Sailing On The Moon Wind

Guest Post by Willis Eschenbach

I grew up on a remote cattle ranch surrounded by miles of forest, far from street lights. The nights were large and silent and very dark when there was no moon. But when the moon was full, the forest at night was full of life. It was clear that the moon had a huge effect on the animal life. The farmers in the area often planted by the moon. Whether that did any good I don’t know. I do know that the moon rules the ocean, though. When I fished commercially for anchovies off of Cannery Row in California, we’d take a week off during each full moon. You couldn’t catch the anchovies during that time, they were too skittish. And the difference between night diving with and without the moon is startling.

midnight on the water moonWhen I was younger, I read in several places that the moonlight doesn’t influence the weather. What the sources said was that it was just too weak to affect the temperature. Heck, you can find people making that claim today. There was no scientific evidence for a detectable effect of moonlight on temperature until 1995, when an article in Science magazine called “Influence of Lunar Phase on Daily Global Temperatures” (paywalled, as usual) said that their comparison with lower tropospheric temperatures showed a temperature difference between full moon and new moon of 0.02°C.

What does that have to do with the moon wind? And what is a “moon wind” when it is at home, anyhow? Well, when I was younger, I once sailed across the Pacific as the first mate on a fifty foot (15m) gaff-rigged staysail schooner. The skipper and I split the navigation duties. This was well before GPS, so the navigation was all done with a sextant and a chronometer.

The skipper took the noon shots, the ones that firmly establish the latitude (north-south). I took the star shots at dawn and at dusk. The navigation wasn’t done while someone else ran the boat. In the morning watch, I was usually the only one awake. I’d set the sails to where the ship would self-steer, and then take the sextant shots. In the evening, the other three guys would usually all be up, but the drill was the same. Self-steer, and sextant.

Sailboats are sloooow, a typical day we would make maybe a hundred miles, less when there’s no wind, and the Pacific is very wide. As a result, I got to watch lots of sunrises and sunsets, plus taking in a lot of late-night skies sitting on deck talking story with the boys.

Including the obligatory breakdowns, we were four months at sea. As day followed day, I became more and more attuned to the cycles of the weather. One of the things that I noticed was what I later found out was called a “terminator wind”. Great name, it sounds ominous. I didn’t know that at the time, so I just called them the “dusk wind” and the “dawn wind”.

A “terminator wind” is a wind that blows across the “terminator”, the moving line on the earth that divides day from night. The sun heats the air on the day side of the terminator line. The heated air rises, and cold dense air from the night side of the terminator flows in to replace the rising heated air on the day side. As a result, the terminator wind always blows from night to day. This leads to a morning/night difference. In the morning the dawn breeze blows from the dark areas further to the west of my location, and towards the sunlit areas east of my location where the sun has already risen. In other words, the dawn breeze is always and forever a west wind.

In the evening, on the other hand, the sun has set in areas to the east of my location. So an east wind blows from the nighttime there, towards the west, where the sun still warms the earth. As a result, the dusk breeze is always and forever an east wind.

The opposite direction of these two winds leads to a curious phenomenon. This is that for relatively steady overall winds, the dawn and dusk winds will alternately oppose the underlying wind, or it will increase the underlying wind. This is most visible when there is a light constant east wind. At the dawn breeze is a west wind, so it opposes the light east wind and leads to a short period of calm around dawn. At dusk, on the other hand, the terminator wind blows from the east, so the dusk breeze reinforces the underlying east wind and leads to a brief gusty period around dusk … and if there is a light underlying west wind, the opposite is true.

Now, here is where the moon came in. After I’d spent enough nights at sea, watching the comings and goings of the moon, I noticed that the moon has a terminator wind just like the sun. I started calling it the “moon wind”, I didn’t know from terminators, I was on a boat in the middle of the sea, I made up a name. I first noticed the moon wind in the doldrums, where the air is often quite calm, with no wind of any kind. In those peaceful conditions, with the boat not moving at all, the terminator wind from the moon is quite apparent … at least it is to sailors hoping for any kind of wind in the doldrums. It obeys the same rule as the dusk and dawn wind in that it always blows from areas with no moon to areas with the moon. Of course, it is much weaker, and only detectable on calm nights. On a calm night it is a sliver of a breeze, just enough to send small wavelets shimmering in the emerging moonlight.

During the time before the full moon, when the moon is waxing, we have only moonsets at night. As a result, before the full moon, the moon wind is always an east wind. After full moon, we only have moonrises at night, so during that time the moon wind is a west wind.

Since that time, I’ve occasionally noted the moon wind on land as well. You need near full moon, preferably a large flat open area, and fairly calm conditions to be able to detect it. It helps to know what you are looking for. In light east wind conditions after the full moon, for example, the west wind at moonrise opposes the underlying east wind, and is seen as a brief period of calm around the time of moonrise. But if the underlying wind is from the west, the wind at moonrise will reinforce that west wind and lead to a brief gusty period around moonrise.

I bring all of this up for several reasons. One is to point out that the earth responds to a very slight change in conditions. We routinely overestimate the strength of the light coming from the moon. The light from the moon is about a million times weaker than the light from the sun (with a full-moon peak at about 0.006 W/m2). The infrared from the moon’s surface is stronger than that, it’s somewhere around 0.03 W/m2. The sum of the two is only a bit above 0.03 W/m2, that’s thirty milliwatts per square metre, a very tiny amount in terms of the global energy budget.

And yet despite that energy being so small, you can still feel the moon wind at the moon’s terminator line, a wind that arises from that tiny energetic addition. What an astounding system. It is so stable that the global temperature hasn’t varied more than ± 0.5% in the last millennium, and despite that amazing stability, it is also so delicately balanced that thirty milliwatts of energy are enough to make the moon wind come up and shiver the silvery ocean with its breeze …

I also bring this up to point out that there is still a whole lot that we don’t understand about how the weather and the climate work. Let me quote the conclusion of the 1995 Science article:

The existence of an identifiable relation between lunar phase and global temperature begs the question as to its fundamental cause. Presumably the causal factor is lunar, but, as pointed out by researchers examining the relation between precipitation and lunar phase (3, 4), this cannot be demonstrated by statistical analyses alone. Other scientists who have examined the lunar influence on various climatic variables have suggested several causative linkages.

For example, increased thunderstorm activity near the time of the full moon may be related to lunar distortions of Earth’s magnetic tail (5). Another hypothesis advanced to explain the precipitation-lunar phase relation involves the lunar modulation of meteoritic dust (2). Others have speculated that lunar tidal changes could influence Earth’s basic atmospheric circulation patterns, in particular,the position of the subtropical high-  pressure belts(24).

Also, with respect to global temperature variations, a full moon results in an increased solar load due to the moon’s reflection as well as to an increase in infrared emission from the moon’s surface. The infrared flux to Earth is five orders of magnitude less than the direct flux from the sun, whereas the shortwave flux is six orders of magnitude less than the direct flux from the sun (10, 25); the 0.02 K modulation in temperature identified in this study is correspondingly five orders of magnitude less than the mean lower-tropospheric temperature. Feedback responses of global temperature to potentially lunar-related variations in other climatic parameters, such as precipitation, cloudiness, and thunderstorm activity, may also account for the lunar effect on global temperatures.

