Studies of the Ionosphere and Their Application to Radio Transmission

Kirby, S.S.; Berkner, L. V.; Stuart, D.M.

doi:10.1109/jrproc.1934.225867

Cited by 15 publications

(6 citation statements)

References 32 publications

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“…(3) Scattered reflections of the type discussed by Kirby, Berkner, and Stuart [4] are regularly observed at Huancayo. These reflections range upward from about 600 km, depending upon the frequency and the time of day, and are first observed at frequencies somewhat below the F= critical-frequency.…”

Section: Referring Tomentioning

confidence: 97%

“…It has been pointedtout in earlier publications that when the zenithangle of the Sun is small, the F-region is found to separate into two strata, the F•-and the F,.-layers [1,4]. In considering the variation of ionization with virtual height and time, particularly in connection with the further study of this separation, it is convenient to simplify the observed virtual-height versus frequency curves to make possible the construction of iso-ionic charts.…”

Section: Ii---separation Of Ti4t!; F-region Into Two Stratamentioning

confidence: 99%

“…This becomes progressively steeper with time and shows distinct evidence of splitting due to double refraction. As the Sun approaches the zenith this effect becomes distinctly a critical frequency[1,4], which is found to AND H. W. WJgLLS [Vo•.. 30, No. al have a diurnal wtriation.…”

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confidence: 99%

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F‐region ionosphere‐investigations at low latitudes

Berkner¹,

Wells²

1934

Terr Magneti and Atmo Electr

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AbstractsFurther studies of the F-region, ordinarily composed of the F-layer at night which separates into the F•-and Fz-layers at small zenith-angles of theSun, have been continued at the Huancayo Magnetic Observatory of the Department of Terrestrial Magnetism of the Carnegie !nstituticn of Washington during the past year. The separation of the F•-and Fz-layers appears to occur because of a decrease of virtual height of the F•-layer and a marked rise of virtual height of the Fz-layer. To adequately represent this effect, iso-ionic charts showing the change of virtual height and ionization with time have been constructed. This construction is made possible by a convenient simplification of the virtual height versus frequency graphs obtained from the observed data. the iso-ionic curves of Figure 4 referring to the F•-layer can also be considered approximately as the ion-distribution along the 12th parallel of latitude for this date. To obtain a further idea of the geographical distribution of this layer it is of interest to refer to the evidence obtained at Washington by Kirby, Berkner, and Stuart [4]. The maximum F• critical-frequency of 4500 kc, reported for summer noon at Washington (zenith-angle about !4ø), corresponds very closely to the results given for Huancayo in Figure 7. This provides a powerful argument in view of the flatness of the diurnal characteristic at noon that the north-south distribution of ionization must be similar to the distribution along a parallel for equal zenith-angles. As the zenith-angle of the Sun increases with season to about 60 ø at Washington, the curves and description of the magnitude and character of the F• critical-frequency on the average agree quite well with the iso-ionic chart of Figure 4 for correspondingly greater zenith-angles of the Sun. It seems pr•fi)al)le, therefore, that isoionic curves for the F•-layer drawn along the meridian fr(•m a point directly under the Sun (that is perpendicular to Fig. 4 at 12 h 15 •") would appear approximately similar to Figure 4]J, at least up to about 60 ø (17•). ()n this basis Figure 9 gives the best conception of the geographical distrit)ution of this layer that can 1)e obtained from available data. . /50-IONIC CURVES GIVoeN IN

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Section: Referring Tomentioning

confidence: 97%

Section: Ii---separation Of Ti4t!; F-region Into Two Stratamentioning

confidence: 99%

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F‐region ionosphere‐investigations at low latitudes

