Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Bad Moon Rising

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TIDES are a consequence of the gravitational attraction of the earth to both the moon and the sun with the moon generally being more than twice as strong as the sun because it is so much closer to the earth. The moon rotates around the earth with the lunar day approximately 50 minutes longer than then the mean solar day. When the sun and the moon are both pulling in the same direction higher tides, known as spring tides occur.   Really high spring tides are known as king tides.

Gradually the moon and the sun will fall out of step until their pulls are opposing resulting in neap tides.

The size of tides is not only affected by the direction of the gravitational pulls from the moon and the sun, but also their distance from the earth that changes because their orbits are elliptical. The astronomical phenomena while complex are predictable forming cycles that repeat with characteristics unique to each place on earth, tending to vary in predictable ways with topography and sea depth.

Controversial New Zealand-based weather forecaster Ken Ring has posted comment about the king tides associated with the full moon this Sunday:

“PERIGEE is the name astronomers give to the closest earth-moon distance for the month. On 6 May [2012] it is the May perigee. It will coincide with full moon. The moon will swing in 356,953 kms from earth, and will look extra-big and extra-bright as it rises at sunset. On the day of any full moon the moon rises above the horizon at the exact second that the sun disappears beyond the horizon, which in Auckland on 6 May will be 5.24pm.

“And not only does this month’s perigee coincide with full moon but this perigee will be the nearest to earth of any this year, as the distance of the moon’s close approach varies and the apparent size varies by up to 20%. The last closest was 20 March 2011 and the next time it will be as close will be January 2014. This month’s full moon is due to be about 17% brighter than average. In contrast, later this year on Nov. 29, the full moon will coincide with apogee, the moon’s furthest distance from earth, which will be relatively smaller and dimmer.

“There is always reason to be careful around all perigees, as they exaggerate whatever else is going on in weather. Closest perigees are even more reason to be vigilant. Last year’s closest perigee in March brought the Japanese tsunami earthquake and a 7-intensity earthquake in Christchurch. As usual, the normal sea tides around the world will be particularly high and low. This is because at perigee, the moon exerts over 40% more tidal force than during its next apogee two weeks later. King tides are primarily king tides in the land, and large earthquakes occur with double the frequency in the week of perigee.

“Closer perigees increase that seismic risk. Sea mammals have already started beaching in Peru which portends earthquake activity in that region. Perigees bring high winds because the extra gravitational pull on the atmosphere created by the moon’s proximity creates turbulence…

Read more here: http://www.predictweather.co.nz/ArticleShow.aspx?ID=398&type=home

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Comments

  1. spangled drongo says

    It’s a magnificent moon tonight Jen, even though it is not quite full.

    Does anyone know if there is a HAT [highest astronomical tide] predicted for anywhere on the planet for this moon?

  3. Stephen Dawson says

    Is there a reason for quoting Ring? He claims to be able to predict earthquakes, frequently issuing predictions sufficiently vague to accommodate anything that may happen.

  5. bazza says

    Thanks Luke, at least the song has credibility. Anybody looking for evidence on Rings forecast on anything – don’t bother – seems kiwis are shy publishers. If you do a ring search, you may come up with the tale of the Herbert River Ringtailed Possum, sadly at risk from rising temperatures shrinking its mountain habitats. Surely a more appropriate topic for those with a genuine interest in conservation issues.

  7. Luke says

    Alas Jen – we never seem to get the stats though do we? i.e. give us the forecast record on 10 years of independent data … sigh

  8. Tony Price says

    Ken Ring omits a few significant factors in his “masterful” (hah!) understanding of the Moon/Earth/Sun system (surprise anyone?). Even closest perigees vary in effect because the Earth’s axis is tilted wrt the plane of its solar orbit, and the Moon’s orbit is tilted wrt. that plane but at a different angle. The latter is the reason the Moon’s angle above the horizon varies greatly, and that angle has a big impact on tides and the way they vary from place to place, much bigger at any location than the effect of perigee or apogee, whatever alarmists like King say. People like him don’t necessarily tell lies, but they omit “inconvenient facts” which dilute or even totally devalue their predictions of doom.

    F’rinstance, have a look at this Moonrise/Moonset/Zenith table for Adelaide, which is relevant to the Murray mouth debate. It also shows the Earth/Moon distance, which is entirely relevant even if you don’t want to follow the rest of this.
    http://www.timeanddate.com/worldclock/astronomy.html?obj=moon&month=5&year=2012&obj=moon&afl=-1&day=1&n=5

    Now go to http://www.bom.gov.au/oceanography/tides/MAPS/victor.shtml#map, which is a tide selector for Victor Harbor. and select 1st. May as the start date and click “SUBMIT”. Unfortunately you have to go back and select another date to see beyond the first week. OR go to
    http://tides.willyweather.com.au/sa/fleurieu-peninsula/goolwa-beach.html
    and use the pop-up calendar to select 1st. May. This page has a nice graphical display below the table, but you must select the start date for both if you want to keep them in sync. It’s easy to page forwards and back using the L/R arrows. Ian Mott introduced me to this one, but the tide data is rounded to the nearest 5cm, which dilutes the message somewhat. Does WillyWeather assume fishermen and pleasure boaters are too dumb to cope with raw data? Beats me why they round it.

    Compare the tide heights from this table with the zenith angle in the Moon table, day-by-day, and draw your own conclusions. Jennifer’s interest in this topic and tidal patterns has spurred me to post on my blog once I’ve found some suitable graphics.

  9. Jennifer Marohasy says

    Luke,

    Given all the resources the BOM has, it should be easy enough for them to provide a reliability score and benchmark their long range forecasts, including agains their competitors like Ken Ring.

