From techno-science.net This tip came in on our tip & notes page, and at first I was quite surprised because I could not see a possible mechanism for it. Then as I read the translation (from French) it started to make more sense. I’ll point out my friend Jim Goodridge published an essay on WUWT about correlation of the PDO and rainfall with LOD: California Climate, PDO, LOD, and Sunspot Departure
Here’s the graph from the current article of interest:
And here’s some excerpts describing possible mechanisms:
Some authors, notably Bourget et al (1992), had begun to reveal correlations between solar activity and the length of day, and more recently, Abarca del Rio et al (2003) and Winkelnkemper (2008) in his thesis noted that the amplitude of the component semi-annual (6 months period) of the length of day and atmospheric angular momentum were anti-correlated with changes in the same period of the ” solar constant (the solar constant expresses the amount of solar energy (actually a lighting power) which would be one …) “.
What could be the link between certain changes in day length, the zonal winds and solar activity? To help answer this question, The Mouël and colleagues analyzed a series of 48 years (from 1962 to 2009) of daily measurements of the length of day, the service provided by the International Earth Rotation and systems reference located at the Observatoire de Paris. They have extracted the component of period 6 months and showed significant variations in the amplitude of this component, about 30%, they compared the one hand the number of sunspots (the Wolf number, a traditional indicator of solar activity measured for several centuries) and also the flux of galactic cosmic ray.
The authors show a good correlation between these three parameters, more precisely (Figure), it is the evolution of cosmic rays and the amplitude of the semi-annual day length are correlated (correlation coefficient the order of 0.7), and are in phase. The correlation is improved when we remove the curve (In geometry, the word curve or curved line designates certain subsets of the plan, the usual space. ,…) example of day length linear trend which could be related to phenomena occurring in the nucleus. It is established also that variations in cosmic rays are out of phase with sunspots and shifted about a year (this is attributed to the mechanism of modulation of galactic cosmic rays by the solar wind (solar wind is a stream plasma consisting essentially of ions and electrons are ejected from the high …) and its magnetic field).
How the speed of rotation of the Earth can it be sensitive to the modulation of cosmic rays?
The answer is in the system of winds. Those who contribute most to the seasonal variations of angular momentum are the winds of relatively low altitude (Altitude is the vertical elevation of a place or object relative to a baseline.) below 30km . Taking an average over a year (A year is a unit expressing the duration of time between two occurrences of an event linked to the revolution …), the difference between radiation (Radiation is energy transfer under form of waves or particles, which can occur by radiation …) received from the Sun ((weight percent)) and one that is emitted by the Earth outward into the great length of wave (A wave is the propagation of a disturbance occurring on its passage a reversible variation of properties …) (IR) is positive towards the equator and negative beyond 40 degrees latitude (Latitude is an angular value, expression north-south position of a point on Earth (or another …).
This latitude gradient must be balanced by a flow of energy (in the common sense energy means anything that allows a work, making the heat, …) from the equator to the poles: the transportation (transport, from the Latin trans, beyond, and portare wearing is wearing something, or someone one, a place …) is provided by the Southern movements (that is to say along the geographic meridians) of the atmosphere, averaged in longitude (Longitude is an angular value, expressing the position east-west from a point on Earth (or another …), and eddies. The zonal winds are the result of this transport because of conservation of angular momentum: going to the poles is approached the axis of rotation of the Earth and changes in this distance must be compensated by changes in speed. The seasonal variations in insolation lead to variations of the same period of the carriage along the meridians and, from there, the mean zonal winds.
There is another route by which clouds can be affected: the atmosphere is indeed penetrated by a vertical electric current of a few nano-Ampere per square meter (the meter (the meter (symbol m, the Greek metron, measure) is the basic unit of length in the International System. … It is defined) square (a square is a regular polygon with four sides is a quadrilateral that is both a rectangle (it a. ..) ( symbol m) is the unit area of the international system.), which fluctuates with the ionospheric currents and therefore the solar activity. These vertical currents electrically charged clouds and, again, change their micro-physical state. Both mechanisms can indeed co-exist. What characterizes them is that those variations induced by solar activity is measured in tenths of a percent and not in parts per thousand. That’s where the important niche amplification (We are talking about force amplifier for a whole range of systems that amplify the efforts: mechanics ,…) of the phenomenon.
Thus, the Earth (specifically the mantle), the rotation is accelerated or slowed according to the fluctuations of cosmic rays under the influence of solar activity through the zonal winds, provide a wonderful device integration variations in atmospheric angular momentum and zonal wind circulation that it is difficult to measure directly.
Full article and translation here
h/t to WUWT reader Steward