Solar wind connection to regional climate

Lu et al. (2008) have shown that there is a robust relationship between solar wind dynamic pressure and the winds and temperatures in the northern polar winter stratosphere and troposphere. These wind and temperature variations are indicative of the Northern Annular Mode of climate oscillation which largely determines the predominant winter weather pattern across Europe. The signature of solar wind dynamic pressure in the lower atmosphere data is stronger and statistically more robust than those associated with either the QBO or the 11-yr solar cycle, and the timescales suggest that the most likely link is a dynamical one. Clilverd et al. (2006) predicted that solar cycle number 24, which is just beginning, would be unusually low. This has since been circumstantially supported by recent observations which show that the current solar minimum is the lowest for 200 years, that the onset of cycle 24 has been delayed, and that the solar wind dynamic pressure is ~20% lower than the previous cycle, the weakest it has been during the era of in-situ spacecraft measurements. Taken together this evidence that we are currently entering an era of low solar wind dynamic pressure, and the evidence that solar wind dynamic pressure is related to the NAM imply that, between 2012 and 2017 (the next solar maximum), we are likely to see drier winter weather with fewer storms in the UK and Scandinavia together with wetter weather in Southern Europe. However, while the statistical evidence for a relationship between the solar wind dynamic pressure and the NAM is very strong (>99%), a physical connection is not understood. The aim of the proposed research is to substantiate whether a physical connection exists by exploring, using both observations and models, just how the solar wind dynamic pressure can connect to the stratosphere in the polar regions, and hence how it can be strongly correlated with the Northern Annular Mode.