Mo 16 March Tue 17 March Wed 18 March

08:30 Welcome (Katja Matthes)

Chair Session 1: Eugene Rozanov Chair Mixed Session: Kalevi Mursula Chair Session 3: Irina Mironova

08:40 Greg Kopp: Solar Radiative Forcingof Climate (invited)

08:30 Joanna Haigh: Solar spectralvariability and the Earth’s atmosphere(invited)

08:30 Bernd Funke: Energetic particleimpact on the atmosphere and the link toregional climate: Observational constraintsand current understanding (invited)

09:00 - 13:00: Outreach 09:00 - 12:30

Guided Visit of GEOMAR

09:15 Tobias Schiefendecker: Aconnection between the solar sunspotcycle and water vapor in the UpperTroposphere Lower Stratosphere?

09:40 Natalie Krivova: Measurements andmodels of solar irradiance variability in thesatellite-era

09:30 Annika Seppälä: Energetic particleforcing of the Northern Hemisphere winterstratosphere: comparison to solarirradiance forcing

09:30 Pekka Verronen: Modelling the ionchemistry of mesosphere for particleprecipitation studies

09:55 Frédéric Clette: Re-calibrating theSunspot Number: diagnostics andimplications

09:45 Amanda Maycock: The solar--‐ozone feedback in observations andmodels

09:45 Yvan Orsolini: Downard Transportof Nitrogen Oxides Produced by EnergeticParticle Precipitation

10:10 Raimund Muscheler: Sun-climatelinkages inferred from the paleorecord

10:00 Monika Andersson: Solar-cycleeffect of energetic electron precipitationseen in mesospheric ozone

10:00 Holger Nieder: Solar influence onthe MLT region: NOx production andglobal model studies

10:25Florian Adolphi: Persistent linkbetween solar activity and Greenlandclimate during the Last Glacial Maximum

10:15 Manuel Lopez-Puertas: Solar cycleand seasonal variability of CO and CO2 inthe mesosphere and lower thermosphere

10:15 Jasa Calagovic: Can isolatingspecific cloud types provide evidence of acosmic ray - cloud link?

10:40 Poster Session 1 with coffee break 10:30 Poster Mixed Session with coffeebreak 10:30 Poster Session 3 with coffee break

12:30 - 14:00 Lunch break 12:30 - 14:00 Lunch break 12:30 - 14:00 Lunch break / group photo

Planeterrella Sessions Planeterrella Sessions Planeterrella SessionsChair Session 2: Thierry Dudok de Wit Chair Session 4: Hauke Schmidt Chair Mixed Session: Yoav Yair

14:00 Mojib Latif: The Hiatus in GlobalWarming (invited)

14:00 Stefan Brönnimann: Solarinfluences on climate in observations,reconstructions, and climate models overthe past millennium (invited)

14:00 Martin Visbeck: Integrated MarineScience: Ocean - Climate - Society(invited)

14:30 Stergios Misios: Solar signals inCMIP-5 Simulations: Effects ofAtmosphere-Ocean Coupling

14:45 Martin Andrews: A simulated laggedresponse of the North Atlantic Oscillationto the Solar Cycle over the period 1960-2009

15:00 Timo Asikanen: Long-term variationand solar wind drivers of energetic particleprecipitation

15:00 Gabriel Chiodo: The impact of afuture solar minimum under a climatechange scenario

15:00 Kunihiko Kodera: Where should weexpect solar signal on the Earth's surface

15:15 Mai Mai Lam: Response of thelower atmosphere to changes in the globalatmospheric electric circuit associated withsolar wind variability

15:15 Lon Hood: Origin of the TropicalLower Stratospheric Response to 11-YrSolar Forcing

15:15 Radan Huth: Effects of the 11-yearsolar cycle on tropospheric circulation inthe Southern Hemisphere in winter

15:30 Ville Maliniemi: Long-term relationbetween geomagnetic activity andNorthern Hemisphere winter circulation

15:30 Ewa Bednarz: Separating the role ofdirect radiative heating and photolysis inmodulating the atmospheric response tothe 11-year solar cycle

15:30 Colin Price: Using Radio Waves toMonitor the Variability of MesopauseTemperatures

15:45 Konstantin Herbst: On theProduction of Cosmogenic Radionuclidesdue to Galactic and Solar Cosmic Rays

15:45 Anne Kubin: The 11-year solarsignal in ocean-coupled climate modelswith and without interactive chemistry

15:45 Eija Tanskanen: Solstice dominancein geomagnetic activity during high-speedstreams

18:30 Ice Breaker, Wissenschaftszentrum18:00 Dinner Steigenberger Hotel ContiHansaSchloßgarten 7, 24103 Kiel

