The global morphology of the quantity ∝ Nv.dh in the D- and E-regions of the ionosphere

George, P

doi:10.1016/0021-9169(71)90166-8

Cited by 33 publications

(3 citation statements)

References 5 publications

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“…There is also evidence, though less direct, that there is a latitudinal gradient in N over the equatorial region that may be more commonplace than the profile displacements associated with counter electrojets. George [1971] examined the morphology of radio-wave absorption as measured by the pulse reflection (A1) method at 2.2 MHz, and found that absorption increased with increasing magnetic dip angle from the dip In support of our conjecture, we note that radiowave absorption would vary significantly with latitude if N varied according to that in Figure 4. For example, a 2.2 Noting that metallic ions have lifetimes that are 105 times greater than those of molecular ions, we see from (1) that an excessively large transport velocity would not be needed if the effective c• is correspondingly smaller.…”

Section: Introductionsupporting

confidence: 67%

First incoherent‐scatter measurements of the equatorial E layer obtained with the ALTAIR radar

Tsunoda¹

1995

Geophysical Research Letters

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We describe the first incoherent‐scatter (IS) radar measurements made of the daytime E layer at equatorial latitudes. Using ALTAIR, a steerable IS radar located in the Kwajalein Atoll, we not only show that the E‐layer profiles are consistent with those obtained in situ by rockets, we present the first direct evidence of a latitudinal gradient in plasma density in the bottomside E layer that extended from 3°N dip latitude to beyond 6°N. We suggest that the gradient involves the electrodynamic transport of metallic ions, e.g., the gradient could be produced by the equatorial metallic‐ion fountain or possibly by the dumping of metallic ions at the base of the E layer by the wind‐shear mechanism for sporadic E. We close with a brief discussion of the implications of such a gradient on the equatorial electrojet.

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Section: Introductionsupporting

confidence: 67%

First incoherent‐scatter measurements of the equatorial E layer obtained with the ALTAIR radar

Tsunoda¹

1995

Geophysical Research Letters

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“…In order to elucidate further the latitude dependence of absorption, the quantity B (the subsolar absorption values, i.e., the extrapolated values of L at X = 0) has been used in deriving the A-figure, i.e., B([ + /L) 2, for each station [George, 1971]. Fig.…”

Section: Seasonal Dependencementioning

confidence: 99%

“…The measurement of A 1 absorption is one of the simplest techniques for monitoring the morphology of and patrolling the lowermost region of the earth's ionosphere [ George, 1971 ]. The dependence of the absorption on seasonal, geographical, and solar cycle variations is potentially one of the most interesting topics in which the inadequacy of the simple relationship was felt long ago.…”

Section: Introductionmentioning

confidence: 99%

Global features of lower ionospheric radio wave absorption in relation to middle atmospheric temperature variation and wind circulation

Samanta¹

1976

Radio Science

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The A1 absorption data for a large number of stations have been utilized to study the global features of the lower ionospheric radio wave absorption. The seasonal index ns (defined in the relation L = Bs (cos χ)ns, where L is the monthly median value of absorption, and χ, the midmonth solar zenith angle), is found to decrease rapidly and smoothly with increasing latitude and also with increasing solar activity for all stations. The constant cos χ plot of seasonal values of absorption versus month shows summer as well as winter enhancements when considered on a global scale. Such plots versus latitude show maximum absorption values at around the tropical region, an increase in the absorption values at high latitudes above 50°N, with a minimum around 40°–50°N, and a fall toward the equator below 23°N during sunspot minimum. A secondary maximum with a strong peak is observed around 50°N with a minimum around 45°N during sunspot maximum. The plots of absorption values as well as temperatures for 30 and 50 km heights versus cos χ show loop‐like structuring, indicating a considerable time dependence between them. Absorption and temperature at 30 km show a similar seasonal trend, whereas temperatures at 30 and 50 km show an opposite trend in their seasonal variations. The direction of looping of both temperature and absorption changes near about 35°N between low and high latitudes. Both temperature and absorption show large variabilities during winter periods. These findings have been explained in terms of the seasonal variation of the middle atmospheric wind circulation, and the importance of the dynamics of the lower ionosphere in controlling the aeronomy has been demonstrated.

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The Ionosphere

Dieminger¹,

Hartmann²,

Leitinger³

1996

The Upper Atmosphere

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The global morphology of the quantity ∝ Nv.dh in the D- and E-regions of the ionosphere

Cited by 33 publications

References 5 publications

First incoherent‐scatter measurements of the equatorial E layer obtained with the ALTAIR radar

First incoherent‐scatter measurements of the equatorial E layer obtained with the ALTAIR radar

Global features of lower ionospheric radio wave absorption in relation to middle atmospheric temperature variation and wind circulation

The Ionosphere

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