[Rhetorical Question] Do you think that the Moon might have something to do with it?

SUMMARY

Given the link to the 8.85/9.1 year lunar tidal cycles, what the Brandt et al. (2011) paper is telling us is that:

a) The Moon is continuously producing semi-monthly pulses of (easterly moving) Equatorial Kelvin waves and (westerly moving) Equatorial Rossby waves that are rushing across the equatorial Atlantic Ocean.

b) These produce the high baroclinic [Atlantic] basin [oscillation] modes. This can be thought of as a slow resonant sloshing motion of the surface waters of the equatorial Atlantic that is constrained by the coasts of eastern South America (at the Mouth of the Amazon) and eastern Equatorial Africa (at Equatorial Guinea).

c) These, in turn, are driving the 4.5-year cycle seen in the upwelling of energy from the depths of the equatorial Atlantic Ocean.

Reference:

Brandt, P., Funk, A., Hormann, V., Dengler, M., Greatbatch, R.J., and Toole, J.M., 2001, Interannual atmospheric variability forced by the deep equatorial Atlantic Ocean, Nature volume473, pages497–500

Main Conclusion: 

"We propose that the variability in the equatorial zonal surface flow is not due to wind forcing with the same period but rather is a mode internal to the ocean, with its origin in the abyss (perhaps as deep as several thousand metres). If this is indeed the case, then the observed atmospheric variability in the 4–5-yr period band in the equatorial Atlantic can be interpreted as a consequence of internal ocean dynamics."


Brandt et al. (2011) contends that the Tropical Atlantic (meteorological) variability has two dominant modes:

1) The meridional mode that peaks in the boreal spring and is characterized by a latitudinal (N-S) sea-surface temperature (SST) gradient that drives cross-equatorial wind velocities anomalies from the colder to the warmer hemisphere.

2) The zonal mode that is most pronounced during the boreal summer and is characterized by a longitudinal (E-W) SST gradient along the Equator that is associated with marked zonal wind anomalies. The boreal summer months also correspond to a time when there is a seasonal maximum in equatorial upwelling deep-ocean water that leads to the development of the eastern Atlantic SST cold tongue.

Historically, the variability of the eastern equatorial Atlantic SSTs has been best represented by the ATL3 index. This index measures the average SST anomaly inside a box with a latitude range of 3^O S – 3^O N, and a longitude range of 0^O E – 20^O W. The ATL3 index is used as a proxy to monitor the effects of the zonal and meridional modes upon the gradients in SST in the Tropical Atlantic.

Brandt et al. (2001) show that, during the last couple of decades, the ALT3 index shows significant variability on interannual timescales with a dominant periodicity between about 4 – 5 years. They find that the variance of the different ocean parameters is maximized by adopting a harmonic period of 1,670 days (= 4.5723 tropical years). The associated amplitude of these fluctuations is 0.29 +/- 0.08 C, when averaged over the ATL3 region, with the largest amplitudes (~ 0.4 C) occurring in the eastern equatorial Atlantic Ocean.

In addition, Brandt et al. (2011) find that:

1) the oceanic surface zonal geostrophic velocity anomaly, measured along the Equator between longitudes 15^O W – 35^O W, and

2)  the zonal velocity measured at 1000-m depth, as observed by the Argo floats, between 1^O S – 1^O N and 15^O W – 35^O W.

both exhibit inter-annual variations that is best described by a harmonic period of 1,670 days.

Confirmation of these results is provided by the curves displayed in figure 1b (shown below - Brandt et al. 2011). 

The top part of figure 1b shows the ATL3 SST anomaly index (red dashed line) and the HADISST anomaly (red thin solid line- presumably covering the same zone as the ATL3 index), with its 1,670-day harmonic fit (red thick solid line). In contrast, the bottom part of figure 1b shows the oceanic surface zonal geostrophic velocity anomaly (black thin solid line), with its 1,670-day harmonic fit (black thick solid line), and the zonal velocity at a depth of 1000-m (black dots with standard error bars), with its 1,670-day harmonic fit. 

Figure 1

Analysis of the zonal velocities at 1,000-m depth reveals a periodic behavior that is similar to the SST and surface geostrophic zonal velocity anomalies (Fig. 1b), with the dominant period of the Argo float drift data being 4.4 years [over the period from 1998 to 2010]. The data shows a series of jets, alternating with depth, with a vertical wavelength of 300 to 700 metres.  Interestingly, linear internal wave theory indicates that the downward phase velocity of the equatorial deep jets (~100 metres per year) corresponds to an upward energy propagation that reaches the surface and affects sea-surface conditions.

