Publications

Mapping solar activity predicts extreme space weather

Communications Highlights, Press releases, Publications
Image credit: NASA/GSFC/SDO via Flickr (https://www.flickr.com/photos/nasamarshall/36084784530/in/photolist-WYFXgq-H23uUf-egcv1D-JPW9Lg-2om9385-7uNYCV-pvyZdV-rtto5q-rx2vZh-d5UHAf-rhSm38-eSqM1Q-6zxYvb-apCzE2-d5UHiu-9H574x-csBTnw-U5C8ov-8cATGx-nvDmy9-d6x8hh-oKtj56-csBTpY-oX69UY-ueqRkC-usYAun-dZEcn7-dtBfWJ-efJGiG-94PupK-d5UJF5-8q1Lru-j6mSQZ-b8wsMi-egifLq-boi589-ch8t4W-psENeq-dm45RP-v36oFT-p7Pc2U-oKtjjz-nMZDYf-bozyiY-d5UJiq-dZEcib-aoWSDN-TzEYJf-bxkQBK-ch8suW)
NASA/GSFC/SDO via Flickr

A regular clock correlating different solar activities provides, for the first time, a physical explanation for the observed cycle of solar activity.

BERN, SWITZERLAND, 18.04.2024 – The variable nature of the solar cycle is a perplexing issue in solar physics with wide-ranging implications for space weather on the Earth impacting societal activities. Utilizing the Hilbert transform of sunspot numbers, former ISSI Johannes Geiss fellow Sandra Chapman from the University of Warwick in the UK together with co-author Thierry Dudok de Wit from the International Space Science Institute Bern in Switzerland and the University of Orléans in France have devised a method to synchronize the fluctuating 11-year Schwabe cycle to a simple, uniform clock. This innovative approach allows for the correlation of extreme space weather events, as indicated by the aa index (i.e., the longest continuous record of the magnetic field), with solar active region dynamics dating back to 1874.
Key findings reveal a pivotal transition point: when over 90% of solar active regions converge within approximately 15° of the solar equator, the occurrence of the most severe space weather events diminishes. This shift occurs from regions characterized by high gradients in solar differential rotation, capable of fueling coronal mass ejections, to areas where rotational dynamics remain relatively constant across latitudes.
Moreover, the study elucidates the onset of moderate space weather events, coinciding with 27-day solar rotation recurrences in the aa index. This correlation aligns with the relocation of solar active region centroids to within 15° of the solar equator, indicating stable and persistent source regions for high-speed solar streams.
These findings provide a compelling physical explanation for the observed two-component cycle of activity in the aa index, shedding light on the intricate relationship between solar dynamics and space weather phenomena. Such insights hold promise for enhancing our ability to predict and mitigate the societal impacts of extreme space weather events.

Chapman, S.C. and Dudok de Wit, T. (2024). A solar cycle clock for extreme space weather, Scientific Reports, https://doi.org/10.1038/s41598-024-58960-5

Author details

Sandra Chapman (1,2) and Thierry Dudok de Wit (3,4)

  1. Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, Coventry, UK (s.c.chapman@warwick.ac.uk)
  2. Department of Mathematics and Statistics, University of Tromso, Norway
  3. International Space Science Institute, Bern, Switzerland (thierry.dudokdewit@issibern.ch)
  4. LPC2E, University of Orleans/CNRS/CNES, France

Note to the media

When reporting on this story, please mention the ISSI Johannes Geiss fellowship of Sandra Chapman.

Press release text by Fabio Crameri

ISSI Press Contact:
Fabio Crameri
ISSI Communication Specialist
Bern, Switzerland
fabio.crameri@issibern.ch

More information

The International Space Science Institute (ISSI) is an Institute of Advanced Studies, where scientists from all over the world meet in a neutral, welcoming, and multi-disciplinary setting to discuss relevant and compelling topics related to four Disciplines: Astrophysics, Heliophysics, Planetary Science and Earth Science. ISSI’s mission is to advance science by facilitating scientific community interactions, meetings and discussions aimed at a deeper understanding of results from different space missions, ground-based observations, and theory. This is achieved through a broad portfolio of scientific opportunities that include: International Teams, Workshops, Working Groups, Forums, or visits of individual Visiting Scientists. For additional information related to ISSI and to the opportunities it offers, see: www.issibern.ch.

