Thermospheric winds and temperatures above Mawson, Antarctica, observed with an all-sky imaging, Fabry-Perot spectrometer

Abstract

Abstract.A new all-sky imaging Fabry-Perot spectrometer has been installed at Mawson station (67 • 36 S, 62 • 52 E), Antarctica. This instrument is capable of recording independent spectra from many tens of locations across the sky simultaneously. Useful operation began in March 2007, with spectra recorded on a total of 186 nights. Initial analysis has focused on the large-scale daily and average behavior of winds and temperatures derived from observations of the 630.0 nm airglow line of atomic oxygen, originating from a broad layer centered around 240 km altitude, in the ionospheric F-region.The 1993 Horizontal Wind Model (HWM93), NRLMSISE-00 atmospheric model, and the Coupled Thermosphere/Ionosphere Plasmasphere (CTIP) model were used for comparison. During the geomagnetically quiet period studied, observed winds and temperatures were generally well modelled, although temperatures were consistently higher than NRLMSISE-00 predicted, by up to 100 K. CTIP temperatures better matched our data, particularly later in the night, but predicted zonal winds which were offset from those observed by 70-180 ms −1 westward. During periods of increased activity both winds and temperatures showed much greater variability over time-scales of less than an hour. For the active night presented here, a period of 45 min saw wind speeds decrease by around 180 ms −1 , and temperatures increase by approximately 100 K. Activeperiod winds were poorly modelled by HWM93 and CTIP, although observed median temperatures were in better agreement with NRLMSISE-00 during such periods.Average behavior was found to be generally consistent with previous studies of thermospheric winds above Mawson. The collected data set was representative of quiet geomagnetic and solar conditions. Geographic eastward windsCorrespondence to: C. Anderson (c.anderson@latrobe.edu.au) in the afternoon/evening generally continued until around local midnight, when winds turned equatorward. Geographic meridional and zonal winds in the afternoon were approximately 50 ms −1 weaker than expected from HWM93, as was the transition to equatorward flow around midnight. There was also a negligible geographic zonal component to the post-midnight wind where HWM93 predicted strong westward flow.

Registering upper atmosphere parameters in East Siberia with Fabry—Perot Interferometer KEO Scientific “Arinae”

“…One of the currently available methods for recording the spectral composition of optical radiation with this sensitivity is a method for observing interference in parallel rays in the Fabry-Perot interferometer [Born, Wolf 1973]. There are many scientific instruments (for example, [Wu et al, 2004;Shiokawa et al, 2012;Anderson et al, 2009;Ignatiev et al, 1998]) that use this method to study optical airglow. The field of view of these instruments, except for that described in [Anderson et al, 2009], is units of degrees, so in a single observation session we can obtain characteristics of only a certain local region of the celestial sphere.…”

“…There are many scientific instruments (for example, [Wu et al, 2004;Shiokawa et al, 2012;Anderson et al, 2009;Ignatiev et al, 1998]) that use this method to study optical airglow. The field of view of these instruments, except for that described in [Anderson et al, 2009], is units of degrees, so in a single observation session we can obtain characteristics of only a certain local region of the celestial sphere. [Ignatyev, Yugov, 1995]); however, the use of twodimensional CCD matrices for recording interference patterns and the computational capabilities of modern computers open up somewhat greater possibilities of image processing.…”

Spatial sampling of the thermospheric vertical wind field at auroral latitudes

“…[7] The Mawson Scanning Doppler Imager (Mawson SDI) has been described previously [Anderson et al, 2009]. This instrument is of the type described by Conde and Smith [1997].…”

Registering upper atmosphere parameters in East Siberia with Fabry—Perot Interferometer KEO Scientific “Arinae”

“…Одним из известных на сегодняшнее время до-ступных методов регистрации спектрального со-става оптического излучения, обладающим указан-ной чувствительностью, является метод наблюде-ния интерференции в параллельных пучках в ин-терферометре Фабри-Перо [Борн, Вольф 1973]. Существует значительное количество научных установок (например Anderson et al, 2009;Игнатьев и др., 1998]), использующих его для исследования опти-ческого свечения верхней атмосферы Земли. Поле зрения этих установок, за исключением устройства, описанного в [Anderson et al, 2009], составляет единицы градусов, поэтому в однократном сеансе наблюдения можно получить характеристики толь-ко некоторой локальной области небесной сферы.…”

“…Существует значительное количество научных установок (например Anderson et al, 2009;Игнатьев и др., 1998]), использующих его для исследования опти-ческого свечения верхней атмосферы Земли. Поле зрения этих установок, за исключением устройства, описанного в [Anderson et al, 2009], составляет единицы градусов, поэтому в однократном сеансе наблюдения можно получить характеристики толь-ко некоторой локальной области небесной сферы. Поэтому для расширения функциональных воз-можностей некоторые из этих установок сканируют небесную сферу при помощи автоматизированных перископических входных окон.…”