Our analyses show a significant empirical relation between lunar phase and daily planetary temperature over the past 15 years. The lunar phase appears to produce a modulation of approximately 0.03 K in the lower troposphere, with the warmest daily temperatures over a synodic month coincident with the occurrence of the full moon. The results not only confirm the suspicions of many past scientists but also suggest that the daily global temperature measurements are quite accurate. Most important, lunar influence is identified as another potential forcing mechanism to consider in the analysis of variability in the short-term, global temperature record.

Finally, I bring all of this up to remind myself of why it is that I took up the study of the weather and the climate—because I greatly enjoy being out in the weather, experiencing its multifold phenomena, and struggling to understand why it does what it does when it does it.

And so that is my wish for all of you— calm starry nights outdoors, good friends, and a glass of grog, with the moon a pirate’s silver coin rising out of the ocean, and the moon wind to blow your ship of life to the port of your dreams …

w.

NOTES:

I have calculated the strength of the moonlight by multiplying the moon’s albedo times the TSI times the cross-sectional area of the moon. This gives something approximating the total luminance of the daylight side of the moon, in watts. I then divide this by the area of a hemisphere whose radius is the earth-moon distance, in square metres. This gives 0.006 W/m2 as an estimate of the strength of the moonshine.

For the IR a similar procedure is followed. The illuminated side of the moon has an average temperature of around 60°C (this is calculated as the fourth root of the average of the temperature to the fourth power). I converted this to W/m2 using the Stefan-Boltzmann equation with an emissivity of 0.95, and multiplied it by the cross-sectional area of the moon to give something approximating the IR luminosity of the moon in watts. Then I followed the same procedure as with the sun, dividing the total IR luminosity by the area of the hemisphere with radius equal to the earth-moon distance. This give 0.028 as an estimate for the IR from the moon.

These figures are in agreement with the estimates that I have found in the literature for those two variables, moonlight and moon IR. Note that there are a variety of simplifying assumptions in the calculations, as I am only interested in a rough calculation. Here are the figures I have used:

Moon Polar radius, 1736, km
Moon Bond albedo, 0.11, units
Solar irradiance, 1367.6, W/m2
Moon Cross-section, 9,467,805, sq km
Moon Cross-section, 9.46781E+12, sq m
Moon's Shortwave Luminosity, 1.42472E+15, watts
Earth-moon distance, 378000, km
Earth-moon distance, 3.78E+08, m
Hemispheric area with earth-moon radius, 2.24E+17, sq. m.
Lunar reflections at earth's surface, 0.006, W/m2
Moon surface temp., 60, °C
Moon emissivity, 0.95
Moon's day-side average radiation, 663.54, w/m2
Moon's longwave luminosity, 6.28225E+15, watts
IR at earth's surface, 0.028, w/m2
Total energy (short + longwave), 0.034, w/m2

… from Willis’s upcoming autobiography, entitled “Retire Early … and Often” …

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107 thoughts on “Sailing On The Moon Wind

  1. Willis, you are very intriguing to say the least. Enjoy your posting. Now on to the article…

    Are you trying to summarize then that solar panels can be 24 hour generating machines when the moon is full and the night is clear?

  2. Only when people have had to be out in the weather and ‘at its mercy’ that it is really appreciated. Sailors and pilots understand and respect the awesome power of what some might think is just a ‘fluffy cloud’ or a gentle swell. As you point out Willis, scientists are only just barely understanding what sailors, including the Vikings knew as lore.

  3. An interesting hypothesis supported by your observations, but your article contains a supposition that all of the wind due to the sunrise or moonrise. An article from Scientific American – http://www.scientificamerican.com/article.cfm?id=does-the-moon-have-a-tida – points out that the atmosphere is subject to the tidal effect from the sun and the moon as well, and postulates that the stronger effect exhibited by the sun (20 times greater than the moon, whereas the tidal effect from the moon on the oceans is stronger) is mostly because of the solar heating.

    I do support your hypothesis that the irradiance from moon will have an effect, but I believe most of what you observed may have been caused by the tidal effect.

  4. That would put climate sensitivity to moon light at about 0.6 °C per W/m2, which if it were translated to 2XCO2 (3.7 W/m2) disregarding frequency as a possible climate sensitivity variable (a mistake IMO) would be about 2.2 °C per 2XCO2.

    [0.02 / 0.034 = 0.58 x 3.7 = 2.18]

  5. Very lovely Christmas Eve gift to your readers, Willis. May the Moon light your way and the Moon Wind be at your back.

  6. Seems like, if it were mostly a tidal effect, there’d not be as sudden an onset as Willis describes, since there’d be no terminator involved, just a gradual and steady buildup to a peak followed by a gradual and steady fall off.

  7. As a horticulturist/market gardener/farmer, thank you for putting into clear words what I can’t, I could rabbit on, but not in the concise and definite way you are able to.

    All you have said in this post is self evident to anyone who works with crops/seasonal processes

    Thanks Willis

  8. What a beautiful demonstration of that inspired combination of awe and curiosity that is the hallmark of the true scientist. Willis Eschenbach’s detailed account of his observations is as delightful as it is perceptive; and, having made his observations and pondered them in his heart, he uses mathematics to draw his conclusions, even going so far as to verify textbook values ab initio.

    No such posting as this could ever appear on any of the Team’s lavishly-funded websites: for those blinkered adherents of the New Religion say “I believe”, where the scientist says “I wonder”.

    When Willis publishes his book of postings, this entry should have pride of place.

  9. Michael Tremblay says:
    December 24, 2012 at 7:06 pm

    An interesting hypothesis supported by your observations, but your article contains a supposition that all of the wind due to the sunrise or moonrise. An article from Scientific American – http://www.scientificamerican.com/article.cfm?id=does-the-moon-have-a-tida – points out that the atmosphere is subject to the tidal effect from the sun and the moon as well, and postulates that the stronger effect exhibited by the sun (20 times greater than the moon, whereas the tidal effect from the moon on the oceans is stronger) is mostly because of the solar heating.

    I do support your hypothesis that the irradiance from moon will have an effect, but I believe most of what you observed may have been caused by the tidal effect.

    Thanks, Michael. The moon wind is far too short-lived a phenomenon to be due to the tidal effect. The tides change slowly from low to high over about six hours. The moon wind, on the other hand, typically starts stirring just as the moon peeps over the horizon (at sea) and stops blowing not long after the moon clears the horizon a few minutes later.

    That, plus the fact that it blows in the proper direction across the terminator at moonrise and moonset, identifies it as a terminator wind.

    Regards,

    w.

  10. There is also another mechanism by which the Moon influences the weather [not the climate because the moon's orbit and other characteristics do not change on a time scale of a few thousand years or shorter]: the Moon influences the distance between the Sun and the Earth, thus modulates TSI accordingly [by 0.5 milliW/m2].

  11. Interesting subject matter and nicely written.
    It led me to a question I have often pondered but have never heard discussed by ‘scientists’ namely…is atmospheric/ climate energy dissipated by ‘work’?

    I live by the sea and on gusty days you can see thousands of white topped waves out at sea and hear the crashing of the breakers on the beach. After storms we regularly find dunes have been relocated, heavy objects removed and deposited etc. In deserts too wind moves millions of tons of sand causing erosion.

    If you or I were to spend a few hours manually moving the branch of a tree backwards and forwards we would become tired and hungry because of the energy expended, the wind does this on an hourly basis, not to mention causing buildings and structures to sway.