Credit

CC BY-SA 4.0

The Quest for Ancient Space Weather Reports

Communications From the Teams, Highlights, Publications, Science
The great auroral display seen in Augsburg on 6 March 1582, reproduced in Usoskin et al. (2023) with permission from Zentralbibliothek Zürich, Department of Prints and Drawings/Photo Archive (shelfmark: ZB Graphische Sammlung (GSB), PAS II 19/4).
The great auroral display seen in Augsburg on 6 March 1582, reproduced in Usoskin et al. (2023) with permission from Zentralbibliothek Zürich, Department of Prints and Drawings/Photo Archive (shelfmark: ZB Graphische Sammlung (GSB), PAS II 19/4).
Earliest Records of Solar Events

The Sun often produces eruptive events on different energetic and temporal scales. It might, however, also produce events, so-called extreme solar events, whose energy could be orders of magnitude greater than anything we have observed during recent decades. But what is an extreme solar event? How strong can they be and how often do they occur?

To find answers to these and other questions, the ISSI team around Fusa Miyake from Nagoya University in Japan and Ilya Usoskin from Oulu University in Finland went back, far back in time.

Using a combined approach with so far unused measured and archival data, the team studies extreme space weather events that would have catastrophic impact not only on our astronauts and their equipment, but also on our power and communications infrastructure here on the ground.

The examined historical records date back over three millennia! One significant finding is the earliest documented reports of candidate aurorae known today, with a Babylonian astronomer reporting a “red glow” in 567 BCE and possible auroral sightings in Assyrian cuneiform tablets from 679–655 BCE. Additionally, the Bamboo Annals, an ancient Chinese text, describe a celestial event involving a “five-coloured light” in the last year of King Zhāo of the Zhōu Dynasty.

These reports have been correlated with modern records and analysed to determine their likelihood as auroral events, providing insight into ancient space weather occurrences. This research not only extends our space weather chronology but also suggests the existence of a solar minimum around 810–720 BCE, termed the “Neo-Assyrian Grand Minimum“, challenging previous understandings of solar activity during that period.

Read more about this fascinating undertaking in: Usoskin, I., Miyake, F., Baroni, M. et al. Extreme Solar Events: Setting up a Paradigm. Space Sci Rev 219, 73 (2023). https://doi.org/10.1007/s11214-023-01018-1

Solar and Stellar Dynamos: A New Era

Spotlight Publications

New Topical Collection published in Space Science Reviews (Open Access)

Large-scale and small-scale dynamos generating magnetic flux are fundamental processes in astrophysics, for which solar and stellar dynamos provide crucial paradigms. During the last two decades, a wealth of new observational results, together with a new generation of large-scale numerical simulations, gave important insights in the complex interactions of turbulent convection, rotation, and magnetic fields by self-excited dynamo action in the Sun and other stars. 

This open-access collection edited by Manfred Schüssler, Robert Cameron, Paul Charbonneau, Mausumi Dikpati, Hideyuki Hotta and Leonid Kitchatinov, presents results from the ISSI Workshop “Solar and Stellar Dynamos: a New Era”, held 13–17 June 2022, which reviewed and put into perspective the results from observations, simulations, and simplified models. It covers the whole range of topics discussed during the meeting: solar and stellar observations from space and ground, numerical simulations, turbulence theory, and dynamo models.

This collection will be also published as #90 in the Space Science Series of ISSI.

The Heliosphere in the Local Interstellar Medium – Into the Unknown

Spotlight Publications, SSSI Volumes

Volume 88 in the Space Sciences Series of ISSI

“The Heliosphere in the Local Interstellar Medium”, the Proceedings of the first ISSI Workshop (6-10 November 1995), held in Bern, Switzerland and edited by R. von Steiger, R. Lallement, and M.A. Lee and published in 1996, was the first International Space Science Institute (ISSI) book (#1) in the Space Sciences Series. This book covers the knowledge gained in the subsequent 27 years that revolutionized our understanding of the interaction of the heliosphere with the very local interstellar medium (VLISM). Entirely new regions of space have been explored! The Voyagers both crossed the termination shock, passed through the heliosheath, crossed the heliopause, and entered the interstellar medium. New Horizons was launched with more modern instrumentation and explores low-latitude regions of the outer heliosphere. Energetic neutral atoms observed by IBEX and CASSINI allowed exploration of the heliosphere over the whole sky. The initial reconnaissance of the heliosphere and VLISM is complete with in situ measurements, observations of energetic neutral atoms (ENAs), neutral VLISM H and He, UV emissions, and interstellar dust.

