Tropical Storms in the Equatorial Pacific Ocean are being triggered by the passage of Kelvin Waves

 N.B. If our claim is correct that Equatorial Kelvin Waves (EKWs) are being generated by the interaction between maxima in the lunar atmospheric/oceanic tides with minima in the diurnal sea-level pressure variations in the tropics (please read): 

https://astroclimateconnection.blogspot.com/2019/09/a-lunar-tidal-mechanism-for-generating.html 

then this post implies that the lunar tides must play a crucial role in initiating the Westerly Wind Bursts (WWBs) in the western equatorial Pacific ocean that are directly responsible for weakening the easterly equatorial trade winds that help trigger El Nino events.

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If you visit Kyle MacRitchie's excellent blog site on Tropical waves at:

https://www.kylemacritchie.com/learn-about-tropical-waves/

he states that convectively decoupled Equatorial Kelvin Waves (EKWs) can have outflows from their convection zones that cause Equatorial Rossby Wave (ERWs) trains to develop in their wake. 

He indicates that these ERWs aren't as strong as those created by MJOs since EKWs generally move from west-to-east along the Earth' equator at 3 to 4 times rate of Madden Julian Oscillations (MJOs).  

In addition, MacRitchie states that Kelvin waves provide favorable conditions for the development of Tropical Cyclones i.e. intense convection, low-level vorticity (in the form of trailing ERWs), vertical shear, and mid-level moisture.

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I light of this, we present a report on the passage of a convectively-decoupled Kelvin Wave across the Equatorial Pacific Ocean, over the last several days, that has set off a series of weak tropical storms and possibly one Hurricane.

The following plot shows the location of MJOs in the equatorial regions of the Indo-Pacific (as represented by the MJO phase - vertical axis) for times between May 15th and September 15th, 2019 (horizontal axis).

This plot showed that the most recent MJO event:

a) started off the east coast of equatorial Africa (MJO Phase 1) around the 17th of August, 

b) reached the region on the Equator between the Philippines and New Guinea (MJO phase 5), around about the 4th -- 5th of September, where it started producing Westerly Wind Bursts (WWBs) to the north of Papua New Guinea.

c) generated a convectively decoupled Kelvin wave, most likely around September 8th, that began moving out across the equatorial Pacific Ocean at a speed of roughly 1350 km/day, reaching the coast of South America roughly 9 -- 10 days later.  

The following weather map shows that the passage of the convectively decoupled Kelvin wave (between September 8th to 17th) generated at least 5 weak topical tropical storms and possibly one hurricane, straddling the Earth's equator at roughly 15 degrees north latitude.

Ref: (https://earth.nullschool.net/)

The following plots show that:

1) the MJO event produces WWBs in the western equatorial Pacific ocean between the 8th and 11th of September.

2) the convectively de-coupled EKW that emerges from the MJO event (sometime after September 8th) starts to move across the equatorial Pacific ocean leaving a series of weak tropical storms in its wake (starting on September 13th), straddling the Earth's equator at roughly 15 degrees North latitude.

3) the cumulative westerly wind flows that are produced on the southern sides of this string of tropical storms effectively eliminates the easterly equatorial trade winds as far east as the mid-Pacific ocean, at 160 degrees West longitude (N.B. the red vertical line on the Equator marks the most easterly longitude of the stalled trade winds for that date).

 All it would take is a series of vigorous EKWs like this one to trigger a major El Nino event, showing that the lunar atmospheric/oceanic tides must play a role in initiating these significant climate events.  

8th Sept

9th Sept

10th Sept

11th Sept

12th Sept

13th Sept

14th Sept

15th Sept

16th Sept

17th Sept

A lunar tidal mechanism for generating Equatorial Kelvin waves

To find out more details about the lunar tidal mechanism that could generate Equatorial Kelvin waves, please read the following post.

