Guest Post by Willis Eschenbach
Once on a lovely hot August day in eastern Oregon, my gorgeous ex-fiancee and I sat entranced and watched a parade of dust devils. I’ve written about dust devils before, they’re one of my favorite emergent phenomena.
Like many such emergent climate phenomena, dust devils are driven by a temperature difference between the surface and the surrounding atmosphere. Once that temperature difference (called “delta-T”) is exceeded, dust devils form spontaneously.
The relevant climate effect of the dust devils is to move heat aloft from the surface, and thus cooling the surface. And since they are temperature-driven, dust devils form first and preferentially on the hottest part of the local surface. From there, they are generally moved away from that hot spot by the wind, and eventually die away and disperse entirely.
In this case, the hottest spot in the local area was a plowed field in a large area of small scattered bushes near the road. When we saw the dust devil form over the field we stopped in awe. It was big, lifting clouds of dust from the fertile ground. Then the wind moved it off of the hot spot, parallel to the road. Once it left the plowed field, it was throwing up less dust. But to replace it the dust devil tossed leaves and twigs and pebbles.
So the dust devil drifted away with the wind … and just when we were getting ready to start the car and leave we looked, and another one was forming over the plowed field. Out of nothing it spun into reality, growing, growling, whistling, kicking up dust … and then, once it was towering high above us, it followed its now-distant twin out of the plowed field and along the road into the wider world.
And then, of course, another dust devil formed over the plowed field … and for a half hour, it was groundhog day—over and over again, dust devils forming, strengthening, leaving home for their big adventure down the highway, and eventually dying out. I didn’t take any photos, but here’s a shot from the web that looks like what we saw.
I bring this up to highlight the fact that this system of cooling the surface with emergent climate phenomena is extremely effective because it is concentrated on the warmest spots. These are the very spots that are in greatest need of cooling, as well as being the spots where cooling will have the largest effect. The dust devils formed over and over in that same hot spot, and nowhere else in the surrounding fields.
With that as prologue, let me say that one of the reasons I greatly enjoy writing for the web is the immediate feedback that I get. The most valuable feedback is when someone points out something that I’ve done wrong. I can’t begin to calculate how many years of wasted effort I’ve been saved by someone saying “Um, dude … did you notice that you totally went off the rails right here?” … or more likely, something equally correct but much less pleasant. Fortunately, even unpleasant corrections are gold, they keep me out of blind alleys.
The next most valuable kinds of feedback are suggestions and support for further investigations, and in that regard comes this post. In my last post, Glimpsed Through The Clouds, I put up a movie I made of the seasonal changes in the relationship between sea surface temperature and thunderstorms. Upon viewing it, a commenter wrote:
it would be interesting to see if this effect persists seasonally and if it varies through el nino/la nina periods. prevailing wind direction and ocean/ land temp differences will be factors.
great work once again willis .
So this is my entry in the temperature/thunderstorm Nino/Nina derby. The Nino/Nina gauge under the globe shows the value of the MEI, the Multivariate ENSO Index, for that month. The colors show the height of the clouds, with the high clouds being thunderstorms and the highest thunderstorms being the most powerful and having the greatest cooling effect. The black outlines, on the other hand, show sea surface temperatures of 27°, 28°, and 29°C. Note how the thunderstorms line up very neatly with the temperatures. Note also the steepness of the increase in thunderstorm strength with increasing temperature, as shown in Figure 6 in my previous post, Glimpsed Through The Clouds. The temperature varies by a mere couple of degrees, and in response, the number and strength of the thunderstorms vary from none all the way up to YIKES!
Not much to say except to marvel at how the thunderstorms constantly move so that they are exactly where they need to be in order to have the maximum cooling effect … what an amazing planet this is.
w.