Finally, Brandt et al. point out that the observations in the equatorial Atlantic reveal a similar periodic behavior for the deep-jet oscillations over varying time intervals and depths. They suggest that a consistent behavior of this nature could arise from the development of high baroclinic [Atlantic] basin [oscillation] modes established by the eastward propagation of Kelvin and Rossby waves.

The Connection to the Lunar Tidal Cycles

Interestingly, the 1670-day periodicity associated with the upward propagation of energy from the ocean depths in the equatorial Atlantic Ocean is half 9.145 tropical years or if you believe the 4.4-year periodicity associated with Argo float data (for the zonal velocities at 1000-m depth), half of 8.8 tropical years.  

What is fascinating is that each of these periods is close to well-known long-term cycles associated with the lunar tides.

The 9.145 tropical year periodicity is close to the observed 9.1-year cycle in the world mean temperature. Half of this 9.1-year variation (i.e. 4.55 tropical years = 1662 days) is often associated with the harmonic mean of half the 18.6-year Lunar Nodical Cycle (i.e. LNC/2 = 9.3 years) and the 8.85-year Lunar Anomalistic Cycle (LAC). Similarly, the twice the 4.4.-year period that is associated with the Argo float data (i.e. 8.8 years) is reasonably close to the 8.85-year LAC.

Figure 2 below shows that 1670-day harmonic-period that is representative of the upwelling of energy from the depths of the equatorial Atlantic Ocean, compared to the rate of change of the angle between the lunar line-of-apse and the Earth-Sun line, as measured at the time of Perihelion [units - degree per year].

Figure 2

The very close phase alignment between these two phenomena raises the possibility that the lunar tides are responsible for the eastwardly propagating Kelvin and Rossby waves that are believed to produce the high baroclinic [Atlantic] basin [oscillation] modes. It is believed that these, in turn, are driving the upwelling of energy from the depths of the equatorial Atlantic Ocean.

Support for this hypothesis is given by the lunar tidal model developed by the author in February 2019, details of which can found at:

http://astroclimateconnection.blogspot.com/2019/02/the-lunar-tidal-model-part-4.html

N.B. Unfortunately, the short time periods covered by the equatorial SST data [17 years for the Brandt et al (2011) data and 12 years for the Argo float data], means that there has been insufficient time to distinguish whether a periodicity of 8.85 years or 9.1 years best fits the SST data.

The 2013 Prediction of Greater Than Normal Rainfall over SE Australia and Flooding in the Brisbane Valley in 2029 (+/- 1 year)

In 2013, I predicted that SE-Australia needed to prepare for hot dry conditions in the summer of 2019 (i.e. the 2018/19 summer) and possible extensive flooding in 2029 (+/- 1 year).

In 2018/19, the SE of Australia had one of its hottest summers and it is currently experiencing one of its most severe droughts.

The Federal Government and BOM (Bureau of Meteorology) have ignored the 2018/19 prediction and they seem to have no interest in understanding why there could be extensive flooding in 2029.

1. Evidence to Support the Prediction of Flooding in the Brisbane Valley in 2029 (+/- 1 year).

Further evidence that the Moon may have an important role in determining the frequency of extreme weather events in Australia is provided in Table 1. This table shows the dates of major floods in the Brisbane River Valley since the Europeans first discovered the region in 1825.

Table 1

 

Table 1 reveals that the major floods recorded at Brisbane and/or Ipswich are separated by a period of time that is equal to the Lunar Draconic Cycle of 18.6 years. Unfortunately, the general picture is clouded by the fact that there appear to be three parallel sequences of 18.6 years that fade in and out and sometimes there are floods that occur 3 years prior to expected sequence date. 

The 1825 lunar flood sequence is the only one that persists over the 188-year record with the other sequences (i.e. those starting in 1856 and 1889) fading out after only a few cycles. If the 1825 lunar flood sequence continues, we should expect to a significant flooding event in either Brisbane or Ipswich in 2029 (+/- 1 year). 

2. Evidence to Support The Prediction of Above Average Rainfall Over SE Australia in 2029.

Finally, the top of the figure on the front of this submission (shown above) shows a sequence of maps of Australia’s annual rainfall, starting in 2010.5 and going back till 1899 in steps of time that are equivalent to the 18.6-year lunar Draconic cycle. In all but one case (i.e. 1899) the rainfall over south-eastern Australia was significantly above average in these years. If this sequence persists then we should expect greater than normal rain over south-eastern Australia in 2029 (+/- 1 year).

Factors Which Affect the Location and Strength of High-Pressure Cells Over South-Eastern Australia During the Southern Summer (DJF)

Updated 10/05/2019

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 and south with the seasons.

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

4. On average, the centre of the 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).

The Semi-Permanent High-Pressure Cells in the STHR

1. During the summer months (DJF), there are four semi-permanent high-pressure cells embedded within the Southern Hemisphere 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.

