THETHE EVEREVER CHANGINGCHANGING SUNSUN

SolarSolar influenceinfluence onon climateclimate

C. de Jager SolarSolar activityactivity duringduring holoceneholocene [ref: Solanki et al.]

PresentPresent maximummaximum isis highesthighest ofof pastpast 99 millenniamillennia (as(as farfar asas plasmaplasma ejectionejection fromfrom sunsun isis concerned;concerned; butbut notenote conflictingconflicting evidenceevidence AntarcticAntarctic vs.vs. GreenlandGreenland iceice cores)cores) [Solanki et al.; Muscheler et al.] NorthernNorthern HemisphereHemisphere TemperaturesTemperatures [source: Anders Moberg et al., 2005]

•• Medieval maximum (AD 1000 – 1200) •• Broad minimum around 1600 (Little Ice Age) •• Strong 20th century increase BasicBasic datadata forfor thethe periodperiod 16191619 –– 19641964

Smoothed Group Sunspot Number (left; ref. Hoyt & Schatten) and smoothed Northern Hemisphere Temperature [ref: Moberg et al.] BasicBasic datadata forfor thethe periodperiod 16191619 -- 19641964 Smoothed Group Sunspot number (left) and Source function (= ejected plasma ~ open solar flux) [refs: Hoyt & Schatten for GSN; Usoskin & Solanki for S-function] OutlineOutline ofof talktalk

•• TwoTwo mainmain aspectsaspects ofof solarsolar variability:variability: - Active regions around sunspots - Coronal plasma ejections of various kinds •• DoDo thesethese influenceinfluence tropospherictropospheric temperaturestemperatures andand whatwhat isis thethe mainmain driverdriver ofof sunsun--inducedinduced climateclimate change?change? •• TheThe solarsolar dynamodynamo •• ForecastingForecasting solarsolar activityactivity BASICBASIC SOLARSOLAR DATADATA

ActivityActivity CentersCenters andand EjectionEjection ofof solarsolar plasmaplasma SunspotsSunspots andand activeactive regionsregions

AA sunspotsunspot groupgroup [DOT observations] SurroundingSurrounding facularfacular fieldsfields higherhigher temperaturestemperatures areare locatedlocated onon toptop ofof photosphere;photosphere; emitemit variablevariable (UV)(UV) radiationradiation fluxflux CoronalCoronal massmass EjectionsEjections (Lasco on SOHO spacecraft) TheThe centercenter ofof activityactivity

•• SunspotsSunspots andand thethe surroundingsurrounding activeactive regionsregions •• FacularFacular fieldsfields •• SolarSolar flaresflares andand theirtheir effectseffects •• CoronalCoronal MassMass EjectionsEjections •• ProminencesProminences ofof variousvarious kindskinds (will(will notnot beenbeen discusseddiscussed here)here) SunspotSunspot numbersnumbers

•• RZ = Zürich sunspot number (dashed)

•• RG = group sunspot number (solid; ref. Hoyt & Schatten)

•• Use of RG advisable •• Maunder minimum from 1652 – 1704 •• During MM few spots but normal activity in plasma ejection TimeTime delaysdelays ofof variousvarious kinds:kinds:

•• HighHigh latitudelatitude activityactivity followsfollows oror precedesprecedes (?)(?) sunspotsunspot activityactivity byby halfhalf aa SchwabeSchwabe cyclecycle •• GnevyshevGnevyshev Gap:Gap: spotspot activityactivity maximamaxima inin thethe twotwo hemisphereshemispheres areare notnot simultaneous;simultaneous; delaysdelays averageaverage aa yearyear •• EnergeticEnergetic EmissionsEmissions Delay:Delay: energeticenergetic emisissionemisission followfollow spotspot maximummaximum byby roughlyroughly 11 –– 22 yryr TheThe energeticenergetic emissionsemissions delaydelay

•• EnergeticEnergetic emissionsemissions suchsuch asas XX oror γγ--rayray flaresflares (black)(black) delayeddelayed byby aboutabout oneone yearyear withwith respectrespect toto spotspot numbersnumbers ((lighterlighter shadedshaded;; ref. J. Allen)) EquatorEquator--wardward andand polepole--wardward driftdrift sunspotsunspot areaarea andand highhigh latitudelatitude magneticmagnetic fieldsfields [ref: Hathaway) VariationVariation intensityintensity GreenGreen CoronalCoronal lineline [Green line: 530.3 nm; FeXIV; ref. Makarov et al.] PlasmaPlasma ejectionejection

