Could it be the missing key? The solar wind blasts charged particles, electrons, stuff, towards Earth at 500 km a second — that’s one to two million miles per hour. It speeds up, slows down and shifts in direction as it travels past the Earth and has its own magnetic field. The wind speed varies from 300 km per second up to 800 and the impact on Earth changes with our magnetic field and our seasons. You might think this kind of monster flow might have some effect on our climate. But modern climate models are 95% certain that none of this matters. Only crazy people would think that a electrons flying past at a million miles per hour could “do something” to our stratosphere, or ozone, or cloud cover.
Curiously, a recent study shows that when the solar wind is fastest, the North Atlantic is coldest on the surface. The NAO (North Atlantic Oscillation) appears to correlate. The effect is strongest in the northern winter months. Notably the modern expert climate models fail to predict any of the cycles within our major ocean basins. How immature is our understanding of space weather?
Could changes in the solar wind be the driver of the NAO? Will it turn out to be the mechanism for Force N or D?
Fig. 2. Seasonal mean spatial distribution of the correlation between SWS and SST; for MAM (a), JJA (b), SON (c), and DJF (d). The solid dark lines are the boundaries of the regions where the statistical confidence exceeds 99% with the t-test and the dashed dark lines are the boundaries of the regions where the statistical confidence exceeds 95%.
The solar-wind speeds peak about 3 or 4 years after the TSI and sunspots peak in each cycle. That doesn’t suggest the one solar cycle lag we are looking for. Perhaps if we had more data on solar wind speeds we could figure out whether the wind speeds correlated with the TSI in the cycle earlier?
Fig. 1. Time series analysis of monthly average of 10.7 cm solar radiation flux, solar wind electric field and solar wind speed, Fig. 1(a), and the NAO index, Fig. 1(b), as standardized monthly indices from 1963 to 2010. In Fig. 1(a) the dashed line is for 10.7 cm solar flux, the solid line for solar wind electric field, and the dotted line for solar wind speed.
Why the North Atlantic? Researchers don’t know exactly, they speculate:
The North Atlantic region seems to be favored for many of the observed responses, as found in the correlation of atmospheric
geopotential height (GPH) with solar wind geo-effective electric field (GEF) (Boberg and Lundstedt, 2003); of GPH with solar wind speed (SWS) (Zhou et al., 2014); and of surface air temperature (SAT) with energetic electron precipitation (EEP) and the geomagnetic activity that accompanies it (Seppälä et al., 2009; Baumgaertner et al., 2011; Maliniemi et al., 2013).
Every second solar cycle is different
When the sun flips north-south polarity the wind is more likely to hit Earth at a different angle — described as the solar wind clock angle. The Bz component is the north south component. Bz negative phases which are “southward” interplanetary magnetic conditions. That’s also when the geomagnetic storm activity is highest. So every second solar cycle the correlation changes.
Below the Fig 6a is Bz minus, and Fig 6 b is Bz positive.
Fig. 6. As for Fig. 2(d), but dividing winters into those with average negative Bz (a), and those with average positive Bz (b).
Something is going on in the Bz negative cycles in the far northern Atlantic — (that’s the blue blob near Greenland in fig 6a).
In Fig. 6(a) we see a stronger SST response to the SWS when Bz is negative than in 6(b) when Bz is positive, in the high geomagnetic
latitude region near Iceland and southern Greenland.
With negative Bz more solar wind energy enters the magnetosphere–ionosphere system than with positive Bz, increasing energetic particle precipitation and ionospheric electric fields associated with magnetic storms. Increased response with negative Bz is not consistent with UV or total irradiance forcing.
If the correlation is meaningful, the next question is whether this is driven through stratospheric ozone, or though an electrical response of clouds and storm dynamics. It’s all speculation at this stage.
The Australian BOM Solar Wind Speed page
H/t Lance (Siliggy) and thanks to Lance W too.
Abstract
A significant correlation between the solar wind speed (SWS) and sea surface temperature (SST) in the region of the North Atlantic Ocean has been found for the Northern Hemisphere winter from 1963 to 2010, based on 3-month seasonal averages. The correlation is dependent on Bz (the interplanetary magnetic field component parallel to the Earth’s magnetic dipole) as well as the SWS, and somewhat stronger in the stratospheric quasi-biennial oscillation (QBO) west phase than in the east phase. The correlations with the SWS are stronger than those with the F10.7 parameter representing solar UV inputs to the stratosphere. SST responds to changes in tropospheric dynamics via wind stress, and to changes in cloud cover affecting the radiative balance. Suggested mechanisms for the solar influence on SST include changes in atmospheric ionization and cloud microphysics affecting cloud cover, storm invigoration, and tropospheric dynamics. Such changes modify upward wave propagation to the stratosphere, affecting the dynamics of the polar vortex. Also, direct solar inputs, including energetic particles and solar UV, produce stratospheric dynamical changes. Downward propagation of stratospheric dynamical changes eventually further perturbs tropospheric dynamics and SST.
REFERENCE
Zhou, Tinsley, Chu and Xiao (2016) Correlations of global sea surface temperatures with the solar wind speed