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1. THE ROLE OF COSMIC RAYS IN ATMOSPHERIC PROCESSESA. ZaniniINFN Sez.TorinoVia P. Giuria 1, Torino, Italy

2. The search of a causal link between star activity and Earth climate comes far away in human history… Tycho Brahe in 1573,De Nova Stella, included an introduction to an almanac for the year in which he states that stars could have some influence on the turbulence of weather and other weather patterns. He argued that the “astro-metereology” should be able to predict the weather on the basis of the heavenly configurations. • Mathematical Contemplation of Ticho Brahe of Denmark on the New and Never Previously Seen Star First Observed in the Month of November 1572

3. More recently… That there is a causal connection between the observed variations in the forces of the Sun, the terrestrial magnetic field and the meteorological elements has been the conclusion of every research into this subject… • The elucidation of exactly what the connection is and the scientific proof of it is to be classed among the most difficult problems presented in terrestrial physics…. • …the sequence of cause and effect is so far masked in the complex interaction of the many delicate forces in operation…. • F.H.Bigelov (US Dept Agriculture Weather Bureau, Bulletin No.21 1898) Today…

4. …Today “Solar radiation, clouds, ocean currents and the atmospheric circulation act together in a complex and chaotic way to produce our climate..” John H. Seinfeld, Californian Institute of Technology, 2001 Cosmic ray effects, modulated by solar activity could be relevant to climate change?

5. Cosmic rays - sun activity - climate change: a missing link • Global warming • Cosmic ray variability due to solar activity • Cosmic ray variability and atmospheric effects • Historical evidences (proxies) • Recent observations (clouds) Hypothesis: a causal link between GCR-Sun activity-cloud cover produces effects on short and long term climate changes An High Mountain Observatory Network as a new approach to climate studies

6. COSMIC RAYS CHARACTERISTICS GCR (Galactic cosmic Rays): galactic origin, generated outside the solar system, in supernovae explosions and accelerated by the shockwaves ACR (Anomalous Cosmic Rays): galactic origin, generated in the interplanetary space. SCR (Solar Cosmic Rays): events following the 11 year cycles. Primary radiation: 87% protons, 12% a particles, 1% HZE (High Z Elements).

7. COSMIC RAYS in atmosphere Secondary radiation: is produced by interaction of primary cosmic rays with atmospheric nuclei (O e N); the atmospheric cascade is characterized by: 1. N component (nucleonic component), which includes all the particles that are subjected to strong interaction; 2. Soft component (electromagnetic component), which consists of electrons, positrons and electromagnetic quanta; 3. Hardcomponent (muon component).

8. Calculated hadron fluence rates as a function of altitude for different input conditions ( ) high latitude, solar minimum activity; () high laditude solar maximum activity, ( ) low latitude solar minimun activity. A.Ferrari, M.Pelliccioni, T.Rancati, “Calculation of the Radiation Environment Caused by Galactic Cosmic Rays for Determing Air Crew Exposure”, Rad. Prot. Dos. 93, 2, 101-114 Nucl. Tech. Pub. (2001).

9. Figura? Cosmic ray variability on Earth Cosmic ray intensity on Earth depends on • Depth in atmosphere • Natural and anthropogenic components • Geomagnetics conditions • Periodicity of Solar activity

10. The sun is an active star The sun is a G2V star Sun mass 1.99 x 1030 kg Mass density 1.4 g/cm3 g: 2.74 m s2 T: 5780 K Revolution period around the galactic center :200 Myrs Position at 2/3 from the galctic center

11. The Sun is a variable star Solar surface is periodically characterized by outstanding events (solar flares, Coronal Mass Ejections, Filament Disruptions). The solar activity is described by sunspot numbers, characterized by an 11-year cycle. The sunspot number unit is the Wolf number: R =K(10g+m) Single spot Group of spots The solar magnetic field changes its polarity each sunspot maximum. The total duration of the magnetic cycle is 22 years.

12. Solar flares: Increase of the cromospheric activity, with emission of very energetic particles The solar wind is a shielding for GCR. Higher solar activity corresponds to lower cosmic ray flux on Earth.

