摘要:

The direct relation between the geomagneticSq‐variation and the vertical electron drift of theF2 region on the magnetic equator is examined.It is shown that the electric field in theF2 region accompanied bySqelectric current produces the vertical drift which is sufficient to interpret the main features of the anomaly of theF2 region on the equator. It is to be noticed that the main term of the drift velocity is diurnal. The daily variations of the maximum electron density and its height in theF2 region are calculated under consideration of the vertical electron drift for the reasonable distribution of decay coefficient with altitude inferred by observed results. The calculatedF2 daily variations have a striking resemblance with those observed near the magnetic equator. When the ion production takes its maximum value at about 200 km, there appears a lower secondary maximum of electron density which agrees, well with the observedF1 layer.The change of characteristics of daily variations of theF2 region with the sunspot‐eycle is likely to be accounted for by a slight shift of the phase of the dr

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00241

年代:1955

数据来源: WILEY

摘要:

A pulsed double‐Doppler radar technique has been employed to study the 90.7 Mc/sec signals reflected from auroral ionization. A spectrum analyzer was used in conjunction with the radar to measure the power spectra of the auroral echoes. The Doppler data are compared with observations of the visible aurora and with simultaneous echoes on 56 and 106 Mc/sec non‐coherent high‐resolution radar equipment. An interpretation of the Doppler data is given, and several theoretical models of the reflection mechanism are examined in terms of their effect on the observed sp

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00257

年代:1955

数据来源: WILEY

摘要:

The brightness of the daytime sky has been measured using rocket‐borne stereocameras. An upper limit of 0.0075 candle/ft2was found for the brightness at altitudes ranging from 80 to 220 km. This limit is consistent with the brightness being due entirely to Rayleigh scattering. No evidence of high altitude clouds was foun

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00271

年代:1955

数据来源: WILEY

摘要:

The problem of determining the induced field components outside a horizontal two‐layer earth has been tackled from theoretical point of view. The expressions obtained have been applied to evaluate the induced magnetic field due to an oscillating magnetic dipole on the surface of the earth. Two separate cases have been considered, for example, (i) two layers of nearly equal conductivities, and (ii) a conducting layer over an insulating medium, and the formulae have been reduced to a form amenable to numerical integratio

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00279

年代:1955

数据来源: WILEY

摘要:

A series of conductivity measurements made in a large sealed sphere has shown that in ordinary outside air the suspended nuclei or pollution normally so modify the ionic combination that the electrical conductivities approach equality. Equal conductivities are normally associated with an excess in the density of the small positive ion. It is found that with decreasing pollution the value of the negative conductivity increases more than does the positive, and the ionic densities approach equality. In clean air, equal densities of the positive and negative light ions are observed, and the conductivities become proportional to the commonly accepted laboratory values for the ionic mobilities. The results are consistent with recently developed expressions for the diffusion of ions and their attachment to atmospheric particles.

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00289

年代:1955

数据来源: WILEY

摘要:

To investigate solar eclipse effects of December 25, 1954, a study was made of the day‐to‐day trend in the hourly values of the magnetic elements at Hermanus during the control period December 23–26, 1954. A cooperative program is sugg

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00297

年代:1955

数据来源: WILEY

摘要:

Applying statistical tests to 428 SC's, the frequency of occurrence is found to be independent of time of day. Statistical tests indicate that the average sizes of SC's and of IP are both significantly greater during the daylight hours at Huancayo. Also from 102 SC's occurring between 08hand 14h75° WMT at Huancayo, we find that the average size of SC's is greater for those days with the larger diurnal variation (Sq) inH. This result is not only statistically significant but also the average size of SC's was about 50 per cent greater for the group of days with 50 per cent greater diurnal variation inH. The diurnal variation of SC'S averaged on 75° WMT for San Juan and Honolulu is practically negligible. The augmentation of SC sizes at Huancayo withSqinHat Huancayo was found to be the same whether the average size of the same SC's at San Juan and Honolulu was large or small. No significant diurnal variation was found in the frequency of occurrence of SC's observed both at Huancayo and Watheroo. A simple explanation is offered for the diurnal variation in the frequency of SC's found by Newton from Greenwich results.The relation of daytime enhancement of the size of SC's toSqinHat Huancayo indicates that the current system responsible is closely associated with the electrojet effect responsible for the large diurnal variation inHat Huancayo. The effects found are not predicted on the basis of the Chapman‐Ferraro theory of magnetic storms in its present form. One possibility being examined is that the electric currents in the atmosphere near Huancayo are driven by electrojets of polar regi

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00299

年代:1955

数据来源: WILEY

摘要:

During November 1954, a simple radar system, designed for observation of auroral echoes at 51.9 Mc/sec, was operated at Point Barrow, Alaska. Because this location is north of the accepted maximum of the auroral zone, most of the visible aurora is seen to the south of the observing station. The radar used a continuously‐rotating antenna to see with equal sensitivity in all directions, but more than 90 per cent of the echoes were obtained from directions north of east and west. Echoes were obtained only from 500 to 1100 km. These effects are explained by the theory of Moore as enlarged by Booker, Gartlein, and Nichols, requiring near‐perpendicularity of radio ray paths to the lines of the earth's magnetic field.During visible aurora, propagation at 51.7 Mc/sec was investigated over an 800‐km path from College to Barrow, across the auroral zone. Bursts of signal due to meteor ionization were readily observed. Propagation associated with aurora was almost non‐existent, even with visible aurora at the mid‐path. If the theory of auroral echoes of Harang and Landmark were true, auroral propagation should have been readily

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00317

年代:1955

数据来源: WILEY

摘要:

Variations ofF2‐region height with season and solar activity have been explained in terms of the author's picture of ionization distribution in theFregion. Different types of behaviours ofF2‐region height at different latitudes are accounted for with the presently accepted model of temperature distribution in the upper atmosph

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00325

年代:1955

数据来源: WILEY

摘要:

The magnetizations of 343 samples of Permian and Triassic sediments from the United States are compared to magnetizations that have been reported for sediments of approximately the corresponding age in England. It is demonstrated that an impressive number of the observations are in essential agreement simply on the basis of assuming that the rocks were magnetized by a geomagnetic field about like the one today, the essential difference being that this field was in a significantly different orientation. This result is discussed in terms of slip of an outer shell of the earth relative to the axis of revolution.

ISSN:0148-0227    

DOI:10.1029/JZ060i003p00329

年代:1955

数据来源: WILEY