Planeterrella Sessions

Thu 19 March

09.10 Margit Haberreiter: Our currentunderstanding of the variations of solarspectral irradiance (keynote)

09:00 Franz-Josef Lübken: ScientificHighlights from ROMIC

09:00 Karen Aplin: Effects of energeticparticles in the lower atmosphere(keynote)

Mini Conference onSun-Climate Connectionsfor pupils

Minikonferenz Sonne-KlimaWechselwirkungen fürSchüler:

(Andreas Villwock)

- Westshore: Introduction toGEOMAR, visit of Gliderlaboratory andmeteorological instruments

- Eastshore: visit oftechnology and logisticscentre where expeditions areplanned, instruments andobserving systems such asunder water vehicles aredeveloped, repaired andmaintained.Bus transfer between westand east shore and back toWissenschaftszentrumincluded

Teilnehmer: 10. Klasse(Geo-Profil/NaWi-Profil),GymnasiumKronshagen undDoppeljahrgang (11/12,Chemie-Profil),Max-Planck-SchuleKiel

Programm:- 9:00-10:00 Begrüßung undEinführung (Katja Matthes)- 10:00-12:45Gruppenaktivitäten1. Planeterrella (JeanLilensten, Verónica Salazar)2. Mini Poster Session (RémiThiéblemont)3. Mini Oral Session (BenLaken, Jasa Calogovic,Raimund Muscheler)- 12:45-13:00Verabschiedung

12:30 - 14:00 Lunch break

14:00 - 15:30 Wissenschaftszentrum

Scientific Discussion on Future Directions ofSun-Climate Research

14:30 Kalevi Mursula: Long-term variationof the solar wind and its suggested effectson the Earth’s atmosphere and climate(keynote)

14:30 Klarie Tourpali: Modelling theImpact of Solar Variability on the Earth'sAtmosphere and Climate (keynote)

Panelists:

Guy Brasseur (MPI-Met, Hamburg)

Greg Kopp (LASP, Boulder)

Gian-Kasper Plattner (University of Bern)

16:30 - 18:00 GEOMAR (Hörsaal Westufer)

Public Panel Discussion on Sun-Climate Connections

Öffentliche Podiumsdiskussion zum Sonneneinflussauf das Klima

16:00 Poster Session 2 16:00 Poster Session 4- Prof. Dr. Guy Brasseur (MPI-Met, Hamburg),- Dr. Gian-Kasper Plattner (Universität Bern)- Dr. Margit Haberreiter (PMOD, Davos)- Prof. Dr. Katja Matthes (GEOMAR, Kiel)

Moderation: Dr. Andreas Villwock (Leiter GEOMARPressestelle)

REPORT ON THE CONFERENCE ON SUN–CLIMATE CONNECTIONS

Kiel (Germany), March 16–19, 2014

http://scc.geomar.de

Over 90 participants attended the Sun-Climate Connections (SCC) conference, which addressed recentadvances in our understanding of the multiple connections between solar variability, and the Earth’sclimate. This meeting stood out by its highly multidisciplinary character, addressing issues such asthe impact of energetic electrons precipitating into the atmosphere, the role of the global electric cir-cuit, and the modelling of the ozone response to solar variability. The programme included a paneldiscussion with members from the broader climate community. This discussion highlighted the roleof multidisciplinary interactions, the need for better including the various solar forcings in climatesystem studies, but also the importance of having a multidisciplinary framework for pursuing suchstudies on the longer term. One day was also devoted to outreach activities, including a public debate;a team of highly motivated young scientists took care of 70 high school students, debating with themthe causes of global warming, discussing solar impacts on the Earth’s climate, and showing auroras ona Planeterrella aurora simulator.

The impact of solar variability on the Earth’s climate has all the ingredients of a fascinating problem:it involves a series of complex physical mechanisms with observations that are often too scarce toprovide definite statements, and it is also a problem with direct societal consequences.

The objective of the Sun-Climate Connections (SCC) conference was to address this problem by pro-viding an overview of our current understanding of Sun-climate connections, and address the fullchain of processes by which solar variability affects climate. This very successful meeting lasted forfour days and was attended by over 90 scientists, representing an unusually broad spectrum of dis-ciplines, such as atmospheric physics, solar physics, climatology, heliospheric physics, cosmic rayphysics, etc. In particular, all layers of the Earth’s atmosphere were represented, from the lithosphereup to deep space. This event coincided with the final science meeting of COST Action TOSCA1 (“To-wards a more complete assessment of the impact of solar variability on the Earth’s climate”), thanksto which scientists coming from 20 European countries have been working together on this issueduring the last four years.