    Likewise how much energy would be used in moving the thousands of tons of water, in its various forms that climate shunts around… apparently effortlessly?

    Perhaps the reason why any temperature increase caused by ‘greenhouse gases’ is almost undetectable is that any extra energy in the system is used up in physical work at the interface between the planet at the atmosphere.

    I’m sure WUWT readers will be able to shed some light on the subject.

  12. A fascinating read and beautifully written.. made my Christmas morning even better here in Indonesia.

    Merry Christmas to you!

  13. Fun stuff. The description doesn’t sound consistent with a tidal explanation. That would have also occurred at the new moon, as the tides do.

    At least that’s one reaction from a land-lubber indoors bookworm type. Sail on!

  14. You can probably dismiss the idea that it’s the tide because the correlation is with the phase of the moon, unless tides also correlate with phase, which I have no clue about…yet.

  15. Back in the 1980’s I became interested in the lunar phase vrs tidal effects on the weather, upon reprocessing lunar phase data on precipitation trends by the declination relative to the equator I got a little over a 7 fold increase in signal to noise ratio. There were at the time many articles published about moon rise and set times, effects in the precipitation rate changes per hour, due to the moon winds small but measurable effects, mostly from France as lunar based research funding had ceased in the USA by the mid to late 50’s. (before computers were usable)

    It is the lunar declinational tidal effects on the atmosphere that are the most dynamic effects, they determine the timing of the out breaks of severe weather, peak wind speeds of cyclone activity from tornadoes to hurricanes. The past four cycles ~6558 days apart that were the same declinational angle and same phase of the moon that it is for the current cyclic period for each day able to forecast about 80% of the normal natural variability of the weather. For instance the composite snow potentials for the 24th and 25th of December (this Christmas) is following rather well the patterns laid down the past four cycles.

    http://www.aerology.com/?location=NorthAmerica&mapType=Snwd&date=12%2F24%2F2012

    This pattern generated effect forecast has a lead time of one cycle 6558 days or about 18 years, so by using lunar declinational patterns usable long range forecasts CAN be extended greatly.

  16. I would love to see a full moon rise over an empty ocean but that’s not apt to happen. But a full moon is approaching this week. We have 30 cm. of snow on the ground on which the horses just got a Christmas measure of hay. There are deer in the fields, and we saw 5 wild turkeys yesterday. The nearest street light is about 10 miles away. Bright moon on fresh snow. Priceless.

    Thanks Willis, and

    Merry Christmas and a Joyous New Year !!

  17. Slightly off topic, but I had the pleasure of seeing a lunar rainbow (not a halo) over water in the Caribbean after a rain shower one summer evening . Full moon, very pale colors, but the real thing. Waaay cool.

  18. @ Charles Gerard Nelson

    I’ve been pondering along the same lines. It seems to me the Sun’s energy has a lot of work to do here on Earth. I wonder if we look at the Earth not as one system but an amalgamation of subsystems it might make the work question easier to think about. If we do take it as one big system I’m thinking we’ll have to consider it more the conversion of energy from one form to another rather than work, but essentially I think it will come down to the same thing: energy removed from the so-called radiation balance. For example, photosynthesis converts about 0.2 W/m2 of solar energy to chemical energy. Of course some of this will be converted back to IR when it’s converted back from chemical energy to various other forms (i.e.: I radiate IR, but all of my calories don’t go into producing heat). I realize 0.2 W/m2 doesn’t sound like a lot but considering the estimated energy imbalance could be on the order 0.6 W/m2 it wouldn’t take too many examples of similar magnitude to deflate the energy imbalance argument. How much energy goes into various subsurface layers never to be seen or heard from again, essentially dissipated into irrelevance?

    Still pondering…
    Global Energy Imbalance = 0.6 (+/-) 17 (LOL) W/m2

    http://joannenova.com.au/2012/10/blockbuster-earths-energy-balance-measured-models-are-wrong/

    Global Photosynthesis = 0.2 W/m2

    http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/energyflow.html

  19. Hi Willis,

    Always an enjoyable read, when you start reminiscing on how you get your insights.

    In greek folklore weather prediction/ explanation the moon and its phases play a dominant role. Maybe because we were a maritime people.

    One expects the weather to change at the change of phase, i.e. one moon week. If it is rainy for the rains to go, if it it windless, for winds to come etc,. Also the farmers planted and harvested according to the moon phases.

    You might be interested in this article on lunar planting.

    Dr. Frank Brown of Northwestern University performed research over a ten-year period of time, keeping meticulous records of his results. He found that plants absorbed more water at the time of the full moon. He conducted his experiments in a laboratory without direct contact from the moon, yet he found that they were still influenced by it.

    This link also talks about the moon and plants . It seems New Age culture has tuned into these old observations.

  20. Willis,

    I took flying lessons back in the early ’60s at the north edge of the (Phoenix) Valley of the Sun when that was pretty much open desert. I came up with the opposite observation about the sun’s effect on local winds. Whether it was due to some local effect of the foothills, or what, I know that the wind near sunrise and sunset always ‘came’ from the sun. That was pretty evident, because you always ended up facing the sun during takeoff and landing practice. I had rationalized it as the air was warmer where the sun was and therefore expanded away from it.

    Oh well, another beautiful theory ravaged by a gang of brutal facts.

  21. Charles Gerard Nelson says:
    December 24, 2012 at 8:55 pm

    Interesting subject matter and nicely written.
    It led me to a question I have often pondered but have never heard discussed by ‘scientists’ namely…is atmospheric/ climate energy dissipated by ‘work’?

    The short answer is “Yes”. Here’s a quote from Thermodynamic optimization of global circulation and climate, by Bejan and Reis:

    The mechanism has been recognized before, not only in the modelling of atmospheric dynamics (Lin, 1982; Lorenz et al., 2001), but also in the description of natural convection itself. See, for example, p. 111 in (Bejan, 1984). . .the convection loop is equivalent to the cycle executed by the working fluid in a heat engine. In principle, this heat engine cycle should be capable of delivering useful work if we insert a propeller in the stream: this is the origin of ‘wind power’ discussed nowadays in connection with the harnessing of solar work indirectly from the atmospheric heat engine loop. In the absence of work-collecting devices, the heat engine cycle drives its working fluid fast enough so that its entire work output potential is dissipated by friction in the brake at the interface between what moves and what does not move’.

    All the best,

    w.

  22. Sometime ago the late Ernst-Georg Beck first said that “CO2 amount in air varies monthly with lunar phases” without suggesting any possible mechanism. I thought that sounded stupid and embarrassing for the sceptics. So I did a bit of digging on his data and then came across the temperature effect you write about. He was right. And then I put the two together.as a subtle sign that CO2 levels follow temperature.
    References are at http://www.anenglishmanscastle.com/archives/004166.html

  23. Personally I would attribute the moon wind to tidal effects rather than to temperature effects of the moon.
    Merry christmas.

  24. Thanks for this very interesting story and I envy you having sailed the Pacific; I have only ever done stretches on the North Sea.

    But the “moon wind” you describe may have a more plausible cause in the tides produced by the Moon than being due to temperature. As the Moon induces tides of several meters in water, the tidal effects on a much lighter medium as is air are correspondingly much bigger. This causes a low level pressure wave traveling through the atmosphere in sinc with the Lunar (and to a lesser extent Solar) aspects. Your observation that it’s most noticeable at full moon fits with this.

