Energetics and Composition in the Thermosphere

Burns, A. G.; Wang, W.; Solomon, S. C.; Qian, Liying

doi:10.1002/9781118704417.ch4

Cited by 13 publications

(10 citation statements)

References 49 publications

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“…Every geomagnetic storm is unique, since the interplanetary magnetic field, solar wind, and magnetospheric drivers are diverse (Burns et al 2014). Not only does the magnetospheric convection and auroral precipitation vary from one storm to another, but the preconditioned state of the T-I system prior to storm onset may also contribute to its progression.…”

Section: Science Objectivesmentioning

confidence: 99%

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

et al. 2017

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The Earth's thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understanding the global-scale response of the thermosphere-ionosphere (T-I) system to these drivers is essential to advanc- ing our physical understanding of coupling between the space environment and the Earth's atmosphere. Previous missions have successfully determined how the "climate" of the T-I system responds. The Global-scale Observations of the Limb and Disk (GOLD) mission will determine how the "weather" of the T-I responds, taking the next step in understanding the coupling between the space environment and the Earth's atmosphere. Operating in geostationary orbit, the GOLD imaging spectrograph will measure the Earth's emissions from 132 to 162 nm. These measurements will be used image two critical variables-thermospheric temperature and composition, near 160 km-on the dayside disk at half-hour time scales. At night they will be used to image the evolution of the low latitude ionosphere in the same regions that were observed earlier during the day. Due to the geostationary orbit being used the mission observes the same hemisphere repeatedly, allowing the unambiguous separation of spatial and temporal variability over the Americas.

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Section: Science Objectivesmentioning

confidence: 99%

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

et al. 2017

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“…He found that the temperature of the polar mesosphere increased by 5-10 K, while the polar stratosphere temperature decreased. Analyses of SABER/TIMED temperature data conducted by Chang et al (2009) and Jiang et al (2014) showed that periodic oscillations of the temperature of the lower thermosphere had good correlation with oscillations in geomagnetic activity.…”

Section: Introductionmentioning

confidence: 96%

Response to Anonymous Referee #2 statistic significance

Anonymous

2017

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The long-term temperature changes of the mesopause region at the hydroxyl molecule OH (6-2) nighttime height and its connection with the geomagnetic activity during the 23rd and beginning of the 24th solar cycles are presented. Measurements were conducted with an infrared digital spectrograph at the Maimaga station (63 • N, 129.5 • E). The hydroxyl rotational temperature (TOH) is assumed to be equal to the neutral atmosphere temperature at the altitude of ∼ 87 km. The average temperatures obtained for the period 1999 to 2015 are considered. The season of observations starts at the beginning of August and lasts until the middle of May. The maximum of the seasonally averaged temperatures is delayed by 2 years relative to the maximum of the solar radio emission flux (wavelength of 10.7 cm), and correlates with a change in geomagnetic activity (Ap index). Temperature grouping in accordance with the geomagnetic activity level showed that in years with high activity (Ap > 8), the mesopause temperature from October to February is about 10 K higher than in years with low activity (Ap < = 8). Cross-correlation analysis showed no temporal shift between geomagnetic activity and temperature. The correlation coefficient is equal to 0.51 at the 95 % level.

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“…Burns et al . [] investigated the physical processes that cause a neutral temperature enhancement at low‐middle latitude during geomagnetic storms. Their study showed that high‐latitude energy input during geomagnetic storms primarily causes an increase of temperature around the auroral oval as a result of Joule heating.…”

Section: Discussionmentioning

confidence: 99%

“…Their study showed that high‐latitude energy input during geomagnetic storms primarily causes an increase of temperature around the auroral oval as a result of Joule heating. The temperature in low‐middle latitude and lower altitude is changed, in turn, by the propagation and dissipation of large‐scale waves generated near the auroral zone (compressional heating and cooling by expansion) [ Burns et al ., , Figure ]. Therefore, when there is a multiday periodic oscillation in high‐latitude energy inputs during recurrent geomagnetic activity, the global temperature in the lower thermosphere can also have oscillations of the same periods, as those seen in the SABER data.…”

Section: Discussionmentioning

confidence: 99%

“…The different responses of the lower thermospheric temperature to the recurrent geomagnetic activity in the two hemispheres are seen in both observations and model simulations. The energy deposition during recurrent geomagnetic activity, in the form of Joule heating and particle heating, depends on the ionospheric conductivity conditions in each hemisphere [ Wang et al ., ; Burns et al ., ]. Ionospheric conductivity changes with season and other geophysical conditions; the differences in these conditions in the two hemispheres, such as the different geomagnetic field configuration in the southern and northern hemispheres, lead to differences in the magnitudes and locations of Joule heating and particle heating which, in turn, could cause the different responses of the lower thermospheric temperature to the recurrent geomagnetic activity in the two hemispheres.…”

Section: Discussionmentioning

confidence: 99%

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Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity

Jiang

Wang

et al. 2014

JGR Space Physics

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Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity and solar EUV radiation have been investigated using neutral temperature data observed by the TIMED/SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry) instrument and numerical experiments by the NCAR-TIME-GCM (National Center for Atmospheric Research-thermosphere-ionosphere-mesosphere electrodynamics-general circulation model). The TIMED/SABER data analyzed were for the period from 2002 to 2007 during the declining phase of solar cycle 23. The observations show that the zonal mean temperature in the lower thermosphere oscillated with periods of near 9 and 13.5 days in the height range of 100-120 km. These oscillations were more strongly correlated with the recurrent geomagnetic activity than with the solar EUV variability of the same periods. The 9 day and 13.5 day oscillations of lower thermospheric temperature had greater amplitudes at high latitudes than at low latitudes; they also had larger amplitudes at higher altitudes, and the oscillations could penetrate down to~105 km, depending on the strength of the recurrent geomagnetic activity for a particular time period. The data further show that the periodic responses of the lower thermospheric temperature to recurrent geomagnetic activity were different in the two hemispheres. In addition, numerical experiments have been carried out using the NCAR-TIME-GCM to investigate the causal relationship between the temperature oscillations and the geomagnetic activity and solar EUV variations of the same periods. Model simulations showed the same periodic oscillations as those seen in the observations when the real geomagnetic activity index, Kp, was used to drive the model. These numerical results show that recurrent geomagnetic activity is the main cause of the 9 day and 13.5 day variations in the lower thermosphere temperature, and the contribution from solar EUV variations is minor. Furthermore, we also found that consecutive coronal mass ejection events could cause long-duration enhancements in the lower thermospheric temperature that strengthen the 9 day and 13.5 day signals, and this kind of phenomenon mostly occurred between 2002 and 2005 during the declining phase of solar cycle 23.

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Energetics and Composition in the Thermosphere

Cited by 13 publications

References 49 publications

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

Response to Anonymous Referee #2 statistic significance

Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity

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