LowLow-- andand highhigh--latitudelatitude ejectionsejections LatitudesLatitudes ofof ActiveActive RegionsRegions comparedcompared withwith thosethose ofof plasmaplasma ejectionejection [ref: Hundhausen] TwoTwo sourcessources forfor plasmaplasma ejection.ejection. ThreeThree questionsquestions

•• From Centers of Activity; chiefly Coronal Mass Ejections (latitude below 40 ̊̊ ) •• At higher latitudes: from coronal holes, polar faculae, ephemeral active regions. •• The totality of all these ejections define the Source Function S (Solanki; Usoskin et al.)

•• Q1: How is S known? •• Q2:Relation S – cosmogenic radionuclides deposit rate •• Q3: Relative contribution of low- and high-latitude sources to S function AnswersAnswers toto threethree questions:questions:

•• 1.1. SourceSource functionfunction describesdescribes strengthstrength ofof openopen solarsolar fluxflux inin EarthEarth environmentenvironment →→ modulationmodulation ofof cosmiccosmic rayray fluxflux →→ changechange inin depositdeposit ofof cosmogeniccosmogenic radionuclidesradionuclides ((14C,C, 10 BeBe ……)) [refs: Solanki, Usoskin et al.; Beer et al.; Muscheler et al.] •• Hence,Hence, sourcesource functionfunction isis derivedderived (via(via physicalphysical theory)theory) fromfrom thethe raterate ofof depositdeposit ofof cosmogeniccosmogenic radionuclidesradionuclides 2.2. RelationRelation SS--functionfunction –– 10BeBe depositdeposit raterate [Ref. De Jager and Usoskin, submitted] 3.3. StronglyStrongly variablevariable plasmaplasma ejectionejection fromfrom lowlow-- resp.resp. highhigh--latitudelatitude areasareas

•• OpenOpen solarsolar fluxflux duringduring MAXMAX oror MINMIN ((notenote:: arbitraryarbitrary units)units)

•• LowLow latitudeslatitudes:: 2.752.75 0.550.55 •• HighHigh latitudeslatitudes:: 0.480.48 2.382.38 3.3. HighHigh-- andand lowlow--latitudelatitude plasmaplasma fluxesfluxes

•• AverageAverage ratioratio betweenbetween SS--fluxesfluxes fromfrom lowlow latitudeslatitudes andand highhigh latitudeslatitudes == 1.21.2 (= average over 3 cycles; 1967.5 – 1998.5; refs. Wang, Kane, re. Wang & Sheeley, 2002; Cf. also Shrivastava, 2003: ~ 1.0) •• Note:Note: lowlow latitudelatitude ejectionsejections (CME(CME’’s)s) areare fromfrom ActivityActivity CentersCenters andand hencehence correlatecorrelate stronglystrongly withwith SunspotSunspot numbers.numbers. HighHigh latitudelatitude ejectionsejections areare not.not. HOWHOW DOESDOES THETHE SUNSUN INFLUENCEINFLUENCE CLIMATECLIMATE

IrradianceIrradiance variationsvariations oror cosmiccosmic rayray modulationmodulation byby plasmaplasma clouds?clouds? 1.1. SolarSolar irradianceirradiance variationsvariations •• Less than 0.1% variation during cycle (upper frame) •• Correlated with average magnetic field (middle) •• and sunspot numbers (lower frame) •• Sunspot number R is proxy for irradiance variation •• Gnevyshev Gap (two maxima) OriginOrigin ofof irradianceirradiance variationsvariations

•• Variations largest in ultraviolet spectrum, less in infrared; little or none in visible [ref Lean, 2000] •• Photospheric emissions (emitted in visual part of spectrum) do not vary •• Origin of variations: low- chromospheric levels of Active Regions •• Sources: scattered magnetic fields ( ~ 50 – 200 Gauss) in Active Region area SolarSolar UVUV emissionsemissions areare absorbedabsorbed inin terrestrialterrestrial stratospherestratosphere