  25. I was ground crew on a balloon for a few years. At dawn, the gentle wind would pause, just as you noted, and we would fly. Then a bit later the winds would pick up again (it was best to have landed before that…) Yet at dusk it was not the same… at dusk the winds would sometimes get stronger. Now I know why…

    @Anna V:

    My Father once taught me to grow potatoes. He was of Irish / Amish mixed background. He had a ‘formula’ for when to plant. Sadly, I didn’t pay enough attention to remember it correctly. I, being ‘scientific’ even as a child, dismissed it as nonsense and fables… Perhaps not, I now think…

    It basically was to plant at a given phase of the moon such that the ‘Potato eyes would not see the full moon’. There was a particular Irish holiday day named (as they are solar year based) and then an offset to the full moon. I wish I remembered more of it…

    Supposedly it gave more potatoes or more reliably than planting on other dates.

    @All:

    Tonight, after our Christmas Eve feast, we walked outside. A full-ish moon was up, with a spectacular halo around it and a star just to the East, inside the ring (a star that we speculated might be a planet…). A spectacular sight.

    After a giant downpour and intense rains yesterday, today was sunny and clear, with a crisp cold night setting in.

    The world is a spectacular place. The moon makes it even more so.

  26. OT a bit, Willis, I’ve spent quite a bit of time in the emptier sections of northern California and eastern Oregon. Moonless nights are dark, but, at least to me, not that dark. I’ve stopped on SR 36 and SR 44 late at night and once your eyes adapt, with the aid of the stars, the Milky Way and the odd meteor it could be bright enough to read largish type, or even occasionally make a guess at color if the air is clear enough. One of the sad truths of city life is that city lights enhance darkness.

  27. Lovely post, Willis. Lucid and informative as always, but with a touch of poetry, and a very pleasant surprise on my break from last-gifts wrapping. I completely agree with “M’lud” – this deserves top billing when you gather your various posts into an omnibus.

    Best of Holidays to you and yours.

    PJ

  28. Willis: fabulous post, explaining the usual dusk period of calm in English waters that has hitherto always puzzled me. Two minor points –
    In one of your replies you say that tides vary slowly over 6 hours: they follow simple harmonic motion of course, with the fastest movement in the middle of the 6 hours.
    You don’t mention Earthlight, the sunlight reflected first by the Earth and then by the moon – visible as the “old moon in the arms of the new”.
    I trust you had a very merry Solstice.

  29. Willis … beautiful observation and mathematical support. I’m also a tragic (racing) yachtsman of many decades standing (still) and I’ve had the same experience as yours but never given it any thought other than to know where to point the bow and anticipate what sails to have up. The full moon always presented impending enhanced conditions at sea … either the wind was much stronger or flat calm, nothing in between.

  30. Ed,
    Remember that while in shallow waters the tide can have a range of several metres in places, for instance in the North Sea away from nodal points, there is only a small rise and fall in the middle of the oceans.

    And, OT I know, but Willis, how many times have you seen the “green flash” at sunset? I’ve only seen it 5 times in 39 years at sea, and didn’t believe in it until I saw it for the first time.

  31. Willis, lovely writing and so explicit.
    I have observed that a cloud shadow also produces increased wind as it passes but maybe it is just coincidence that this happens. As a farmer working on horseback the shadow effect was welcome.

    Merry Christmas and may the New Year be all you could wish.

  32. As another commenter already noted: wondering about the things you see in real life and finding an explanation is what it is all about. Having the gift of thought and logic in combination with a poetic mind can lead to scientific art.

    Thanks for a great read. Merry Christmas!

  33. For everyone who commented, my thanks.

    For those who say it was the tides wut done it, let me repeat what I posted above.

    The moon wind is far too short-lived a phenomenon to be due to the tidal effect. The tides change slowly from low to high over about six hours. The moon wind, on the other hand, typically starts stirring just as the moon peeps over the horizon (at sea) and stops blowing not long after the moon clears the horizon a few minutes later.

    That, plus the fact that it blows in the proper direction across the terminator at moonrise and moonset, identifies it as a terminator wind.

    I do have some experience with tidal winds on which to base this opinion. I lived and fished nights for a year on Tomales Bay. Fishing nights puts a man in tune with the ocean. I had the good fortune to be fishing with a world-class artist (and fisherman and boatbuilder) named Clayton Lewis. He had a hundred year old rowboat that was used to ferry crews out to the square-riggers. We fished out of that, two sets of oars. We were setting a beach seine for perch and other fish. If fishing puts a man in tune with the ocean, rowing nights puts a man in tune with wind and current.

    Now, Tomales Bay is long and narrow, with the opening pointing directly into the prevailing northwest winds, and hills on both sides of the bay. Tides around here have about a six-foot (two-metre) swing.

    So as you can imagine, when the bottom of the atmosphere above Tomales Bay drops by six feet, it will definitely take some air coming in to fill up that space. The infilling wind, for whatever reasons, doesn’t come off of the hills on either side of the bay. It comes right down from the mouth.

    Just as with the terminator wind, the tidal wind sometimes opposed and sometimes increased the prevailing northwest wind. We always tried to play that to our advantage, because we had to row from home to the fishing grounds, which were sometimes miles upwind.

    That tidal wind leads to another curious condition. The tidal wind will blow in times of dead calm. Sometimes these would last for a couple of days, and then the wind was like the whole Bay breathing in and out through the mouth. Anyhow, in those conditions the curious thing is that the tidal current is always moving opposite to the wind. When the tide is coming in, the wind is going out. That tends to set up the funny steep-sided little choppy waves that you get when the wind is opposed to the current.

    Anyhow, the moon wind is not a tidal wind. As you can see, I am intimate with tidal winds, I’ve seen them in action.

    w.

  34. Willis,tThanks for an interesting post!
    The “dawn wind” is very evident on a still morning or light wind where I live. The wind will drift towards the sun. Time to adjust the deer stand or relocate,

    As far as wildlife goes, daytime freshwater fishing sucks on a full moon. Same with deer and grouse hunting.

    Interesting observations as to the effect of the moon on winds. I’ll keep this in mind and watch /observe closely.

  35. lsvalgaard says:
    December 24, 2012 at 8:37 pm
    /////////////////////////////////////////////////////

    It has many many effects on climate, for example it influences the length of the Earth day (which may have been only about 7 to 8 hours in duration, shortly after the moon’s formation, and which is slowly increasing in length now standing at about 24 hours) and of course, it plays a part in the atmospheric diurnal bulge whereunder the atmosphere is constantly being pulled and flexed. Whilst some of these effects may be small, the fact is that we do not fully understand what effect these (and others) may have and to what extent they may be material.

    Whilst this is only anedotal, I have the impression that in autumn/winter, it often feels colder on full moon nights.

    PS. Interesting article Willis, Happy Christmas to all.

  36. A very Happy Christmas to all at WUWT and thank you for a fascinating read.
    I was also reading about the UK RNLI who are working on a new design of lifeboat for those days and nights when the weather is not so pleasant (make to cope with a real hurricain not a Sandy)

    http://www.telegraph.co.uk/motoring/news/9745940/The-Christmas-road-test-Shannon-class-lifeboat.html

    It has some very interesting features which are very suited to the work it will have to do and it seems to be a great toy on a good day!
    All the best for the new year to you all
    James Bull

  37. The farmers in the area often planted by the moon. Whether that did any good I don’t know.

    The gardeners here in france still and the farmers may but I’m not sure. I asked my neighbours why and the response ?

