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Opgenoorth, Hermann J.ORCID iD iconorcid.org/0000-0001-7573-5165
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Publications (10 of 29) Show all publications
Mann, I. R., Di Pippo, S., Opgenoorth, H. J., Kuznetsova, M. & Kendall, D. J. (2018). International Collaboration Within the United Nations Committee on the Peaceful Uses of Outer Space: Framework for International Space Weather Services (2018-2030). Space Weather: The international journal of research and applications, 16(5), 428-433
Open this publication in new window or tab >>International Collaboration Within the United Nations Committee on the Peaceful Uses of Outer Space: Framework for International Space Weather Services (2018-2030)
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2018 (English)In: Space Weather: The international journal of research and applications, ISSN 1542-7390, E-ISSN 1542-7390, Vol. 16, no 5, p. 428-433Article in journal, Editorial material (Other academic) Published
Abstract [en]

Severe space weather is a global threat that requires a coordinated global response. In this Commentary, we review some previous successful actions supporting international coordination between member states in the United Nations (UN) context and make recommendations for a future approach. Member states of the UN Committee on the Peaceful Uses of Outer Space (COPUOS) recently approved new guidelines related to space weather under actions for the long-term sustainability of outer space activities. This is to be followed by UN Conference on the Exploration and Peaceful Uses of Outer Space (UNISPACE)+50, which will take place in June 2018 on the occasion of the fiftieth anniversary of the first UNISPACE I held in Vienna in 1968. Expanded international coordination has been proposed within COPUOS under the UNISPACE+50 process, where priorities for 2018-2030 are to be defined under Thematic Priority 4: Framework for International Space Weather Services. The COPUOS expert group for space weather has proposed the creation of a new International Coordination Group for Space Weather be implemented as part of this thematic priority. This coordination group would lead international coordination between member states and across international stakeholders, monitor progress against implementation of guidelines and best practices, and promote coordinated global efforts in the space weather ecosystem spanning observations, research, modeling, and validation, with the goal of improved space weather services. We argue that such improved coordination at the international policy level is essential for increasing global resiliency against the threats arising from severe space weather.

Keywords
space weather, United Nations, COPUOS, UNISPACE+50
National Category
Computer Systems
Identifiers
urn:nbn:se:uu:diva-366843 (URN)10.1029/2018SW001815 (DOI)000435285400001 ()
Available from: 2018-12-03 Created: 2018-12-03 Last updated: 2018-12-03Bibliographically approved
Andrews, D. J., Opgenoorth, H. J., Leyser, T. B., Buchert, S., Edberg, N. J. T., Morgan, D. D., . . . Withers, P. (2018). MARSIS Observations of Field-Aligned Irregularities and Ducted Radio Propagation in the Martian Ionosphere. Journal of Geophysical Research - Space Physics, 123(8), 6251-6263
Open this publication in new window or tab >>MARSIS Observations of Field-Aligned Irregularities and Ducted Radio Propagation in the Martian Ionosphere
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2018 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 123, no 8, p. 6251-6263Article in journal (Refereed) Published
Abstract [en]

Knowledge of Mars's ionosphere has been significantly advanced in recent years by observations from Mars Express and lately Mars Atmosphere and Volatile EvolutioN. A topic of particular interest are the interactions between the planet's ionospheric plasma and its highly structured crustal magnetic fields and how these lead to the redistribution of plasma and affect the propagation of radio waves in the system. In this paper, we elucidate a possible relationship between two anomalous radar signatures previously reported in observations from the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on Mars Express. Relatively uncommon observations of localized, extreme increases in the ionospheric peak density in regions of radial (cusp-like) magnetic fields and spread echo radar signatures are shown to be coincident with ducting of the same radar pulses at higher altitudes on the same field lines. We suggest that these two observations are both caused by a high electric field (perpendicular to B) having distinctly different effects in two altitude regimes. At lower altitudes, where ions are demagnetized and electrons magnetized, and recombination dominantes, a high electric field causes irregularities, plasma turbulence, electron heating, slower recombination, and ultimately enhanced plasma densities. However, at higher altitudes, where both ions and electrons are magnetized and atomic oxygen ions cannot recombine directly, the high electric field instead causes frictional heating, a faster production of molecular ions by charge exchange, and so a density decrease. The latter enables ducting of radar pulses on closed field lines, in an analogous fashion to interhemispheric ducting in the Earth's ionosphere.