Berkner¹,

Wells²

1934

Terr Magneti and Atmo Electr

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“…Since the discovery of the winter anomaly in daytime f o F 2 (the critical frequency of the F 2 layer) by Kirby et al [1934] and the semiannual effect in the F 2 region by O. Burkard in 1951, there are many studies on the ionospheric seasonal behaviors, conventionally conducted with f o F 2 or N m F 2 , and TEC [e.g., Feichter and Leitinger , 1997; Huang et al , 1989; Jakowski et al , 1981; Ma et al , 2003; Mayr and Mahajan , 1971; McNamara and Smith , 1982; Torr and Torr , 1973; Unnikrishnan et al , 2002; Yonezawa , 1971; Yu et al , 2004; Yuen and Roelofs , 1967; Zeng et al , 2008; Zou et al , 2000] as well as modelings [e.g., Millward et al , 1996; Pavlov and Pavlova , 2005; Richards , 2001].…”

Section: Introductionmentioning

confidence: 99%

Seasonal variations of the ionospheric electron densities retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate mission radio occultation measurements

et al. 2009

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[1] We collected the ionospheric electron density (N e ) profiles from the FORMOSAT-3/ COSMIC (F3/C) radio occultation measurements to investigate the seasonal behaviors of daytime N e in the altitude range of 200-560 km. Harmonic analysis of the N e at different altitudes provides unprecedented detail of the seasonal behaviors of N e at low solar activity (LSA). Global maps of seasonal harmonic components indicate that there are strong annual and semiannual variations in daytime N e , which have distinct latitudinal and altitudinal dependency. The semiannual component predominates over the annual variation in the equatorial regions and at high latitudes in the East Asian and South Atlantic sectors at low altitudes, and at higher altitudes the semiannual component predominates in the equatorial region, but recedes in other regions. The semiannual variation peaks in equinoctial months in most regions, while it has maxima in solstice months, first in the South Pacific region (around 30°S, 120°W) at 250 km altitude and expanding over the South Pacific and South Atlantic oceans at higher altitudes. Moreover, there is a region around 45°S, 30°W with a dominant semiannual component, moving toward east-north with increasing altitude in the range of 200-270 km. These two interesting features are novel but are not reported yet. The relative amplitude of the annual component of N e has hemispheric asymmetry, which is prominent at high altitudes in the Southern Hemisphere. The winter/seasonal anomaly widely exists in the Northern Hemisphere and southern low latitudes and in Indian Ocean region at low altitudes but gradually disappears at higher altitudes. Further, in equatorial regions, a new finding is the obvious wave-like pattern in the longitudinal structure of the amplitudes of seasonal harmonic components in equatorial regions, which supports possible couplings of sources with lower atmospheric origins in the longitudinal variations of N e .

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“…It had been observed for several years by the National Bureau of Standards [7,8] at Washington and the Bell Telephone .…”

Section: Introductionmentioning

confidence: 99%

Ionosphere studies during partial solar eclipse of February 3, 1935

Kirby¹,

Gilliland²,

Judson³

1936

J. RES. NATL. BUR. STAN.

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,Virtual height and critical-frequency measurements of the several regions of the ionosphere were made during the day of the solar eclipse of February 3, 1935, and during several days before and after the eclipse day. The eclipse was found to produce a decrease of the critical frequency of each region. The decrease of critical frequency was approximately in time phase with the eclipse, thus indicating an ionizing agency (probably ultraviolet light), originating in the sun and propagated at approximately the velocity of light. The decrease of equivalent electron density in each region during the eclipse was compared with the decrease in the exposed area of the sun's disk, and found to indicate that the ionization of the normal E region was diminished when the ionizing agency was decreased, by recombination of + and -charges, while the ionization of the F2 region and a high stratum of the E was diminished by a process of attachment of electrons to neutral particles.

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Studies of the Ionosphere and Their Application to Radio Transmission

Cited by 15 publications

References 32 publications

F‐region ionosphere‐investigations at low latitudes

F‐region ionosphere‐investigations at low latitudes

Seasonal variations of the ionospheric electron densities retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate mission radio occultation measurements

Ionosphere studies during partial solar eclipse of February 3, 1935

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