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Richard J. Reed

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Richard J. Reed

Ramage (1982) has presented evidence, based on extensive verification data for precipitation forecasts, that the percent of correct forecasts decreases approximately linearly with increasing precipitation frequency. However, only a limited range of precipitation frequency was examined in his study. Here the theoretical reltionship between these quantities is derived for the full range of precipitation frequency with use of a model that assumes the forecasts to be unbiased and the Heidke Skill Score to be independent of precipitation frequency. It is shown that for this simple model the relationship is quadratic, the percent correct dropping from 100% for a relative precipitation frequency of zero to a minimum value for a relative frequency of 0.5 and rising again to 100% for a relative frequency of 1.0. The data presented by Ramage appear to fit the quadratic relationship well, within the limited range shown in Fig. 4 of his article.

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Richard J. Reed

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RICHARD J. REED

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All available meteorological rocket soundings through the summer of 1966 are harmonically analyzed to obtain the amplitude and phase of the semidiurnal variation of the meridional wind component in summer for stations located near 30° and 37°N and of the zonal wind component in summer for the stations near 30°N. The results support the earlier finding that a phase reversal occurs at a height of 45–50 km rather than at the theoretically predicted height of 25–30 km. It is suggested that the difference between observation and theory may be attributed to the neglect of the basic wind structure in the theoretical calculation.

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Richard J. Reed

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Useful forecasts may be obtained by graphical integrations of the dynamical prediction equations for a barotropic and a two-level baroclinic atmosphere. Such forecasts may be prepared without the aid of special equipment and are therefore particularly valuable as a means of training forecasters in physical prognosis.

The present paper reviews the physical principles, modeling assumptions, and methods of solution used in graphical prediction and introduces a method of obtaining surface forecasts which is considerably faster and simpler than previous methods. The predicted surface pressure is shown to be the sum of two components: (1) the pressure advected to the spot by one-half the 500-mb. wind and (2) a pressure change reflected down from aloft (actually one-half the 500-mb. height change expressed in equivalent pressure units at 1000 mb.). The movement of surface pressure systems is thus seen to be largely dependent on upper-level steering, while the deepening is found to be related to the vorticity advection at high levels, since this mainly determines the 500-mb. height changes.

Twenty sample surface forecasts prepared by the graphical method during July 1959 are presented and compared with the forecasts for the same dates issued by the National Weather Analysis Center. Little difference in accuracy is apparent.

Typical shortcomings and failures of the graphical prognoses are discussed. It is believed that the most serious errors are due to the use of only the initial 500-mb. charts in advecting the pressure systems. If the 500-mb. forecasts had been available earlier, it appears that a significant increase in accuracy could have been achieved by using both initial and forecast 500-mb. contours in performing the advections.

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Richard J. Reed

The atmospheric sciences, no less than other fields of scientific endeavor, are experiencing growing demands and budgetary pressures for more direct concern with the problems of society. At the same time, the field has advanced to the stage where the meteorologist himself senses the need for more massive efforts, if progress is to be made with many of the major scientific problems. Thus the era ahead promises to be one in which increased emphasis is given to large problems of social and economic consequence such as weather prediction, weather and climate modification, and air pollution. The attacks on these large, complex problems will necessarily be multidisciplinary and will require new organizational alignments within government and educational institutions and new patterns of cooperation between public and private sectors. They will also necessitate a vast growth in size and sophistication of measuring and data handling systems.

The Global Atmospheric Research Program is discussed as a concrete example of a large, long-term program of the type foreseen. The likely effect of this and similar large programs on research and education in the universities is examined.

The trend towards greater emphasis on “big science” threatens to diminish the role of the individual in the scientific quest. In forging new modes of operation, it is important to avoid organizational structures which will stifle individual responsibility and initiative.

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RICHARD J. REED

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The annual temperature regime in the tropical stratosphere between 100 mb. and 10 mb. is examined on the basis of five years of data from six stations, ranging in latitude from 9° N. to 34° N. The principal result of interest is the finding of a pronounced semiannual component in the temperature variation above the 30-mb. level (24 km.), especially at stations near the equator. It is suggested that this may be caused by the direct absorption of solar ultraviolet radiation by ozone in a region where the heating cycle is predominantly semiannual.

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Richard J. Reed

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Richard J. Reed

The progress made in weather prediction since national weather services began issuing forecasts is traced and assessed. Specific contributions of J. Bjerknes to this program are pointed out. Lessons learned from the historical record concerning factors and conditions responsible for the important advances are considered, and a limited evaluation is then made of the increase in forecast skill that resulted from these advances. Finally, some comments are offered on the future prospects of weather prediction.

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Richard J. Reed

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No abstract available.

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