Keywords
Mars, ionosphere, irregularities, MARSIS, crustal fields, plasma
National Category
Fusion, Plasma and Space Physics Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-368054 (URN)10.1029/2018JA025663 (DOI)000445731300011 ()
Funder
Swedish Research Council, 621-2014-5526Swedish National Space Board, 162/14
Available from: 2018-12-07 Created: 2018-12-07 Last updated: 2018-12-07Bibliographically approved
Liemohn, M. W., McCollough, J. P., Jordanova, V. K., Ngwira, C. M., Morley, S. K., Cid, C., . . . Vasile, R. (2018). Model Evaluation Guidelines for Geomagnetic Index Predictions. Space Weather: The international journal of research and applications, 16(12), 2079-2102
Open this publication in new window or tab >>Model Evaluation Guidelines for Geomagnetic Index Predictions
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2018 (English)In: Space Weather: The international journal of research and applications, ISSN 1542-7390, E-ISSN 1542-7390, Vol. 16, no 12, p. 2079-2102Article in journal (Refereed) Published
Abstract [en]

Geomagnetic indices are convenient quantities that distill the complicated physics of some region or aspect of near‐Earth space into a single parameter. Most of the best‐known indices are calculated from ground‐based magnetometer data sets, such as Dst, SYM‐H, Kp, AE, AL, and PC. Many models have been created that predict the values of these indices, often using solar wind measurements upstream from Earth as the input variables to the calculation. This document reviews the current state of models that predict geomagnetic indices and the methods used to assess their ability to reproduce the target index time series. These existing methods are synthesized into a baseline collection of metrics for benchmarking a new or updated geomagnetic index prediction model. These methods fall into two categories: (1) fit performance metrics such as root‐mean‐square error and mean absolute error that are applied to a time series comparison of model output and observations and (2) event detection performance metrics such as Heidke Skill Score and probability of detection that are derived from a contingency table that compares model and observation values exceeding (or not) a threshold value. A few examples of codes being used with this set of metrics are presented, and other aspects of metrics assessment best practices, limitations, and uncertainties are discussed, including several caveats to consider when using geomagnetic indices.

Abstract [en]

Plain Language Summary: One aspect of space weather is a magnetic signature across the surface of the Earth. The creation of this signal involves nonlinear interactions of electromagnetic forces on charged particles and can therefore be difficult to predict. The perturbations that space storms and other activity causes in some observation sets, however, are fairly regular in their pattern. Some of these measurements have been compiled together into a single value, a geomagnetic index. Several such indices exist, providing a global estimate of the activity in different parts of geospace. Models have been developed to predict the time series of these indices, and various statistical methods are used to assess their performance at reproducing the original index. Existing studies of geomagnetic indices, however, use different approaches to quantify the performance of the model. This document defines a standardized set of statistical analyses as a baseline set of comparison tools that are recommended to assess geomagnetic index prediction models. It also discusses best practices, limitations, uncertainties, and caveats to consider when conducting a model assessment.

National Category
Geophysics Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-375858 (URN)10.1029/2018SW002067 (DOI)000455442300015 ()
Funder
EU, FP7, Seventh Framework Programme, 606716 SPACESTORMEU, Horizon 2020, 637302 PROGRESSEU, Horizon 2020, 776287 SWAMIEU, Horizon 2020, 776011
Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-02-01Bibliographically approved
Welling, D. T., Ngwira, C. M., Opgenoorth, H., Haiducek, J. D., Savani, N. P., Morley, S. K., . . . Liemohn, M. W. (2018). Recommendations for Next-Generation Ground Magnetic Perturbation Validation. Space Weather: The international journal of research and applications, 16(12), 1912-1920
Open this publication in new window or tab >>Recommendations for Next-Generation Ground Magnetic Perturbation Validation
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2018 (English)In: Space Weather: The international journal of research and applications, ISSN 1542-7390, E-ISSN 1542-7390, Vol. 16, no 12, p. 1912-1920Article in journal (Refereed) Published
Abstract [en]