2. Wilson [2012] has shown that variations in the latitude anomaly of the peak of the summer (DJF) STHR over Eastern Australia exhibit the same period and phase as that of the 18.6-year draconic spring tidal cycle.

3. 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.

This may not seem like much, but it does represent a shift of at least 100 kilometers in latitude and it can become important when it is combined with longitudinal shifts in the relative location of the centre of the semi-permanent high off SE Australia.

4. Support for the lunar influence upon the latitudinal shifts of the summer STHR is provided by the fact that the -12.57 μsec change in the length-of-day (LOD) associated with the 18.6-year Draconic lunar tides could be explained if the mass of air above 3000 m in the STHR (of both hemispheres) is systematic shifts backward and forward in latitude by one-degree over a period of 18.6 years. 

http://astroclimateconnection.blogspot.com/2012/06/simple-model-for-186-year-atmospheric.html

5. Wilson and Sidorenkov [2013] used the longitudinal shift-and-add method to show that there are westerly moving N=4 standing wave-like patterns in the summer (DJF) mean sea level pressure (MSLP) anomaly maps of the Southern Hemisphere between 1947 and 1994. They showed that the standing wave patterns in the MSLP anomaly maps circumnavigate the Earth with periods of 36, 18, and 9 years [moving at 10, 20 and 40 degrees west per year, repectively]. Wilson and Sidorenkov [2013] claim that the N=4 standing wave patterns in the MSLP are just long-term lunar atmospheric tides that are produced by the 18.6-year lunar Draconic cycle.

6. For example, figure 6 a-c from Wilson and Sidorenkov [2013] displayed below shows that, as result of these tidally driven atmospheric standing waves, a large negative anomaly of atmospheric pressure passed from east to west through the Great Australian Bight on or around the year 1971 moving at about 10 degrees per year towards the west.

7. It does not take much to realize that such slow-moving longitudinal atmospheric anomalies being driven by the 18.6-year Draconic lunar tidal cycle would have a significant effect upon the relative strength and location of the semi-permanent high-pressure cells located in the Tasman Sea and the Great Australian Bight. This is particularly true given that these longitudinal changes in the relative strength and location of the semi-permanent high-pressure cells are being matched in period and phase by corresponding changes in the latitude of the peak of the STHR (Wilson 2012).

8. Hence, it very likely that changes in the temperatures and rainfall experienced over the SE corner of the Australian continent should exhibit periodicities that match the 18.6-year lunar Draconic tidal cycle.

9. This 18.6-year pattern shows up in the annual rainfall anomaly of Victoria between 1900 and 2013.

10. This is confirmed by the following graph of the normalized auto-correlation of the Victorian rainfall (positive) anomalies between 1900 and 2017.

Please read the following three blog posts: 

What is the Australian Bureau of Meteorology Trying to Hide?

http://astroclimateconnection.blogspot.com/2018/12/what-is-australian-bureau-of.html

A 2013 Prediction of Severe Drought in South-Eastern Australia in 2019, Willfully Ignored by the Australian Government.

http://astroclimateconnection.blogspot.com/2019/04/a-2013-prediction-of-severe-drought-in.html

Another 2013 prediction that the temperatures in SE Australia would be above normal in 2019 - Completely ignored by the Government!

http://astroclimateconnection.blogspot.com/2019/05/another-2013-prediction-that.html

References:

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.

Wilson I.R.G. and Sidorenkov N.S., Long-Term Lunar Atmospheric Tides in the Southern Hemisphere. Open Atmos Sci J 2013; 7: 51-76

Another 2013 prediction that the temperatures in SE Australia would be above normal in 2019 - Completely ignored by the Government!

Reference:

Wilson I.R.G. and Sidorenkov N.S., Long-Term Lunar Atmospheric Tides in the Southern Hemisphere. Open Atmos Sci J 2013; 7: 51-76

https://benthamopen.com/contents/pdf/TOASCJ/TOASCJ-7-51.pdf

How long does it take for the egg-shape of the lunar orbit to align with both the phase of the Moon and the annual seasonal cycle?

The 31/62/93/186-Year Perigee-Syzygy Lunar tidal Cycle

If you start out with a new moon at its closest point to the Earth [i.e. closest Perigee] around perihelion [i.e. at the start or end of the annual seasonal cycle], then the Line-of-Apse [representing the longest dimension of the egg-shape of the lunar orbit] must rotate seven times around the Earth with respect to the stars (i.e. 7 x 8.8506 = 61.954 ~ 62.0 tropical years) before a new moon reoccurs at closest Perigee at the same point in the annual seasonal cycle (e.g. perihelion).