    I heard him speak at a conference in Mulwala (shores of Lake Yarrawonga) a couple of years ago, he had been brought to Australia by some NSW beef producers who claim his almanac gives a better long range forecast than anyone else. …especially for extreme rainfall events.

    Tony,

    Ken Ring is a fascinating fellow and has provided overviews of the very phenomena you suggest he lacks an understanding of. Why do you mock him?

    Everyone,

    Wellington was hit with a magnitude 4.2 earthquake this morning.
    Of course its a big leap from correlation to causation.
    And I’ve just remembered this post: http://jennifermarohasy.com/2011/03/moon-above-tokyo-at-time-of-earthquake/

  10. Tony Price says

    Jennifer said:

    Tony,

    Ken Ring is a fascinating fellow and has provided overviews of the very phenomena you suggest he lacks an understanding of. Why do you mock him?

    You’re right – I shouldn’t have mocked without reading more of what he says, and I confused him with someone else. I did what I criticise in others – mea culpa. However, I still think he overblows the importance of the Earth-Moon distance, for the reasons I stated. He might well be right, but his reasoning has a few holes IMHO (and for me, it’s my HO that matters!).

  11. Luke says

    Ah Jen – there’s often an excuse with these guys not to show and tell.

    You make x predictions on y years/seasons/months/days of independent data and tell us how you go… that simple. Don’t tell us about a few successes and homespun anecdotes – give us the stats.

    BoM have looked at a few – including Inigo Jones – there’s usually nothing in it

    I’m sure Bazza will have an independent look ! He’s an optimistic mug punter for prediction schemes.

    It very very simple. He should show a full prediction run on some independent data. If you don’t well …. he doesn’t need to reveal his method to do this.

    Last lunar prediction I stupidly chased down a few weeks ago after Ian Wilson revved me up said the last few years were dry …. gurgle

    You want BoM’s stats – email David Jones ! It’s not as if they don’t have these things.

  13. Debbie says

    The moon looked awesome at my place last night.
    It was bright enough to not even bother turning on the lights or using a torch. We could have driven around our properties without using our headlights if we had wanted to. I could have gone out for a midnight ride on my horse. It was quite spectacular.
    It also had a huge ring around it…..huge.
    A couple of us were laughing at the ‘old wives tale’ about a ring around the moon and the number of starts inside the ring being a forecaster of rain.
    We were laughing particularly because we had checked BoM earlier and also watched the weather reports and it was saying that we would have a clear frosty morning and clear skies with no rain (or their lowest % ranking).
    It was also very cold and frosty by midnight.
    According to the old wives tale….as there were no stars inside the ring….we should have been expecting rain early today….there looked to be very little chance of that..
    Guess what happened here this morning?
    It was also perfect as we had just finished sowing all our canola….it couldn’t have been better.
    That is just an anectdotal comment by the way…I am not claiming that anyone had any better chance of predicting the 5mls we had this morning than anyone else…..we were happy though 🙂
    Maybe there is more to that ‘ring around the moon’ theory ?
    Maybe the moon does affect our weather/climate patterns more than we realise?
    Ken Ring may be onto something….can’t see any problem with him pursuing it, that’s for sure.

  14. Johnathan Wilkes says

    Well Luke, I never heard of K Ring before and don’t particularly care whether he is right or wrong, but reading that first link and the comments, I have to say they have no evidence one way or other either simply accusations.

    As to the content and comments? Typical of any partisan blog, proves nothing and shuts down inconvenient comments.

  15. bazza says

    Debbie, the same moon shone on me. Be assured that humans have been trying for thousands of years to detect lunar influences. The links showed nothing. So as to your point “can’t see any problem with him pursuing it, that’s for sure.” I see a problem and stuff that is demonstrably not evidence based should be jumped on. And you followed Jens lead in then trying to deflect on to BOM forecast accuracy.

  16. Debbie says

    Gee whiz Bazza,
    I was just sharing a funny story and also commenting on the moon and relating it to the post.
    I have no idea why that ruffled your feathers so badly?
    BTW I don’t have a problem with BoM. We use their site all the time.
    I don’t find them infallible however, do you?
    I just found it amusing that the old theory actually played out on this particular occaision.
    It doesn’t usually have any higher degree of success and I suspect it was more likely an amusing fluke.
    I don’t have an opinion either way but I also don’t have a problem with people studying lunar influences.

  17. Tony Price says

    Comment from: Debbie May 7th, 2012 at 4:28 pm:

    Maybe the moon does affect our weather/climate patterns more than we realise?

    I’m certain it does; the tides shift a lot of water twice a day. It’s certain the ocean controls climate, not the atmosphere, as some would have us believe. For example, is it not possible that apart from the watery oscillations, which must affect winds, though the effect might be small (who knows?), the tidal bulge must compress the atmosphere above to some extent. Simple mechanics indicates that the greater mass of water is pulled much more than the lesser mass of the atmosphere above. Higher pressure, small change in the winds leads to…? Just a thought.

  18. John Sayers says

    The cycle of the moon is a frequency – that frequency can be octavised up and up (doubling frequency) to a frequency of A435…the frequency that Bach, Beethoven etc wrote their music.

    The French took the A435 up to A440 in the later 19th century. It made the instruments sound brighter.

    Yet Jimmy Hendricks preferred to play in the lower 435 region, approximately a semitone lower.

  19. Debbie says

    Tony,
    In that respect I agree with you.
    There is no doubt that lunar cycles affect tides and there is no doubt that the ocean affects weather.
    How much the moon affects currents, ocean temps and the amount of vapour as well as winds and extreme storm events is not as well known.
    Whether lunar cycles can be used to predict climate behaviour is an interesting concept and I can’t see the problem with people wanting to research this hypothesis.

  20. Luke says

    Debs – just get them to send in their forecast/hindcast validation when they’re ready to go public.

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