Vertical Gradients of Temperature, Humidity, and Wind Direction: A Preliminary Report on the Kite Observations of 1898

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U.S. Government Printing Office, 1899 - Temperature inversions - 71 pages
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On kite construction, operation, and observation procedures; with data on temperature gradients, humidity, andvapor pressure, for selected weather stations.

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Page 17 - The decrease between 5,000 and (ˇ,000 feet was only 3 per cent, while between 6,000 and 7,000 feet it was 10 per cent. The lowest percentage, 52, was found at Omaha, and the highest, 77, at Pierre. (See table on vapor pressure, p. 20. A comparative statement of the results obtained from the kite, balloon, and mountain observations is given herewith. In obtaining these results the records of 1,123 kite ascensions were used.
Page 16 - The average morning gradient was 4.8° per thousand feet. The afternoon gradients were larger, but not decidedly so, the average value being 5.8° per thousand feet. The greatest rate of decrease is still found at 1,000 feet, and the least up to 5,000 feet, if the few observations at 7,000 feet are not considered as of equal weight. The morning, afternoon, and mean gradients for the different elevations from 1,000 to 8,000 feet, inclusive, are given in the following table: DECKKASK OF TEMPERATUR«...
Page 13 - ... chapter on the Kite Meteorograph, Construction and Operation, is added by Prof. CF Marvin. Kite ascensions were commenced at seventeen stations in April 1898, and were continued to November 1898, but only those for the months of May to October inclusive have been used for the preparation of this report. Temperature conditions at all elevations and under varying conditions of weather and time have been computed in terms of the gradient in degrees Fahrenheit for each 1000 feet, and the increase...
Page 8 - GO to 80 pounds, if not moie, and from 8,000 to 10,000 feet of wire will be out. To wind all this wire in under such conditions is really a very laborious operation, and generally requires two men at pretty hard work for from a half to three-quarters of an hour or more. As sent out to stations the hand reels contained from 2,600 to 3,000 turns of tempered steel music wire, 0.028 of an inch in diameter. The normal tensile strength of this wire was about 1ÎOO pounds.
Page 17 - Washington, where the mean difference was 14 per cent; Omaha, where it was 29 per cent; Springfield, 111., where it was 21 per cent, and Fort Smith, where it was 12 per cent, the surface humidity being the higher except at Fort Smith. At the remaining thirteen stations except Lansing, the upper air humidity equaled or exceeded that at the surface, but the difference at no place exceeded 10 per cent.
Page 16 - ... feet forbids a definite statement to that effect. The morning gradients were also greatest up to 1,000 feet, and least up to 5,000 feet, and the rate of decrease was about the same as the mean rate, the curves showing a very close agreement in this respect.
Page 16 - The largest gradient, 7.4° per thousand feet, was found up to 1,000 feet, and thereafter there was a steady decrease up to 5,000 feet, the rate of decrease becoming less as the altitude increased. The gradient up to 5,000 feet was 3.8° per thousand feet.
Page 17 - THOUSAND FEET. RELATIVE HUMIDITY. The relative humidities at and above the surface of the earth differed but little except at 7,000 feet, where the surface humidity was 11 per cent less than that above. With this exception the greatest difference was 3 per cent, and, except at 2,000 and 8,000 feet, the upper air percentages were the lower. The mean result obtained from all the observations showed CO per cent at the surface and 58 per cent above, a difference of 2 per cent.
Page 10 - ... strips are interposed between the thermometer bulbs and the metal of the inclosing tube, thereby still further insulating the thermometer bulbs. These bulbs consist of a pair of tempered-steel bourdon pressure tubes, forming a curl of about seveneighths of a complete circle about 1J inches in diameter. The major and minor axes of the elliptical cross section of the tubes measure approximately 0.5 and 0.1 of an inch, respectively. The tubes are filled with pure alcohol under pressure, and are...
Page 17 - ... that observed simultaneously at the earth's surface. The mean of the percentages thus obtained was 59, and there was a steady, though not by any means uniform, decrease with increase of altitude. The percentage at 1500 feet was 82, and at 8000 feet 44. The decrease was most rapid between 2000 and 5000 feet, where it averaged 9 per cent for each 1000 feet. The decrease between 5000 and 6000 feet...

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