    The moon pulls the oceans and the water table. Therefore the water table is nearer the surface at full moon than at new moon.

    Not sure that I believe it but they grow great veg.

  38. Thank you Anthony Willis and all who sail on the good ship WUWT
    Talking about the moon reminded me of Dylan Thomas’s poem And Death Shall Have No Dominion

    And death shall have no dominion.
    Dead man naked they shall be one
    With the man in the wind and the west moon;
    When their bones are picked clean and the clean bones gone,
    They shall have stars at elbow and foot;
    Though they go mad they shall be sane,
    Though they sink through the sea they shall rise again;
    Though lovers be lost love shall not;
    And death shall have no dominion.

  39. “One is to point out that the earth responds to a very slight change in conditions.” Like a change in atmospheric CO2 levels?

    But thanks for the interesting article. Some might be interested in an article about trying to illuminate the moon by using lasers. See http://what-if.xkcd.com/13/ – it is interestingly funny.

  40. A lovely read of “silent nights”. Thanks Willis!

    But I want to add something about tides and forcing.

    First to Michael Tremblay.

    The article you are refering to says:

    Apparently, Laplace had suspected this, suggesting that the strong solar tide was primarily generated by solar heating and not by solar gravity.

    Which means that the twenty times stronger pressure effect from the Sun is not a tidal effect, not by solar gravity, but by solar heating. And when the same article says: .although the solar gravitational forcing is less than half that of the moon… it’s a bit confusing.

    The facts are as I have understood: The gravitational field from the sun is far stronger at earth than the gravitational field from the moon, as a matter of fact more than 173 times stronger. Still, the moon causes a bigger tidal wave than the sun. I guess that is why it’s called the tidal EFFECT. The explanation is that the moons gravitational field has a greater change on the length from one side of the earth to the other compared to sun. The moon draws relatively stronger on the water on the side where it is, than on the other side, compared to sun that has a more homogenous gravitational field within the same length at the earths distance. The difference for the moon compared to the sun is a change about to times more.

    The sun has a stronger gravitational field, and a larger distance from the sun makes that field more homogenous over a certain length. The moon has a weaker gravitational field, and as it is nearer to the the earth it gives a field that varies more over the same length. The field strength will decrease more over a certain length nearer to the gravitational center.

  41. I suppose it is redundant to observe that the obsesion with monthly ‘averages’ in temperature and other records means that any signals that WOULD be visible in those records are erased by the sampling methodology.

    I believe that anything that is not sampled at very short intervals (< hourly?) and then alligned to a period of 19 years makes big assumptions about the influence of both of the most important gravitional forces on our planet.

    19 years is the Metonic cycle cycle and is very close to a full cycle of both sun and moon as regards Earth – as has long been known. http://en.wikipedia.org/wiki/Metonic_cycle.

  42. In another career (another life) I worked on and around solar furnaces. The big 30 kw (thermal) government one was aligned with laser methods during our daytime work day. But there was a small student built and operated 5 kwt furnace that I supported and got to play with after I retired from all my varied paying jobs. We found some clever ways to do mirror alignments using moonlight. There was always a way to play with the little furnace day or night. The government guys frowned on playing with their multi-storied mirror arrays. We were allowed to moon track one night on the big furnace and while no one was watching the team did a standard solar run being very careful to keep ourselves out of the beam. We set the attenuator shutters to slightly open, set up a metal target and did a long exposure shot. The 2 inch spot was very bright and when we quickly waved our hand through the beam it was warm. We went full open on the attenuators, did another shot and found the beam to be very noticeably (uncomfortably) “hot”. Next time I play with the small furnace, I think we should run it during a full moon night and take some calorimeter readings paying attention to what humidity is that night (at the surface and for the local rawinsonde flight). Nature is already an amazing learning experience and getting to play with natural systems is awe inspiring, dangerous and humbling at the same time. Lots of fun too. Thanks Willis and thanks Anthony and the WUWT team. Holiday greetings to all.

    Bernie

  43. The Earth-Moon system is unique in the solar system, although akin to Pluto-Charon. The barycenter of the Earth-Moon system still lies within our planet, but will eventually migrate out of it, as our satellite continues receding. The barycenter of Pluto-Charon lies outside Pluto.

    Earth & Moon engage in an intricate dance as they orbit the sun, with our path based upon the system barycenter. Were it not for the accident of the Moon, Earth would be a very different planet. To cite but one of many effects, it’s possible that we wouldn’t have plate tectonics (at least not to the same degree) if so much of our planetary crust wasn’t collected outside the atmosphere.

    Merry Christmas & may all your Northern Hemisphere Christmases be white. Unless of course you’re old enough not to enjoy snow any more.

  44. milodonharlani says:
    December 25, 2012 at 7:49 am
    Earth & Moon engage in an intricate dance as they orbit the sun, with our path based upon the system barycenter.
    Actually not. We orbit the barycenter of the Sun and the Earth-Moon.

  45. My Granpa McCoy was Ulster Irish background and Scot(Gr.Granma born in Edinburgh) The always looked to the moon for planting, Granma McCoy was Native American and added her own concepts to the planting cycle. What was interesting was there were some of the same concepts concerning the
    lunar Cycle. I.e. the times to plant and how to plant. Of course there were no doubt cross cultural
    influences due tot he nature of the crossroads of Appalachia on Granma’s part, but they would never deviate from the planting season protocol..
    Also they were quite successful at it..

  46. milodonharlani says:
    December 25, 2012 at 7:49 am
    Earth & Moon engage in an intricate dance as they orbit the sun, with our path based upon the system barycenter.
    Depending on what you call the ‘system’. If the ‘system’ is that consisting only of the Sun, the Earth, and the Moon, you are correct.

  47. E.M. & Anna,
    In the instructions for planting, my Blackberry plant provider says to not expose the bare roots to direct sunlight. I have not seen the research on this but I do as suggested and plant them just at dusk when no sun hits the spot I want them. I have also heard that some seeds will germinate only when full sun and hot ground cause them to develop. Many generations of growing things in the area would allow farmers to notice such things and, say, not till the soil under full sun. This might simply keep ‘weeds’ from growing faster than the desired plants.

    In more mechanized farming areas — tractors with lights – I have seen equipment in the fields well after dark. It is not much of a stretch to assume previous generations planted by moon light because they could. The moon, having a regular pattern, could be factored into a planting schedule. Such as, ‘We’ll have a full moon in ten days and we’ll plant the beans then.’ Besides, working in fields in mid-afternoon with full sun is not a pleasant experience.

    This isn’t meant to dismiss any ‘Moon effects’ – only to say practical experience and common sense can go a long way toward understanding such things. Today, most folks are several generations away from the land and experience and common sense and, so, a lot is lost.
    ———-

    9 AM Christmas day here and we are getting a fine (as in small) snow here; 4 inches the NWS thinks.
    Merry Christmas.

  48. Perhaps the moon provides an out for the next Ice Age. We could silver it and augment the TSI, possibly enough to brunt the freeze-up. However, Willis’s sailboat would probably go a bit crazy in the moon wind. A wonderful essay Willis.

