominent in the stratosphere, except at the lower levels. No single longitudinal interval appears to dominate the effect.

Benchmark Stations for the Measurement of Presently Missing Parameters

Benchmark stations, more commonly called “reference stations,” have been of great importance in climatic research and for monitoring long-term environmental changes. The stations of the U. S. “Climatological Benchmark Network” record temperature and precipitation. Reference measurements of other parameters commonly made include, in addition, such things as barometric pressure, humidity, wind velocity, insolation and atmospheric turbidity. A plea is made for preservation of the present climatic reference stations, and for maintenance and improvement of stations for reference measurement of solar radiation.

A Voice of Conscience Is Stilled

On the afternoon of May 18, 1973, members of his family, colleagues and friends gathered in a flower-banked chamber of the Smithsonian Institution in Washington, D.C. to pay tribute to Eugene Rabinowitch. The beautiful memorial service was illuminated by a series of eulogies, spoken by close associates of the Bulletins editor-in-chief. They heightened the realization of loss in the passing of one of the great scientist-humanists of the twentieth century.Herewith we publish excerpts from some of the eulogies which describe the life and work of Eugene Rabinowitch and which reflect his philosophy. These remarks are followed by messages from members of the world scientific community which Eugene Rabinowitch served as a powerful voice of conscience.

Twenty‐Fourth Award of the William Bowie Medal

No request that has come my way in many, many years has given me the deep sense of satisfaction that I have derived from the honor of preparing and delivering this citation for a respected and beloved friend. Sydney Chapman has painted bold, skillful strokes across the whole broad canvas of geophysics. Ever since 1910, when he first unlimbered his scientific talents as a young chief assistant at the Royal Observatory at Greenwich, he has participated continuously and creatively in the study of geomagnetism. Graduate students entering astro-geophysics today, challenged by his astonishing command of the tools of their trade, find it hard to believe that this is the same Sydney Chapman who, nearly five decades ago, published his first great works on the kinetic theory of gases.