1939: Meteorology

While progress in the field of meteorology during 1939 was not spectacular, neither did it lag. Research went forward to develop greater accuracy in both short range and long range forecasting. The use of that marvel of atmospheric recording devices, the radiosonde, was extended and the instrument itself improved.

The U. S. Weather Bureau continues to advance its hurricane forecast efficiency in the low latitude Atlantic Ocean region. A greater number of upper air observations than ever before is now available and a higher frequency of observations, both at sea level and in the upper air has been established. Some eighty stations in the West Indies and the Caribbean supply data twice each day and steamships plying southern waters report several times daily during an impending or suspected hurricane in accordance with Weather Bureau requests. Besides, additional radiosonde stations have been opened at strategic points and more are planned.

It has long been the belief of some of those associated with weather forecasting that an accurate knowledge of the behavior of the atmosphere over the oceans is of greater importance for accurate daily predictions than those over the land for which predictions are made. If this philosophy be true, then a large number of daily observations widely scattered over the oceans is vital.

The coordination of pressure variations in the Iceland and Aleutian Lows may eventually be definitely related to the movement of centers of action across North America and in consequence the accurate prediction of such movements may be realized. In this connection should be noted the continuation of the program of experimental five-day weather forecasting by the Massachusetts Institute of Technology based in large part upon atmospheric pressure readings over the ocean. Thus far the institute has corroborated the theory of meteorologists of some thirty years ago with reference to the apparent correlation in behavior of the great permanent pressure areas over the Atlantic and Pacific Oceans.

Publication of Abstracts.

The announcement of a section in the publication Biological Abstracts to be known as Bioclimatology-Biometeorology is of considerable importance. It will be devoted to abstracts of papers in the fields of biology, medicine and agriculture which reveal the close associations of climatological or meteorological phenomena with these sciences. The ecological relations of such elements as temperature, moisture and winds to the distribution of plants and the lower animals have been long recognized. Similarly, although less convincingly, correlations have been attempted between atmospheric conditions and man's physiological behavior. Then too, crops and weather have had their share of attention. In all these fields there has been an intensification of activity reflecting a rapidly growing interest. The literature is scattered. Hence, the abstracting of these papers in a single periodical should be advantageous to those interested not only in keeping themselves conveniently abreast of the activities of others, but perhaps also in the establishment of common research techniques and the reciprocal utilization by many of the research workers, of the results of each others' endeavors.

Micro-meteorology.

Studies in micro-meteorology continued in the Muskingum Valley of Ohio as a part of the national government's conservation program. This work which involves the collection of data from hundreds of observation posts within a relatively small area, points toward a better understanding of the dynamics of cyclones and anti-cyclones and the effects of precipitation upon soil erosion and river floods. Among some of the important data derived from this research are those bearing upon great variations in intensity and rates of rainfall within single rain storms and the relations of these elements in the presence of different types of vegetation to rates of erosion and run-off.

Antarctic Expedition.

Another Antarctic expedition under Admiral Byrd sponsored by the U. S. Government got under way. While this expedition was organized primarily to validate a claim to be made by the government to lands which Admiral Byrd has already explored, it has for its object as well, the gathering of more meteorological data as a basis for studies of possible relationships between Antarctic atmospheric behavior and weather changes over other parts of the earth. A large volume containing data collected during his last two expeditions was published late in the year by the U. S. Weather Bureau under the title: Meteorological Results of the Byrd Antarctic Expeditions; 1928-30, 1933-1935, Supplement No. 41.

War Censorship.

An account of the status of meteorology during 1939 could not be satisfactory without reference to the censorship of weather news and the dissemination of data by the warring powers. Not only was reference by radio commentators to the state of the atmosphere prohibited but the hand of the censor reached the North American continent by way of preventing the printing of Canadian weather observations on the daily maps issued by the U. S. Weather Bureau. Publication of such records a week or ten days after they were made was permissible. Thus the daily weather map beginning in early September took on a more or less 'decapitated' appearance since the absence of readings for Canadian stations necessitated the termination of isotherms and isobars at our northern border. It will be a matter of great interest after the peace is declared to learn to what extent, if at all, these checks against weather data falling into the hands of Germany handicapped their forecasts and therefore, military maneuvers. Advance in the technique of forecasting facilitated by air-mass analysis may have greatly reduced the effectiveness of this censorship.