Data-model validation of ground magnetic perturbation forecasts, specifically of the time rate of change of surface magnetic field, dB/dt, is a critical task for model development and for mitigation of geomagnetically induced current effects. While a current, community-accepted standard for dB/dt validation exists (Pulkkinen et al., 2013), it has several limitations that prevent more complete understanding of model capability. This work presents recommendations from the International Forum for Space Weather Capabilities Assessment Ground Magnetic Perturbation Working Team for creating a next-generation validation suite. Four recommendations are made to address the existing suite: greatly expand the number of ground observatories used, expand the number of events included in the suite from six to eight, generate metrics as a function of magnetic local time, and generate metrics as a function of activity type. For each of these, implementation details are explored. Limitations and future considerations are also discussed.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-375857 (URN)10.1029/2018SW002064 (DOI)000455442300002 ()
Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-02-01Bibliographically approved
Marque, C., Klein, K.-L., Monstein, C., Opgenoorth, H. J., Pulkkinen, A., Buchert, S., . . . Thulesen, P. (2018). Solar radio emission as a disturbance of aeronautical radionavigation. Journal of Space Weather and Space Climate, 8, Article ID A42.
Open this publication in new window or tab >>Solar radio emission as a disturbance of aeronautical radionavigation
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2018 (English)In: Journal of Space Weather and Space Climate, ISSN 2115-7251, E-ISSN 2115-7251, Vol. 8, article id A42Article in journal (Refereed) Published
Abstract [en]

On November 4th, 2015 secondary air traffic control radar was strongly disturbed in Sweden and some other European countries. The disturbances occurred when the radar antennas were pointing at the Sun. In this paper, we show that the disturbances coincided with the time of peaks of an exceptionally strong (similar to 10(5) Solar Flux Units) solar radio burst in a relatively narrow frequency range around 1 GHz. This indicates that this radio burst is the most probable space weather candidate for explaining the radar disturbances. The dynamic radio spectrum shows that the high flux densities are not due to synchrotron emission of energetic electrons, but to coherent emission processes, which produce a large variety of rapidly varying short bursts (such as pulsations, fiber bursts, and zebra patterns). The radio burst occurs outside the impulsive phase of the associated flare, about 30 min after the soft X-ray peak, and it is temporarily associated with fast evolving activity occurring in strong solar magnetic fields. While the relationship with strong magnetic fields and the coherent spectral nature of the radio burst provide hints towards the physical processes which generate such disturbances, we have so far no means to forecast them. Well-calibrated monitoring instruments of whole Sun radio fluxes covering the UHF band could at least provide a real-time identification of the origin of such disturbances, which reports in the literature show to also affect GPS signal reception.

Place, publisher, year, edition, pages
EDP Sciences, 2018
Keywords
Sun: radio radiation, Sun: flares, Sun: solar-terrestrial relations
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-367389 (URN)10.1051/swsc/2018029 (DOI)000446555400002 ()
Available from: 2018-12-04 Created: 2018-12-04 Last updated: 2018-12-04Bibliographically approved
Witasse, O., Sanchez-Cano, B., Mays, M. L., Kajdic, P., Opgenoorth, H., Elliott, H. A., . . . Altobelli, N. (2017). Interplanetary coronal mass ejection observed at STEREO-A, Mars, comet 67P/Churyumov-Gerasimenko, Saturn, and New Horizons en route to Pluto: Comparison of its Forbush decreases at 1.4, 3.1, and 9.9 AU. Journal of Geophysical Research - Space Physics, 122(8), 7865-7890
Open this publication in new window or tab >>Interplanetary coronal mass ejection observed at STEREO-A, Mars, comet 67P/Churyumov-Gerasimenko, Saturn, and New Horizons en route to Pluto: Comparison of its Forbush decreases at 1.4, 3.1, and 9.9 AU
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2017 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 8, p. 7865-7890Article in journal (Refereed) Published
Abstract [en]

We discuss observations of the journey throughout the Solar System of a large interplanetary coronal mass ejection (ICME) that was ejected at the Sun on 14 October 2014. The ICME hit Mars on 17 October, as observed by the Mars Express, Mars Atmosphere and Volatile EvolutioN Mission (MAVEN), Mars Odyssey, and Mars Science Laboratory (MSL) missions, 44h before the encounter of the planet with the Siding-Spring comet, for which the space weather context is provided. It reached comet 67P/Churyumov-Gerasimenko, which was perfectly aligned with the Sun and Mars at 3.1 AU, as observed by Rosetta on 22 October. The ICME was also detected by STEREO-A on 16 October at 1 AU, and by Cassini in the solar wind around Saturn on the 12 November at 9.9AU. Fortuitously, the New Horizons spacecraft was also aligned with the direction of the ICME at 31.6 AU. We investigate whether this ICME has a nonambiguous signature at New Horizons. A potential detection of this ICME by Voyager 2 at 110-111 AU is also discussed. The multispacecraft observations allow the derivation of certain properties of the ICME, such as its large angular extension of at least 116 degrees, its speed as a function of distance, and its magnetic field structure at four locations from 1 to 10 AU. Observations of the speed data allow two different solar wind propagation models to be validated. Finally, we compare the Forbush decreases (transient decreases followed by gradual recoveries in the galactic cosmic ray intensity) due to the passage of this ICME at Mars, comet 67P, and Saturn.

