Tuesday, May 15, 2012

New paper finds 'significant and robust' influence of solar activity on tropical climate

A paper published today in the Journal of Atmospheric and Solar-Terrestrial Physics finds that the Madden–Julian Oscillation (MJO),  the largest element of the intraseasonal (30–90 days) variability in the tropical atmosphere, has "a clear solar signature" that is "shown to be both statistically significant and robust."

The paper adds to hundreds of other peer-reviewed publications showing significant solar influences on climate, despite the intent of the IPCC to dismiss the importance of the Sun.

A correlation of mean period of MJO indices and 11-yr solar variation

  • Elena BlanterabCorresponding author contact informationE-mail the corresponding author
  • Jean-Louis Le Mouëla
  • Mikhail Shnirmanab
  • Vincent Courtillota
  • a Geomagnetism and Paleomagnetism, Institut de Physique du Globe de Paris, 1 rue Jussieu, Paris, France
  • b Institution of Russian Academy of Sciences – Institute of Earthquake Prediction Theory and Mathematical Geophysics, Profsoyuznaya str. 84/32, Moscow 117997, Russia


This paper focuses on the decadal to multi-decadal evolution of the spectral properties of the Madden–Julian Oscillation (MJO). Guided by former studies, we test whether the ∼11-yr (Schwabe) cycle of solar activity could be reflected in the spectral features of MJO indices: namely, we study the evolution of MJO mean period within different period ranges and compare these with the evolution of solar activity. We focus on solar proxies best linked to UV emission and cosmic rays: sunspot number WNF10.7 flux, core-to-wing ratio MgII, and galactic cosmic rays (GCR). A clear solar signature in MJO spectral properties is indeed found and shown to be both statistically significant and robust. UV proxies are found to be better correlated with MJO mean period than GCR, thus supporting rather the ozone mechanism of solar impact on MJO. The overall correlation with solar activity is found to be stronger in the Indian Ocean. Long periods (e.g. 50–80 day) are better correlated with solar activity than shorter periods (e.g. 30–60 day). A marked change in the relationship between MJO mean period and solar activity takes place in the declining phase of solar cycle 23, adding to its unusual character

1 comment:

  1. http://www.sciencedirect.com/science/article/pii/S1364682609002673?np=y