 Please click on the diagram below to activate the GIF animation

If you were to observe the Moon from a fixed point on the Equator at the same time each day, you would notice that the sub-lunar point on the Earth's surface appears to move at a speed of 15 — 20 m/sec from west-to-east. This results from the fact that the west-to-east speed of the Moon along the Ecliptic (as seen from the Earth’s center) varies between 15.2 — 19.8 m/sec. 

Interestingly, the west-to-east group (and phase) velocity for the convectively-decoupled Equatorial Kelvin wave (EKW) is 15 — 20 m/sec, as well. This remarkable "coincidence" raises the question:

Could it be that easterly moving convectively-decoupled EKW are produced by the interaction between the day-to-day movement of the lunar-induced atmospheric/oceanic tides with a meteorological phenomenon that routinely occurs at roughly the same time each (24 hr) solar day?

One meteorological phenomenon that fits this bill is the atmospheric surface pressure variations measured at any given fixed location in the tropics. At many points near the equator, the atmospheric surface pressure spends much of its time sinusoidally oscillating about its long-term mean with an amplitude of 1 to 2 hPa (or millibars). Generally, this regular daily oscillation is only disrupted by the passage of a tropical low-pressure cell (e.g. tropical lows, tropical storms, and Hurricanes, Typhoons, and Cyclones).

For example, figure 1 shows the diurnal surface pressure variations in the Carribean as measured by Haurwitz (1947). What this figure indicates is that, like many points near the Earth's equator, the atmospheric surface pressure reaches a minimum near 4:00 -- 4:30 a.m. and 4:00 -- 4:30 p.m.

Figure 1

Source; Figure 1 of Haurwitz B., 1947, Harmonic Analysis of the Diurnal Variations of Pressure and Temperature Aloft in the Eastern Caribbean, Bulletin of the American Meteorological Society, Vol. 28, pp. 319-323.  

This leads us to propose the hypothesis that:

Hypothesis: 

EKWs are generated when the peak in the lunar-induced tides passes through the local meridian at roughly 4:00 a.m. and 4:00 p.m. local time, when the diurnal surface pressure is a minimum. This type of lunar tidal event takes place once every half synodic month = 14.77 days.

Some important points to note:

* The lunar-induced tidal peak in the atmosphere and oceans passes through the local meridian (during its daily passage from west-to-east) both when the Moon is passing through the meridian, and when the Moon is passing through the anti-meridian. This is due to the semi-diurnal nature of the tides.

** If you select times when the Moon passes through the local meridian at a fixed time (e.g. 4:00 p.m. or 4:00 a.m.), you are in fact selecting times when the Moon is at a specific phase (or a fixed point in the Synodic month). Hence, when the Moon is passing through the meridian at 4:00 p.m., the Moon has a Waxing Crescent phase (~33.3 %), and when the Moon is passing through the local anti-meridian at 4:00 p.m. it has a Waning Gibbous phase (~33.3 %).

The following diagram shows a view of the Earth (fawn-colored circle) as seen from above the North Pole, in a frame-of-reference that is fixed with respect to the Sun. In this frame-of-reference, the Earth rotates and the Moon revolves in a clockwise direction. Included in this diagram is a light blue elliptical annulus that represents the sea-level atmospheric pressure at the Earth's equator. This ellipse highlights the fact that the sea-level atmospheric pressure is typically a minimum at 4 a.m. and 4 p.m., and a maximum at 10 a.m. and 10 p.m. In addition, there is a dark blue elliptical annulus that represents the lunar-induced tides in the Earth's atmosphere and oceans. 

If you click on the gif animation you will see the lunar-induced tidal peak at 4.00 a.m. (4.00 p.m.) move to 4.00 p.m. (4.00 a.m.) over a 14.77 day period, where it induces an atmospheric Kelvin wave that travels along the Earth's equator from west-to-east at a speed of 15 -- 20 m/sec. Then you will see the whole process repeat itself when the lunar-induced tidal peak at 4.00 p.m. (4.00 a.m.) moves to 4.00 a.m. (4.00 p.m.) over the remaining 14.77 days of the lunar Synodic cycle.       

Please click on the diagram below to activate the GIF animation

[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