Switch Between El Nino and La Nina is Caused by Subsurface Ocean Waves Likely Driven by Lunar Tidal Forcing
Authors: Taotao Qian
Jialin Lin
Journal: Scientific Reports (2019)
Discipline: Multidisciplinary
Keywords: ENSO; climate variability; forecasting; El Nino; La Nina
Affiliations: Atmospheric Science Program, The Ohio State University, Columbus, USA. ., Atmospheric Science Program, The Ohio State University, Columbus, USA.

Abstract:  The El Nino-Southern Oscillation (ENSO) is the dominant interannual variability of Earth's climate system, and strongly modulates global temperature, precipitation, atmospheric circulation, tropical cyclones and other extreme events. However, forecasting ENSO is one of the most difficult problems in climate sciences affecting both interannual climate prediction and decadal prediction of near-term global climate change. The key question is what cause the switch between El Nino and La Nina. For the past 30 years, ENSO forecasts have been limited to short lead times after ENSO sea surface temperature (SST) anomaly has already developed, but unable to predict the switch between El Nino and La Nina. Here, we demonstrate that the switch between El Nino and La Nina is caused by a subsurface ocean wave propagating from western Pacific to central and eastern Pacific and then triggering development of SST anomaly. This is based on analysis of all ENSO events in the past 136 years using multiple long-term observational datasets. The wave's slow phase speed and decoupling from atmosphere indicate that it is a forced wave. Further analysis of Earth's angular momentum budget and NASA's Apollo Landing Mirror Experiment suggests that the subsurface wave is likely driven by lunar tidal gravitational force. 

Retracted: No

PubPeer comments:
 If the findings in this paper prove out to be true, the implications would be wide-ranging and would arguably lead to the biggest advancement in climate science in decades. The current models of GCMs could then include the tidal forcing and improve measurably the characterization and predictions of natural global climate variability and thus reduce the uncertainty in the anthropogenic global warming signal. Alas, the verification of any tidal effect is more qualitative than quantitative according to the paper s findings. For example, there is no direct cycle-by-cycle correlation of any of the ENSO cycles to known tidal cycles. What could have helped in the paper is if they had included our analytical solution to Laplace s Tidal Equations that we have formulated and solved for the equatorial Pacific thermocline. Our model has been developed and socialized via the following citations: * Pukite, P.  Analytical Formulation of Equatorial Standing Wave Phenomena: Application to QBO and ENSO. American Geophysical Union, Fall Meeting 2016 * Pukite, P.  Biennial-Aligned Lunisolar-Forcing of ENSO: Implications for Simplified Climate Models. American Geophysical Union, Fall Meeting 2017 * Pukite, P. R., Coyne, D., Challou, D. J.  Ephemeris calibration of Laplace s tidal equation model for ENSO. American Geophysical Union, Fall Meeting 2018 * Pukite, P., Coyne, D. and Challou, D., 2018.  Mathematical Geoenergy: Discovery, Depletion, and Renewal (Vol. 241) . , John Wiley Sons, see Chapter 11 12 The key to correlating the ENSO cycles to the tidal cycles is to assume that an annual impulse amplifies the long-period tidal factors and then applying the non-linear Laplace s Tidal Equation (LTE) modulation that is derived from our analytical solution. The premise of the Lin Qian paper remains the same as ours. The fact that the ocean s thermocline shows a highly reduced effective gravity (due to the density differences above and below the thermocline), it then becomes sensitive to angular momentum variations, thus leading to standing-wave sloshing at the thermocline. ![] We calibrate the lunar factors to an equivalent variation in the *solid* earth rotation as Lin Qian also imply as necessary from the earth s angular momentum budget. So that every delta in the earth s angular momentum variation is accounted for by lunar and solar gravitational torque. However, the equivalent response in a *fluid* is challenging due to the non-linearity of Navier-Stokes and this is where the LTE modulation comes in, as the LTE solution is a non-linear simplification of Navier-Stokes along the equator. ![] In summary, my PubPeer contribution here is not a criticism of the paper but a necessary supplement to previously reported findings that have been overlooked in Lin Qian s citations. ,