Keywords
interplanetary coronal mass ejection, Forbush decrease, Mars, comet 67P, Saturn, New Horizons
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-336648 (URN)10.1002/2017JA023884 (DOI)000411788800002 ()
Funder
Swedish National Space Board, 135/13Swedish Research Council, 621-2013-4191
Available from: 2017-12-15 Created: 2017-12-15 Last updated: 2017-12-15Bibliographically approved
Sanchez-Cano, B., Hall, B. E., Lester, M., Mays, M. L., Witasse, O., Ambrosi, R., . . . Reyes-Ayala, K. I. (2017). Mars plasma system response to solar wind disturbances during solar minimum. Journal of Geophysical Research - Space Physics, 122(6), 6611-6634
Open this publication in new window or tab >>Mars plasma system response to solar wind disturbances during solar minimum
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2017 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 122, no 6, p. 6611-6634Article in journal (Refereed) Published
Abstract [en]

This paper is a phenomenological description of the ionospheric plasma and induced magnetospheric boundary (IMB) response to two different types of upstream solar wind events impacting Mars in March 2008, at the solar minimum. A total of 16 Mars Express orbits corresponding to five consecutive days is evaluated. Solar TErrestrial RElations Observatory-B (STEREO-B) at 1AU and Mars Express and Mars Odyssey at 1.644AU detected the arrival of a small transient interplanetary coronal mass ejection (ICME-like) on the 6 and 7 of March, respectively. This is the first time that this kind of small solar structure is reported at Mars's distance. In both cases, it was followed by a large increase in solar wind velocity that lasted for similar to 10days. This scenario is simulated with the Wang-Sheeley-Arge (WSA) - ENLIL + Cone solar solar wind model. At Mars, the ICME-like event caused a strong compression of the magnetosheath and ionosphere, and the recovery lasted for similar to 3 orbits (similar to 20h). After that, the fast stream affected the upper ionosphere and the IMB, which radial and tangential motions in regions close to the subsolar point are analyzed. Moreover, a compression in the Martian plasma system is also observed, although weaker than after the ICME-like impact, and several magnetosheath plasma blobs in the upper ionosphere are detected by Mars Express. We conclude that, during solar minimum and at aphelion, small solar wind structures can create larger perturbations than previously expected in the Martian system.

Keywords
ICME transient, fast solar wind stream, ionosphere of Mars, Martian plasma system, Martian boundaries, solar minimum
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-331894 (URN)10.1002/2016JA023587 (DOI)000405534800049 ()
Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2017-10-27Bibliographically approved
Kauristie, K., Morschhauser, A., Olsen, N., Finlay, C. C., McPherron, R. L., Gjerloev, J. W. & Opgenoorth, H. J. (2017). On the Usage of Geomagnetic Indices for Data Selection in Internal Field Modelling. Space Science Reviews, 206(1-4), 61-90
Open this publication in new window or tab >>On the Usage of Geomagnetic Indices for Data Selection in Internal Field Modelling
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2017 (English)In: Space Science Reviews, ISSN 0038-6308, E-ISSN 1572-9672, Vol. 206, no 1-4, p. 61-90Article, review/survey (Refereed) Published
Abstract [en]