Another way of saying this is that a new moon at closest perigee will reoccur at the same point in the annual seasonal cycle (e.g. perihelion), once every three Perigee-Syzygy cycles plus one Full Moon Cycle (i.e. [3 x 20.2937] + 1.1274 = 62.0085 tropical years) or 55 Full Moon Cycles (where 1.0 FMC = 1.1274 years = the time required for the egg shape of the lunar orbit to precisely return to pointing at the Sun).

Hence, if you start out with a new moon at closest perigee at or near the time of perihelion, you will get a Full Moon at closest perigee, on roughly the same day, 31 years later, and a New Moon at closest perigee, on roughly the same day, 62 years after the starting date.

How long does it take for the tilt of the lunar orbit to align with both the phase of the Moon and the annual seasonal cycle?

The 93/186-Year Draconic Cycle

 If you start out with a new moon at the ascending node of the lunar orbit [i.e. the same point in the tilt of the lunar orbit] around Perihelion [i.e. at the start or end of the annual seasonal cycle], then the Line-of-Nodes [representing the tilt of the lunar orbit] must rotate five times around the Earth with respect to the stars (i.e. 5 x 18.5999 = 92.9996 ~ 93.0 tropical years) before it returns to a full moon at the descending node around perihelion.

This means that if you start out with a new moon at or near the time of perihelion that is close to one of the nodes of the lunar orbit and at perigee, 93 tropical years later you will have a full moon that is close to the opposite node and at perigee on roughly the same day of the year. This is true because:

1150.5 lunar synodic months = 33974.9425 days = 93.0203 tropical years
1233 lunar anomalistic months = 33974.7600 days = 93.0198 tropical years and
1248.5 draconic months =33974.4577 days = 93.0190 tropical years.

[N.B. The full tidal cycle is actually 186 years long since it takes this long for the Moon to return to a New Moon phase at a time when it  returns to the same node, at perigee, and at perihelion].

How long does it take for the egg-shape and tilt of the lunar orbit to realign with both the phase of the Moon and the annual seasonal cycle?

 In order to get a sense of the times when the 31/62/93/186-year lunar Perigee-Syzygy cycle and the 93/186-year lunar Draconic Cycle mutually reinforced each other, curves are plotted in Fig. (14) that indicate the strength of alignment between the two cycles between the years 1857 and 2024.

The blue curve in the above figure shows the angle between the line-of-nodes of the lunar orbit (i.e. the tilt of the lunar orbit) and the Earth-Sun line at the time of Perihelion (theta). The curve is derived in such a way as to highlight the southern summers where there is close alignment. This is done by plotting the function 1/(1+ theta). 

Similarly, the brown curve in this figure shows the angle between the line-of-apse of the lunar orbit (i.e. the egg shape of the lunar orbit) and the Earth-Sun line at the time of perihelion (phi) plotted as the function - 1/(1 + phi).  The functions represented by the blue and brown curves in this figure are used to generate the red curve.

The red curve is an alignment index that is designed to represent the level of reinforcement of the 93/186-year Draconic tidal cycle by the 31/62/93/186-year Perigee-Syzygy tidal cycle. This is done by plotting the values of the blue curve at times when there is a close alignment of the line-of-apse and the Earth-Sun line at perihelion (i.e. when phi < 16°).

The red curve shows that are two epochs 1872 to 1917 and 1973 to 2019, each lasting about 45 years, where there is a strong mutual reinforcement of the Draconic tidal cycle by the Perigee-Syzygy tidal cycle. Individual peaks in the mutual reinforcement occur roughly once every 9.3 years and comparable peaks in the two climate epochs are separated from each other by 93 years.

The Mutually Reinforcing Tidal Model

The fact that the Draconic tidal cycle is mutually enhanced by the Perigee-Syzygy tidal cycle has an observable effect upon the climate variables in the South Eastern part of Australia.

The figure below shows the median summer time (December 1st to March 15th) maximum temperature anomaly. This data is obtained from the Australian BOM High-Quality Data Set 2010, by taking the average for the cities of Melbourne (1857 to 2009 – Melbourne Regional Office – Site Number: 086071) and Adelaide (1879 to 2009 – Adelaide West Terrace – Site Number 023000 combined with Adelaide Kent Town – Site Number 023090), between 1857 and 2009 (blue curve).

Superimposed on this figure is the alignment index curve from the previous figure above (red curve).

A comparison between these two curves reveals that on almost every occasion where there has been a strong alignment between the Draconic and Perigee-Syzygy tidal cycles, there has been a noticeable increase in the median maximum summer-time temperature, averaged for the cities of Melbourne and Adelaide.

Hence, the mutual reinforcing tidal model predicts that the median maximum summer-time temperatures in Melbourne and Adelaide should be noticeably above normal during the summer of 2018/19.