Red Pill 4 - Take this Red Pill and You Start Seeing Reality!

You are now are deep down the rabbit hole and you are beginning to see the real world!

[Please click on the "RED PILL 1, 2 & 3" links if you haven't read these red pills.]

RED PILL 1 The influence of cycles in the atmospheric lunar tides upon the Earth's atmospheric pressure can be re-inforced (i.e weaponized) if they constructively interfere with the annual seasonal cycle. 

RED PILL 2 If the lunisolar atmospheric tides that are associated with the Peak Seasonal Spring Tides play a role in influencing the Earth's atmospheric pressure, you should see variations in this pressure that occur at intervals of 3.8-year (= 1/5th the Metonic Cycle).

RED PILL 3 If the lunisolar atmospheric tides that are associated with the Peak Seasonal Draconic Spring Tides play a role in influencing the Earth's atmospheric pressure, you should see variations in this pressure that occur at intervals of 9.3-year (= 1/2th the 18.6-year precession cycle of the lunar line-of-nodes).

RED PILL 4  supports the conclusion that long-term changes in the lunar tides caused by the slow (18.6-year) precession of the tilt of the lunar orbit with respect to the Ecliptic, in combination with the more dominant solar-driven seasonal cycles, play an important role in determining the observed inter-annual to decadal variations of the peak latitude anomaly of the summer (DJF) subtropical high-pressure ridge over Eastern Australia (Lsa) between 1860 and 2010.

THERE ARE FIVE MAIN TAKEAWAYS FROM RED PILL 4

1. This post looks for evidence of a correlation between long-term changes in the lunar tidal forces and the interannual to decadal variability of the peak latitude anomaly of the summer (DJF) subtropical high-pressure ridge over Eastern Australia (Lsa) between 1860 and 2010. 

2. A simple "resonance" model is proposed that assumes that if lunar tides play a role in influencing Lsa, it is most likely one where the tidal forces act in "resonance" with the changes caused by the far more dominant solar-driven seasonal cycles. With this type of model, it is not so much in what years do the lunar tides reach their maximum strength, but whether or not there are peaks in the strength of the lunar tides that re-occur at the same time within the annual seasonal cycle. 

3. The “resonance” model predicts that if the lunar atmospheric tides associated with the seasonal peak lunar cycles have a measurable effect upon Lsa then there should be significant oscillatory signals in Lsa that vary in-phase with the 9.31-year seasonal peak draconic spring tides, and the 3.80-year seasonal peak spring tides. 

4. This is exactly what we see in the real world Lsa data over Eastern Australia between 1860 and 2010. Wilson [6] identifies significant peaks in the spectrum of Lsa at 9.4 (+0.4/-0.3) and 3.78 (± 0.06) tropical years. In addition, the study shows that the observed 9.4-year signal is in-phase with the draconic tidal cycle.

5. Thus, red pill 4 supports the conclusion that long-term changes in the lunar tides caused by the slow (18.6-year) precession of the tilt of the lunar orbit with respect to the Ecliptic, in combination with the more dominant solar-driven seasonal cycles, play an important role in determining the observed inter-annual to decadal variations of the peak latitude anomaly of the summer (DJF) subtropical high-pressure ridge over Eastern Australia (Lsa) between 1860 and 2010. 

A. The Sub-Tropical High-Pressure Ridge

1. The Hadley atmospheric circulation cells ensure that the Earth is surrounded by two broad bands of high-pressure roughly located 30 degrees north and south of the Equator. These bands of high pressure are known as the Sub-Tropical High-Pressure Ridge (STHR).

2. The peaks of the STHRs slowly drift from north to south, and vice versa, with the seasons.

3. During the Southern Hemisphere Winter (in July), the peak of the Southern STHR is located at roughly 27 S.

4. On average, the centre of the Southern STHR moves south by six degrees to 33 S during the height of the Southern Hemisphere Summer (i.e. January), with the peak of the pressure ridge moving as far as 42 to 43 S during the latter half of summer (i.e. February).

5. During the summer months (DJF), there are four semi-permanent high-pressure cells embedded within the Southern STHR. The first is centered on the island of Tahiti in the South Pacific, the second is centered on the island of Tristan Da Cunha in the South Atlantic, the third is located off the west coast of Australia in the Indian ocean, and the fourth is located off the South-Eastern coast of Australia. The latter is often split between the Tasman Sea and the Great Australian Bight with the relative strength and location of the two cells changing over time.

B. The Peak of the Sub-Tropical High-Pressure Ridge Over Eastern Australia

The UK Met Office Hadley-Centre (UKMO) has published a data set called hadSLP2r.asc (Adam and Ansell [1]; www.hadobs.org [2]) that contains the mean monthly sea-level pressure (MSLP), averaged over 5 x 5-degree latitude-longitude bins, between the years (January) 1850 to (June) 2010. 