•• DoDo notnot reachreach tropospheretroposphere •• Hence,Hence, inin orderorder toto affectaffect tropospherictropospheric physicsphysics somesome kindkind ofof stratospherestratosphere –– tropospheretroposphere couplingcoupling isis neededneeded 2.2. TheThe otherother aspectaspect ofof solarsolar variability;variability; a.a. lowlow--latitudelatitude ejectionsejections

•• FromFrom ActiveActive Regions:Regions: coronalcoronal massmass ejectionsejections •• CMECME--massmass isis 101012 toto 101013 kgkg •• SpeedSpeed atat EarthEarth distancedistance 200200 toto 25002500 km/seckm/sec •• MagneticMagnetic fieldsfields fromfrom CME’sCME’s carriedcarried alongalong intointo heliosphereheliosphere contributecontribute forfor ~~ 54%54% toto ‘Open‘Open solarsolar flux’flux’ (interplanetary(interplanetary magneticmagnetic fieldfield atat EarthEarth distance)distance) b.b. HighHigh latitudelatitude componentcomponent (~(~ 46%)46%)

•• Solar wind, mainly high latitude coronal holes; varies during cycle; prominent during minimum •• Other ejection: from high latitude (ephemeral) active regions, polar faculae, structures associated with polar prominence zone

•• All abrupt ejections (low- and high-latitude) cause: •• Co-rotating Interaction Regions = interplanetary shocks at collision of solar plasma ejections with earlier emitted slower wind OpenOpen solarsolar fluxflux (( ~~ SS--function)function) Left:Left: annualannual data;data; Right:Right: smoothedsmoothed [ Refs: Lockwood et al.; Solanki et al.] OpenOpen solarsolar fluxflux again.again. [Smoothed data from Solanki, Usoskin et al.] ModulationModulation ofof cosmiccosmic rayray fluxflux byby magneticmagnetic shieldingshielding inin heliosphereheliosphere CloudCloud coveragecoverage variationvariation parallel to cosmic ray flux [ref Svesnsmark&Friis-Christensen] CosmicCosmic rayray –– cloudsclouds scenarioscenario

IncreasedIncreased solarsolar activityactivity yields:yields: •• StrongerStronger openopen solarsolar flux;flux; hencehence •• LargerLarger cosmiccosmic rayray deflection;deflection; causingcausing •• decreasedecrease ofof cosmiccosmic rayray flux;flux; causingcausing •• ReducedReduced cloudcloud formation;formation; hencehence •• IncreasedIncreased solarsolar irradianceirradiance onon EarthEarth andand •• TemperatureTemperature increaseincrease ProxiesProxies forfor cosmiccosmic rayray activityactivity •• CosmogenicCosmogenic radionuclidesradionuclides suchsuch asas 10Be,Be, 14C,C, etc.etc. areare proxiesproxies forfor thethe cosmiccosmic rayray fluxflux •• SinceSince observedobserved cosmiccosmic rayray fluxflux dependsdepends onon fluxflux ofof solarsolar ejectedejected magnetizedmagnetized plasma,plasma, cosmogeniccosmogenic radionuclidesradionuclides informinform usus onon pastpast solarsolar plasmaplasma ejectionejection activityactivity •• IceIce corescores andand sedimentssediments offeroffer wayway toto studystudy pastpast historyhistory ofof solarsolar SourceSource FunctionFunction Hence:Hence: twotwo possiblepossible mechanismsmechanisms forfor sunsun –– climateclimate interactioninteraction

•• VariationVariation ofof UVUV radiance,radiance, duringduring thethe solarsolar cyclecycle asas wellwell asas secularsecular changeschanges •• VariationVariation ofof cosmiccosmic rayray flux,flux, duedue toto variablevariable sourcesource functionfunction (( plasmaplasma ejection)ejection)

•• WhichWhich ofof these,these, oror both??both?? CorrelationCorrelation analysisanalysis showsshows reasonablereasonable dependencedependence NHNH temperaturestemperatures onon GroupGroup SunspotSunspot NumberNumber ((GSNGSN)) ButBut weakerweaker dependencedependence ofof NHNH temperaturestemperatures onon SourceSource FunctionFunction FullFull andand partialpartial correlationcorrelation coefficientscoefficients forfor RR-- andand SS--dependencedependence forfor variousvarious temperaturetemperature setssets [de Jager & Usoskin, submitted]

