Earth and the solar wind. | Credit: NASA/GSFC
There’s a nuclear fusion reactor in the neighborhood that weighs 300,000 times more than Earth. It’s eight minutes away at the speed of light, has 99.8% of the mass of the solar system, and surrounds us with changing magnetic and electric fields while it rains down charged particles. Some years the Sun throws ten times as much extreme-UV our way as it does in other years. Virtually none of this is included in mainstream climate models.
The constant wind of charged particles blows at a million miles an hour — the flow waves and wiggles, shifting direction. The speed of the solar wind correlates with sea surface temperatures in the Atlantic. The solar magnetic field reaches right to the edge of the solar system, but despite that size, it turns itself completely upside down every 11 years. Reconnecting magnetic field lines cause explosions in space, and we have barely started to collect data on this. During the magnetic cycle the sun changes color, though the changes are invisible to us. The spectrum rolls from more UV to more infra red, and each type of light has different effects. Unlike infra red, UV transforms oxygen into highly reactive ozone which creates warming in certain zones, sometimes high over the poles, sometimes more so over the equator. These warmer blobs expand and it’s possible that they shift the jet stream positions, which affects cloud formation and albedo. UV also reaches further into the oceans where it affects plankton, which in turn produce gases that seed denser clouds. Forests and plants on land also seed clouds and influence rain.
Running through all of this, and from a different direction, are cosmic rays which also appear to seed clouds. Their path through our atmosphere is also affected by the solar magnetic field.
Complicating things even further, the Sun may have a dual core — two dynamos operating in the north and south on cycles that are nearly but not quite in sync.
Years from now, people will gasp that the so called experts of the millennium thought the Sun could have little effect — apart from just shining light upon us.
The extra sunlight coming from a more active Sun appears to have a much larger effect than it should in the long run, but has no effect in the year that it occurs. Something is both neutralizing it in the short run, but amplifying it in the long term. David Evans lists below some different mechanisms, with references, for ways that the Sun could be controlling our cloud cover, or albedo. There are undoubtedly others that could be Force D, N or X. One factor is briefly “notching” out the effect of the small spike in solar light during the peak of a solar cycle (Force N). Paradoxically, some other factor appears to be at work throughout the cycle but is delayed by one solar cycle (Force D) — it works in the opposite direction to Force N.
— Jo
25. Possible Force N,D, or X Mechanisms
Dr David Evans, 2 June 2016, Project home, Intro, Previous, Next.
We don’t know the mechanisms behind forces X, N, or D. In this post we canvas a few of the possibilities, but offer no opinion on which if any it might be.
Possibilities
Among others:
- Solar stimulation of ozone via UV or energetic electron or particle precipitation — which changes the relative proportions of ozone and the relative heights of the tropopause at the poles and equator, which in turn affects the degree of north-south extent in the jet streams, which affects the amount of air mass mixing at boundaries of climate zones, which determines cloudiness and albedo (Wilde 2010 and 2015, Woollings, Lockwood, Masato, Bell, and Gray 2010 [1]).
- Cosmic rays are suspected of encouraging cloud formation and thus affecting albedo, and are influenced by the Sun’s magnetic field, so they may be involved in force D. Cosmic rays decrease during TSI peaks, presumably decreasing clouds and albedo and warming the Earth’s surface, so they are not responsible for force N.
- Solar stimulation of plankton — which produce aerosols that affect clouds (McCoy, et al., 2015 [2])
- Meteoritic dust influences albedo, depositing particles large enough to reflect and scatter light but small enough to persist in the stratosphere for months. Meteor rates vary inversely with sunspot numbers (Ellyet, 1977 [3]), so, like cosmic rays, they might explain force D but not force N. The dust contains minerals that catalyze plankton growth (see previous point). (This possibility suggested by Peter Sinclair, a reader of this blog, and there will be a blog post by Peter on this soon.)
- The interplanetary electric field affects cloud cover (Voiculescu, Usoskin, and Condurache-Bota, 2013 [4]).
