This series consists of Scientific reports, Technical reports and Final reports issued by the Geophysical Institute on all contracts and grants.
-
The determination of the luni-solar variations in the magnetic elements at Sitka, Alaska
Joseph C. Cain
The Chapman-Miller method of calculating harmonic coefficients for luni-solar daily variations is here applied to the hourly values of the magnetic elements at Sitka, Alaska for the period 1902-1952. The formation of the group sum sequences for groupings of the data according to solar activity, magnetic activity, lunar phase and lunar distance using punched card methods is described.
-
Evaluation of chemical methods for the determination of atmospheric ozone
Nalin R. Mukherjee
Since the concentration of the ozone in the atmosphere near the earth's surface is of the order of 10 gm. per gm. of air, the quantitative determination of this ozone by chemical methods is rather difficult. Therefore, the different methods have been evaluated to determine the best, all conceivable precautions being taken into account. The chemical methods may be classified into two groups --Titer Methods and Spectro-chemical Methods. Among the former, two; namely, the Thiosulphate and Arsenite Methods, have been proposed and used. For the low concentration of ozone in the atmosphere near the earth 's surface, the Thiosulphate Method is found to give unreliable results due to the instability of the thiosulphate solution as well as to various side reactions which could not be controlled. The arsenite solution, however, is much more stable than the thiosulphate solution. Side reactions are very few and can largely be controlled. Reliable results can be obtained by the Arsenite Method when employing proper precautions. The oxidants and other interfering substances in the atmosphere present serious problems. Some oxidants behave like ozone as far as the reactions with the chemical reagents are concerned. Their occurrence in the atmosphere and their effects on the chemical reagents used for the quantitative determination of the atmospheric ozone are discussed in detail. Suggestions are made for their elimination from the atmosphere without affecting the ozone concentration.
-
Zenith night sky light measurements at College, Alaska
John B. Wilcox, Fred F. Kohls, and Harold Cronin
For purposes of studying the character of time fluxuations in arctic night sky brightness, we have erected a photoelectric monitory system at the Ballaine’s Lake Field Station (latitude N64°52', longitude W147°49'). The unit was set in operation September 27, 1949, and dismounted June 6, 1950, when it became evident that further observations would be impossible due to lengthening days. Although no apparatus has been available by which the response curves of phototubes could be calibrated absolutely, a standard by which bright ness recordings of different phototubes can be reduced to approximate absolute values has been evolved. A limited investigation of a possible correlation between fluxuations in the intensity of upper atmospheric emissions and sporadic conditions in the ionosphere has been made.