We present a review on geomagnetic indices describing global geomagnetic storm activity (Kp, am, Dst and dDst/dt) and on indices designed to characterize high latitude currents and substorms (PC and AE-indices and their variants). The focus in our discussion is in main field modelling, where indices are primarily used in data selection criteria for weak magnetic activity. The publicly available extensive data bases of index values are used to derive joint conditional Probability Distribution Functions (PDFs) for different pairs of indices in order to investigate their mutual consistency in describing quiet conditions. This exercise reveals that Dst and its time derivative yield a similar picture as Kp on quiet conditions as determined with the conditions typically used in internal field modelling. Magnetic quiescence at high latitudes is typically searched with the help of Merging Electric Field (MEF) as derived from solar wind observations. We use in our PDF analysis the PC-index as a proxy for MEF and estimate the magnetic activity level at auroral latitudes with the AL-index. With these boundary conditions we conclude that the quiet time conditions that are typically used in main field modelling (, and ) correspond to weak auroral electrojet activity quite well: Standard size substorms are unlikely to happen, but other types of activations (e.g. pseudo breakups ) can take place, when these criteria prevail. Although AE-indices have been designed to probe electrojet activity only in average conditions and thus their performance is not optimal during weak activity, we note that careful data selection with advanced AE-variants may appear to be the most practical way to lower the elevated RMS-values which still exist in the residuals between modeled and observed values at high latitudes. Recent initiatives to upgrade the AE-indices, either with a better coverage of observing stations and improved baseline corrections (the SuperMAG concept) or with higher accuracy in pinpointing substorm activity (the Midlatitude Positive Bay-index) will most likely be helpful in these efforts.

Place, publisher, year, edition, pages
SPRINGER, 2017
Keywords
Geomagnetic indices, Geomagnetic quiescent times
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-321568 (URN)10.1007/s11214-016-0301-0 (DOI)000399021100004 ()
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2017-05-08Bibliographically approved
Stolle, C., Olsen, N., Richmond, A. D. & Opgenoorth, H. J. (2017). Topical Volume on Earth's Magnetic Field-Understanding Geomagnetic Sources from the Earth's Interior and Its Environment. Space Science Reviews, 206(1-4), 1-3
Open this publication in new window or tab >>Topical Volume on Earth's Magnetic Field-Understanding Geomagnetic Sources from the Earth's Interior and Its Environment
2017 (English)In: Space Science Reviews, ISSN 0038-6308, E-ISSN 1572-9672, Vol. 206, no 1-4, p. 1-3Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
SPRINGER, 2017
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-321567 (URN)10.1007/s11214-017-0346-8 (DOI)000399021100001 ()
Available from: 2017-05-08 Created: 2017-05-08 Last updated: 2017-05-08Bibliographically approved
Hall, B. E., Lester, M., Nichols, J. D., Sanchez-Cano, B., Andrews, D. J., Opgenoorth, H. J. & Fraenz, M. (2016). A survey of superthermal electron flux depressions, or "electron holes," within the illuminated Martian induced magnetosphere. Journal of Geophysical Research - Space Physics, 121(5), 4835-4857
Open this publication in new window or tab >>A survey of superthermal electron flux depressions, or "electron holes," within the illuminated Martian induced magnetosphere
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2016 (English)In: Journal of Geophysical Research - Space Physics, ISSN 2169-9380, E-ISSN 2169-9402, Vol. 121, no 5, p. 4835-4857Article in journal (Refereed) Published
Abstract [en]

Since Mars lacks a global intrinsic magnetic field, the solar wind interacts directly with the Martian upper atmosphere and ionosphere. The presence of localized intense remnant crustal magnetic fields adds to this interaction, making the Martian plasma system a unique environment within the solar system. Rapid reductions in the electron flux, referred to as electron holes, occur within the Martian induced magnetosphere (IM). We present a statistical analysis of this phenomenon identified from proxy measurements of the electron flux derived from measurements by the Analyser of Space Plasmas and Energetic Neutral Atoms Electron Spectrometer experiment on board the Mars Express (MEX) spacecraft. The study is completed for the period of 9 February 2004 to 9 May 2014. Electron holes are observed within the IM in more than 56% of MEX orbits during this study period, occurring predominantly at altitudes less than 1300km, with the majority in the negative X Mars-Centric Solar Orbital direction. The spatial distribution above the surface of Mars is observed to bear close resemblance to that of the crustal magnetic fields as predicted by the Cain et al. [] magnetic field model, suggesting that they play an important role in the formation of these phenomena.

Keywords
electron holes, plasma void, electron depression, induced magnetosphere, Mars' plasma environment, Mars Express
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-300976 (URN)10.1002/2015JA021866 (DOI)000380025500069 ()
Funder
Swedish National Space Board, DNR 162/14Swedish Research Council, DNR 621-2014-5526
Available from: 2016-08-23 Created: 2016-08-16 Last updated: 2017-11-28Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-7573-5165

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