Monday, November 4, 2013

New paper finds the Sun controls European & North Atlantic weather via ocean oscillations

A paper published today in the Journal of Geophysical Research Atmospheres finds changes in solar activity over the 11-year solar cycle had a significant, lagged effect on North Atlantic & European weather patterns over the 140 year period from 1870-2010. According to the authors, "The analysis reveals a statistically significant 11-year solar signal over Europe and the North Atlantic provided the data are lagged by a few years. The delayed signal resembles the positive phase of the North Atlantic Oscillation (NAO) following a solar maximum. The corresponding sea surface temperature response is consistent with this." 

The paper suggests a solar amplification mechanism by which tiny 0.1% changes in solar irradiance during solar cycles have a lagged effect on the natural North Atlantic Oscillation (NAO), which in turn has large effects upon North Atlantic & European weather patterns. The paper adds to many other peer-reviewed publications finding solar amplification mechanisms including ocean oscillations such as ENSO and the NAOatmospheric oscillations such as the Madden-Julian Oscillation, Quasi-biennial Oscillation, Aleutian LowEurasian pattern, & Asian monsoon, and via stratospheric ozone, and sunshine hours/clouds.

A Lagged Response to the 11-year Solar Cycle in Observed Winter Atlantic/European Weather Patterns

Lesley J. Gray, Adam A. Scaife, Daniel M. Mitchell, Scott Osprey, Sarah Ineson, Steven Hardiman, Neal Butchart, Jeff Knight, Rowan Sutton, Kunihiko Kodera

DOI: 10.1002/2013JD020062

The surface response to 11-year solar cycle variations is investigated by analysing the long-term mean sea level pressure and sea surface temperature observations for the period 1870–2010. The analysis reveals a statistically significant 11-year solar signal over Europe and the North Atlantic provided the data are lagged by a few years. The delayed signal resembles the positive phase of the North Atlantic Oscillation (NAO) following a solar maximum. The corresponding sea surface temperature response is consistent with this. A similar analysis is performed on long-term climate simulations from a coupled ocean–atmosphere version of the Hadley Centre model that has an extended upper lid so that influences of solar variability via the stratosphere are well resolved. The model reproduces the positive NAO signal over the Atlantic / European sector but the lag of the surface response is not well reproduced. Possible mechanisms for the lagged nature of the observed response are discussed.

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