The hadSLP2r data has been used to create a meridional profile of the MSLP, for each of the summer months (i.e. December, January, and February) for the years 1852 to 2010 (hereafter referred to as the UKMO data set). This has been done by taking a latitudinal average of three 5 x 5-degree bins centered at 140E, 145E, and 150E, for each 5-degree step in latitude between 0 and 65 degrees south. N.B. the profile data points have not been weighted to correct for the difference in area between 5 x 5-degree bins with changing latitude. 

The following figure shows the ranges in latitude and longitude over the Australian Continent that are used to create the mean meridional profile for the summer months (DJF), for each year between 1852 and 2010.  

The following figure shows a meridional profile of the MSLP for February 1984. 

The profile shown in this figure is a typical example of the meridional profiles found in the UKMO data set. In this profile, we can see a zone of low pressure produced by the Summer Monsoonal Trough centered near 10 degrees S, a ridge of high pressure produced by the STR near 40 deg S, and the second zone of low pressure, south of 60 degrees, that is associated with the Sub-Polar Trough.  

Bezier Functions (Microsoft Excel) and Cubic Spine curves were fitted to each of the monthly meridional profile curves to determine their peak latitudes (L). Monthly anomalies for L were obtained using a mean monthly value of L for the base period 1961-1990 (William and Stone [3]).

William and Stone [3] point out that it is important to investigate the monthly anomaly of L on a seasonally-averaged, rather than annually-averaged basis. Following their advice, we have taken the latitude anomalies for December, January, and February for each year and averaged them together to give a mean summer value for the anomaly of L (hereafter referred to as Lsa) for all of the years from 1851 to 2010. N.B. Lsa is defined so that a positive value means that the STR is north of the mean latitude for that summer season.

The following figure shows the anomaly of the peak latitude of the Summer Sub-Tropical High-Pressure Ridge over Eastern Australia (Lsa) for the years from 1851 to 2010. 

    

 A program called Redfit 3.8e (Schulz and Mudelsee [4]) was used to generate a Lomb-Scargle periodogram of the LSA data set. The parameters used in the configuration file needed to run Redfit were set to values that maximize the spectral resolution of the periodogram (N.B. for a detailed description of the parameters used with Redfit see Schulz and Mudelsee [4]). 

 The resulting spectrum is displayed in the figure below. The output of Redfit program indicates that the noise in the periodogram is consistent with an AR1 (red-noise) process. The solid continuous dark line running across the top of the spectrum in the figure is the critical false alarm level (CFAL) (Thomas [5]). Any periodic signals that have peak amplitudes exceeding this threshold level are believed to be inconsistent with an AR1 origin and so are considered significant. 

Hence, the only significant peaks in the spectrum in the following figure are those at 9.4 (+0.4/-0.3) and 3.78 (± 0.06) (N.B. the errors of the periods given are set at ± half of the 6dB bandwidth). The 9.4-year peak is consistent with the period of the 9.3-year seasonal draconic spring tidal cycle and the 3.8 year peak with the 3.8 year period of the seasonal spring tidal cycle.

(A Lomb-Scargle periodogram of the LSA data set. The spectral amplitude is scaled such that the area under the spectrum is an estimator for the data variance.)

What this spectrum tells us is that the variations in the latitude anomaly of the peak of the summer (DJF) STHR over Eastern Australia exhibit the same period as that of the 18.6-year draconic tidal cycle (Wilson [6]).

In essence, what this means is that, on average, the latitude of the peak of the STHR moves back and forth in latitude by one degree between the years where the Line-of-Nodes of the lunar orbit points directly towards or away from the Sun at the time of Perihelion, and the years where the Line-of-Nodes is at right angles to the Earth-Sun line at the time of Perihelion.

References

[1] Allan RJ, Ansell TJ. A new globally complete monthly historical mean sea level pressure data set (HadSLP2): 1850 – 2004. J Climate 2006; 19: 5816-42. 

[2] www.hadobs.org, hadSLP2r, accessed: Mar 2011.

[3] Williams AJ, Stone RC. An assessment of relationships between the Australian subtropical ridge, rainfall variability, and high-latitude circulation patterns. Int J Climatol 2009; 29: 691-709.

[4] Schulz M, Mudelsee M. REDFIT: estimating red-noise spectra directly from unevenly spaced paleoclimatic time series. Comp Geosci 2002; 28: 421-6.

[5] Thomson DJ. Time series analysis of Holocene climate data. Philosophical Trans R Soc Lond Ser A 1990; 330: 601-16.

[6] Wilson I.R.G. Lunar tides and the long-term variation of the peak latitude anomaly of the summer Sub-Tropical High-Pressure Ridge over Eastern Australia. Open Atmos Sci J 2012; 6: 49-60.