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Self-maintenance orbits using the perturbations due to air drag and due to Earth’s oblateness

Amin Mohamed R.

Mechanics and Mechanical Engineering

2020

Vol. 24, nr 1

56--60

The focus of this paper is the design of a selfmaintenance orbit using two natural forces against each other. The effect of perturbations due to Earth’s oblateness up to the third order on both the semi-major axis and eccentricity for a low Earth orbit satellite together with the perturbation due to air drag on the same orbital parameters were used, in order to create self-maintenance orbits. Numerical results were simulated for a low earth orbit satellite,which substantiates the applicability of the results.

Detection of Antarctic oscillation signals in Earth’s oblateness variations

Duan P., Liu G., Tu Y., Huang C.

Acta Geophysica

2017

Vol. 65, no. 4

635--644

Variations of Earth’s oblateness (J2) reflect a large scale mass redistribution within the Earth system. The climate effect causing J2 interannual variations is still not clear, though previous studies indicated it may be related to El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). However, we have a new discovery of the significant Antarctic Oscillation (AAO) signals in J2 interannual variations, especially on 4–6 year scales based on cross wavelet and wavelet coherence analysis with 95% confidence test during 1979–2012. The results additionally indicate that the close phase relationship between J2 and AAO (AAO leading J2 variations by 3 ± 2 months in phase) is far superior to that between J2 and ENSO/PDO on 4–6 year scales. In this work, we discuss, for the first time, a possible geophysical mechanism of AAO effecting J2 variations. The investigations are based on the definition of AAO and its spatial-temporal behavior influencing the large-scale mass movement. Finally, an approximate quantitative estimate of the AAO imprint on J2 with an emphasis on the atmospheric contribution is made.