    In the 60s, I “sailed” (diesel powered) in a coastal supplies and mail small ship from Liverpool to Lagos to a job with the Geological Survey of Nigeria. I had sailed from Halifax to Southampton a few years earlier- air travel had not yet completely taken over ship travel. To fly, I would have had to fly from New York to Reykjavik to Le Havre or London for that leg at the time. Being a prairie boy from Manitoba, this was a great adventure for me. I turned out to be not a bad sailor after a first bout of sea sickness that descended on me in the first hour out of Halifax and then was gone. The North Atlantic in February is exciting with rough seas – too rough a sea seems not to promote sea sickness. The trip to Lagos was magical with multiple port stops, porpoises rushing at the ships sides, plunging under and reappearing on the other side – they showed up on schedule for dumping of the kitchen waste after meals, flying fish….. The first of a series of military coups, (followed by civil war) in Nigeria took place while I was on route, making for another three year adventure on land.

  49. Thank you. We in the earth sciences need to sit back every one in a while and remind ourselves just why it is we do what we do. I think there is a grounding effect in sharing our narratives. That is one of the reasons you and I blog and share our personal and scientific narratives. Again thank you.

  50. @ Charles Gerard Nelson

    Thank you! I thought I might have been the only one wondering about such things. I’m afraid much of my engineering education has gone to waste since my career has been in electrochemistry and environmental compliance. I occasionally have brine problems to work out which as fate would have it was my favorite part of Dif. Eq., but 90% of my job can be accomplished with a good understanding of algebra, chem 101, and a legaleze bent (for every rule there’s a ton of exceptions). I may dig my Thermo book out of the attic and review; I’ll let you know if anything comes of it.

    @ ALL

    Merry Christmas!

    @ Willis

    Thanks for imparting some more knowledge on us.

  51. Thanks for another nature venture Willis. I retired last evening while in the midst of the comments, and received this quote overnight which seems appropriate to share here.

    “I would feel more optimistic about a bright future for man if he spent less time proving that he can outwit Nature and more time tasting her sweetness and respecting her seniority.”
    E. B. White

  52. Dr. Svalgaard says “We orbit the barycenter of the Sun and the Earth-Moon”, which of course is correct. And on a path more nearly circular than Mars’, whose more highly elliptical orbit is naturally under great influence of Jupiter than is Earth’s.

  53. Jim Sonweed says: December 24, 2012 at 9:49 pm

    Slightly off topic, but I had the pleasure of seeing a lunar rainbow (not a halo) over water in the Caribbean after a rain shower one summer evening . Full moon, very pale colors, but the real thing. Waaay cool.
    =================================
    I have too, on one ccasion only. Yours is the only other account that I seen of this phenomena.

  54. Hmm…

    The light from the moon is about a million times weaker than the light from the sun (with a full-moon peak at about 0.006 W/m2). The infrared from the moon’s surface is stronger than that, it’s somewhere around 0.03 W/m2. The sum of the two is only a bit above 0.03 W/m2, that’s thirty milliwatts per square metre, a very tiny amount in terms of the global energy budget.

    And yet despite that energy being so small, you can still feel the moon wind at the moon’s terminator line, a wind that arises from that tiny energetic addition.

    so, it that small amount of IR can made a discernible difference, imagine what a change of only 1/10,000 or 1/100,000 of the sun’s IR might make.

  55. All this needs a soundtrack.
    May I suggest this classic from 1988:
    Moonwind, by Wavestar…?
    Look for the original, as the re-issues have had the final track replaced…

  56. Stacey says:
    December 25, 2012 at 3:05 am
    How kind of you to bring Dylan Thomas back into focus at a moment when we all have some time to spare for self indulgence!
    I am off to find my copy of Under Milkwood read by Richard Burton and to revisit Llareggub and it’s fishing boat bobbing bible black sea, the awakening town and the beautifully drawn characters from a bygone age whose relevance glisters and resonates through to the 21stC.
    And from the next thread above, one is led to wonder ….. were Willis and blind captain Cat related!

  57. John F. Hultquist says:
    December 24, 2012 at 9:41 pm
    I would love to see a full moon rise over an empty ocean but that’s not apt to happen.

    What’s cool at the full moon at sea is to see the moon rise/set on one horizon while the sun sets/rises at the other!

  58. I wonder if there is another moon effect. Looking at temperature anomalies in the El Niño regions 1 – 4, there are waves rather than loops in the current. Similar-looking features occur in the Agulhas Current off Mozambique and South Africa. These waves seem to occur on a time frame of about 2 weeks. Is the lunar cycle affecting the wind pattern, and therefore the upwelling pattern, and hence the apparent waves in the temperature anomalies?

  59. Dr. Svalgard

    Actually, not. The earth-moon orbit the barycenter of the system consisting of the sun, earth-moon, mercury, venus, mars (and its moons), jupiter, et. al., etc.

  60. Thanks Willis. My God, I can hardly believe it, but somebody has finally explained this to me!

    As a young mineral exploration geologist in charge of a 170,000 sq km project looking for base metals in a vast West Australian Proterozoic sedimentary basin in the early 1980s, I spent two and a half years of three week-on/1week off stints, ‘fly camping’ in the bush: inching my way across a vast, empty landscape in a 4 wheel drive by day, and sleeping under the stars at night, whilst mapping and sampling the stratigraphy of a huge ancient marine basin.

    At night I would usually pick some sort of vantage point to camp on, eg. one of the many flat-topped mesas, from which you could see the landscape below by moonlight and hear the dingos and feral donkeys down there in the creeks as youi went to sleep, and wake to the squarking of flocks of cockatoos if there was any water in them.

    And the one strange phenomenon that I always noticed and could never explain was the way that, long after sunset, when the searing heat and incessant flies of the day had subsided to a cool, stillness and we where sitting beside a glowing campfire, whenever the moon started to rise, a cool breeze sprang up from nowhere and blew throught the world for ten or fifteen minutes, and then died just as suddenly as it appeared, once the moon was fully above the horizon.

    I cannot remember now whether it came from or blew towards the direction of the rising moon, but it was so obviously a phenomenon of moonrise that I always thought of it as the moon wind myself. And now here you are, explaining it.

    I can still see that full moon from the ragged edge of the flat sandstone mesa cap, and the silver-lit, ghostly landscape of creeks and gum trees down below me on the very first night that it happened.

  61. Larry Kirk says:
    December 25, 2012 at 7:00 pm

    … I can still see that full moon from the ragged edge of the flat sandstone mesa cap, and the silver-lit, ghostly landscape of creeks and gum trees down below me on the very first night that it happened.

    Glad to find another man who has experienced the moon-wind. It appears, from the quality of your prose, that the life lived far enough out on the edge to allow you to notice the moon-wind has ruined you, just as it has ruined me, for more mundane pursuits …

    All the best,

    w.

  62. Interesting. I don’t know why I never noticed this before. Willis might know the place I spend alot of time at, its a medium size guitar shaped dry lake in Kumiva Valley, south of the Black Rock Desert, and just south of the Lava Beds. I like it there because generally there is no wind at night, in fact late night is almost always dead still. But, at sunset, the wind can roar at a pretty good clip until about an hour after dark at which point it stops dead. In the dawn, there is always a little breeze (but not nearly like sunset), before once again it stops dead..I assume the lesser wind is because the temperature difference is not as great between the light and dark in the morning…at sunset in the low humidity atmosphere you can literally feel the temperature drop). I have never noticed the moon breeze, though I have never thought to look. Next time I get out there, a couple nights after full moon, I will definitely check this out. The moon would have to rise later than the normal wind stop to be noticed.