MY POLITE REQUEST: Misunderstandings are the bane of the web. To avoid them, please QUOTE THE EXACT WORDS THAT YOU ARE DISCUSSING so we can all be clear about what you are referring to. Please note that although the request is polite, if you do not follow the request my response may indeed be less than polite …
One time when flying on an airway over the water north of
Cuba in the early evening, I saw numerous (at least 2-3
dozen) very tall chimney-like clouds. We were at 25k’ and
I’m guessing the base of the clouds was at ~10k’ with the
tops at ~35k’. The clouds were probably a half-mile wide
at the very most. Unfortunately, I don’t remember the
time of year when this occurred.
Because it was in the evening, they looked like they were
on fire as the colors went from yellow-orange through red
into purple as they usually do. It was the most amazing
cloud formation I’ve ever seen. As you say, this is an
amazing planet!
I’ve researched this and never found any information on
this. Is this a common occurrence in the tropics? I had
never heard others mention this phenomena and only saw it
this one time. Thanks.
Thunderstorms following the hot spots on a Cuban holiday. Shallow waters, Gulf Stream … and the hotter the spots get, the bigger and taller and more densely packed the thunderstorms get.
Indeed, it is a stunning sight.
w.
To which I’d add that according to the monthly averages shown in the movie at the bottom of my previous post, it was likely in the fall (August to October) when you saw it. The thunderstorm towers are highest that time of year.
Note that you probably need to be flying through one of the red areas on the map to see this … which is why it’s not that common. How often do you fly over Papua New Guinea, for example?
w.
Willis- I apologize profusely for not stating that they
just light cumulus clouds which may have been obvious by
my description. The clouds were heavier further away
toward the coast but they hadn’t formed T-storms yet.
The time of year sounds right as the sun didn’t set that
late like in mid-summer. In some ways, I thought what I
saw would be what the updraft/downdraft columns in a
T-storm would look like if you stripped away the clouds
outside of them. These clouds obviously lacked that
strong vertical winds that is in those columns as they
stood tall like chimneys with almost no motion.
I never made it to the East Indies but did get to
Kwajalein, Guam and the Philippines. We did have to
detour to the south flying from Guam to the Philippines
to get around the backside of a typhoon in December.
Other than that, my contact with the tropics was in the
Gulf and Caribbean whereas you lived many years closer
to the equator in the redder areas and know much more
about clouds than I do. Thanks again.
Blown away by whirlwind
Alanna Kelly – Feb 12, 2018 / 5:00 am
glad i managed to post something positive that prompted further investigation in that great mind of yours willis. i watched that animation through the cycle several times with a daft smile on my face. one of those occasions (that usually arise after reading one of your submissions) where i really rue not having the clarity of thought ,memory or mental ability necessary to understand much of the amazing interactions within our ocean atmosphere system.
i hope you never change your current style of writing and presentation. if it can prompt a reasonable query in my mind it can do it in anyone. being able to convey your thoughts and theories to people with a limited or non existent science background is a talent sadly lacking in many.
i had a quick look back through the global sea surface temperature records after looking at the animation. interesting to watch the increase in altitude and subsequent reduction of the same in cloud tops over the blob in the north west pacific.
Once as a teenager I took the opportunity to step inside of a very small dust devil that was a 15 foot diameter swirl of leaves in a grassy field. Walking with it as it meandered I found the inside to be calm and warm. After half a minute it left me relishing the experience as it wandered away off the field and disappeared.
I cannot help but be mischievous, and raise a ruckus by stating there is nothing scientific about dust devils, though they should in fact be called dust-devi, for they are minor angels, embodying God’s will, (also called scientific Truth.) The Ancient Greeks called them “Zephyrs”.
Although in some respects robotic, in their perfect obedience to God’s law, zephyrs can at times display surprising attributes of God’s will, involving His sense of humor. If you don’t believe me, attempt raking a leaves from a lawn in New England in October, when the air is cool but the sun is hot.
https://sunriseswansong.wordpress.com/2018/01/30/local-view-western-zephyrs/
I’m wondering if it would be possible to add another slider displaying the East-vs-West differential pressure across the Pacific OR some measure of net trade wind velocity.
