SUMMARY (if TL'DR): Just as the Earth's movement around the Sun produces the yearly seasonal cycles in the Earth's weather, the weekly movement of the Earth about the Earth-Moon barycentre produces weekly-seasons in the Earth's synoptic weather.
For more detail see: Celestial Mechanical Causes of Weather and Climate Change N. S. Sidorenkov
Izvestiya, Atmospheric, and Oceanic Physics, 2016, Vol. 52, No. 7, pp. 667–682
Note: μ is what I call ((delta omega)/omega) in my earlier emails.
NATURAL SYNOPTIC PERIODS
The monitoring of the tidal oscillations in the Earth’s rotational speed, the evolution of synoptic processes in the atmosphere, atmospheric circulation regimes and time variations in hydrometeorological characteristics showed that the majority of types of synoptic processes in the atmosphere vary synchronously with the tidal oscillations in the Earth’s rotational speed (Sidorenkov, 2002, 2009). Using historical data, we checked how often the extrema (minima or maxima) of the angular velocity ν coincide with the times of restructuring of elementary synoptic processes (ESPs) according to the typology proposed by G.Ya. Vangengeim (1935). Statistical analysis showed that, in 76% of cases, the times of the extrema of the angular velocity ν coincide within ±1 day with the dates of ESP restructuring. In 24% of cases, the times of the extrema of ν differ by 2 days or more from the nearest dates of ESP restructuring (Sidorenko, 2000, 2002).
The long-term comparative monitoring of variations in meteorological characteristics in Moscow, Vladivostok, etc., with the pattern of tidal fluctuations in the Earth’s rotational speed ν (similar to those shown in Fig. 2) clearly confirms the conclusion that the weather variations coincide with the quasi-weekly extrema of ν (see the website: http://geoastro.ru). The changes in the weather regimes coincide with the extrema of the tidal oscillations in the rotational speed ν. It is evident from all the above that the changes in the synoptic processes in the atmosphere are synchronized with the tidal oscillations in Earth’s rotational speed ν.
Changes in weather occur near the extrema of the tidal oscillations in the Earth’s rotational speed, which correspond to the times of lunstices (standstills of the moon) and lunar equinoxes. Similar to the 3-month seasons of the year, which are associated with the Earth’s revolution around the Sun, weather regimes have a kind of quasi-weekly weather seasons. The quantization of weather regimes was first described by B.P. Mul’tanovskii in 1915 (1933), who called them natural synoptic periods (NSPs). Thus, the NSPs are due to the monthly revolution of the Earth and Moon around their barycenter. Weather responds to the times of lunstices and lunar equinoxes. In contrast to the solar seasons, lunar NSPs are unstable: they vary from 4 to 9 days, with an average duration of 6.8 days. These variations are caused by the frequency modulation of the oscillations in tidal forces due to the motion of the lunar orbit perigee. The plots of the tidal oscillations of ν provide an NSP “timetable,” demonstrating that the NSP durations do not vary randomly. Unfortunately, studies are still being published that incorrectly consider the NSP dynamics in the format of Brownian motion.
The most convincing evidence of the influence of lunar tides on atmospheric processes is the spectra of the equatorial components of the atmospheric angular momentum h1 + ih2 (Fig. 3) in the celestial reference frame (CRF) (Sidorenkov, 2009, 2010; Sidorenkov et al., 2014). In Fig. 3, one can clearly see in the intramonthly part of the spectrum the high line of the fortnightly oscillation 13.6 days.
The narrowness of the line suggests [the] stability [of] the oscillation period [is high].
The width of the spectral peak of the roughly quarter-monthly, or weekly, frequency in Fig. 3 indicates the instability of the period and the high power of the quasi-weekly waves, whose period fluctuates from 4 to 9 days. These lunar tidal waves are manifested in weather as Mul’tanovskii NSPs.
Why have none of the experts on atmospheric tides identified the quasi-weekly and fortnightly oscillations? The reason is that they all use the rotating terrestrial reference frame (TRF), wherein hydrometeorological and hydrophysical characteristics are always measured relative to the stationary terrestrial surface, although the TRF axes rotate with an angular velocity of Ω (1 cycle/day). The waves of gravitational tides revolve at very low velocities μ. When analyzing the measurement results, their angular velocities μ merge with the huge angular velocity of the daily thermal tide wave –Ω (the minus sign is due to the rotation of the thermal tidal wave from east to west) and become virtually invisible for research: μ – Ω ≈ –Ω.
For low-frequency waves of gravitational tides not to be lost in the analysis, one needs to eliminate the angular velocity of the Earth’s rotation Ω, i.e., demodulate the time series of the terrestrial measurements, thus making a transition from the terrestrial (TRF) to the stationary celestial (CRF) reference frame (Sidorenkov, 2009, 2010; Sidorenkov et al., 2014). In this case, the frame axes, as well as the terrestrial surface, are stationary. After the demodulation, the aggregate tidal wave changes not only its velocity but also its direction of motion. Before demodulation, the aggregate tidal wave moves from east to west with an angular velocity of μ – Ω ≈ –Ω ≈ 360°/days
and, after demodulation, it moves from west to east with a velocity of the Moon’s proper motion: ~13°/days. The directions and velocities of the proper motion of tidal waves coincide with those of atmospheric disturbances, and there is synchronization between them (see (Sidorenkov and Sumerova, 2010, 2012) and the website: http://geoastro.ru).
It is believed that the effects of gravitational tides must be uniform on global spatial scales. Our longterm experience shows that, at the times of the extrema of tidal forces, there are changes almost everywhere in the Earth’s spheres, but the signs and phases of these changes are different everywhere. In the same way that every port in the world ocean has its own establishment to calculate the maximum high tide, the manifestations of lunisolar tides in the atmosphere are local. The reason is that, when moving in the atmosphere, the tidal waves (which are up to 28 000 in number in modern expansions of the tidal potential) are reflected from orographic obstacles, as well as baric and thermal inhomogeneities, and interfere with one another to create a variegated interference pattern. Based on the studies of oceantides, the atmosphere may have nodal amphidromic points (at which the tide height is zero at any point in time), where there are no tidal oscillations, and antinodes, where tides are amplified by an order of magnitude.