  63. mike g says:
    December 25, 2012 at 5:37 pm
    Actually, not. The earth-moon orbit the barycenter of the system consisting of the sun, earth-moon, mercury, venus, mars (and its moons), jupiter, et. al., etc.
    Many people think so, but it is nevertheless wrong. These people cannot be convinced by the mathematics of the situation, but occasionally might understand measurements. The total solar irradiance measured at the Earth is a sensitive measure of the distance to the Sun, and that distance shows that the Eat-moon does not orbit the solar system barycenter [and why should it?]. To get a feeling for the physics, ask yourself if the space station orbits the center of the Earth, or the barycenter of the Earth-moon system. Or think of a binary star system [where the system barycenter is halfway between the two stars. Now add a planet in a tight orbit around one of the stars and convince your self that the planet orbits its star and not the system barycenter.

  64. Possibly a way to determine if the lunar wind is radiation or tidally induced would be to see what happens when the moon is in its last quarter. Rising after midnight the crescent moon would be reflecting with less radiative intensity.

    Another lunar anecdote, I love the way a full moon in winter mimics the sun’s summer path.

  65. Really nice post, Willis. I’ve never heard of the terminator winds of sun or moon before. I have known two sailors who were Physics profs; if and when I see them again, I;ll have to bring this up with them.

  66. Willis,

    My goodness,

    What a beautifully written romantic piece, and one that probably includes a wealth of scientific information.

    I’ve never had the pleasure of sailing the Pacific, but you made me feel the solid heat of the doldrums as well as the relief of a gentle wind when the air movement returns.

    What a life you have led!

    Your observations about lunar wind (and the negative responses thereto) remind me of how the observations of ancient farmers regarding the circulatory systems of animals were received – and rejected – by the academics of their day.

    I have no idea if you are correct or not about the lunar wind, but what an interesting avenue of study. It’s a shame that the academics of today are so close-minded.

    By the way, I have a pet theory that the interaction of a large moon (like ours) with a somewhat larger planet (like ours) might be the catalyst for life, given that all the other necessary components for life on the larger sphere are present.

    Do you think academics are ever going to look at that idea?

    Take care – and keep writing. I find your ideas fascinating.

  67. Willis, I think you have to be pre-ruined to go there in the first place, most pleasantly so! Best regards, Larry Kirk.

  68. willis

    i was lookig for poems about the moon wind a I am sure I have read some. Instead I came across this from a balloonists site; see item 6

    http://windwisdom.net/

    I will still look for a poem though as a moon wind deserves a non technical rsponse as well as a practical ne
    tonyb

  69. I wanted to read more so googled “terminator wind” – I get results for wind-up Terminator dolls!

    Interesting reading, thanks Willis.

  70. Page488 wrote, “By the way, I have a pet theory that the interaction of a large moon (like ours) with a somewhat larger planet (like ours) might be the catalyst for life, given that all the other necessary components for life on the larger sphere are present.

    “Do you think academics are ever going to look at that idea?”

    Some academics have argued that the moon helped life arise on earth, among other effects, through the enormous tides during the Archean Eon, when the moon was so much closer to our planet. It also helped stabilize conditions here & absorbed many bolides which otherwise would have hit earth, promoting the evolution of more complicated organisms.

    But at this point, no one can be sure that life developed here or arrived on impactors. Ice has recently been shown to catalyze abiogenetic reactions essential for life as known on this planet. Some meteorites contain many complex organic compounds. Whether the tiny structures observed on the Martian meteorite found on Antarctica are fossils of living things or not remains debatable.

    My guess is that simple lifeforms develop on many worlds, with or without moons, including on moons themselves. Earth however provides particularly salubrious habitats. Life may in fact be inevitable in certain energetic environments, given the rules of our universe.

  71. Energy from moon light will spin a radiometer. So too will the light from the dense arms of the Milky Way. You can measure the change in energy level that accompanies the rise of the galactic center above the horizon. The energy increase is quite obvious. Why would something as big as the earth not be affected? All incoming energy is important to the climate when considered over time. Great story well told, Willis. Nature seen from a pitching deck is never what you see in a book or magazine.

  72. Great post. You added another layer to my knowledge base. Like you, I am (was) a navigator back in the days where celestial observations where the navigational mainstay. However, while you were about as low and slow as it gets, I was high and fast. I crossed from Honolulu to Guam in about eight hours. I never knew such subtleties existed. Having made that crossing numerous time I noted an anomaly you may or may not have spotted. Between Honolulu and Guam there seems to be a magnetic distortion that causes magnetic compasses to deviate from the expected magnetic variation. I always kept a close eye on the heading of the aircraft by celestial means while making that crossing. Invariably, the mag compass would slowly deviate to as much as three or four degrees out there about half way through the crossing and then return to “normal” as we approached our destination.

    Having said that, the layer of knowledge you gave made me think of the ancient Polynesian navigators who read their surroundings even more keenly than you. By the accounts I’ve read their navigation skills included sky conditions, sea conditions, and bird flight patterns that accompanied the more basic steering cues they received from the night sky. They surely were aware of the terminator winds.

    I have always wondered what drove those stone age people to cross thousands of miles of open ocean and how did they know that there was some destination out there ahead. One theory I’ve read is that the Pacific Golden Plover gave them a hint that there were other lands out there someplace. The Golden Plover migrates from the various islands of Polynesia and Micronesia clear up to Alaska, where they nest each summer. Theory has it that the ancients followed the flight path of those birds and found what became known as the Hawaiian Islands. Having seen some of the indian cultures along the Pacific Northwest coastline, clear up to Alaska, I have been struck by the similarities in some of the customs and traditions of the two seemingly separate groups. Especially, those totem poles I’ve seen villages of those Pacific Northwest indians sure remind me of the Polynesian tikis both in appearance and style.

  73. The irony would be delicious if it turns out that the alarmist’s got the moon wrong, after years of yelling that “its not the sun”.

  74. Willis, very interesting and fun as well. Thanks and Merry Christmas.
    This reminds me of many things told to me by an older friend from Oklahoma about the factors causing infiltration of rainwater into the soil. We all know of gravity and capillary forces terms. But he spoke of observations during rainstorms in OK, where cold fronts can move rapidly, of the influence of barometric pressure as well. I will have to think about it and see If I have any correspondence still existing from the 1980’s dealing with his observations.

  75. Willis, yer blood’s worth bottlin’.

    Apropos moon planting, consider the following:

    Immediately prior to an earthquake, wildlife becomes noticeably agitated. A possible cause is the increase in radon released from the fracturing of crustal rocks. The moon induces a tide in the crust and this releases varying amounts of radon dependent on the phase of the moon. Radon is a short-lived radioactive gas that may well influence enzymatic processes in plant cells. This is one of those “dig here” thoughts as EM Smith calls them. Not original with me, but I cannot recall who presented the idea to me more than twenty years ago.

    Hoping everyone enjoyed their festive season. It was a subdued one chez Git as Dr Del Weston and Prof Gavin Mooney who both moved to the Huon Valley this year were murdered a few days ago. They were a charming couple and seemed to fit in well with the other guests for a musical evening we had last winter.

  76. LSvaalbard

    Point taken. And, I could have been convinced by the mathematics. I should have said somehthing like, “Actually, Not.” They orbit the sun and earth-moon barycenter, as modified by the effect of the other solar system bodies.”

