LOD as a sloshing forcing?

Is it possible that the LOD correlation to multidecadal global temperature variations is just an example of a forcing response to an ocean basin’s sloshing behavior?

Changes in LOD are angular momentum changes and those get directly translated to forcing inputs to the precarious thermocline stability.  The ~4 year lag between forcing and response may be explained by the thermal mass in the system.

Continue reading

The QBOM Part 2

I previously wrote about the Quasi-Biennial Oscillation (QBO) and its periodic behavior, and in particular how it interacts with ENSO — tentatively as a forcing. The ability of QBO to recreate the details of the ENSO behavior is remarkable.  The possibility exists however that the forcing connection may be more intimately related to tidal torques which force QBO and ENSO simultaneously.   Over a year ago, I first showed how the lunar tidal periods can be pulled from the QBO time series. See Figure 1 here, where the synodic month of 29.53 days is found precisely.

An interesting hypothesis is that the draconic lunar month of duration 27.2122 days may also be a common underlying significant driver. Unfortunately, the QBO and ENSO data are sampled at only a monthly rate, so we can’t do much to pull out the signal intact from our data … Or can we?

What’s intriguing is that the driving force isn’t at this monthly level anyways, but likely is the result of a beat of the monthly tidal signal with the yearly signal. It is expected that strong tidal forces will interact with seasonal behavior in such a situation and that we should be able to see the effects of the oscillating tidal signal where it constructively interferes during specific times of the year. For example, a strong tidal force during the hottest part of the year, or an interaction of the lunar signal with the solar tide (a precisely 6 month period) can pull out a constructively interfering signal.

To analyze the effect, we need to find the tidal frequency and un-alias the signal by multiples of 2π

So that the draconic frequency of 2π/(27.212/365.25) = 84.33 rads/year becomes 2.65 rads/year after removing 13 × 2π worth of folded signal. This then has an apparent period of 2.368 years.

This post will go into more detail and show how a combination of the synodic tide and draconic tide cycles are the primary forcers for QBO.

Continue reading