Combined ground-based optical support for the aurora (DELTA) sounding rocket campaign

Griffin, E. M.; Kosch, M. J.; Aruliah, A. L.; Kavanagh, A. J.; McWhirter, I.; Senior, Andrew; Ford, Elaina; Davis, C. J.; Abe, Takumi; Kurihara, Junichi; Kauristie, Kirsti; Ogawa, Y.

doi:10.1186/bf03352000

Cited by 8 publications

(15 citation statements)

References 12 publications

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“…The large temperature gradient with altitude in the lower thermosphere results in dramatic observed neutral temperature changes during auroral emission intensity enhancements caused by hard electron precipitation. The effect has also been observed with standard FPI observations of the 557.7 nm emission and combined with ion temperature measurements from the mainland EISCAT UHF radar (Griffin et al, 2006). The neutral temperature results presented here show that the effect can also be dramatic in the upper thermosphere.…”

Section: Discussionsupporting

confidence: 62%

Upper thermospheric neutral wind and temperature measurements from an extended spatial field

et al. 2008

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Abstract.First results are presented from a Scanning Doppler Imager (SCANDI) installed at the Nordlysstasjonen optical observatory near Longyearbyen, Svalbard (78.2 • N, 15.8 • E). Observations of the atomic oxygen 630 nm red line emission, originating in the upper thermosphere at around 250 km, have been used to determine neutral winds and temperatures from multiple zones within an extended spatial field. The instrument utilises all-sky optics to achieve multiple simultaneous measurements, compared to the standard Fabry-Perot Interferometer (FPI) procedure of separate lineof-sight samples within a sequence of narrow angle look directions. SCANDI is colocated with such a standard FPI and comparison of neutral wind velocities between the instruments on the night of 15 March 2007 has revealed detailed and consistent structure in the wind field. Southward meridional wind enhancements of several hundred m/s are observed simultaneously with both instruments, revealing structure on scales not currently considered in thermospheric general circulation models (GCMs). The data from this night also demonstrate the influence of discrete auroral events on thermospheric behaviour. High intensities observed by SCANDI in the presence of auroral arcs coincide with a drop in measured neutral temperatures. This is interpreted as a result of the effective altitude of the 630 nm emission being lowered under conditions of soft auroral precipitation. The optical instruments as a consequence sample a region of lower temperature. This effect has been observed previously with lower thermospheric atomic oxygen emissions at 557.7 nm. The EISCAT Svalbard Radar (ESR) provides ion temperatures and electron densities for the night which confirm the influence of precipitation and heating during the auroral events. The minima of ion temperatures through the pre-midnight period provide a good match to the neutral temCorrespondence to: E. M. Griffin (eoghan@apl.ucl.ac.uk) peratures measured with SCANDI, and to the colocated FPI temperatures.

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Section: Discussionsupporting

confidence: 62%

Upper thermospheric neutral wind and temperature measurements from an extended spatial field

et al. 2008

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“…As described previously, the FPI neutral temperatures are at 500 K level except for the time just after the launch. The reason for this deviation is investigated in detail by Griffin et al (2006) in this issue. Even if the observed temperature jump to ∼650 K for the Skibotn West is an actual neutral temperature enhancement at 120 km, the temperature jump is a local enhancement owing to some localized heating mechanisms such as a particle heating because the KEOPS Northwest temperature is at the 550 K level around that time.…”

Section: Discussionmentioning

confidence: 99%

“…Griffin et al (2006) discussed the temperature peaks between 23:00 on 12 and 2:00 UT on 13 December. It is difficult, however, to simply conclude that the temperature peaks are caused by either changes in the auroral emission height or some localized heating mechanisms, because the rocket trajectory and the sampled volumes of the FPIs do not ovelap directly.…”

Section: Discussionmentioning

confidence: 99%

“…A detailed description of the instruments and observations is presented by Griffin et al (2006) in this issue. The neutral temperatures measured from the two directions closest to the sounding rocket, the Skibotn West and the KEOPS Northwest, at the period from 23:00 UT on 12 to 2:00 UT on 13 December 2004 are shown in figure 11 of Griffin et al (2006). The temperatures from two directions are in very good agreement at ∼500 K just before the launch time.…”

Section: Neutral Temperaturementioning

confidence: 99%

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Observations of the lower thermospheric neutral temperature and density in the DELTA campaign

et al. 2006

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The rotational temperature and number density of molecular nitrogen (N 2 ) in the lower thermosphere were measured by the N 2 temperature instrument onboard the S-310-35 sounding rocket, which was launched from Andøya at 0:33 UT on 13 December 2004, during the Dynamics and Energetics of the Lower Thermosphere in Aurora (DELTA) campaign. The rotational temperature measured at altitudes between 95 and 140 km, which is expected to be equal to neutral temperature, is much higher than neutral temperature from the Mass Spectrometer Incoherent Scatter (MSIS) model. Neutral temperatures in the lower thermosphere were observed using the auroral green line at 557.7 nm by two Fabry-Perot Interferometers (FPIs) at Skibotn and the Kiruna Esrange Optical Platform System site. The neutral temperatures derived from the look directions closest to the rocket correspond to the rotational temperature measured at an altitude of 120 km. In addition, a combination of the all-sky camera images at 557.7 nm observed at two stations, Kilpisjärvi and Muonio, suggests that the effective altitude of the auroral arcs at the time of the launch is about 120 km. The FPI temperature observations are consistent with the in situ rocket observations rather than the MSIS model.

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“…Interactions between the solar wind and the magnetosphere-ionosphere system firstly lead to emission in the noon sector of the auroral oval; then, as interplanetary shock spreads to the night section, magnetic enhancement and even magnetic storms can occur [5,6]. The Fabry-Perot interferometer (FPI), a type of passive sensor, typically has a higher observation height than other ground-based equipment; traditionally, altitudes of auroral emission have been assumed to be close to *240 and *115 km for 630 and 557.7 nm, respectively, which are different with those of mid-latitude airglow emission [7][8][9][10][11]. The all-sky FPI is typically installed at polar sites owing to its large field of view and high resolution [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Observations of thermospheric vector wind over Yellow River Station during auroral substorm events

Liu

Zhang

et al. 2014

Chin. Sci. Bull.

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Strong disturbances associated with auroral substorms originate from the ionosphere-magnetosphere owing to the effects of the solar wind, and the wind field in the ionosphere is related to such substorm activity. Here, we describe the analysis of four auroral substorm events, for which we employed an all-sky Fabry-Perot interferometer to observe the two-dimensional horizontal wind field and combined the results with data from an all-sky charge-coupled device imager, a fluxgate magnetometer installed at Yellow River Station, and the Super Dual Auroral Radar Network. The results demonstrate that, during auroral substorms, the vector wind field is related closely to variations in the ion drift and geomagnetic field. Moreover, we observed a changing wind field of approximately 300 m/s in response to variations in the electric and magnetic fields (likely caused by ion drag) and a disturbance of about 200 m/s that we attribute to the interaction of Joule heating and ion drag.

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Combined ground-based optical support for the aurora (DELTA) sounding rocket campaign

Cited by 8 publications

References 12 publications

Upper thermospheric neutral wind and temperature measurements from an extended spatial field

Upper thermospheric neutral wind and temperature measurements from an extended spatial field

Observations of the lower thermospheric neutral temperature and density in the DELTA campaign

Observations of thermospheric vector wind over Yellow River Station during auroral substorm events

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