Long-Term Lunar Atmospheric Tides in the Southern Hemisphere

Ian R G Wilson,Nikolay S Sidorenkov

doi:10.2174/1874282320130415001

Abstract

The longitudinal shift-and-add method is used to show that there are N=4 standing wave-like patterns in the summer (DJF) mean sea level pressure (MSLP) and sea-surface temperature (SST) anomaly maps of the Southern Hemisphere between 1947 and 1994. The patterns in the MSLP anomaly maps circumnavigate the Earth in 36, 18, and 9 years. This indicates that they are associated with the long-term lunar atmospheric tides that are either being driven by the 18.0 year Saros cycle or the 18.6 year lunar Draconic cycle. In contrast, the N=4 standing wave-like patterns in the SST anomaly maps circumnavigate the Earth once every 36, 18 and 9 years between 1947 and 1970 but then start circumnavigating the Earth once every 20.6 or 10.3 years between 1971 and 1994. The latter circumnavigation times indicate that they are being driven by the lunar Perigee-Syzygy tidal cycle. It is proposed that the different drift rates for the patterns seen in the MSLP and SST anomaly maps between 1971 and 1994 are the result of a reinforcement of the lunar Draconic cycle by the lunar Perigee-Syzygy cycle at the time of Perihelion. It is claimed that this reinforcement is part of a 31/62/93/186 year lunar tidal cycle that produces variations on time scales of 9.3 and 93 years. Finally, an N=4 standing wave-like pattern in the MSLP that circumnavigates the Southern Hemisphere every 18.6 years will naturally produce large extended regions of abnormal atmospheric pressure passing over the semi-permanent South Pacific subtropical high roughly once every ~ 4.5 years. These moving regions of higher/lower than normal atmospheric pressure will increase/decrease the MSLP of this semi-permanent high pressure system, temporarily increasing/reducing the strength of the East-Pacific trade winds. This may led to conditions that preferentially favor the onset of La Nina/El Nino events.

Highlights

Sidorenkov [1] has determined that the frequency spectra of the ENSO indices has significant components that are close to the subharmonics of the free nutation period of the Earth's poles and the superharmonics of the Earth's forced nutation motion
This paper sets out to look for large drifting structures in the mean sea level pressure (MSLP) and sea-surface temperature (SST) anomaly maps of the Southern Hemisphere that might be associated with the long-term lunar atmospheric tides
The longitudinal shift-and-add method is used to search for N=4 standing wave-like spatial features in the summer (DJF) MSLP and SST anomaly maps

Summary

Introduction

Sidorenkov [1] has determined that the frequency spectra of the ENSO indices has significant components that are close to the subharmonics of the free nutation period of the Earth's poles (i.e. the Chandler Wobble) and the superharmonics of the Earth's forced nutation motion (i.e. the 18.6 year lunar nodical wobble). Sidorenkov [1] argues that external forcing by the lunar/solar tides, acting at the superharmonics of the Earth's forced nutation motion, could produce nonlinear enhancements of the oscillations in the EarthAtmosphereOcean system that closely match those that are seen in the ENSO climate variations He asserts that the resultant ENSO climate variations excite the Chandler Wobble through a resonant coupling with the subharmonics of the free nutation period of the Earth's pole. Following on from the work of Sidorenkov [1,2,3,4], Li [5], Li and Zong [6], Li et al [7] have shown that cyclical changes in lunar tidal forcing produce atmospheric tides with periods of 27.3 day and 13.6 days Li and his associates have detected these atmospheric tides in the tropical troposphere at heights above the 700 hPa isobaric surface (~ 3000m). They indicate that the tides are likely to be present in the upper parts of the mid-latitude troposphere, as well

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Conclusion