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J. Neumann

Classical Antiquity, especially Greek Antiquity, not only produced books which either described observations and offered some explanations for and interpretations of physical processes of weather, but also formulated weather-forecasting rules. Forecasts based on “present weather,” in particular, forecasts of fine weather to follow fog on low lands, are cited in this paper. The number of ancient Greek scholars who took an at least partial interest in meteorology is far greater than the number appearing in books or papers discussing meteorological theories or observations in Classical Antiquity.

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J. Neumann

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J. Neumann

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After extension of the definition of land breeze and introductory discussion of the problem of nocturnal thunderstorms, tables are presented for Lydda Airport, Israel, showing the diurnal variation of thunderstorms and the associated surface wind-directions. There is a notable excess of nocturnal thunderstorms with wind directions in the quadrant from which the land breeze blows.

The fundamental fact is pointed out that, because of the curvature of the coast of the eastern Mediterranean (concave toward the sea), the fields of the land breezes and the diurnal winds in the friction layer constitute a convergent wind field, particularly pronounced in the winter. The type of low over the eastern Mediterranean in which land-breeze convergences make an important contribution toward the formation of nocturnal thunderstorms is discussed briefly. A diagram shows the divergent nature of the sea breezes in summer, again, first and foremost, because of the concave curvature of the coast.

A number of stations, located on or near notably convex coasts of the eastern Mediterranean, are shown to have daytime maxima of thunderstorm activity.

U. S. Weather Bureau data also show a diurnal variation of thunderstorms which varies fairly consistently with the curvature of the coast of the United States, notably concave sections of the coast showing either a majority of nocturnal thunderstorms or, at least, a sensibly higher percentage than at the nearest convex section of the coast.

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J. Neumann

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In the equation for the concentration of pollutants from a steady continuous point source, in a stationaryturbulent flow, the factor 1/u enters (u is the mean wind for a given stationary situation). If we are interestedin the concentration along a given wind direction and u denotes the wind speed in that direction and if weseek the average concentration for a class of flow situations (e.g., for the class of statically stable flows),each member of the class representing an individual stationary situation, then the averaging to be appliedis to 1/u and not to u. On the assumption (verified by some examples) that the distribution of u isa "humped" gamma distribution (standard deviation σ less than the average u of u for the class as a whole),we show that the average of 1/u equals 1/(u[1-(σ/u)2]}. Thus the average of 1/u is greater than 1/uand the resulting concentration estimate is larger than the one that would be obtained by the incorrect useof 1/u.

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J. NEUMANN

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An empirical method described by Klein is applied to calculate insolation for the Lake Hefner, Okla., area for 1 year of the Lake Hefner Studies. For some of the months, the computed values show unsatisfactory agreement with the observed amounts, but the computed annual total is in close accord with the observed annual total.

It is suggested that agreement between the monthly values may be improved by introducing a curvilinear regression in the formula whereby account is taken of the depletion of insolation by sky coverage.

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J. Neumann

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J. Neumann

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J. Neumann

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J. Neumann

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J. Neumann

After citing some examples of the importance attached to winds in the classical Greek literature, Aristotle's and Theophrastus's ideas on the sea and land breezes are reviewed. Finally, examples are quoted from the Grecian literature for the good uses made of these breezes in sailing and in sea battles.

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