Effects of heating at high latitudes on global thermospheric dynamics

Straus, Joe M.; Creekmore, Stephen P.; Harris, R. M.; Ching, Barbara K.

doi:10.1016/0021-9169(75)90033-1

Cited by 46 publications

(15 citation statements)

References 34 publications

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“…The timing of the additional energy influx is such that it should induce a strong semidiurnal variation. A more detailed discussion of these energy balance considerations is given, for example, in the work of Straus et al [1975], Nisbet and Glenar (1977), Glenar et al [1978], and Richmond [1979].…”

Section: Energy Considerationsmentioning

confidence: 99%

Latitudinal structure and extension of the polar atmospheric disturbance

Prölss¹

1981

J. Geophys. Res.

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The dissipation of solar wind energy in the upper atmosphere generates a disturbance whose morphology depends on local time, season, and magnetic activity. A statistical analysis of ESRO 4 data reveals that (1) in the afternoon/evening sector the disturbance boundary coincides with the region of electric current dissipation along the auroral oval; (2) in the midnight/early morning sector, dynamical effects extend the disturbance zone to lower latitudes, and this expansion is strongly dependent on season and magnetic activity; and (3) in the late morning sector, direct heating effects along the auroral oval are superimposed on the residuals of the early morning disturbance. These results are consistent with previous observations and provide new boundary conditions for upper atmospheric models.

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Section: Energy Considerationsmentioning

confidence: 99%

Latitudinal structure and extension of the polar atmospheric disturbance

Prölss¹

1981

J. Geophys. Res.

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“…In addition to simplifying the calculations by allowing us to disregard thermodynamics, the use of an empirically determined temperature distribution is considered to be more realistic than that obtainable at present from a consideration of global thermospheric energy sources and sinks. This is especially true with respect to the region near and below the turbopause and with respect to the heat source at high latitudes that exists even during geomagnetically quiet times [Dickinson et al, 1975;Straus et al, 1975]. Under steady state conditions as viewed from the sun, the equations of mass and momentum conservation for the ith atmospheric species in a spherical (r, 0, • Rather, photochemical equilibrium is accomplished by eddy transport of atomic oxygen from its point of formation downward into the mesosphere, where recombination occurs.…”

Section: Mathematical Modelmentioning

confidence: 99%

Dynamical effects on the global distribution of thermospheric atomic oxygen

Straus¹,

Christopher²

1979

J. Geophys. Res

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This numerical study of dynamical effects on the global distribution of atomic oxygen in the thermosphere makes use of a three‐component model of upper atmospheric dynamics which treats the gases N2, O2, and O coupled together by collisions. This model simultaneously treats diurnal and seasonal variations of the distributions of these gases. Specific comparisons of hydrostatic computations with those taking into account wind‐induced departures from hydrostatic equilibrium show that none of these gases can be considered to be in hydrostatic equilibrium below ∼200 km. Global scale winds are shown to cause the observed winter enhancement of atomic oxygen in the lower thermosphere. Comparison of the model results with observational data shows generally good agreement.

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“…Incoherent scatter radars are capable of deducing the neutral wind component parallel to the magnetic field [e.g., $alah and Holt, 1974]. This meridional circulation is not consistent with theoretical expectations for a thermosphere driven solely by absorbed solar EUV and requires the addition of a high-latitude heat source [Dickinson et al, 1975[Dickinson et al, , 1977Straus et al, 1975]. This meridional circulation is not consistent with theoretical expectations for a thermosphere driven solely by absorbed solar EUV and requires the addition of a high-latitude heat source [Dickinson et al, 1975[Dickinson et al, , 1977Straus et al, 1975].…”

Section: Introductionmentioning

confidence: 99%

Neutral thermospheric winds deduced above Millstone Hill, 2. Seasonal wind variations, 1970–1971

Emery¹

1978

J. Geophys. Res.

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Millstone Hill (42.6°N) incoherent scatter data gathered during 1970–1971 were used as input for a local model of the neutral thermosphere. The pressure gradients in the model were adjusted so as to match the exospheric temperature and neutral wind parallel to the magnetic field observed above the radar. Large seasonal variations in the diurnal average horizontal winds were deduced. Annual average zonal velocities were 5 m/s toward the west with an annual variation of ±43 m/s. Meridional velocities were 21 m/s toward the equator in the annual average with annual variations of ±52 m/s. The mean winds were toward the southwest in the summer and the northeast in the winter and tended to be stronger in 1971 than in 1970. The average vertical velocities were found to be generally downward throughout the year. The mean equatorward winds, large annual variations, and average downward velocities are consistent with a global circulation model presented by Dickinson et al. (1977) and require the existence of significant heating of the thermosphere at high latitudes. Seasonal variations calculated using the MSIS (mass spectrometer/incoherent scatter) model pressure gradients were similar, except that in contrast to the observed behavior the intensity of the annual circulation appeared to decrease from 1970 to 1971, reflecting the decline in the solar flux. Since the magnetic activity tends to lag the sunspot cycle by about a year and remained at about the same level over the 2 years, it is suggested that this difference may be accounted for if the influence of the high‐latitude heating is increased.

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Effects of heating at high latitudes on global thermospheric dynamics

Cited by 46 publications

References 34 publications

Latitudinal structure and extension of the polar atmospheric disturbance

Latitudinal structure and extension of the polar atmospheric disturbance

Dynamical effects on the global distribution of thermospheric atomic oxygen

Neutral thermospheric winds deduced above Millstone Hill, 2. Seasonal wind variations, 1970–1971

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