13. The Sun is the driving factor for the climate on the Earth Evidences both from recent observation and from climate proxies suggest that solar variability is an important contribution to climate change Variation of solar irradiance are too small to account the climate variability BUT… The Earth has a high sensitivity to irradiance changes or other mechanisms exist to amplify the solar variations Therefore…

14. Sunspots from 1610-2001(1600-1890 little Ice Age) Maunder Minimum: 1600-1720 (Louis XIV, Le roi Soleil, 1643-1715) River Tames in London regulary frozen Dalton minimum: 1800-1840

15. The global system response Annual and 11 years-cycle mean sea surface temperature (1860-1985) Global mean surface temperature of the Earth (1860-2001)

16. Global warming forcing factors North Hemisphere temperature relative increase from 1610 to 1995 What causes global warming: this is a very strong debate… Solar irradiance [W/m2] CO2 mesurements Vulcanic dust index

17. Climate sensitivity to forcing factors DT [K]=l DF [W/m2] lEvaluated from past climate changes and climate models l [KW-1m2] = 0.3 - 0.7

18. The Sun-Earth link Physical paths connecting variation of the Sun to the Earth climate: • Solar electromagnetic radiation: 0.1 W/m2 per solar cycle <TOO LOW> • Solar wind interaction with magnetosphere: low energy particles only significant in polar regions • GCR modulated by solar activity

19. Satellite observations Both historical and recent observations suggest that cosmic rays may play a significant role in the climate processes Proxies from C14 in Ice cover

20. Cosmic rays - the main cause of ionizationg in atmosphere

21. Earth’s atmosphere • Earth is the only planet with an atmosphere composed of Nitrogen and Oxigen and with liquid water • The sun earth distance give a medium temperature and regulating atmosphere. • The atmosphere maintain a steady state by various driving forces that shape the composition - interaction with ocean biosphere lithosphere solar activity Earth

22. Atmosphere characteristics • Troposphere (convective motions) • Tropopausa: 200 K • Stratosphere Horizontal motion • Stratopausa: -3 C Ozone layer • Mesosphere Coldest region of atm • Mesopausa: -93 C • Thermosphere: 1000 K High ionization thermal conduction Upper atm Middle atm Lower atm

23. Atmosphere composition

24. Growth of some anthropogenic products and greenhouse effects

25. Evidences from climate proxies • Cosa sono I proxy (tesi Castagnoli) (ice core data C14, Be10, Cl36)… • Fig pag 176 CERN

26. Greenhouse effect • H2O, O, CO2, O3 absorb energy at longer wavelenghts and trap heat radiated by the surface : the atmosphere is transparent to solar radiation but opaque to IR

27. Proxies for atm • Pag 115 Historical data: 140 years of instrumental records 1 historical documents 2 Corals : oxigen and isotopes trace metals to reconstruct water temperature 3 fossil pollen 4-Tree rings: tree growth is influenced by climatic conditions 5-Ice cores : high mountains and in polar ice caps O18/O16 ratio 6-Vulcanic eruption :D/H ratio 7-Ocean and lake sediments Old period of warmth are not similar to 20th century warming No global in extent Climatic forcing conditions are different in the past

28. Proxies for cosmic ray intensity The cosmic ray produce cosmogenic nuclides • Cosmogenic radionuclides in ice C14 forms CO2 and exchange with the main reservoirs of the carbon cycle Be10 and Cl36 are attached to aereosol and after 1-2 years are removed from atmosphere by precipitations

29. Interaction of cosmic rays with atmosphere

30. Variation of solar activity • Fig 1 pag 176 • Fig stozhkov • Solar irradiance is varying 0.1%due to solar cycle variation • During the Maunder Minimum, the solar irradiance I was weaker by 3.3Wm-2 • Globallly averaged temperature were cooler by about 0.5-1 K • Another mechanism is required to amlify the effects on climate

31. GCR-Solar variability-cloud formation • Cloud formation • Clouds cover a large fraction of the Earth (65%) and exert a strong net cooling effect • About 30Wm-2 • GCR(modulated by solar activity) -cloud link could provide a sufficient amplifying mechanism for solar-climate variability • pag176

32. Atmospheric effects due to cosmic rays variability • Thunderstorms • Lightening • Rainfall • Particle precipitation • Solar proton and stratospheric ozone depletion • Radioactive nuclei formation • Sprites, elves • Aurorae boreali • Aerosol formation • Cloud cover

33. Thundercloud electricity • Thunderstorm act as a global generator of electric current , maintaining the Earth’s electric charge ( Wilson 1920)

