Variation of the auroral oval size and offset for different magnetic activity levels described by the Kp‐index

Wagner, D.; Neuhäuser, R.

doi:10.1002/asna.201913601

Cited by 5 publications

(7 citation statements)

References 25 publications

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“…The increase trend of the O 2 auroral zone size with the Kp level is also similar to that of the FUV aurora given by Wagner and Neuhäuser (2019) based on the DE1 satellite observations. In addition, the size of FUV auroral zone given by Wagner and Neuhäuser (2019) for solar maximum is larger than that for solar minimum at the same Kp level. This is similar to the size of O 2 auroral zone.…”

Section: Resultssupporting

confidence: 87%

“…The distribution is similar to that of the GUVI auroral precipitation energy flux, which occurred between 65° and 75° MLAT, and was centered around 67–70° MLAT for the Kp = 1 condition (Luan et al, 2015). Furthermore, the radius for Kp = 4 calculated by Wagner and Neuhäuser (2019) is (22.13 ± 1.55)°, which is close to the radius for Kp Level 4 in Table 1. The increase trend of the O 2 auroral zone size with the Kp level is also similar to that of the FUV aurora given by Wagner and Neuhäuser (2019) based on the DE1 satellite observations.…”

Section: Resultssupporting

confidence: 83%

“…Furthermore, the radius for Kp = 4 calculated by Wagner and Neuhäuser ( 2019) is (22.13 ± 1.55)°, which is close to the radius for Kp Level 4 in Table 1. The increase trend of the O 2 auroral zone size with the Kp level is also similar to that of the FUV aurora given by Wagner and Neuhäuser (2019) based on the DE1 satellite observations. In addition, the size of FUV auroral zone given by Wagner and Neuhäuser (2019) for solar maximum is larger than that for solar minimum at the same Kp level.…”

Section: Journal Of Geophysical Research: Space Physicssupporting

confidence: 85%

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Statistical Structure of Nighttime O₂ Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter

Gao

Chen³

et al. 2020

JGR Space Physics

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O 2 aurora is one kind of important molecular aurorae that is not fully understood yet. It is hard to be investigated due to the contamination by nightglow. In this work, we studied O 2 aurora based on the observations of O 2 emission at 1.27 μm from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument during the nighttime over 18 years. The horizontal structure of O 2 auroral zone is given for the first time, and the vertical profile of O 2 auroral volume emission rate is obtained after removing O 2 nightglow contamination. The O 2 auroral intensity and the peak height and peak volume emission rate of the vertical profile averaged over the O 2 auroral zone are studied in detail. For Kp Levels 1-5, the O 2 auroral peak height varies between 104 and 112 km and is negatively correlated with the auroral intensity and peak volume emission rate. The O 2 auroral intensity varies between 0.14 and 5.97 kR, and the peak volume emission rate varies between 0.97 × 10 2 and 41.01 × 10 2 photons cm −3 s −1. Furthermore, the dependences of the O 2 aurora on geomagnetic and solar activities are analyzed. The O 2 auroral intensity and peak volume emission rate exponentially increases with increasing Kp index, whereas the peak height decreases with increasing Kp index. The O 2 auroral intensity and peak volume emission rate under solar minimum condition are larger than those under solar maximum condition. The peak height under solar minimum condition is lower than that under solar maximum condition. Plain Language Summary Aurora is one of the most magnificent phenomena in the Earth's atmosphere. The types of aurora are abundant. Among a wide variety of aurorae, O 2 aurora is one kind of important molecular aurorae. However, we still do not understand it clearly. It is hard to study O 2 aurora using observations from ground and by nadir sounding due to the strong interference by O 2 airglow. The limb sounding by satellite can provide a global distribution of the profiles of atmospheric emissions. This is beneficial for separating O 2 aurora from O 2 airglow and investigating vertical distribution of O 2 aurora. We study O 2 aurora based on the excellent limb sounding of O 2 emission at 1.27 μm by the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry (TIMED/SABER) satellite. O 2 aurora is derived after removing the interference from nightglow, and statistical structures of O 2 auroral zone at different geomagnetic activity levels are displayed for the first time. We find that the structures of the O 2 aurora change with geomagnetic and solar activities. The results provide further understanding of the horizontal and vertical structures of O 2 aurora. The results are helpful for the verification of the excitation mechanisms of O 2 aurora and the development and validation of O 2 auroral models.

