Posts Tagged ‘lunar effects on climate’

Sea surface temperature and the 18.6 year lunar nodal cycle

October 15, 2014

There is a growing body of scientific papers (some reported in my post here) which show long period connections between the 18.6 year lunar nodal cycles and sea level, tidal sedimentation, tidal mixing, sea surface temperature, Arctic climate and even drought. The mechanisms by which these influences are transmitted are hypothesised but are not known.

Compared to solar cycles the lunar cycles are not well known:

The lunar nodal cycle is not something that is very well known but it is another celestial cycle which is clearly not to be ignored. Naturally the IPCC takes no notice of solar cycles, planetary cycles or lunar cycles and all these are lumped into what could be considered “natural variability”.

(Sourced from Wikipedia)

The lunar orbit is inclined by about 5 degrees on the ecliptic. The moon  therefore can lie up to about 5 degrees north or south of the ecliptic. The ecliptic is the plane of the apparent path of the Sun on the celestial sphere, and is coplanar with both the orbit of the Earth around the Sun and the apparent orbit of the Sun around the Earth.

File:Lunar eclipse diagram-en.svg

Lunar eclipse orbital diagram: wikipedia

The lunar nodes precess around the ecliptic, completing a revolution (called a draconitic or nodical period, the period of nutation) in 6793.5 days or 18.5996 years.

The effects of the 18.6 year lunar nodal cycle on climate on tides and geological sediments and on weather and climate have long been of interest (though not apparently for the IPCC).

The lunar nodes and the nodal cycles were known even to ancient astronomy (Greek, Hindu, Tibetan…) and has found a place in both Eastern and Western astrology. Since astrology is not considered “scientific”, suggestions that the lunar nodal cycle has any impact on the earth’s geology and climate are very often treated with ridicule. Yet the undoubted lunar effects on tides and tidal sedimentation and (therefore) geologic events are not disputed. The nodal period also controls when eclipses can occur.

Eclipses occur only near the lunar nodes: Solar eclipses occur when the passage of the Moon through a node coincides with the new moon; lunar eclipses occur when passage coincides with the full moon. A lunar eclipse may occur if there is a full moon within 11° 38′ (Celestial Longitude), of a node, and a solar eclipse may occur if there is a new moon within 17° 25′ of a node.

It is not surprising that the ancient astrologers/astronomers attributed many effects to the lunar nodes and the nodal cycles:

In Hindu astronomy, the ascending node is called Rahu and the descending node is called Ketu. Rahu and Ketu are thus the north and the south lunar nodes. Rahu represents the severed head of an asura, that swallows the sun causing eclipses. Times of day considered to be under the influence of Rahu are considered inauspicious even today in many parts of India (for weddings, starting journeys …..)

A new paper considers the effects of the 18.6 year lunar nodal cycle on Sea Surface Temperature (SST) and the Pacific Decadal Oscillation (PDO).

S. Osafune, S. Masuda and N. Sugiura, Role of the oceanic bridge in linking the 18.6-year modulation of tidal mixing and long-term SST change in the North Pacific, Geophysical Research Letters, DOI: 10.1002/2014GL061737

HockeyShtick reports:

A paper published today in Geophysical Research Letters finds a “significant contribution” of the 18.6 year lunar-tidal cycle to “wintertime sea surface temperatures near the center of action of the Pacific Decadal Oscillation [PDO] in the eastern Pacific,” and that

“This result supports the hypothesis that the 18.6-year tidal cycle influences long-term variability in climate; thus, knowledge of this cycle could contribute towards improving decadal predictions of climate.” [which IPCC climate models do not incorporate]

The approximately 60-year long Pacific Decadal Oscillation [PDO] in-turn profoundly affects global climate and interacts with other ocean and atmospheric oscillations. A very simple climate model based solely upon the sum of the sunspot integral, Pacific Decadal Oscillation [PDO], and Atlantic Multidecadal Oscillation [AMO] explains 96% of climate change over the 20th century: …..


Paper Abstract:The impact of the 18.6-year modulation of tidal mixing on sea surface temperature (SST) in the North Pacific is investigated in a comparative study using an ocean data synthesis system. We show that remote impact through a slow ocean response can make a significant contribution to the observed bidecadal variation in wintertime SST near the center of action of the Pacific Decadal Oscillation in the eastern Pacific. A comparative data synthesis experiment showed that the modified SST variation is amplified by bidecadal variation in the westerly wind. This relationship between SST and wind variations is consistent with an observed air–sea coupled mode in the extratropics, which suggests that a midlatitude air–sea interaction plays an important role in enhancing the climate signal of the 18.6-year modulation. This result supports the hypothesis that the 18.6-year tidal cycle influences long-term variability in climate; thus, knowledge of this cycle could contribute towards improving decadal predictions of climate.

I am of the opinion that climate is predominated by solar effects which are mediated primarily by the oceans over multidecadal periods and only over shorter periods by the atmosphere. And if lunar nodal cycles influence the tidal flows and tidal mixing then they will also influence the climate – also on the decadal scale.

We dance to a celestial music and the moon provides the variations on the climate themes set by the sun.


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