Overpeck & Hughen (1997) C = .60 C = .35 P = .01 • [ Overpeck & Hughen (1997) CTR = .60 CTS = .35 PT(R)S = .01 • Jones et al. (1998) .55 .47 .15 • Mann et al. (1999) .52 .50 .20 • Briffa et al. (2000) .76 .48 .06 • Crowley & Lowery 2000) .77 .43 -.01 • Mann & Jones (2003) .72 .54 .15 • Moberg et al. (2005) .77 .43 .07 •• Average: .67 .45 .09

• Conclusions: stronger correlation of T with R; partial correlation T-S (=keeping R-correlation fixed) small. T-S correlation is not zero because of the significant S-R correlation (due to CME’s from Active Regions). HenceHence:: ••SunSun--relatedrelated NHNH temperaturetemperature variationsvariations areare coupledcoupled toto variationsvariations inin ActiveActive RegionRegion (UV)(UV) radianceradiance ratherrather thanthan toto thosethose inin openopen solarsolar fluxflux THETHE SOLARSOLAR DYNAMODYNAMO

TheThe engineengine ofof solarsolar activityactivity TheThe sun’ssun’s internalinternal rotationrotation •• variesvaries withwith depthdepth andand latitudelatitude

•• tachoclinetachocline atat r/Rr/R○ == 0.69;0.69; strongstrong shearingshearing motionsmotions inin overshootovershoot layerlayer ofof convectionconvection zonezone Tachocline:Tachocline: seatseat ofof dynamo;dynamo; ΩΩ effecteffect

•• ShearingShearing motionsmotions inin existingexisting magneticmagnetic fieldsfields generategenerate poloidalpoloidal magneticmagnetic fieldsfields •• DifferentialDifferential rotationrotation causecause toroidaltoroidal componentscomponents byby stretchingstretching andand amplifyingamplifying fieldsfields •• EquipartitionEquipartition fieldfield strengthstrength 10104 GaussGauss •• FurtherFurther amplificationamplification tilltill 10105 GaussGauss causecause kinkkink instabilityinstability ofof thethe fluxes,fluxes, leadingleading toto fluxflux tubetube detachmentdetachment andand buoyancybuoyancy •• RiseRise timetime isis fewfew months;months; sunspotssunspots atat surfacesurface OscillatingOscillating magneticmagnetic fieldfield inin tachoclinetachocline

MagneticMagnetic fieldfield oscillatesoscillates withwith periodperiod PP == ηη/(/( ππ HH2),), wherewhere HH == storagestorage thicknessthickness ofof field.field. WithWith ηη (turbulent(turbulent magneticmagnetic diffusivity)diffusivity) == 101011 cmcm2 ss-1 andand HH (thickness(thickness tachocline)tachocline)

== .04R.04Ro wewe findfind PP ~~ 44 yryr ActiveActive longitudeslongitudes

•• TwoTwo activeactive longitudes,longitudes, 180180̊ ̊ apartapart [Neugebauer et al., 2000; Ruzmaikin et al. Usoskin et al., de Toma et al.,Caligari et al. Akasofu et al.] •• NonNon--axisaxis symmetricsymmetric modesmodes inin field,field, toto bebe representedrepresented byby twotwo dipolesdipoles •• SimpleSimple representation:representation: wavelengthwavelength ofof periodicperiodic oscillationoscillation ofof tachoclinetachocline isis halfhalf ofof solarsolar circumferencecircumference EquatorEquator--wardward andand polepole--wardward driftdrift demanddemand meridionalmeridional circulationcirculation (~1(~1 m/sec)m/sec) [Hathaway et al; Dikpati et al., and others] FluxFlux amplificationamplification andand emergenceemergence

•• ToroidalToroidal stretchingstretching amplifamplifiesies fieldfield •• AmplificatioAmplificatio byby factorfactor ~100~100 inin ~~ oneone yearyear [Lillo et al. 2005] AA sunspotsunspot cyclecycle hypothesishypothesis

