In Chapter 12 of the book, we provide a short introduction to ocean tidal analysis. This has an important connection to our model of ENSO (in the same chapter), as the same lunisolar gravitational forcing factors generate the driving stimulus to both tidal and ENSO behaviors. Noting that a recent paper [1] analyzing the so-called *long-period* tides (i.e. annual, monthly, fortnightly, weekly) in the Drake Passage provides a quantitative spectral decomposition of the tidal factors, it is interesting to revisit our ENSO analysis in the conventional ocean tidal context …

# Month: February 2019

# Autocorrelation of ENSO power spectrum

In Chapter 12 of the book, we have a description of the mechanism forcing the El Nino / Southern Oscillation (ENSO) behavior. An important ingredient to the modeled forcing is an annual impulse (with a likely biennial asymmetry) that modulates the hypothesized lunar tidal forcing. We will show next how to confirm that the annual impulse exists simply by analyzing the ENSO power spectrum …

# Length of Day

Continuing with Chapter 13 of the book, we also analyze the factors that perturb the Earth’s rotation rate and therefore the observed *length-of-day* (LOD). Researchers continue to update the characterization of the LOD, such as here, which we can compare against a straightforward model based on the accepted lunisolar gravitational forcing factors …

# The Chandler Wobble

In Chapter 13 of the book, we have a description of the mechanism causing the Chandler wobble of the Earth’s polar axis. Last fall, NASA updated a description of their understanding of the axis drift [1] described here, which we can place in context with the model …