This book is a collection reviews from experts in the many aspects of this field that describe the current state of knowledge of the heliosphere’s interaction with the interstellar medium, puzzles yet to be solved, and future plans to continue these studies.

This volume results from a Workshop held at the International Space Science Institute (ISSI) in Bern on 8–12 November, 2021.

The book is edited by J.R. Richardson, A. Bykov, F. Effenberger, K. Scherer, V.J. Sterken, R. von Steiger and G.P. Zank.

This Volume is co-published as open access Topical Collection in Space Science Reviews.

Global Change in Africa

Spotlight Publications, SSSI Volumes

Volume 86 in the Space Sciences Series of ISSI

The main objective of this book is to provide an overview of the benefit of using Earth Observation data to monitor global environmental changes due to natural phenomena and anthropogenic forcing factors over the African continent, and highlight a number of applications of high societal relevance. The main topics presented in the book concern: water resources, floods and droughts, coastal zones changes and exploitation of mineral resources and its impact on the environment. 

The chapters “Enhancing the Uptake of Earth Observation Products and Services in Africa Through a Multi-level Transdisciplinary Approach”, “Water Resources in Africa under Global Change: Monitoring Surface Waters from Space”, “Water Resources in Africa: The Role of Earth Observation Data and Hydrodynamic Modeling to Derive River Discharge”, “The Role of Space-Based Observations for Groundwater Resource Monitoring over Africa”, “Hydrometeorological Extreme Events in West Africa: Droughts”, “Hydrometeorological Extreme Events in Africa: The Role of Satellite Observations for Monitoring Pluvial and Fluvial Flood Risk”, “Artisanal Exploitation of Mineral Resources: Remote Sensing Observations of Environmental Consequences, Social and Ethical Aspects” and “Coastal Zone Changes in West Africa: Challenges and Opportunities for Satellite Earth Observations” are available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

 This volume results from a remote Workshop organized by the International Space Science Institute (ISSI) on 11–15 January 2021.

The volume is edited by A. Cazenave, D. Baratoux, T. Lopez, J.K. Kouamé, J. Beneviste, and L. Moreira and all chapters are co-published open access in Surveys in Geophysics, Volume 44, Issue 1, 2023

Hard Copy >>

 

 

Probing Earth’s Deep Interior using Space Observations Synergistically

Spotlight Publications, SSSI Volumes

Volume 85 in the Space Sciences Series of ISSI

During the recent decades, space missions (e.g., CHAMP, GOCE, GRACE and Swarm) have been developed by space agencies in Europe and the USA to measure the Earth’s gravity and magnetic fields and their spatio-temporal variations. These successful missions have already provided a wealth of groundbreaking results about the permanent and time-variable gravity and magnetic fields of the Earth. However, more can be learned about the Earth’s structure by combining data of the gravity and magnetic fields, together with Earth’s rotation data routinely measured using space geodesy techniques, as well as with the most up-to-date modelling of the Earth’s internal structure. Use in synergy of these global observables and model data represents a unique way to further investigate the physics of the deep Earth’s interior. In addition to the well-known correlation between Earth’s rotation and magnetic field observed at interannual and decadal time scales, recent studies have reported unexpected correlation between spatio-temporal changes of the gravity field and magnetic field, also at interannual time scale. These changes may result from processes occurring in the liquid core and at the core-mantle boundary.

This book gathers a series of chapters that provide state-of-the art overviews on the gravity field, magnetic field and Earth’s rotation observations, and on their interpretation in terms of the deep Earth’s structure, as well as on core dynamics and processes at the core-mantle boundary. This volume results from a Workshop held at the International Space Science Institute (ISSI) in Bern on 1–4 September, 2020.

