摘要:

The distributions of (1) great geomagnetic storms, (2) small storms with “sudden commencement” (SC), and (3) small non‐SC storms through the sunspot cycle are examined. There is a close accordance between the averaged sunspot curve for the past seven cycles and the averaged curve for geomagnetic storms (1) and (2), which is shared by the giant sunspots, solar flares of greatest magnitude, and notable auroral displays. For the small non‐SC storms, the distribution within the sunspot cycle and also the extent of the relationship with sunspots at storm onset differ from those of the previous phenomena. The broad division of small storms according to the SC criterion appears to be of intrinsic significance (probably related to their solar origin), since this division is supported by the differences found in (1) distribution in the sunspot cycle, (2) relation to sunspots, and (3) characteristics (in addition to the SC criterion), including a statistical difference in the tendency to recur at intervals of a synodic rotation (27 days), as announced by E. and O. Thellier in 1948 and confirmed in the present paper. The Greenwich analysis of 1928, showing the statistical non‐recurrence of great storms, is brought u

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00203

年代:1954

数据来源: WILEY

摘要:

A brief appraisal is given of the observations and arguments that are advanced in support of the opinion that during Paleozoic time the earth's magnetic field retained approximately its present orientation, and, except for possible brief excursions, its present sense.

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00215

年代:1954

数据来源: WILEY

摘要:

The magnetisation of igneous rocks is often largely due to thermoremanent components. Several horizontal sheets of acid tuffs in New Zealand exhibit similar magnetisation patterns. Each sheet has a basic minimumQvalue; superimposed on this is an amplitude of polarisation pattern which, for one sheet examined in detail, is found to vary with depth in a similar manner to the inverse ratios of the computed cooling times over the temperature rangeT0→ 0.75T0,T0being the instantaneous temperature of deposition of the lav

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00223

年代:1954

数据来源: WILEY

摘要:

Wind data have been collected at altitudes between 30 and 80 km in the course of six rocket flights at White Sands Proving Ground during 1950 and 1951. Additional wind data to altitudes as high as 40 km have been obtained since 1948 by tracking radiosondes carried aloft by special high‐altitude balloons launched at Belmar, New Jersey. Day‐to‐day wind changes at 30 km are discussed. From the mean wind structure, inferences are drawn as to upper atmosphere temperatures at higher lati

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00233

年代:1954

数据来源: WILEY

摘要:

An examination of the ionospheric records at Kodaikanal, which is located almost on the geomagnetic equator, reveals that the sporadicElayer here has some regular features not observed at other latitudes. It occurs in nearly 93 per cent of the half‐hourly records during the daytime. Two main types ofEsare observed; namely, (1) the patchy type with a well‐marked diurnal variation, and (2) the blanketing type which occurs mostly during afternoons. It is found that neither meteoric activity nor thunderstorm activity has any appreciable influence on the formation of either of the two types ofEs. No correlation is observed betweenEsand the geomagnetic fi

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00239

年代:1954

数据来源: WILEY

摘要:

The height changes produced by vertical electronic diffusion in the presence of negative ions are examined in some detail. Application of the results to theE‐layer shows that a previous qualitative discussion remains vali

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00247

年代:1954

数据来源: WILEY

摘要:

The observed coskzenith‐angle variation of μ‐meson intensity at low elevations is derived on the basis of ap−nmeson momentum spectrum at production. It is found thatk=n‐ 1 to a good approximation, in agreement with experimental evidence. The region of validity of this relationship is d

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00253

年代:1954

数据来源: WILEY

摘要:

The random variations of intensity of signals from point sources caused by the ionosphere greatly affect studies of cosmic static. One cause of these fluctuations is the condition known as spreadF, which indicates the presence of diffuse and irregular echoes from theF‐region of the ionosphere. Analyses of spreadFover Hawaii were completed for the period 1944–1953. The diurnal and seasonal properties are discussed, and a conclusion is reached regarding latitude and longitude effects. Some properties of scintillations at decameter waves are descri

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00257

年代:1954

数据来源: WILEY

摘要:

A study of data from a chain of radio‐wave field‐strength recording stations along the 90th meridian suggests that the “auroral absorption zone” coincides with the zone of maximum frequency of occurrence of visible aurora. North of this, there appears to lie a region in which absorption is extremely low.Although the accuracy of location of the absorption zone is limited by use of fixed transmitters and receivers, as well as by the fact that varying modes of propagation are not taken into account, the indications are that it is somewhat farther north and narrower than has been suggested pre

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00267

年代:1954

数据来源: WILEY

摘要:

The scattering of radio waves by theF‐region of the ionosphere at an equatorial location (Huancayo, Peru) was discussed by Booker and Wells (1938). Subsequent analysis reveals pronouncedly diurnal, seasonal, and annual characteristics. It is fundamentally a nighttime event, with greatest frequency of occurrence in the period from four hours before midnight to four hours after midnight. The scattering is most prevalent during seasons when the sun is overhead and is infrequently observed during May, June, July, and August (local winter) when the noon solar zenith angle becomes as great as 35°. The relative total annual occurrence ofF‐region scatter for the period 1938 through 1945 shows low values during 1941–1942, followed by a rapid increase through 1946, which is not closely related to solar activity. The diurnal properties ofF‐scatter closely correspond to reported characteristics of radio star scintillations with peak activity around midnight. However, the annual or seasonal properties are not in simple a

ISSN:0148-0227    

DOI:10.1029/JZ059i002p00273

年代:1954

数据来源: WILEY