Using incoherent scatter radar to investigate the neutral wind long-term trend over Arecibo

Abstract

[1] Thermospheric neutral winds can be the most important driver when modeling ionospheric densities and temperatures. Several papers in this special edition show interesting features of the neutral winds behavior during the last 30 years at the Arecibo Observatory (18.3°N, 66.75°W; ∼28.25°dip latitude) using Fabry-Perot Interferometer (FPI) data. A neutral wind vector that changes its direction, becoming more dominantly eastward over the years and a meridional neutral wind component that decreases in magnitude, were found. The main goal of this work is to look for similar evidence of long-term trends in the radar derived winds that might support these recent discoveries and explore the associated ionospheric parameter measurements to look for the effects of these changing winds on the ionosphere. With this purpose in mind, Incoherent Scatter Radar (ISR) measurements of the F region vector drifts are used to derive the corresponding meridional thermospheric neutral wind along the magnetic field over Arecibo during 20 years. Major findings include a decreasing long-term trend (lowering) of the height where the F2-layer peak density occurs (hmF2), which could be related with a more increased downward flux of the ionosphere. A slight decrease in the peak density of the F2-layer (NmF2) after local midnight also was found during the period studied. The meridional wind along the magnetic field derived from ISR data also revealed a long-term trend, becoming more northward during the period studied, with a maximum variation between 02:30UT and 05:30UT.Citation: Santos, P. T., C. G. M. Brum, C. A. Tepley, N. Aponte, S. A. González, and E. Robles (2011), Using incoherent scatter radar to investigate the neutral wind long-term trend over Arecibo,

Long‐Term Trends in the Upper Atmosphere Using the Incoherent Scatter Radar Observations Over Arecibo

“…at which the O + ions diffuse downward (Santos et al, 2011). Therefore, the lowering of hmF2 caused by the meridional wind found over Arecibo by Brum et al (2012) and Santos et al (2011), respectively, agree with the theory, and a decrease in electron density would be expected.…”

A comparison of mesospheric and low‐thermospheric winds measured by Fabry‐Perot interferometer and meteor radar over central China

“…However, the lack of neutral wind measurements hinders our dynamic studies in the upper atmosphere. Ground-based instruments such as incoherent scatter radar, meteor radar (MR), medium-frequency radar, lidar, Michelson interferometer, and Fabry-Perot interferometer (FPI) are all capable of detecting the wind and dynamics in the upper atmosphere [Santos et al, 2011;David et al, 2013;Hocking, 1997;Phillips et al, 1994;Yuan et al, 2006;She et al, 2002;Langille et al, 2013;Wu et al, 2004]. Among them, the MR and FPI are two types of instruments to effectively detect waves and winds in the upper atmosphere at relatively low costs.…”

High time and height resolution neutral wind profile measurements across the mesosphere/lower thermosphere region using the Arecibo incoherent scatter radar

“…These include studies that focus on the mesosphere, where the procedure is especially straightforward [Mathews et al, 1981;Rottger et al, 1981;Fukao et al, 1982Fukao et al, , 1985Rottger et al, 1983;Tsuda et al, 1985;Maekawa et al, 1986;Zhou and Morton, 2006]. The techniques and related databases have become sufficiently reliable to support studies of long-term trends over Arecibo [Maekawa et al, 1987;Tepley et al, 2011;Santos et al, 2011;Brum et al, 2012].…”