Mike Borgelt “If thunderstorms regulate the climate, why were they unable to prevent glaciation? There’s been hundreds of meters of ice above Manhattan in the past…….why haven’t Willis’s thunderstorms prevented them from advancing?”
..
And you have an explanation for glaciation?
Milankovitch cycles.
Probably large asteroids. There have been many in the past including the one 265 million years ago that wiped out the dinosaurs. The good news is you have nothing to worry about because H2O NOT CO2 drives the climate and Willis ‘ theory goes a long way in explaining it. In the time period before the next asteroid hitting us you can sit back and relax. The bad news is that a big one will definitely hit us unless we can knock it out of the sky.
Willis’s theory does not explain the recent rise of about 1 degree C in the past 150 years.
Mike wrote:
“Willis’s theory does not explain the recent rise of about 1 degree C in the past 150 years.”
Natural variation, the null hypothesis. explains it well enough.
To prove that humanmade global warming is significant, one has to disprove the null hypothesis, and it has all happened in the past – before the advent of fossil fuels, climate was warmer AND colder, weather was gentler AND wilder, CO2 was higher AND lower – and this old world just kept spinnin ’round. 🙂
_________________________
“There is nothing new under the Sun.”
– Ecclesiastes 1:4-11
A generation goes, and a generation comes,
but the earth remains forever.
The sun rises, and the sun goes down,
and hastens to the place where it rises.
The wind blows to the south
and goes around to the north;
around and around goes the wind,
and on its circuits the wind returns.
All streams run to the sea,
but the sea is not full;
to the place where the streams flow,
there they flow again.
All things are full of weariness;
a man cannot utter it;
the eye is not satisfied with seeing,
nor the ear filled with hearing.
What has been is what will be,
and what has been done is what will be done,
and there is nothing new under the sun.
**************************************
Dust Devils are an emergent climate phenomenon???
You saw them in summer. They are a hot weather phenomenon.
(Hint: hot weather is more prevalent in summer.)
Dust devils are called Willy Willys in Australia are plentiful in hot dusty areas. We saw many of them when we toured there twenty years ago.
.
Warren cole February 15, 2018 at 7:57 pm
Yes, they are emergent phenomena. Why would you think they are not emergent phenomena?
w.
Maybe it’s because “emergent” is used in it’s technical sense of complex system science and most readers are not familiar with this meaning…
Would Warren cole agree that life on this planet is an “emergent phenomenon” ?
Thank you Willis for your work. This post is helpful and informative.
Regarding publishing in the journals – I suggest that it is a largely waste of time.
The problem with publishing in the journals is that they are not only cumbersome, time-consuming and slow, but they produce so many papers that can only be described as nonsense – millions of pages of drivel on “My New Computer Model Projects Even More Global Warming” and “The Impact of Global Warming on Groundhogs with One Left Testicle”, etc., etc.
The once-great journals have destroyed their credibility by publishing so much nonsense about global warming mania, aka climate change, aka whatever-it-is-called-this-week.
It may be that the scientific journals are obsolete – and that online forums like wattsup could become much better, faster means to move science forward. Online feedback is not always helpful, but it is fast and it enables commentary to be discussed openly, without the usual “gatekeepers”, who may actually detract from value.
Regards, Allan
Germonio above raised questions about the ability of climate models to represent these phenomena.
Now, it’s possible to “parameterize” these phenomena. The problem is that the typical resolution of the climate models is about 200 km x 200 km. This is about a third of the resolution of the map in the head post.
The real problem, though, is that the cooling is applied with exquisite precision in the real world, exactly where it is needed. That makes it hard to parameterize. It’s as though someone had a sore. Which is more effective, to put all the medicine on the sore, or to apply the same amount equally distributed all over the surface of their body? I mean, it’s the same amount of medicine either way, right?
I’m not saying that the climate cannot be modeled. I’m saying it is far and away the most complex system we’ve ever tried to model, and that the current generation of models is far from representative or lifelike or reliable or accurate enough to use for setting public policy.
w.