34. Thundercloud electricity • Cosmic rays produce positive-negative light ions • Collision between ions and atmospheric aereosol lead to electrification of aereosols • Light aereosols and light ions (+) rise at higher altitudes (fig a) • Separation of positive-negative charge inside clouds(fig b) • E=3kV/cm Dh=3 4 km

35. Thundercloud electricity • Fair weather E 100 vm-1 (surface E 2Vm-1 15 km • J 2.4 pA m-2 • In clouds E 500Vm-1 • 100kVm-1 before discharge tab3 CErn The yearly average values of atmospheric electric current J and cosmic ray flux at h=8 km in polar region

36. Lighting trigger • GCR may play a decisive role in triggering lighting • Lighting flash from cloud to ground :a series of leaders in rapid steps • Runaway breakdown • High energy particle ( 10e 14-10e15 eV) produce a extensive air shower in the high electric field • Lighting is produced along the ionized tracks of charged secondaries • Rain gushes : dramatic increase in precipitations shorter after lightning due to a sudden increase of droplets coalescence efficiency due to a sharp rise in ionization fig 42 ( over a 100 m wide region - full width of the GCR Shower)

37. Rainfall The decrease of the daily precipitation level during a Forbush decrease (D%=-17.4%) The increase of the daily precipitation level during a SPE (D%=+13.3%)

38. Particle precipitation Solar protons : in correspondence with the solar activity mainly occur during ascending and descending phases. Electron precipitation: mainly occur during descending phases (Forbush decrease)

39. Solar proton and stratospheric ozone depletion • Protons break up molecules of N2 and H2O • Formation of NOx and HOx in the upper atmosphere • Transport in the middle stratosphere and permanence for months • Reactions NO+ O3 O2+NO2 H+O3 OH+O2 • NO2+O3 O2+NO3 OH+O3 H2O+O2 • Ozone depletion • The large SEP in August 1972 ( three years after solar maximum) produced effects down to 10 Km and permanent for 1 year

40. Radioactive nuclei formation • Cosmic rays interaction with atmosphere nuclei • Cosmogenic radionuclides • Nuclide Half life Target Prod. Rate • ( Yrs) (N cm-2 s-1) • Be10 1.5 106 N,O 0.018 • C14 5.7 103 N,O 2.0 • Cl36 3.01 105 Ar 0.0019 • C14 forms CO2 carbon cycle atmosphere ocean, biosphere • Be10 and Cl36 attached to aereosols or H36Cl • After 1 2 years are removed by precipitations or snow • (107 atoms/kg ice) • Reconstruction of the geomagnetic field

41. Aerosol formation • Aereosol : suspension of liquid and solid particles • Relevant to radiative and chemical processes • Ions act as condensation centers • The electric field associated with a ion polarizes molecules in its vicinity - charge-dipole attractive force - ion molecule aggregation • 15-25 km costant mean ion-pair production rate 10/cm-3 sec-1 at ground level 2 ion-pair • Lower altitudes dependence from solar activity.

42. Causes of particle formation in troposphere • H2S04 concentration, • temperature T, • relative humidity (RH), • pressure (P), • surface area of preexisting particle

43. Ion Mediate Nucleation theory IMN, Yu (2001) Explained the enhanced grow rate of sub-nanometer clusters related to ion concentrations

44. Cosmic ray ionization and particle formation

47. 1 free electrons and simple positive ions N+ O+ 2 electrons +O2 negative ions Plasma of ± ions - fast ions molecule reactions- stable ions H3O+ NH4+ NO3- HSO4- recombination -aereosol -massive charged clusters Fig 1 pag 102

48. Cloud formation

49. Sprites Sprites are massive but weak luminous flashes that appear directly above an active thunderstorm system and are coincident with cloud-to-ground or intra-cloud lightning strokes. The brightest region lies in the altitude range 65-75 km, above which there is often a faint red glow or wispy structure that extends to about 90 km. Below the bright red region, blue tendril-like filamentary structures often extend downward to as low as 40 km. Sprites rarely appear singly, usually occurring in clusters of two, three or more. Other events are more loosely packed and may extend across horizontal distances of 50 km or more and occupy atmospheric volumes in excess of 10,000 cubic km.

50. Blue jets Blue jets are a optical ejections from the top of the electrically active core regions of thunderstorms. They typically propagate upward in narrow cones at vertical speeds of roughly 100 km/s (Mach 300), fanning out and disappearing at heights of about 40-50 km. Blue jets are not aligned with the local magnetic field.