Monthly lunar declination extremes' influence on tropospheric circulation patterns

Krahenbuhl, Daniel; Pace, Matthew B.; Cerveny, Randall S.; Balling, Robert C.

doi:10.1029/2011jd016598

Cited by 6 publications

(8 citation statements)

References 17 publications

(20 reference statements)

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“…Support for the findings of Li et al [7] is provided by Krahenbuhl et al [8] who have shown that the 27.3 day lunar atmospheric tides can influence the short-term midlatitude general circulation pattern by deforming the highlatitude Rossby long-waves. They also find that these tidal effects have their greatest influence in the upper troposphere of both hemispheres.…”

Section: Introductionmentioning

confidence: 74%

Long-Term Lunar Atmospheric Tides in the Southern Hemisphere

Wilson¹,

Sidorenkov²

2013

TOASCJ

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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.

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Section: Introductionmentioning

confidence: 74%

Long-Term Lunar Atmospheric Tides in the Southern Hemisphere

Wilson¹,

Sidorenkov²

2013

TOASCJ

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“…The differences in the behavior of the atmosphere with full versus new moon [ Shaffer et al ., ] and southern versus northern declination [ Krahenbuhl et al ., ] are previous work supported by these findings (points 3 and 4 above). These earlier findings further warrant the separate consideration of tidal potential associated with new versus full moon or northern versus southern MLD.…”

Section: Resultsmentioning

confidence: 99%

“…The change in the SAM may be due to Rossby wave breaking [ Wang and Magnusdottir , ; Ndarana et al ., ] associated with MLD as eluded to by Krahenbuhl et al . []. A positive influence associated with and following full moon with smaller MLD . Evidence (Figures and b) suggests that during Austral summer, a strong low‐latitudinal tidal forcing associated with full moon has a positive influence on the SAM.…”

Section: Resultsmentioning

confidence: 99%

“…The daily range in acceleration is taken as the tidal potential per day. As the near‐equatorial versus high‐latitude tidal potential may play an important role in the atmospheric responses noted [ Krahenbuhl et al ., ; Li , ; Li et al ., ], the low‐latitude potential (average potential at 0° and 20°S) and high‐latitude potential (at 65°S) are considered separately. Tidal potential per day per latitude is normalized with respect to the day of year over the entire time series (1910–2013).…”

Section: Methodsmentioning

confidence: 99%

“…This may also indicate that not only the magnitude of tidal forcing but also the rate of change of tidal potential at higher latitudes has a negative influence on the SAM as the rate of increase in tidal potential will be larger if lunar distance decreases while declination increases. The change in the SAM may be due to Rossby wave breaking [Wang and Magnusdottir, 2011;Ndarana et al, 2012] associated with MLD as eluded to by Krahenbuhl et al [2011]. 3.…”

Section: 1002/2013jd021138mentioning

confidence: 99%

See 2 more Smart Citations

Response of the Southern Annular Mode to tidal forcing and the bidecadal rainfall cycle over subtropical southern Africa

2014

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Synoptic weather data and rainfall records are used to support previous suggestions that the decadal-scale cycle in certain climate records may be attributed to the modulation in tidal forcing related to the 18.6 year lunar nodal cycle. The Southern Annular Mode (SAM) is shown to be sensitive to tidal forcing on a daily time scale. It is subsequently shown that the late-summer SAM can be predicted by consideration of tidal potential. The seasonal response in the SAM is also reflected in sea surface temperatures. Observed behavior of the atmosphere suggests that changing tidal potential over the lower versus higher latitudinal regions plays a role. The atmospheric response as reflected in the changing SAM affects the daily rainfall variation in certain subtropical parts of southern Africa where rainfall correlates positively with the SAM. The daily rainfall response subsequently accumulates in a bidecadal rainfall cycle, known over southern Africa as the Dyer-Tyson cycle.

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Lunar influence on equatorial atmospheric angular momentum

2014

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This study investigates the relationship between the equatorial atmospheric angular momentum oscillation in the nonrotating frame and the quasi-diurnal lunar tidal potential. Between 2 and 30 days, the corresponding equatorial component, called Celestial Atmospheric Angular Momentum (CEAM), is mostly constituted of prograde circular motions, especially of a harmonic at 13.66 days, a sidelobe at 13.63 days, and of a weekly broadband variation. A simple equilibrium tide model explains the 13.66 day pressure term as a result of the O 1 lunar tide. The powerful episodic fluctuations between 5 and 8 days possibly reflect an atmospheric normal mode excited by the tidal waves Q 1 (6.86 days) and 1 (7.095 days). The lunar tidal influence on the spectral band from 2 to 30 days is confirmed by two specific features, not occurring for seasonal band dominated by the solar thermal effect. First, Northern and Southern Hemispheres contribute equally and synchronously to the CEAM wind term. Second, the pressure and wind terms are proportional, which follows from angular momentum budget considerations where the topographic and friction torques on the solid Earth are much smaller than the one resulting from the equatorial bulge. Such a configuration is expected for the case of tidally induced circulation, where the surface pressure variation is tesseral and cannot contribute to the topographic torque, and tidal winds blow only at high altitudes. The likely effects of the lunar-driven atmospheric circulation on Earth's nutation are estimated and discussed in light of the present-day capabilities of space geodetic techniques.

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Monthly lunar declination extremes' influence on tropospheric circulation patterns

Cited by 6 publications

References 17 publications

Long-Term Lunar Atmospheric Tides in the Southern Hemisphere

Long-Term Lunar Atmospheric Tides in the Southern Hemisphere

Response of the Southern Annular Mode to tidal forcing and the bidecadal rainfall cycle over subtropical southern Africa

Lunar influence on equatorial atmospheric angular momentum

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