WEATHER NEWS FROM THE STRATOSPHERE

Hawke's Bay Herald-Tribune, Volume 81, Issue 83, 31 December 1937, Page 13

WEATHER NEWS FROM THE STRATOSPHERE

Radio Robots 1 Ascend Ten Miles and Send Back Automatic Reports on Co nditions Which May Revolutionise Forecasting

." OHOWEES THIS AFTERNOON, fair and warmer to-morrow," may be only half of a weather forecast in a few months' time, when studies of the upper air made with the help of robot observers will make possible more accurate and longer-range forecastings, writes Hugh Pendexter in the Christian Science Monitor. The new system of upper air exploration began iu September ui, Fairbanks, Alaska; Burbank, California; Boston, Massachusetts, and Washington, using the newly devised radioimeteorographs — robot weather observers that broadcast their findings from far above the earth to human observers on the ground. The robot observers making flights from the Alaska station will pick up first news of cold waves headed for the UnitedjlBtates. So important does the Weather Bureau consider the condition and behaviour of the polar air currents in relation to weather in the United States that it has detailed two. men in addition to those regularly stationed at Fairbanks to make a special study of depth, temperature, humidity, 4 haracteristies and movements of these upper air streams which produce many of our cold snaps. These cold waves ilsually coine down along Western Canada, across the northwest United States to the Mississippi Yalley region, sometimes extending as far south' as the Gulf. As the general movement of the upper air across the United States is from west to east.

the findings of the Californiun sta- ' tion will be of importanee in forer casting for the entire counfry. Boston, somewhat like the Alaska station, is a focal point at which the movement and characteristics of cold upper air currente originating in the Hudson Bay region — affecting the weather of that part of the country between the Great Lakes and Nova Scotia — may be studied to advantage. Ever since weather forecasting emerged from the hands of the backyaid prophets foreca'sters have been hampered by the lack of up-to-the-mi'nute information of conditions in the upper air — temperature., pressure humidity and wind vel|pity and direction — in making their calculations, In' the first serious attempts to overcome this handicap large box kites were used to carry self-record-lng inistr.uments aloft. This was a long and tedious process frequently requiring several hours before the needed information could be placed in the hands of the forecaster. If there was no wind, the condition of the upper air remained unknown. Crude and unsatisfuctory as this method was, it was the only one ^available until the development of. airplanes. For the past few years frequent flights have been made from 30 points in the United States and Alaska by planes carryiug instruments _ on which the conditions of temperature, pressure

and humidity were Tecorded for varying altitudes up to about three miles. Such flights require : about an hour. The information is not available until the plane comes down. Before going further into the virtues of the radio-tminded robot observer, let's pry of£ the lid and see what makes it tick. The outer casing is a little octagon box of balsa wood, five or six itiches across and about eight inches long, weighing not more than two pounds, with the radio transmit'ter, batteries and instruments registering atmospheric conditions. The radio transmitter is a simple, one-tube affair, operating on a wave band of from 1J to 5 meters. A simple clockwork mechanism drives an eecentric-shaped dislc which contacts the three atmospheric recording devices once during each revolution and also makes a contact with a fixed brealcer point at the beginning of each • revolution of the risk. Each contact sends out a radio impulse which is recorded on a tape by the ground receiving set. The markings registered on the tape consist of YV, indieating the starting point of the 30second cycle, followed by three single V's— one each for temperature, pressure and humidity. The spacing between the single Y's and between them and. tho cycle end YV marks give the data to compute the temperature encountered during any ' 30-second period within one degree Centigrade, the pressure within one-fifteenth of an inch and, the relative humidity within 5 per

cent. Thus the markings on the tape for _ a single cycle might appear: YV Y V V YV. This all seemed very cold and calculating until the writer asked L. T. Samuels, Assistant Chifcf of the Aerological Division of the Weather Bureau, who was demonstrating the robot, how the gadget which registered the humidity worked. "Oh, those hairs you see between the two posts lengthen as the humidity increases," he explained, "delaying or hastening the contact with the revolving disk." Then ha discussed the flight of the robots. "We send them up, towed by 60-inch balloons which are filled with hydrogen," he explained. "Between the balloon and the robot is a parachute. When the balloon reaches an altitude of about 10 miles it bursts in the rarefied atmosphere and the robot rides down to earth on the 'chute." ' ' The mechanism costs about £5, approximately the price of a single airplane flight for similar observation work," he said. "Thus if we never recovered a robot we wouldn't be any worse ofl financially than by hiring planes, and we 11 have our information immediately and from altitudes impossible to reach by airplane. Actually, we are having many of the Tobots recovered and returned to us. ' ' It is the hope of tho Weather , Bureau to establish at least 100 stations from which these radiometeorographs will be sent up at regular intervals, probably at least once daily.

One of the greatest boons of the new method of upper aid reporting will be to airplane traffic. This phase of weather forecasting is becoming a moro and more important part of the Weather Bureau 's service and for this work last-minute information is most essential. As yet little or uothing is known about the constantly ehanging height of the stratosphere above the earth. Until now no way has been available to keep a constant check on its fluctuations, although meteorologists have believed for some time that these changes have a very material effect upon the earth 's weather conditions. With the aid of the radio robot a thorough istudy of the TeTation of stratosphere heights and weather changes may be ob serveil which may prove to be of great value in improving weather forecasting. Further studies of the str.uctures of hurricanes aud what directs the rate and direction of their movements will be made by the use of 'the radiometeorograph. ^ This new method of upper air observation is also being carried on in Russia, France and Belgium, where meteorologists have been at work for several years perfecting instruments which will report by radio minute-by-minute changes in the weather-controlling high air currents, J