| 1. |
- Engebretson, Mark J., et al.
(författare)
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Interhemispheric Comparisons of Large Nighttime Magnetic Perturbation Events Relevant to GICs
- 2020
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Ingår i: Journal of Geophysical Research - Space Physics. - : American Geophysical Union (AGU). - 2169-9380 .- 2169-9402. ; 125:8
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Tidskriftsartikel (refereegranskat)abstract
- Nearly all studies of impulsive magnetic perturbation events (MPEs) with large magnetic field variability (dB/dt) that can produce dangerous geomagnetically induced currents (GICs) have used data from the Northern Hemisphere. Here we present details of four large‐amplitude MPE events (|ΔBx| > 900 nT and |dB/dt| > 10 nT/s in at least one component) observed between 2015 and 2018 in conjugate high‐latitude regions (65–80° corrected geomagnetic latitude), using magnetometer data from (1) Pangnirtung and Iqaluit in eastern Arctic Canada and the magnetically conjugate South Pole Station in Antarctica and (2) the Greenland West Coast Chain and two magnetically conjugate chains in Antarctica, AAL‐PIP and BAS LPM. From one to three different isolated MPEs localized in corrected geomagnetic latitude were observed during three premidnight events; many were simultaneous within 3 min in both hemispheres. Their conjugate latitudinal amplitude profiles, however, matched qualitatively at best. During an extended postmidnight interval, which we associate with an interval of omega bands, multiple highly localized MPEs occurred independently in time at each station in both hemispheres. These nighttime MPEs occurred under a wide range of geomagnetic conditions, but common to each was a negative interplanetary magnetic field Bz that exhibited at least a modest increase at or near the time of the event. A comparison of perturbation amplitudes to modeled ionospheric conductances in conjugate hemispheres clearly favored a current generator model over a voltage generator model for three of the four events; neither model provided a good fit for the premidnight event that occurred near vernal equinox.
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| 2. |
- Watts, Nick, et al.
(författare)
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The Lancet Countdown on health and climate change : from 25 years of inaction to a global transformation for public health
- 2018
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Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 391:10120, s. 581-630
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Forskningsöversikt (refereegranskat)abstract
- The Lancet Countdown tracks progress on health and climate change and provides an independent assessment of the health effects of climate change, the implementation of the Paris Agreement, 1 and the health implications of these actions. It follows on from the work of the 2015 Lancet Commission on Health and Climate Change, 2 which concluded that anthropogenic climate change threatens to undermine the past 50 years of gains in public health, and conversely, that a comprehensive response to climate change could be "the greatest global health opportunity of the 21st century". The Lancet Countdown is a collaboration between 24 academic institutions and intergovernmental organisations based in every continent and with representation from a wide range of disciplines. The collaboration includes climate scientists, ecologists, economists, engineers, experts in energy, food, and transport systems, geographers, mathematicians, social and political scientists, public health professionals, and doctors. It reports annual indicators across five sections: climate change impacts, exposures, and vulnerability; adaptation planning and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement. The key messages from the 40 indicators in the Lancet Countdown's 2017 report are summarised below.
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| 3. |
- Ni, Binbin, et al.
(författare)
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Global distribution of electrostatic electron cyclotron harmonic waves observed on THEMIS
- 2011
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 38, s. L17105-
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Tidskriftsartikel (refereegranskat)abstract
- A global, statistical analysis of electrostatic electron cyclotron harmonic (ECH) waves is performed using THEMIS wave data. Our results confirm the high occurrence of <1 mV/m ECH emissions throughout the outer magnetosphere (L > 5). The strongest (>= 1 mV/m) ECH waves are enhanced during geomagnetically disturbed periods, and are mainly confined close to the magnetic equator (|lambda| < 3 degrees) over the region L <= 10 in the night and dawn MLT sector. ECH wave intensities within 3 degrees <= |lambda| < 6 degrees are generally much weaker but not negligible especially for L < similar to 12 on the midnight side. Furthermore, the occurrence rates and variability of moderately intense (>= 0.1 mV/m) ECH emissions suggest that ECH wave scattering could contribute to diffuse auroral precipitation in the outer (L > 8) magnetosphere where chorus emissions are statistically weak.
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| 7. |
- Takahashi, Kazue, et al.
(författare)
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Propagation of Ultralow-Frequency Waves from the Ion Foreshock into the Magnetosphere During the Passage of a Magnetic Cloud
- 2021
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Ingår i: Journal of Geophysical Research - Space Physics. - : American Geophysical Union (AGU). - 2169-9380 .- 2169-9402. ; 126:2
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Tidskriftsartikel (refereegranskat)abstract
- We have examined the properties of ultralow-frequency (ULF) waves in space (the ion foreshock, magnetosheath, and magnetosphere) and at dayside magnetometer stations (L = 1.6-6.5) during Earth's encounter with a magnetic cloud in the solar wind, which is characterized by magnetic fields with large magnitudes (similar to 14 nT) and small cone angles (similar to 30 degrees). In the foreshock, waves were excited at similar to 90 m Hz as expected from theory, but there were oscillations at other frequencies as well. Oscillations near 90 mHz were detected at the other locations in space, but they were not in general the most dominant oscillations. On the ground, pulsations in the approximate Pc2-Pc4 band (5 mHz-120 mHz) were continuously detected at all stations, with no outstanding spectral peaks near 90 mHz in the H component except at stations where the frequency of the third harmonic of standing Alfven waves had this frequency. The fundamental toroidal wave frequency was below 90 mHz at all stations. In the D component spectra, a minor spectral peak is found near 90 mHz at stations located at L < 3, and the power dropped abruptly above this frequency. Magnetospheric compressional wave power was much weaker on the nightside. A hybrid-Vlasov simulation indicates that foreshock ULF waves have short spatial scale lengths and waves transmitted into the magnetosphere are strongly attenuated away from noon.
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| 9. |
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| 10. |
- Watts, Nick, et al.
(författare)
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The 2020 report of The Lancet Countdown on health and climate change : responding to converging crises
- 2021
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Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 397:10269, s. 129-170
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Forskningsöversikt (refereegranskat)abstract
- The Lancet Countdown is an international collaboration established to provide an independent, global monitoring system dedicated to tracking the emerging health profile of the changing climate.The 2020 report presents 43 indicators across five sections: climate change impacts, exposures, and vulnerabilities; adaptation, planning, and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement. This report represents the findings and consensus of the 35 leading academic institutions and UN agencies that make up The Lancet Countdown, and draws on the expertise of climate scientists, geographers, engineers, experts in energy, food, and transport, economists, social, and political scientists, data scientists, public health professionals, and doctors.
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