- Asymmetries in the motion of the Sun about the center of mass of solar system are correlated with deviations in the Earth’s length of day (LOD). The time rate of change of the LOD correlates with the phase of the North Atlantic Oscillation, while deviations of the LOD from its long term trend correlate with the phase of the Pacific Decadal Oscillation (Wilson 2011 [8]). These ocean oscillations are correlated with decadal changes in surface temperature, so may be responsible for or related to force D.
- The Jovian planets may influence solar activity (Sharp 2013 [5], Wilson 2013 [6], McCracken, Beer, and Steinhilber 2014 [7]) and might also be responsible for changes in force X/D half of a full solar cycle afterwards.
Or there may be solar influences which are not yet explained, e.g. Stober 2010. Force X/D may involve combinations of the factors above.
Possible Clue to Force X/D?
There is a faint chance that the Nimbus-7/ERB measurements of TSI from 1979 to 1993 may have inadvertently measured (some aspect of) force X/D. These TSI measurements are notable both for being the earliest and for disagreeing with later TSI measurements by being notably higher. Nimbus-7/ERB measured or emphasized different parts of the electromagnetic spectrum, such as higher energy UV.
Figure 1: TSI data from late 1978, when satellite observations started. “Instrument offsets are unresolved calibration differences, much of which are due to internal instrument scatter” Source.
Yoshimura (1996 [9]) found that the ERB-TSI lagged the sunspots by 10.3 years (pp. 606–7). Force X/D lags sunspots by that duration, so perhaps the difference between whatever Nimbus-7/ERB measured and what later TSI instruments measured is related to force X/D.
Yoshimura concluded (p. 601): “We argue that the time lags between the TSI and magnetic field variations demand us to consider the influences of the Sun on the Earth and on the space environment through two channels which are physically linked together but their variations may not necessarily be in phase in time. One channel is through the irradiance variations and the other is through the magnetic field variations. Time evolution of a phenomenon on the Earth that is influenced by the Sun can be in phase as well as out of phase with the solar magnetic cycle if this phenomenon is mainly caused by the irradiance variations of the Sun”.
(The Yoshimura paper was drawn to our attention by SunSword, a reader on this blog.)
References
[1^] Woollings, T., Lockwood, M., Masato, G., Bell, C., & Gray, L. (2010). Enhanced signature of solar variability in Eurasian winter climate. Geophysical Research Letters, VOL. 37, L20805, doi:10.1029/2010GL044601.
[2^] McCoy, D. T., Burrows, S. M., Wood, R., Grosvenor, D. P., Elliot, S. M., Ma, P.-L., et al. (2015). Natural aerosols explain seasonal and spatial patterns of Southern Ocean cloud albedo. Science Advances, DOI: 10.1126/sciadv.1500157 .
[3^] Ellyet, C. (1977). Solar influence on meteor rates and atmospheric density variations at meteor heights. Geophysical Research, 10.1029/JA082i010p01455.
[4^] Voiculescu, M., Usoskin, I., & Condurache-Bota, S. (2013). Clouds blown by the solar wind. Environmental Research Letters.
[5^] Sharp, G. J. (2013). Are Uranus & Neptune Responsible for Solar Grand Minima and Solar Cycle Modulation? International Journal of Astronomy and Astrophysics, pp. 260-273. doi: 10.4236/ijaa.2013.33031.
[6^] Wilson, I. R. (2013). The Venus–Earth–Jupiter spin–orbit coupling model. Pattern Recogn. Phys., 1, 147–158.
[7^] McCracken, K. G., Beer, J., & Steinhilber, F. (2014). Evidence for Planetary Forcing of the Cosmic Ray Intensity and Solar Activity Throughout the Past 9400 Years. Solar Phys, DOI 10.1007/s11207-014-0510-1.
[8^] Wilson, I. R. (2011). Are Changes in the Earth’s Rotation Rate Externally Driven and Do They Affect Climate? The General Science Journal.
[9^] Yoshimura, H. (1996). Coupling of Total Solar Irradiance and Solar Magnetic Field Variations with Time Lags: Magneto-thermal Pulsation of the Sun. Astronomical Society of the Pacific, ASP Conference Series, Vol 95, pp. 601 – 608.