1. 10/20/11SESAPS111 Correlation study of atmospheric weather and cosmic ray flux variation Kanishka Dayananda Georgia State University

2. 10/20/11SESAPS112 Outline Introduction Introduction Cosmic ray detectors maintained by Georgia State University Cosmic ray detectors maintained by Georgia State University Meteorological and solar modulation effects on the variation of cosmic ray flux Meteorological and solar modulation effects on the variation of cosmic ray flux Summary Summary

3. 10/20/11SESAPS113 Introduction There is at present a great debate about the causes of the changing climate of the Earth. The studies by Svensmark, show that there is a strong link between cosmic rays and low cloud coverage [1]. Very recently, Lu reported that there is a correlation between cosmic rays and ozone depletion over Antarctica [2]. At Georgia State University we are working on a long-term measurement of secondary cosmic ray flux distribution and are focusing on studying the correlations among variations of cosmic ray flux and atmospheric/space weather.

4. 10/20/11SESAPS114 Our cosmic ray detectors http://phynp6.phy-astr.gsu.edu/~kanishka/OnLineMonitor/index.htm Pot detector - liquid scintillator eMorpho 2paddle detector QNet 2paddle detector2paddle detector HLCO-BaF 2 scintillator QNet 2paddle detector Lanzhou -China

5. 10/20/11SESAPS115 Factors that influence the variation of cosmic ray flux Meteorological effects Meteorological effects atmospheric pressure, temperature, cloud cover etc… atmospheric pressure, temperature, cloud cover etc… Solar modulation effects Solar modulation effects interplanetary magnetic field, solar wind speed etc… interplanetary magnetic field, solar wind speed etc… The barometric effect is the major influencing factor on the secondary cosmic ray particles[3]. The barometric effect is the major influencing factor on the secondary cosmic ray particles[3]. Therefore it is necessary to eliminate the barometric effect first to unfold the solar modulation of the cosmic ray flux. Therefore it is necessary to eliminate the barometric effect first to unfold the solar modulation of the cosmic ray flux.

6. 10/20/11SESAPS116 Barometric effects on secondary cosmic ray flux Pot – counts 11/3010 – 01/27/10 Correlation coefficient ( r ) = -0.64

7. 10/20/11SESAPS117 Correction of counts for pressure  barometric coefficient I = counts P = pressure I = corrected counts I o = measured counts P 0 = mean pressure Reference [4] Variation of solar parameters in year 2010 http://omniweb.gsfc.nasa.gov/form/dx1.html

8. 10/20/11SESAPS118 Correction of counts for pressure cont… 11/30/10 – 01/27/10 Correlation coefficient ( r ) = -0.64 Uncorrected counts Correlation coefficient ( r ) = -0.02 11/30/10 – 01/27/10 Corrected counts

9. 10/20/11SESAPS119 Seasonal variation in the pot detector counts

10. 10/20/11SESAPS1110 Daily % variation of counts & weather parameters

11. 10/20/11SESAPS1111 Forbush decrease events detected by pot detector

12. 10/20/11SESAPS1112 Forbush decrease events A ug 05 2011 Sep 26 2011

13. 10/20/11SESAPS1113 Summary Results confirm that there is an anti-correlation between secondary cosmic ray flux and atm pressure. Results confirm that there is an anti-correlation between secondary cosmic ray flux and atm pressure. Results also confirm that the anti-correlation between secondary cosmic ray flux and atm temperature is due to expansion of the height of the atm pressure levels. Results also confirm that the anti-correlation between secondary cosmic ray flux and atm temperature is due to expansion of the height of the atm pressure levels. Since our pot detector is sensitive for both charged particles and neutrons, we are currently working on studying the correlation between variation of neutrons and cloud coverage. Since our pot detector is sensitive for both charged particles and neutrons, we are currently working on studying the correlation between variation of neutrons and cloud coverage. These results can be used to unfold the solar modulation effects on the cosmic ray flux. These results can be used to unfold the solar modulation effects on the cosmic ray flux. Our long-term goal is to build a world wide cosmic ray detector network and predict the variation of atmospheric and space weather using the cosmic ray flux variation. Our long-term goal is to build a world wide cosmic ray detector network and predict the variation of atmospheric and space weather using the cosmic ray flux variation.

14. 10/20/11SESAPS1114 References 1. 1. N.D. March and H. Svensmark, Low Cloud Properties Influenced by Cosmic Rays, Phys. Rev. Lett. 85, 23 (2000). 2. 2. Q.-B. Lu, Correlation between Cosmic Rays and Ozone Depletion, Phys. Rev.Lett. 102, 118501 (2009). 3. 3. A. Chilingarian, T. Karapetyan, Calculation of the barometric coefficients at the start of the 24 th solar activity cycle for particle detectors of Aragats Space Environmental Center, Advances in Space Research 47 (2011) 1140–1146. 4. 4. L.I. Dorman, Cosmic Rays, Variations and Space Exploration. Amsterdam, North-Holland, 1974. 5. 5. S. Tilav, P. Desiati, T. Kumwabara, D. Rocco, F. Rothmaier, M. Simmons, and H. Wissing, “Atmospheric Variations as Observed by IceCude”, Proceedings of the 31st ICRC, 2009. 6. 6. M. Bertaina, L. Briatore, A. Longhetto, G. Navarra, The atmospheric moun flux in correlation with temperature variations in the low stratosphere(50-200mb), Proceedings of the 30 th International Cosmic Ray Conferrencs.

15. 10/20/11SESAPS1115 Thank you

16. 10/20/11SESAPS1116 Backup slides

17. 10/20/11SESAPS1117 % Variation of atm heights of different atm pressure levels

18. 10/20/11SESAPS1118 % Variation of atm temperatures of different pressure levels

19. 10/20/11SESAPS1119 Correlation of temperature and counts in different atm pressure regions

20. 10/20/11SESAPS1120 Correlation of temperature and counts in different atm pressure regions cont…