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Section: Resultssupporting

confidence: 87%

Section: Resultssupporting

confidence: 83%

Section: Journal Of Geophysical Research: Space Physicssupporting

confidence: 85%

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Statistical Structure of Nighttime O₂ Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter

Gao

Chen³

et al. 2020

JGR Space Physics

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“…For example the AO boundaries are correlated with the Kp index (e.g. Carbary, 2005;Nsumei et al, 2008;Wagner and Neuhäuser, 2019).…”

Section: Kp Binning Of Particle Datamentioning

confidence: 99%

Polar particle flux distribution and its spatial extent

Yakovchuk¹,

Wissing²

2023

J. Space Weather Space Clim.

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Context: The main challenge in atmospheric ionisation modelling is that sparse measurements are used to derive a global precipitation pattern. Typically this requires intense interpolation or scaling of long-term average maps. In some regions however, the particle flux might be similar and a combination of these regions would not limit the results even though it would dramatically improve the spatial and temporal data coverage. Aims: The intention of this paper is to statistically analyse the particle flux distribution close to the geomagnetic poles labelled as Polar Particle Flux Distribution (PPFD) and identify similar distributions in neighbouring bins. Those bins are grouped together and the size of the PPFD-area is estimated. The benefit is that single measurements within the PPFD-area should be able to represent the particle flux for the whole area at a given time. Methods: We use spatially binned energetic particle flux distributions measured by POES and Metop spacecraft during 2001--2018 to identify a Kp-dependent area with a similar flux distribution as the one found close to the geomagnetic poles (|magn. lat|>86°). First, the particle flux is mapped on a magnetic local time (MLT) vs. magnetic latitude grid. In a second step the gridded data is split up according to Kp-levels (forming the final bins). Third, the particle flux in every bin has been recalculated in order to replace zero-count rates by rates based on longer measurement periods which results in more realistic low flux end of the particle distribution. Then the binned flux distributions are compared to the PPFD. A "$\Delta$-test" indicates the similarity. A threshold for the $\Delta$-test is defined using the standard deviation of $\Delta$-test values inside the (|magn. lat|>86°) area. Bins that meet the threshold are attributed as PPFD-area. Results: Polar Particle Flux Distributions and the corresponding PPFD-areas have been determined for all investigated particle channels, covering an energy range of 154~eV--300~keV for electrons and 154~eV--2.5~MeV for protons. Concerning low energy channels a gradual flux increase with rising Kp has been identified. High energy channels show a combination of background population and solar particle event (SPE) population that adds up with increasing Kp. The size of the PPFD-area depends on particle species, energy and geomagnetic disturbance, as well as MLT. The main findings are: a)~There are small but characteristic hemispheric differences. b)~Only above a certain energy threshold the PPFD-areas increase with particle energy. c)~A clear enlargement with rising Kp is identified - with exceptions for very low Kp. d)~The centre of the PPFD-area is shifted towards midnight and moves with Kp. Asymmetries of the boundaries could be explained by auroral intensity. e)~For low energy particles the main restriction of the PPFD-area seems to be the auroral precipitation.

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“…Esteíndice describe las perturbaciones en el campo magnético de la Tierra y es usado para decidir si es necesario emitir alertas y advertencias geomagnéticas para los usuarios afectados por estas perturbaciones 5 . Los principales efectos se dan sobre la red eléctrica, los usuarios de señales de radio que se reflejan en la ionosfera o que pasan a través de ella y los observadores de la aurora [97]. Losíndices AE, AU y AL fueron diseñados por T. N. Davis y M. Sugiura en 1966.…”

Section: ¿Cómo Monitorear El Clima Espacial?unclassified

La influencia del Sol en la Tierra y otros planetas:Clima espacial

Gómez‬

2021

Rev. Bras. Ensino Fís.

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Variation of the auroral oval size and offset for different magnetic activity levels described by the Kp‐index

Cited by 5 publications

References 25 publications

Statistical Structure of Nighttime O₂ Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter

Statistical Structure of Nighttime O₂ Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter

Polar particle flux distribution and its spatial extent

La influencia del Sol en la Tierra y otros planetas:Clima espacial

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Variation of the auroral oval size and offset for different magnetic activity levels described by the Kp‐index

Cited by 5 publications

References 25 publications

Statistical Structure of Nighttime O2 Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter

Statistical Structure of Nighttime O2 Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter

Polar particle flux distribution and its spatial extent

La influencia del Sol en la Tierra y otros planetas:Clima espacial

Contact Info

Product

Resources

About

Statistical Structure of Nighttime O₂ Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter

Statistical Structure of Nighttime O₂ Aurora From SABER and Its Dependence on Geomagnetic and Solar Activities in Winter