Results 181 to 190 of about 6,139 (217)

Magnetic storm response of lower thermosphere density

Journal of Geophysical Research: Space Physics, 1996
Measurements of atmospheric density near 200 km from the Satellite Electrostatic Triaxial Accelerometer (SETA) experiment are used to delineate the temporal, seasonal‐latitudinal, and day/night dependences of the response to magnetic storm‐related perturbations in high‐latitude energetic inputs.
J. M. Forbes, R. Gonzalez, F. A. Marcos, D. Revelle, H. Parish   +4 more
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Thermosphere Density Model Calibration

2007
Thermospheric density models are a main source of error in the orbit determination and prediction of low Earth satellites. The empirical models that are in wide use today show large systematic errors when compared with data derived from accelerometers and spacecraft tracking. This accuracy limit is inherent in their model formulation, which is based on
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Thermosphere densities derived from Swarm GPS observations

Advances in Space Research, 2020
Abstract After the detection of many anomalies in the Swarm accelerometer data, an alternative method has been developed to determine thermospheric densities for the three-satellite mission. Using a precise orbit determination approach, non-gravitational and aerodynamic-only accelerations are estimated from the high-quality Swarm GPS data.
van den IJssel, Jose, Doornbos, Eelco, Iorfida, Elisabetta, March, Günther, Siemes, Christian, Montenbruck, Oliver   +5 more
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Semi-annual Variation in Thermospheric Density

Nature, 1968
KING-HELE1 has reported a semi-annual variation in thermospheric density at about 190 km with a maximum to minimum ratio of 1.45. Cook's hypothesis2 that the semi-annual variation is caused by the modulation of the helium content of the lower thermosphere, originally coined to account for the variation at 1,100 km, clearly cannot be applied to explain ...
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Thermospheric neutral density response to solar forcing

Advances in Space Research, 2008
Abstract Recent measurements by the Solar EUV (Extreme Ultra Violet) Experiment (SEE) aboard the Thermosphere–Ionosphere–Mesosphere Energetics and Dynamics satellite (TIMED) provide solar EUV spectral irradiance with adequate spectral and temporal resolution, and thus the opportunity to use solar measurements directly in upper atmospheric general ...
L. Qian, S.C. Solomon, R.G. Roble, B.R. Bowman, F.A. Marcos   +4 more
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A Blending Technique in Thermospheric Density Modeling

AIAA/AAS Astrodynamics Specialist Conference and Exhibit, 2008
Uncertainty in the atmospheric density is a crucial error source for the propagation of satellites in low earth orbit (LEO). As a result, establishing accurate thermospheric neutral density models are important to predict the motion of these satellites.
Jung Soo Kim, David Spencer, Timothy Kane, Julio Urbina   +3 more
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Semi-annual variation of the thermospheric density

Advances in Space Research, 1987
Abstract Thermospheric densities were determined from the orbital data of four satellites covering a height range of 266 to 500 km during 1975 to 1982. Using three different thermospheric models (DTM, MSIS, C), the index characterizing the semi-annual density variation was computed and analysed with respect to height and time using a regression by ...
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A North–South asymmetry in thermospheric density

Advances in Space Research, 2006
Abstract Utilizing the opportunity that our previously analyzed drag material covers the whole latitude interval between 84°N and 84°S, we have reanalyzed our 16 thousand observed total density data comparing them with model densities as a function of different parameters.
E. Illés-Almár, I. Almár
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Accuracy of Earth's Thermospheric Neutral Density Models

AIAA/AAS Astrodynamics Specialist Conference and Exhibit, 2006
[Abstract] Atmospheric drag remains the dominant uncertainty for low altitude satellite precision orbit determination . Empirical models are used to estimate satellite drag. Model accuracies have shown little improvement in the past 35 years. A new Ja cchia -Bowman 2006 (JB2006) empirical model has been developed as part of the Air Force Space Command ...
Frank Marcos, Bruce Bowman, Robert Sheehan   +2 more
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Midlatitude neutral thermosphere density and temperature measurements

Journal of Geophysical Research, 1969
Midlatitude neutral thermosphere density and temperature measurements, noting effect of atomic oxygen adsorption by ...
David T. Pelz, George P. Newton
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