  77. mike g says:
    December 26, 2012 at 11:29 am
    They orbit the sun and earth-moon barycenter, as modified by the effect of the other solar system bodies.
    no, that is still incorrect. There is no measurable effect of the ‘other bodies’ on the distance between the Sun and the Earth-Moon [on time scales of interest]. The center of mass of the Sun, Earth, and Moon depends just on those three bodies.

  78. Great posting. This reminds me of the accounts I’ve heard of in the past which describe the disappearing knowledge of Polynesian seamen. Apparently, they could tell the location of land many miles away just by looking at the shape and size of the waves (choppiness, I think) around their canoe. That probably required a lifetime or more of careful observation.

    As for the moon wind itself, it reminds me of the puzzled descriptions of a wind that accompanies eclipses (same principle; somewhat
    different cause despite involvement of the sun and moon). It seems clear that there would be such a wind as cooler air flows out of the umbra. After all, this same phenomenon can be experienced sitting in your garden on one of those May days when the sun is out and the sky is clear except for a few large fluffy clouds sailing across. If you are sunning yourself, eyes shut, you know when you are in their path simply from the noticeable cool breeze that precedes them by 20 seconds or so. I would never have noticed this without relaxed contemplative thought as I sat there apparently doing nothing. As a ‘towny’ I didn’t have the exposure to the cycles and patterns of nature that people formerly took for granted. It requires immersion and a clear, open mind to see them, as with the 4 months or so at sea that Willis describes.

    As we all know, there are subtle patterns at play all around us waiting to be discovered, teased out from the background noise. And scientists often talk, correctly, of datasets being too small or short-lived or clinical studies needing more participants to reveal any statistical trend. As this post shows, the ‘dataset’ can consist of multiple casual observations over long periods before you even realise there is a new phenomenon to be measured at all. That is sometimes the way the first step in a new scientific discovery happens. It’s the Eureka moment. And it often comes from mining the data of everyday experience…but only if we care to experience nature in all its detail.

  79. Hello Willis,

    There’s a good example of the use of the “terminator wind” in a naval battle in about 430 BC, in Thucydides’ History of the Peloponnesian War. The battle happened at the mouth of the Gulf of Corinth, and the Athenian admiral Phormio waited for this dawn wind to come up so that it would disrupt the closely spaced formation that an enemy fleet had taken.
    I hadn’t taken the trouble to understand the dawn wind phenomenon until this post of yours, so Thank You.

    Andrew Farquharson.

  80. Charles Gerard Nelson says:
    December 24, 2012 at 8:55 pm

    Interesting subject matter and nicely written.
    It led me to a question I have often pondered but have never heard discussed by ‘scientists’ namely…is atmospheric/ climate energy dissipated by ‘work’?

    Indeed; some “work” degenerates rapidly into heat, like the waving of a branch, but other work leaves a persistent alteration behind. Not until some hypothetical great averaging event, like the Big Crunch, will some of that be reduced to ‘raw entropy’. So there are ‘sinks’ in the energy equation, in real and present time, which may need accounting for.

    The compliment to Willis from Christopher is well-deserved. And kudos to Lord Monckton for his graciousness and perspicuity in making it.

  81. Brian H says:
    December 26, 2012 at 9:38 pm

    Charles Gerard Nelson says:
    December 24, 2012 at 8:55 pm

    Interesting subject matter and nicely written.
    It led me to a question I have often pondered but have never heard discussed by ‘scientists’ namely…is atmospheric/ climate energy dissipated by ‘work’?

    Indeed; some “work” degenerates rapidly into heat, like the waving of a branch, but other work leaves a persistent alteration behind. Not until some hypothetical great averaging event, like the Big Crunch, will some of that be reduced to ‘raw entropy’. So there are ‘sinks’ in the energy equation, in real and present time, which may need accounting for.

    The compliment to Willis from Christopher is well-deserved. And kudos to Lord Monckton for his graciousness and perspicuity in making it.

    Thanks, Brian, for your good wishes. I intend to do my best to live up to Lord Moncton’s somewhat undeserved comment.

    Regarding the existence of “sinks” in the energy equation, other than the energy sink of the ocean, I fear I can’t think of any that would rise above the noise. For example, consider the creation of fossil fuels as an energy sink. Energy gets bound up in plant life, and some plant life gets turned into oil. The total amount of fossil fuel sequestered in the earth is estimated to be on the order of 1e+8 terawatt-hours of energy. It took millions of years to fill this particular energy sink. That’s a whole lot of energy, about a thousand times the annual global energy use.

    But on the scale of the energy that flows into, through, and out of the Earth on a constant basis, even fossil fuels are tiny. I can’t think of any possible “sink” for a significant quantity of energy at other than geological scales. Even at geological scales,

    Here’s the thing. The 1e+8 terawatt-hours in total fossil fuel energy is about the same as the amount of solar energy that the Earth intercepts per year. This means that if that same energy sink were operating today, we would be stowing away and sequestering only one-millionth of the solar energy passing through the system.

    That’s enough to make a difference … but only over a long, long, long time. On an annual or decadal basis, the sequestration of one millionth of the incoming energy is not detectable or significant in any way.

    So I’ll have to ask you, Brian, what energy sinks you might be referring to that would be large enough to make a difference to the global energy budget?

    All the best,

    w.

  82. Thanks, Willis.
         The poetry of your prose is spellbinding, and almost always leads to a chorus of comment and additional insights and perplexities which expands your initial base as you trigger intriguing knowledge and conjecture from others.
         So there is another level of thanks from me to the commenters.

  83. Superb post by Willis. Thought provoking and with good literary style. Gives rise to an ambition to sail the Pacific. Just as a side thought there is now documented evidence of wind variation during solar eclipses link “news.bbc.co.uk/2/hi/science/nature/2515045.stm”. Although the effect is small it might be interesting to do some wind measurements during a lunar eclispe ?

  84. Late to this party, but enjoyed the holiday treat from Willis. For a moment, reading the title, I thought, “But the Moon has no atmosphere!” Unless, of course, it were the moon of a different planet, or perhaps our own eons ago, when it might have had one. A great title for a SF story, at any rate.

    /Mr Lynn

  85. Bless your heart for ending a rather crappy year with pure mystical earth poetry. You have put my head back in the stars where it belongs. Very theraputic. Happy New Year! Thanks again bro’…

  86. I recently visited the Hopper exhibition in Paris. Here a description of the “Evening Wind” by the Metropolitan Museum of Art, that reminds me of your essay. Hopper often used morning or evening lights in his painting. Probably these changing lights, winds and atmospheres were inspiring.
    All the best for 2013 !

    Evening Wind, 1921
    Edward Hopper (American, 1882–1967)

    In this work, the viewer catches an unknown individual in the most private of moments. In an everyday scene that acquires drama and mystery in Hopper’s hands, a naked woman kneels on the edge of a bed. Her face is veiled by her long hair as she turns her head toward the window in surprise or fear, reacting to the sudden movement of the curtain at the open window. Hopper has included very few details in the interior of the room, so that the scene remains universal in its emotional impact. His etching technique creates a sharp contrast between the darkness of the heavily crosshatched background and the untouched white paper of the space outside the window, and the area of the scene is so shallow that the viewer feels a physical closeness to the woman, as if present in the room with her.

    Here’s the link to the drawing:

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