WEATHER Men of Many Countries Cooperate in the Second Polar Year

About 50 years ago, 12 nations, namely, Austria, Denmark, England, Canada, Finland, France, Germany, the Netherlands, Norway, Russia, Sweden, and the United States, organized 14 expeditions to go into polar regions and establish stations to-make simultaneous observations of meteorological, magnetic, and auroral conditions during the period from August 1882 to August 1883, according to a prearranged international plan. These expeditions rendered great service.

Yet many problems remained to perplex the students of meteorology, terrestrial magnetism, and atmospheric electricity.  Accordingly, meteorologists in 1928 proposed that the First International Polar Year should be commemorated by a Second Polar Year exactly 50 years after the first one. The International Meteorological Organization, a world-wide association of meteorologists and geophysicists, appointed in 1929 the International Commission for the Polar Year, 1932-33. This organization invited the International Geodetic and Geophysical Union to cooperate in the undertaking. This invitation was accepted. Then began the task of enlisting the aid of the various countries and interested organizations, and carrying out the preliminary steps of the Polar Year program.

Forty-four nations signified their willingness to cooperate. The Department of Terrestrial Magnetism of the Carnegie Institution of Washington, the International Geodetic and Geophysical Union, the Permanent Council for the Exploration of the Seas, and the International Scientific Radio Union, joined whole-heartedly in the endeavor. The work of coordinating the program was done by the International Commission for the Polar Year, 1932-33, under the presidency of D. la Cour, director of the Danish Meteorological Service.  This commission held many conferences, received and sifted numerous proposals, drew up detailed instructions regarding necessary observations, instruments, etc., and furthered the undertaking in many ways.

Thus with the collaboration of many nations the Second Polar Year began on August 1,1932. It closed on August 31, 1933, in the Northern Hemisphere and on December 31, 1933, in the Southern Hemisphere. The meteorological work invelved the customary observations at fixed hours 2 or 4 times per day, as well as the continuous registration of barometric pressure, temperature, humidity, wind direction and velocity, precipitation, and sunshine. It required frequent observations of clouds and weather as well as other phenomena.

Observations of the upper atmosphere were made by releasing small balloons, filled with hydrogen gas, and watching them through a theodolite (a telescope similar to a surveyor’s transit with devices for measuring horizontal and vertical angles) to determine the free-air wind directions and velocities. Larger balloons were sent up carrying self-recording instruments to indicate the barometric pressure, tempera- ture, and humidity of the air to great heights well into the stratosphere. When found and returned to the meterological stations these instruments furnished valuable information.

For the first time on a large scale, balloons were used to carry radio-meteorographs, which sent radio signals to the earth depicting the barometric pressure and the temperature of the air continuously. This means of investigating conditions at great heights proved invaluable for sparsely settled regions where the chance of finding the instrument was meager. Moreover, it furnished a record immediately. Airplanes carrying self-recording instruments were also employed at various places, including Alaska, to determine conditions aloft.

In addition, a number of stations made observations of atmospheric and terrestrial magnetism and electricity.

The purpose of the Polar Year was to study conditions on a world-wide scale, and preparations are now being made by the Deutsche Seewarte of Hamburg, Germany, to publish a weather chart for each day of the Polar Year covering the entire Northern Hemisphere, both land and sea. Practically all countries with territory or ships north of the Equator are contributing observations to this end, so that meteorologists may follow cyclones and anticyclones, cold waves, etc., anywhere around the world. Observations of winds and other conditions in the atmosphere from the ground to far into the stratosphere also are being published. By means of these, the circulation of the atmosphere from one hemisphere to the other, east and west, north and south, may be better understood, and weather forecasters will have facts by which to judge when, where, and even how the cold air from polar regions comes into conflict with the warm air from equatorial regions and produces rain.

WEATHER Relations in Successive Months Studied by U. S. Meteorologists

The tendency of certain weather characteristics to persist for considerable periods is well known.  Comparatively wet or dry, warm or cool weather, of a given month often carries over into succeeding months. Two or more months in succession rather frequently have weather of the same general character. An examination of weather records shows that this tendency is somewhat pronounced for certain weather conditions and for certain areas; but it is not generally true for different kinds of weather in any particular area nor for all areas.  In fact some localities show quite as marked tendencies to opposite conditions from month to month as others do for agreement. The following summaries indicate these relations for selected States, based on the average State rainfall and average State temperatures for the four principal crop-growing months (May-August). The States, in general, represent; areas in which different climatological conditions prevail.

For Nebraska (the records covering 58 years from 1876 to 1933), May rainfall was above normal 24 times and for these years June, July, August, and the summer (June-August) had above normal in just half the years and below normal in the other half. However, for the 25 years in which June had above-normal rainfall July also had above-normal rainfall 16 times and below normal only 9 times, making agreement between the 2 months in 64 percent of the years. For the 24 years in which July had above normal only 10 years had above normal in August. Considering only the months when rainfall was 1 inch or more above normal, no striking relations are shown except in the case of June with July. June had rainfall of 1 inch or more above normal in 9 years and for these 9 years July had above normal 7 times and below normal only twice.

