Climatologies of nighttime thermospheric winds and temperatures from Fabry‐Perot interferometer measurements: From solar minimum to solar maximum

Abstract

We present a climatology of quiet time thermospheric winds and temperatures estimated from high‐resolution Fabry‐Perot interferometer measurements of the 630.0 nm airglow emission spectral line shape. Three locations are examined in this long‐term study: northeastern Brazil (August 2009 to August 2014), a midlatitude site in North Carolina, USA (June 2011 to December 2014), and a midlatitude site in Morocco (November 2013 to December 2014). We discuss the day‐to‐day, seasonal, and solar cycle trends and variations of thermospheric meridional winds, zonal winds, neutral temperatures, and for the first time vertical winds. Observations made from solar minimum to solar maximum (with F10.7 values ranging from ∼70 to ∼159 solar flux units) confirm that neutral temperatures have a strong solar cycle dependence. However, this data set shows that the neutral winds are more closely tied to the seasonal variation, rather than the solar cycle. We also present comparisons between the two midlatitude sites and include neutral wind comparisons to the updated Horizontal Wind Model 14.

Climatology of thermospheric neutral winds over Oukaïmeden Observatory in Morocco

“…2), representing a significant database from which climatological averages will be derived in this study. These nights extend the initial climatologies presented by Fisher et al (2015), where the first year of observations from this site was presented. The period covered in the present study coincides with a period of decreasing solar activity covering the end of the maximum of solar cycle 24 through its declining phase, as shown in Fig.…”

“…In order to create climatologies, we adopted the method detailed in Fisher et al (2015). Following this, we eliminate all non-physical values in the measured neutral winds that are not automatically removed from initial processing.…”

“…These neutral parameters are crucial as they are a key driver of plasma motion. Similar systems previously deployed in other parts of the world have demonstrated their utility in capturing the solar cycle, seasonal, and daily fluctuations of the neutral winds (e.g., Emmert et al, 2006;Meriwether et al, 2011;Brum et al, 2012;Fisher et al, 2015). Combined with data from existing sites in the American sector and elsewhere, the data from Africa will play a critical role in understanding large-scale tidal features in the upper atmosphere as well as understanding longitudinal variability in these larger-scale features.…”

Statistical analysis of ionospheric mid-latitude trough over the Northern Hemisphere derived from GPS total electron content data

“…It is reasonable to suppose that the equatorward wind makes a greater contribution to TEC values in winter. The midlatitude meridional winds are equatorward through the night and generally peak around 0100-0200 LT (Emmert et al 2002;Fisher et al 2015). During winter, the equatorward neutral winds have a more dominant effect in increasing the ionization with MLT than the ordinary ionic recombination in lowering the ionization because of the lower TEC value.…”

Simultaneous 6300 Å airglow and radar observations of ionospheric irregularities and dynamics at the geomagnetic equator

“…At Jicamarca, the ISR has been used to study the seasonal dependence of the MTM (Bamgboye and McClure, 1982) and the MTM has been observed with FPIs at locations near the magnetic equator (Meriwether et al, 2008;Fisher et al, 2015). A signature of the MTM, known as a brightness wave, can be observed using an ASI.…”