Discussion on length of day – the changes in the speed the Earth spins at

Posted: September 9, 2011 by tallbloke in climate, Ocean dynamics, solar system dynamics

This is a placeholder for a thread on Length of Day (LOD), awaiting some input from Paul Vaughan to help shape it.

We have had some discussion on the Spencer and Braswell thread, which deserves it’s own place. See there for links to Paul’s WUWT thread, and some useful papers.

Comments
  1. Paul Vaughan says:
    September 10, 2011 at 5:16 pm

    Discussion continued from:

    Spencer and Braswell 2011: Resignation of journal editor and Trenberth’s attack don’t change facts

    –
    IF it appears to be a matter of resonance & amplification, this just emphasizes that we need to mobilize discussion away from misleading anomalies towards the clarity of absolutes.

    Regards.

  2. Paul Vaughan says:
    September 10, 2011 at 7:47 pm

    Greetings to All,

    Tallbloke was asking about this:

    There’s a table summarizing the components here:

    Solar, Terrestrial, & Lunisolar Components of Rate of Change of Length of Day

    Also noted there:
    “The above tables & figures, while certainly nothing new to science, have been summarized here for the benefit of those striving to efficiently develop the foundations necessary to appreciate and build upon the recent seminal work of Le Mouël, Blanter, Shnirman, & Courtillot (2010).”

    The knowledge summarized in the figure is uncontroversial & decades old.

    See for example Table 5 [pdf p.23] here:

    Gross, R.S. (2007). Earth rotation variations – long period. In: Herring, T.A. (ed.), Treatise on Geophysics vol. 11 (Physical Geodesy), Elsevier, Amsterdam, in press, 2007.

    Click to access Gross_Geodesy_LpER07.pdf

    Click to access Gross_Geodesy_LpER07.pdf

    People aren’t taking the time to get a conceptual handle on the nature of summary discontinuities arising from windowed aliasing from the multiscale spatiotemporal framework. It may be years or decades before enough influential people make the conceptual investment necessary to see the sheer simplicity.

    Recently WUWT commenter Patricia Régnier drew my attention to this illuminating distillation of the conventional mindset:
    “On comprend, mais cela équivaut à chercher ses clefs au pied d’un réverbère parce que c’est là qu’il ya de la lumière.”
    http://www.pensee-unique.fr/theses.html#lod

    From Google Translate (for those who can’t read Acadian):
    “It is understandable, but it is like looking for his keys at the foot of a street lamp because that’s where there’s light.”

    It’s not primarily a physics problem. The mechanisms are all known, accepted, & uncontroversial (e.g. the terrestrial year, which has a summer/winter in opposite hemispheres every 6 months). The root of the impasse is misconception of the spatiotemporal sampling framework.

    Tomas Milanovic (known for his penetrating lucid commentary) revealed his primary reason for entering the climate discussion while responding to a comment I made at Judith Curry’s blog Climate Etc.

    The core of my comment:
    “Misinterpreting multiscale spatial phase reversals as temporal features is a seriously FUNDAMENTAL error.”

    Milanovic’s response:
    “Yes I agree with that and it is the first reason for my guest post here (spatio-temporal chaos).”

    Please see the full exchange here:

    Phase locked states

    The fundamental point evading almost everyone involved in the climate discussion:
    Pattern summaries are a function not only of real pattern, but also of spatiotemporal aggregation criteria.

    The physics is known, but almost no one in the climate discussion has a clue about the topology of the sampling framework and its conceptual implications. The spatiotemporal version of Simpson’s Paradox is effectively holding the discussion hostage. As Judith Curry pointed out in one of her best pieces to date, such ignorance plays into the hands of those who need the perception & persuasion of so-called (but fundamentally mislabeled) “uncertainty”:

    Can we make good decisions under ignorance?

    With Absolute Sincerity,
    Paul L. Vaughan, M.Sc.

  3. tallbloke says:
    September 10, 2011 at 8:05 pm

    Agreed.

    Please could you tell us more about the model you constructed here:

    Solar, Terrestrial, & Lunisolar Components of Rate of Change of Length of Day

    The table above the graph gives the quantities necessary for reconstruction. I found the description of the ‘contribution’ a bit difficult to follow. LAC and LNC I take to be the lunar apse cycle and Lunar nodal cycle. The ‘Semi-annual’ term confused me, as the quantity seems to be half the lunar month of 29.53 days. I also found the idea of an absolute value for ‘polarity’ a bit challenging.

    I’d welcome some elucidation if you find the time.

    Edit: Heh, you pre-empted me while I was writing. 🙂

  4. Paul Vaughan says:
    September 10, 2011 at 10:11 pm

    Easy as 1-2-3:

    1.
    2.
    3.

    Earth doesn’t only naturally integrate; it also naturally aliases. Differential (because Earth doesn’t have a stationary internal ~11 year clock) pulse-position modulation of this [ ] yields patterns 1, 2, & 3.

    It’s actually dead simple, but misconceptions abound and people are conditioned to assume that the development of understanding of natural climate can only be incremental.

    Left related notes over here:
    http://www.drroyspencer.com/2011/09/a-primer-on-our-claim-that-clouds-cause-temperature-change/

    Whenever EOP are admitted to the discussion surrounding that whole misunderstanding, they will come down on it like a fair judge’s gavel. EOP are the arbiters of climate disputes.

    For Corbyn fans who don’t understand Milanovic, note the narrative shift premiering in one of Corbyn’s recent releases:

    Piers Corbyn – WeatherActionNews2011No17:

    “[…] THIS holds that solar-magnetic-particle effects and Lunar modulations DRIVE the whole world’s weather and climate machine – like a 4 dimensional cosmic jig-saw”

    “Solving the solar-lunar-terrestrial cosmic jigsaw
    […] Once pieces of a jig-saw start to join up the whole takes on new meaning. Our work is game-changing – a new paradigm in sun-earth relations, weather and climate is beginning.”

    Not saying I agree with everything Corbyn says – just drawing parallels:

    Corbyn’s ‘4-dimensional solar-lunar-terrestrial jig-saw’
    = Milanovic’s ‘spatiotemporal chaos’

    […which I want to call alleged chaos, acknowledging that it’s probably an ephemerally useful bridge concept, since awareness has to be built solidly in small horse-before-cart steps that learners can tolerate, in contrast to being pushed so far & so fast that they prematurely cave to frustrated rejection impulses.]

    Only complex top-down time series analysis methods (with magnification & focal length adjusted with sharp awareness of the spatiotemporal sampling frame) can see the global patterns spatiotemporally aliased into geophysical records; standard bottom-up methods (the conventional mainstream’s usual choice) are not equipped to deal with spatiotemporally aliased data.

    Best Regards to All.

    [Tim edited in inline images. Are hosted by WUWT WordPress site.]