The chapters ‘Gravity Variations and Ground Deformations Resulting from Core Dynamics’, ‘Rapid Variations of Earth’s Core Magnetic Field’, ‘A Dynamical Prospective on Interannual Geomagnetic Field Changes’, ‘Core Eigenmodes and their Impact on the Earth’s Rotation’, ‘Earth’s Rotation: Observations and Relation to Deep Interior’, ‘Interiors of Earth-Like Planets and Satellites of the Solar System’, ‘Correction to: Interiors of Earth-like planets and satellites of the Solar System’, ‘Fluid Dynamics Experiments for Planetary Interiors’, ‘Structure, Materials and Processes in the Earth’s Core and Mantle’, ‘Correction to: Structure, Materials and Processes in the Earth’s Core and Mantle’ and ‘Applications and Challenges of GRACE and GRACE Follow-On Satellite Gravimetry’ are available open access under a Creative Commons Attribution 4.0 International License via link.springer.com. 

The book is edited by Veronique Dehant, Mioara Mandea,  Anny Cazenave, Lorena Moreira and all chapters are co-published open access in Surveys in Geophysics, Volume 43, Issue 1, 2022. 

Hard Copy >>

 

 

Surface-Bounded Exospheres and Interactions in the Inner Solar System

Spotlight Publications

New Topical Collection published in Space Science Reviews (Open Access)

A new collection of 8 review articles has been completed and is available online in Space Science Reviews, a printed book version will be published as volume 84 of the Space Sciences Series of ISSI.

Studying the evolution of the surfaces and atmospheres of planetary bodies in the solar system is fundamental to our understanding of the present state of the solar system. Exospheres are the interfaces between the planetary body and the open space, so that, studying the exospheric filling and loss processes is the way to expand knowledge of the body’s evolution. While the exospheres are present around any kind of planetary body, they are quite different if we consider the bodies with an atmosphere and those without a collisional gas envelope.  In the latter case the exosphere is directly connected to the surface, thus, it is called surface-bounded exosphere, since the surface release processes are also the exospheric filling ones and atoms and molecules collide with the surface far more frequently than collisions with each other. 

Edited by Anna Milillo, Menelaos Sarantos, Benjamin D. Teolis, Go Murakami, and Peter Wurz, this collection presents results from the ISSI Workshop “Surface Bounded Exospheres and Interactions in the Solar System”, held 20–24 January 2020, which reviewed the knowledge on the surface-bounded exosphere conditions, generation, variability and loss processes, from theoretical, observational and experimental points of view. The output collects the present state of knowledge on this subject and drafts a roadmap for future investigations in view of the next missions, i.e., BepiColombo to Mercury or orbiters and landers to be operated on the Moon.

Complete Topical Collection in Space Science Reviews >>

Human-Caused Warming and Naturally Occurring Cycles Together Regulate Extreme Ocean Events

Spotlight Johannes Geiss Fellowship, Publications, Science

Global sea level and extreme ocean events are rising due to human-caused climate change. The amount of rise in sea level and number of increase in extreme events, however, vary greatly from region to region and they also change over time. To fully understand these changes and thus build the capability of predicting when and where they may occur in the future, we must also consider naturally occurring climate variability. By combining in situ and satellite observations with model simulations, Weiqing Han and collaborators recently investigated the sea level Height EXtreme (HEX) events and co-occurring Marine heatwaves, dubbed Compound Height-Heat EXtreme (CHHEX) events, along Indonesian coasts of the Indian Ocean since the 1960s, particular since 1993 when satellite altimetry data have become available. They found out that most of the HEX and CHHEX events occured during the period from 2010 to 2017. Sea level rise due to the anthropogenic warming and naturally occurring decadal climate variability combined to boost up the HEXs from 2010 to 2017. While the individual HEX-alone events are mainly driven by enhanced northwesterly winds associated with the Indian and/or Australian monsoons from December to March, CHHEXs occur in May-June and November-December mainly in years when negative Indian Ocean Dipole (IOD) and La Niña, the negative phase of the El Niño – Southern Oscillation (ENSO), co-occur. The ENSO and IOD are the dominant natural internal climate variability patterns at interannual time scale. When they co-occur, the intensified equatorial westerly winds and longshore northwesterly winds drive the HEX and CHHEX events. A recent study – published in Nature Communications in October 2022 – suggests the importance of the interplay between interannual-to-decadal climate variability and anthropogenic warming in shaping the extremes, which may help improve decadal predictions and near-term projections of the high impact extreme events. For further details, see the University of Colorado Boulder news release.