•• Production of flux tubes: ongoingongoing processprocess •• Assume: basic oscillation of tachocline and superimposed randomly appearing unstable loops [Ruzmaikin; Usoskin et al.] ChaoticChaotic dynamodynamo appearsappears inin smoothedsmoothed datadata by plotting Spoloidal against R (toroidal field) [deJager & Duhau] MainMain conclusionconclusion

•• AtAt timetime scalesscales ofof SchwabeSchwabe cyclecycle oror above:above: highhigh--latitudelatitude fieldfield isis notnot correlatedcorrelated withwith toroidaltoroidal (low(low--latitude)latitude) fieldfield •• BestBest example:example: MaunderMaunder MinimumMinimum •• ThisThis conclusionconclusion hashas inferencesinferences forfor thethe originorigin ofof highhigh--latitudelatitude phenomenaphenomena •• NoteNote alsoalso thethe quasiquasi--chaoticchaotic jumpsjumps ((e.g.e.g. 1704,1704, 1922)1922) TheThe alphaalpha effecteffect

•• WeakerWeaker fieldsfields areare liftedlifted butbut dodo notnot reachreach surfacesurface •• ‘Explode’‘Explode’ inin convectionconvection zone;zone; areare deformeddeformed byby cycloniccyclonic convection,convection, withwith simultaneoussimultaneous expansionexpansion andand rotationrotation →→ thethe αα effecteffect •• WhenWhen arrivingarriving atat thethe surfacesurface thesethese fieldsfields areare chieflychiefly poloidalpoloidal •• TheyThey ascendascend primarilyprimarily parallelparallel toto solarsolar axisaxis •• HenceHence appearappear inin higherhigher latitudeslatitudes HysteresisHysteresis andand phasephase catastrophecatastrophe

•• A plot of R-max (toroidal field)against aa-min (poloidal) shows hysteresis. Another feature: phase catastrophy (1921-’23). [Duhau; Duhau & Chen] ForecastingForecasting solarsolar activityactivity

IsIs itit possiblepossible toto forecastforecast thethe behaviorbehavior ofof thisthis chaoticchaotic system?system? QuasiQuasi--periodicitiesperiodicities •• FiveFive significantsignificant (quasi(quasi--)periods)periods inin solarsolar activity:activity: 1111 yrsyrs (Schwabe);(Schwabe); 2222 yrsyrs (Hale);(Hale); 11--22 yrsyrs (quasi(quasi--biennial,biennial, BasilevskayaBasilevskaya);); 8888 yrsyrs ((GleissbergGleissberg);); 205205 yrsyrs (De(De VriesVries oror SuessSuess);); 23002300 yrsyrs ((HallstattHallstatt).). •• AllAll quasiquasi--periodsperiods areare variablevariable andand nonenone ofof themthem isis constantconstant inin time.time. GleissbergGleissberg periodperiod hashas eveneven twotwo maxima,maxima, interchanginginterchanging inin importanceimportance duringduring pastpast centuriescenturies •• PhasePhase catastrophescatastrophes havehave occurredoccurred atat leastleast twice:twice: ~~ 17881788 andand ~~ 19221922 IsIs forecastingforecasting possible?possible?

•• RatioRatio betweenbetween strengthsstrengths ofof poloidalpoloidal andand toroidaltoroidal fieldsfields appearappear toto varyvary withwith time;time; notnot correlatedcorrelated inin intervalsintervals ≥≥ SchwabeSchwabe cycle.cycle. BestBest example:example: MaunderMaunder Minimum.Minimum. •• SolarSolar dynamo:dynamo: nonnon--linearlinear system,system, aa quasiquasi periodicperiodic engineengine withwith thethe propertiesproperties ofof deterministicdeterministic chaos.chaos. •• ItsIts futurefuture isis unpredictableunpredictable SUMMARYSUMMARY OFOF TALKTALK

•• Two aspects of variability: plasma ejection and UV radiance •• NH temperature correlated with variation in UV radiance •• Plasma ejection from low- and high-latitude areas •• Dynamo: seated in tachocline. Main aspect: the toroidal fields. Byproduct: poloidal magnetic fields. •• Toroidal fields generate activity centers; poloidal fields in high latitude magnetic areas •• Dynamo is chaotic and unpredictable system