The scientific programme consisted of series of review talks, and more focused short talks, withplenty of time for poster discussions. The themes of the four sessions were: 1) Impact of Variationsin Solar Radiative Forcing, 2) Impact of Interplanetary Perturbations, 3) Effects of Energetic Particleson Earth’s Atmosphere and Climate, and 4) Modelling studies of solar influences on climate. The re-view talks were given by Karen Aplin (Oxford), Bernd Funke (Granada), Margit Haberreiter (Davos),

1http://www.tosca-cost.eu

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Joanna Haigh (London), Greg Kopp (Boulder), Kalevi Mursula (Oulu), and Kleareti Tourpali (Thessa-loniki). Some review talks addressed neighbouring fields of research, such as paleoclimatology (byStefan Brönnimann, Bern), marine science (Martin Visbeck, Kiel), and the hiatus in global warming(Mojib Latif, Kiel).

Several presentations gave firmer ground to mechanisms that had already been investigated for sev-eral years, showing increasingly good agreement between observations and model results. A typi-cal example is the impact of solar UV variability on stratospheric ozone, including mechanisms bywhich the troposphere eventually gets affected. Some presentations also highlighted recent evolu-tions, such as the relevance of the global electric circuit in modulating the impact of galactic cosmicrays on cloud condensation. Likewise, energetic electron impacts on middle atmosphere ozone werefound to be more frequent than previously assumed, and their impact on regional climate may becomparable to that of the UV forcing. We are also witnessing a paradigm shift with the importanceof regional impacts of solar activity. So far, the global impact of solar variability had been found tobe small, if not hidden in natural variability. However, some of the regional impacts now turn out besignificant. We are thus dealing with global effects that have different regional manifestations.

The fourth day of the meeting was devoted to outreach activities. We had invited three classes ofhigh-school students to get engaged in several activities. One of them was the observation of auroraswith a Planeterrella2 aurora simulator (see picture below). Another one was interactive poster view-ing, together with several young scientists. The third activity was a debate on the role of the Sun inrecent global warming. At that debate, the students discovered how easily one can be fooled whenthere is no critical look. Later in the day, we held a public debate at GEOMAR on the role of the Sunin recent global warming.

Another special event was the panel discussion on future directions in Sun-climate research, forwhich we had invited three experts: Guy Brasseur (Hamburg), Greg Kopp (Boulder), and Gian-KasperPlattner (Bern). Two major difficulties with Sun-climate studies are 1) the weakness of solar signa-tures in climate records, as compared to natural climate variability, and 2) the presumably smallcontribution of the Sun to recent global warming, which has directed the attention to more signifi-cant effects, such as the role of man-made greenhouse gases. In addition to this, Sun-climate studiesare inherently multidisciplinary, in the sense that an expertise in several domains is needed in orderto make progress. For example, the role of the global electric circuit cannot be properly understoodwithout bringing together experts in solar wind forcing, in galactic cosmic rays, in aerosol formation,in atmospheric chemistry, and of course in atmospheric electricity.

Unfortunately, there are very limited opportunities for allowing scientists from such different disci-plines to meet and work together on such issues. This may partly explain why solar forcing ends upbeing considered as a marginal effect in the assessments of the IPCC, even though large uncertaintiesremain regarding its magnitude. Many of the participants of the SCC conference are also strongly in-volved in international initiatives such as SOLARIS-HEPPA, TOSCA and VarSITI/ROSMIC, and thereis no doubt that greater attention will now be given to finding solutions for fostering stronger collab-orations between different scientific communities.

Another issue that came up regularly during the meeting was the impending interruption of severalkey observations. The last decade has witnessed an unprecedented combination of observations thathave deeply improved our understanding of the Sun–Earth system. This period is now coming to anend, as several missions are coming are about to be interrupted. Two examples are stratosphericozone observations, and solar spectral irradiance measurements. This major problem highlights theneed for programmes that ensure a continuous monitoring of the Sun–Earth system, and not just ofthe troposphere.

2http://planeterrella.osug.fr

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Acknowledgements

We hereby would like to express our deepest thanks to the various organisations whose financialsupport made this conference possible (also by funding the participation of several young scientists):

• Cooperation in Science and Technology (COST action ES1005)

• Scientific Committee on Solar-Terrestrial Physics (SCOSTEP)

• Helmholtz Centre for Ocean Research Kiel

• International Association of Meteorology and Atmospheric Sciences (IAMAS)

• European Geosciences Union (EGU)

and also the highly efficient local organising committee, led by Katja Matthes.

Figure 1: Group picture, from an upper atmosphere perspective.

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Figure 2: Close-up of the Planeterrella aurora simulator, showing here auroras surrounding two in-teracting planets.

Figure 3: During the public debate. From left to right: Margit Haberreiter, Katja Matthes, GuyBrasseur, and Gian-Kasper Plattner.

Figure 4: Discussions between young post-docs and high-school students.

Thierry Dudok de Wit and Katja MatthesMay 10th, 2015

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