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The Relations Between Solar Wind Variations and the North Atlantic Oscillation

Rasheed Al- Nuaimi and Kais Al- Jumily. The Relations Between Solar Wind Variations and the North Atlantic Oscillation. Department of Atmospheric Sciences College of Science, Al- Mustansiriyah University Baghdad, Iraq , .

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The Relations Between Solar Wind Variations and the North Atlantic Oscillation

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  1. Rasheed Al-Nuaimi and Kais Al-Jumily The Relations Between Solar Wind Variations and the North Atlantic Oscillation Department of Atmospheric Sciences College of Science, Al-Mustansiriyah University Baghdad, Iraq,

  2. Heat radiation from the Sun is believed to be the primary factor for the Earth’s climate condition. • This phenomenon is not sufficient to explain the observed global climate fluctuations on Earth during the last century. • Several attempts have been made over the last decade to clarify if variations in the solar activity could, to some extent, be responsible for these climate fluctuations. Introduction

  3. Investigate the possible relation between solar wind variations and the North Atlantic Oscillation (NAO). Aim of Work

  4. The NAO is the dominant mode of winter climate variability in the North Atlantic region ranging from central North America to Europe and much into Northern Asia. • The NAO is a large scale seesaw in atmospheric mass between the subtropical high (the Azores High) and the polar low (the Icelandic Low) in the North Atlantic region. • The corresponding index varies from year to year, but also exhibits a tendency to remain in one phase for intervals lasting several years. The North atlantic oscillation (NAO)

  5. Nao index • An Index can be constructed that represents the phase of NAO • Most commonly the NAO index is based on the surface pressure (SLP) between the Subtropical (Azores) high and the Subpolar (Island) low • Very often the pressure readings from two stations one on Iceland and the other either Azores , Lisbon or Gibraltar are used to construct the NAO index

  6. The NAO index shows large variations from year to year. This interannual signal was especially strong during the end of 19th century • Sometimes the NAO index stays in one phase for several years in a row. This decadal variability was quit strong at the beginning and the end of the 20th century

  7. The Positive NAO index Phase • The positive NAO index phase shows a stronger than usual subtropical high pressure center and a deep than normal Icelandic low. • The increased pressure results in more and stronger winter storms crossing the Atlantic Ocean and more northerly track. • This results in warm and wet winters • in Europe and in cold and dry winters in northern Canada and Greenland. • The eastern US experiences mild and wet winter conditions.

  8. The Negative nao index phase • The negative NAO index phase shows a weak subtropical high pressure a weak Icelandic low. • The reduced pressure gradients results in a fewer and weaker winter storms crossing on a more west-east pathway. • They bring moist air into the Mediterranean and cold weather in northern Europe. • The US east coast experiences more cold air outbreaks and hence snowy winter conditions. • Greenland, however, will have milder winter temperature s.

  9. Imapcts of NAO

  10. Solar WInd Charge particles (mostly protons and electrons) streaming outward from the sun at 450 km/s

  11. Some of the most geoeffective solar wind parameters are: • Flow speed (V) • Proton density (n) • Southward component (Bs )of the interplanetary magnetic field • Bs is equal to -Bz when Bz < 0 and equal to 0 when Bz ≥0, where Bz is the interplanetary magnetic field component parallel to the Earth’s magnetic dipole. Solar wind parameters

  12. By using these three parameters one can construct proxies for: • The dynamical pressure (P) • The electric field strength (E) of the solar wind. • The pressure (P) exerted on the Earth’s magnetosphere is best represented by (nV2 ) whereas the electric field (E) can be described by (Bs V).

  13. A widely used measure of the overall geomagnetic activity is the planetary magnetospheric (Kp ) index. • The Kp index is evaluated using the amplitude of the variation of the horizontal magnetic components X and Y at the Earth’s surface at geomagnetic latitudes between 48o and 63o.

  14. The NAO indices were obtain from http://www.ncdc.noaa.gov/paleo/pubs/cook2002/cook2002.html • The solar wind data and the planetary magnetosphericKp index were obtained from http://omniweb.gsfc.nasa.gov/html/ • The group sunspot numbers were obtained from: http://spidr.ngdc.noaa.gov/spidr/dataset.do DATA Sources

  15. Annual averages of E, P, and Kp for the period of 1967-2000 were used to investigate the possibility of solar wind relation with the NAO. Results and discussion

  16. NAO with Kp Cor=0.56

  17. NAO with P Cor=0.36

  18. NAO with E Cor=0.52

  19. NAO with group sunspot numbers Maunder Minima (cycles -10 to -4) and Dalton Minima (cycles 6 and 7) are evident in the NAO data Cor=0.56

  20. Results indicated that there is a low correlation between (P) and NAO (~ 0.36) • Relatively high correlation exists between (Kp) and NAO (~ 0.56) and between (E) and NAO (~0.52) • This suggests that solar wind is in some way affecting the large-scale pressure systems in Earth. Conclusions

  21. A more in depth study is needed through analysis of monthly means of data.

  22. Thank You

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