Characterization of Thermospheric Vertical Wind Activity at 225‐ to 295‐km Altitude Using GOCE Data and Validation Against Explorer Missions.

Autor: Visser, T., March, G., Doornbos, E. N., Visser, C. C., Visser, P. N. A. M.
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Zdroj: Journal of Geophysical Research. Space Physics; Jun2019, Vol. 124 Issue 6, p4852-4869, 18p
Abstrakt: Recently, the horizontal and vertical cross wind at 225‐ to 295‐km altitude were derived from linear acceleration measurements of the Gravity field and steady‐state Ocean Circulation Explorer satellite. The vertical component of these wind data is compared to wind data derived from the mass spectrometers of the Atmosphere Explorer C and E and Dynamics Explorer 2 satellites. From a statistical analysis of the 120‐s moving‐window standard deviation of the vertical wind (σ(Vz)), no consistent discrepancy is found between the accelerometer‐derived and the mass spectrometer‐derived data. The validated Gravity field and steady‐state Ocean Circulation Explorer data are then used to investigate the influence of several parameters and indices on the vertical wind activity. To this end, the probability distribution of σ(Vz) is plotted after distributing the data over bins of the parameter under investigation. The vertical wind is found to respond strongly to geomagnetic activity at high latitudes, although the response settles around a maximum standard deviation of 50 m/s at an Auroral Electrojet index of 800. The dependence on magnetic local time changes with magnetic latitude, peaking around 4:30 over the polar cap and around 01:30 and 13:30 in the auroral oval. Seasonal effects only become visible at low to middle latitudes, revealing a peak wind variability in both local summer and winter. The vertical wind is not affected by the solar activity level. Key Points: Vertical wind standard deviations derived from linear accelerations are consistent with those derived from mass spectrometryGeomagnetic activity and local time are main drivers of vertical wind activity at high latitudes; local time and season at low latitudesThe vertical wind standard deviation levels out at 10–50 m/s (5th and 95th percentiles) for AE index levels above 800 [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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