Figure: Linear trend maps of satellite observed sea level and surface wind stress from 1993-2018 (left figure).  Time series of monthly-mean sea level anomalies from tide gauge observation (black curve) at Java coast (location marked “x2” in the left panel), from satellite observation at the nearest grid point (red), and from the European Centre for Medium-Range Weather Forecasts (ECMWF) Ocean Reanalysis System 4 (ORAS4) ocean reanalysis data at the nearest location (blue)(right figure). (Credit: W. Han)

 

 

Weiqing Han

Prof. Weiqing Han (University of Colorado at Boulder, USA) is elected Fellow of American Meteorological Society in 2023 and was selected as the Johannes Geiss Fellow in 2020. Because of the Covid-related travel restrictions, Weiqing Han visited ISSI for the first time in summer 2023. Weiqing has been working on a number of research topics, including understanding the remote versus local forcing in driving year-to-year variations of the U.S. east coasts sea level, exploring the roles of atmospheric intraseasonal oscillations – particularly the Madden-Julian Oscillation – in causing sea level extremes along the Indonesian coasts, finding new climate patterns in the tropical Atlantic and Indian Oceans, and investigating the Indian-Pacific-monsoon interactions as well as the global linkage of decadal sea level patterns.

edited by Andrea Fischer

The Heliosphere in the Local Interstellar Medium: Into the Unknown

Spotlight Publications

New Topical Collection published in Space Science Reviews (all papers are Open Access)

A new collection of 18 review articles has been completed and is available online in Space Science Reviews, a printed book version will be published as volume 88 of the Space Sciences Series of ISSI.

This collection presents results from the ISSI Workhop “The Heliosphere in the Local Interstellar Medium”, held 8–12 November 2021, which aims to describe the complete heliosphere, including the heliopause and the effects of the heliosphere on the LISM. It covers observations and modelling and highlight what has been learned and what is still not understand. Although emphasis is on the results of the past decade, the full interaction from pickup ions to the termination shock to the LISM is covered with the goal of making this a complete reference.

This Topical Collection is edited by John D. Richardson, Andrei Bykov, Frederic Effenberger, Klaus Scherer, Rudolf von Steiger, Veerle J. Sterken, and Gary P. Zank.

Introduction: Richardson, J.D., Bykov, A., Effenberger, F. et al. The Heliosphere in the Local Interstellar Medium: Into the Unknown. Space Sci Rev 219, 6 (2023). https://doi.org/10.1007/s11214-023-00957-z

Complete Topical Collection in Space Science Reviews >>

 

Global Change in Africa

Spotlight Publications

New special issue in Surveys in Geophysics (partial Open Access) >>

The contribution of Africa to global greenhouse gas emissions is among the least important, yet Africa’s “key development sectors have already experienced widespread losses and damages attributable to anthropogenic climate change, including biodiversity loss, water shortages, reduced food production, loss of lives and reduced economic growth” (IPCC, 2022). Consequently, a prioritized task for Africa is to improve climate resilience in order to achieve sustainable and equitable development and to guarantee the quality of life for its population. In that context, in January 2021 the International Space Science Institute (ISSI, Bern) organized a workshop on “Global Change in Africa”. The main objective of the workshop was to investigate the benefits of using Earth Observation (EO) data to monitor global environmental changes due to natural phenomena and anthropogenic forcing factors over the African continent and to highlight a number of applications of high societal relevance. Another objective was to discuss the opportunities for collaborations between the international transdisciplinary scientific community and local research institutes as well as with African national and intergovernmental agencies. The workshop, in hybrid form due to the COVID-19 epidemic, gathered 31 participants from 11 different countries, including 6 participants from Africa.

This special issue will be reprinted as as the Volume 86 in the Space Science Series of ISSI and is edited by Anny Cazenave, David Baratoux, Teodolina Lopez, Jean Kan Kouamé, Jérôme Benveniste and Lorena Moreira.