In general, deficiencies of rainfall show a greater tendency to carry over from month to month than do excesses. In Nebraska for the 58 years of record May had 1 inch or more below normal 15 times and for these 15 years June had below normal 9 times, July 11 times, and August 9 times, while the summer, as a whole (June—August) had below normal 11 times. June had 1 inch or more below normal in 16 years and in 10 of these July also had below normal. But little relation is shown between deficiencies in July and August rainfall.

The records show a rather marked tendency in Nebraska for either an unusually wet or an unusually dry spring to be followed by a dry summer. Six years of the 58 had 1 inch or more above normal rainfall in the 3 spring months (March-May) and 4 of the 6 had below-normal rainfall in summer (June-August); 4 had 1 inch or more below normal in spring and of these 4 years, 3 also had below normal in summer.

With regard to temperature, there is a much greater tendency for warm weather to persist from month to month than for cool weather to carry over. When temperatures were below normal in Nebraska there were substantially the same number of opposite as of like conditions for the following months, except in June and July. June was 1° F. or more below normal 18 times in the 58 years and of these 18 years July also was below normal 12 times. However, during these 58 years of record in Nebraska the average May temperatures were above normal by 1° or more 23 times and for these 23 years, June had above normal 17 times, July 13, August 17, and the summer 18 times.  Also for the 25 years when the June temperature was 1° or more above normal, 72 percent of the Julys were warmer than normal and also a like percentage of Augusts.

In the case of Ohio rainfall for the 61 years of record there is little or no relation shown between May and the succeeding summer months, either when May was comparatively wet or when the month had below-normal rainfall. However, for the 30 years when June had above normal July also had above normal 20 times, but for the 36 years when July had above normal August had like conditions only 15 times. The records show some interesting comparisons for the months having rainfall deficiencies in this State. For the 61 years of record May had 1 inch or more below normal 17 times and for these 17 years June had below normal 8 times, July 4 times, and August 10 times.  However, for the 9 years with 1 inch or more below normal in June, July had below normal 7 times, or in 78 percent of the years, and August had like conditions 6 times.

   The 46 years of record for Pennsylvania indicate that May does not afford a good index for the succeeding month’s rainfall in that State.  Here 12 of the 46 years had 1 inch or more below normal in May and for these 12 years June had below normal only 3 times, July 4 times, and August 5 times, while the summer, as a whole (June—August) had below normal only 3 times. However, for the 11 years in which the deficiencies in June were 1 inch or more, July also had below normal 9 times, and August 7 times; while for the 9 years in which July had deficiencies of 1 inch or more 7 of the 9 years had below normal in August also. Again for the 14 years when May had above-normal rainfall amounting to 1 inch or more, only 3 Junes had above normal, 5 Julys, and 6 Augusts. Here again conditions reverse themselves with June, for of the 9 years when that month had an excess above normal of 1 inch or more, 7 of the 9 had above normal in July also. For the 12 years when July had 1 inch or more above normal, the August record was 50-50.

May temperatures in Pennsylvania appear from the record to afford a better index of conditions for succeeding months than does the rainfall. During the 56 years May was 1° or more cooler than normal 14 times and for these 14 years June, July, and August were cooler than normal 9 times, or in 64 percent of the years, while for the 15 Junes with deficiencies in temperature of 1° or more, 10 had below-normal temperatures in July, and 9 in August. In the 12 years when July was relatively cool 8 had below-normal temperatures in August. Pennsylvania shows also a decided tendency for a warm month to be succeeded by like conditions.

The record for Alabama, typical of the Southern States, shows a decided tendency for wet months to be followed by opposite conditions. For example, for the 50 years of record available, May had 1 inch or more above-normal rainfall 16 times and for these 16 years June had above normal 7 times and July only twice. There were 11 Junes with 1 inch or more above normal and for these 11 July had above normal in only 2 years, and August in 3. Also for the 8 years when July had similar excesses, there were only 2 years with above normal in August. However, there is shown for Alabama a much closer relation between dry months. For the 19 years when May had a deficiency of 1 inch or more of rainfall, 14 of the 19 also had below normal in June, 10 in July, and 12 in August. Again, for the 17 years with like deficiencies in June, July had below normal 11 times; for the 14 years with 1 inch or more below normal in July, August was below 10 times. Thus the records show a decided tendency in this State for a wet month to be succeeded by below-normal rainfall and for deficient rainfall to carry over into the succeeding months. However, when the spring and the summer seasons are considered as a unit there is a marked seasonal relation shown. For example, during the 50 years under consideration in Alabama there were 21 springs (March—May) with rainfall 1 inch or more above normal and for these 21 years the succeeding summer (June—-August) had above normal 15 times, representing 71 percent of the years. Again there were 22 springs with rainfall below normal to the amount of 1 inch or more and for these 22 the succeeding summer had below normal 14 times.