摘要:

Daily normals (averages) of C4have been computed for each day of the year using the ‘final’C4figures for the 72‐year period 1884–1955. The significance of departures of the daily averages from a smoothed continuum is discussed. The observed departures can be attributed to random sampling fluct

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00115

年代:1960

数据来源: WILEY

摘要:

Following the mathematical development of Chapman and Miller, Tschu has described a practical method of determining the lunar daily variation of geophysical elements. By application of the Chapman‐Miller method as described by Tschu, the lunar semidiurnal variation of geomagnetic horizontal intensity at Alibag is worked out for the equinoctial season by making use of the hourly values of the element for the period 1940 to 1944. The expressionL(H)=1.2 sin(2τ+62°)±0.3whereL(H) is the amplitude of the lunar variation in the horizontal intensityHand τ is the lunar time reckoned from lower transit of mean moon at Alibag is obtained for lunar semidiurnal variation.L(H) is a maximum when the lunar time is 2 lunar hours past midnight or noon. The solar diurnal variation is also determined up to 4 harmonics. A comparison of these results with similar results for Kodaikanal suggests that solar and lunar variations are independent of eac

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00119

年代:1960

数据来源: WILEY

摘要:

According to the McMath‐Hulbert Observatory working list of world‐wide flares there were more than 6700 solar events during the IGY for which at least one observer estimated the importance to be>¯1. According to reports to World Data Centers the flare patrol was gratifyingly complete and uniform. However, examination of the starting times of the reported flares reveals evidence for a serious lack of homogeneity in the IGY flare data. Approximately twice as many flares,>¯1, were reported per hour from 05hto 16hUT as during the remainder of the Universal Day. This strong dependence on UT exists in the flare data for each month of the IGY.Examination of the patrol hours and flare reports for May and July 1958 for each of the 19 Hα cinematographic patrol stations shows that the principal photographic patrol stations fail to confirm the very high rate of flare occurrence for 05hto 16hUT that appears in the total IGY data. Visual observations between 05hand 16hUT, apparently constitute the principal source of inhomogeneity in the flare data. For the hours 17 to 04 in the Universal Day the IGY flare reports are based primarily on the cinematographic patrol.Comparison of the number of flares and subflares indicates that in the IGY data for the hours 05 to 16 UT many flare events are listed as flares that probably would have been classified as subflares by the principal cinematographic obs

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00123

年代:1960

数据来源: WILEY

摘要:

The observing records of E.E. Barnard and more recent patrol photographs of the sky have been studied for an indication of a nightly variation in the occurrence of auroras at Yerkes Observatory. There appears to be a maximum probability in the neighborhood of local magnetic midnight, as at stations closer to the auroral zone. Some implications to auroral theory are discussed.

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00133

年代:1960

数据来源: WILEY

摘要:

A report is given of preliminary measurements in Melbourne and Antarctica of the twilight and nightglow sodium emissions. These observations were part of the program of the Australian National Antarctic Research Expeditions (ANARE). A photometer with a filter of 5 Ångström bandwidth was used. Continuous measurements of the intensity were begun when the earth's shadow was about 20 km above the earth. The height of the sodium layer causing the twilight emission was about 90 km in both Melbourne and the Antarctic. The ratio of twilight intensity to the nightglow intensity at the end of twilight varied between 15 and 50. It is suggested that further study of the ratio may clarify several problems associated with the nightglo

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00137

年代:1960

数据来源: WILEY

摘要:

The possibility of magnetic coupling between the polar regions of the earth's ionosphere and the interplanetary gas has led to the suggestion that the polar ionosphere may not rotate with the earth. The depth to which the effects of the interplanetary drag might penetrate is examined here with the aid of two simple models. The results are not conclusive, but they do indicate that heights as low as theEregion may be involved.

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00141

年代:1960

数据来源: WILEY

摘要:

The number density of small negative ions in the atmosphere was measured in 1958 on a series of eight balloon flights which reached altitudes of 115,000 feet over Minneapolis (45°N). A pronounced decrease in the number density of small negative ions was observed at the tropopause on seven of the eight flights, and similar decreases were observed at numerous temperature inversions in the stratosphere. The results strongly suggest the presence and bunching of ‘dust’ above the temperature inversions.In the absence of dust and ionizing agents other than cosmic rays, the number density of negative ions increases with altitude to 50,000 feet, where a maximum of approximately 5500 ions/cm3occurs. Above this altitude the number density decreases to a value near 2000 ions/cm3at 115,000 feet; this result is contrary to the almost constant value expected in the stratosphere from cosmic‐ray data and the Thomson

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00145

年代:1960

数据来源: WILEY

摘要:

A brief review is given of the resonance theory of atmospheric tidal oscillations including both thermal and gravitational excitation. Semiempirical wind patterns for various latitudes are given in Figure 1, and the semiempirical variation of solar semidiurnal wind velocities with height are given in Figure 2, based on (1) solar barometric variations at ground level [Chapman, 1951], (2) wind measurements at balloon heights [Johnson, 1955], (3) radio meteor echo experiments [Greenhow and Neufeld, 1955], (4)E‐region winds from radio pulse techniques [Briggs and Spencer, 1954], and (5) airglow cell movements [Roach and others, 1958]. Finally, current work on the extension of modern tidal theory (valid for a neutral envelope) into the dynamo region is discussed [White, in press

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00153

年代:1960

数据来源: WILEY

摘要:

The polarization twist imposed on 106.1 Mc/s radio waves by the ionosphere has been investigated by using the moon as a passive reflector, the purpose being to determine the total electron column density even at altitudes above the known ionosphere. Because the antenna is capable of being continuously directed at the moon for 12 consecutive hours, observations are possible from the pre‐dawn ionization minimum to the noon‐time maximum. A true‐height profile computed from vertical‐incidence ionosonde data of September 16, 1957, suggests that the total electron content throughout the entire ionosphere is not a constant factor of the integrated electron content computed up to the level of maximum ionization

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00173

年代:1960

数据来源: WILEY

摘要:

The band of frequencies propagated via the ionosphere by the high‐angle ray and that propagated by the low‐angle ray are both limited at their low‐frequency ends by reflections that occur at lower ionospheric heights. Methods are developed in this paper for the calculation of these l

ISSN:0148-0227    

DOI:10.1029/JZ065i001p00177

年代:1960

数据来源: WILEY