“If thunderstorms regulate the climate, why were they unable to prevent glaciation? There’s been hundreds of meters of ice above Manhattan in the past…….why haven’t Willis’s thunderstorms prevented them from advancing?”
Willis says thunderstorms have a cooling effect. In a warm room, that’s all you need for an A/C thermostat.
But in a cooling world (caused by Milankovitch cycles, asteroids, and/or who knows what), thunderstorms may help build glaciers by sending water vapor to the cold areas to become snow and eventually ice.
Compare an image of the Laurentide Ice Sheet with figure 3 in the Glimpsed Through The Clouds post.
Coincidence?
If you like people who think outside the dogma box, you might like this:
http://scottishsceptic.co.uk/2015/02/13/toward-a-new-theory-of-ice-ages-xi-hadley-cells/
zazove
Feb 15, 2018 @ur momisugly 3.37 pm
Good query ! This is an ancient recollection, originating – I think – from an NACA Technical Note or Technical Report. I have spent some time digging through my archives, and will continue to do so till I find the answer, or run out of steam.
In the meanwhile, have a look at NACA TN 2734 by Souter and Emerson, where they cite Humphreys, who calculated that a 4″ diam hailstone – 0.7 SG – would require 83 m/s for sustenance. This is 272 fps and if one allows (say) a 1G hoist to get it back up to altitude in a timely way, then this becomes 544 fps; and if then one chucks in a few knots for the Missus and the Kids, and one for Grandma, we have a large number.
My own calculations would put the required velocity somewhat lower, and I suspect Humphreys allowed for fine grain turbulence and used Cd = 0.1, assuming RN > 6 X 10^5. This latter is reasonable, but if one assumes a lower RN of (say) 10^5, just below the step, then Cd jumps to 0.47, cutting velocity requirement by a factor of almost 5. Huge difference !
And then we have a new record hailstone of 8″ diameter, which is troublesome, not knowing from whence within the Bell curve it comes ! Much easier to measure things in a metrology lab !
These beasts (Cb) are avoided by pilots; I have had some near misses, myself, and some of my glider mates, with more than 20,000 hours on power, tell some terrible stories !
I repeat; this is not the source I recollect, but I shall keep digging.
I’m ex-ATC, so have an interest in aviation.
Fascinating read – I’ve almost run into one while walking one day – it had just formed in a plowed field a short distance away from me and crossed the path so close I could have taken a step forward and been in it. Unfortunately I didn’t see any more form so it must have taken care of any needed cooling. I’ve seen others grow to the size of a tornado – minus the clouds of course. I’ve heard of hurricanes being called “natures air conditioners”; it would appear that thunderstorms are as well.
Hi Willis,
Dust Devils are Thermals – see what Brian James Lydon wrote above.
If you haven’t already, you might find some useful insights by looking up stuff about gliders (sailplanes) and soaring flight. Getting the weather right and finding & using thermals is essential if you want to be a successful soaring pilot and you have to be pretty good at it to be a national or world champion. You’ll probably find interesting information from people looking at the same phenomena from a different perspective.
gareth February 16, 2018 at 1:54 am
Not really. Thermals are a fairly large area of slowly rising air that extends vertically from something like a plowed field. It turns slowly, and doesn’t pick up dust. Nor does a thermal generally take off and wander around the landscape. They stay above e.g. the plowed field where they formed. None of these are true of dust devils.
Regarding soaring, I’ve flown a sailplane as well as several other light aircraft. And I was heavily involved in both powered hang gliding and a small amphibian sport aircraft in Fiji. So while you are right about things to be learned in the air, “looking up stuff about gliders” probably isn’t the most productive use of my time …
w.
Willis stay out of the atmosphere You are too important to risk your life in gliders and small aircraft.
In addition to the thunderstorm effect shown here, it is well known that hurricanes strengthens over oceans when the ocean temperature is above 27°, so there seems to exist some sort of threshold value on 27°.
Or, could it be something else? Perhaps the 27° is just serving as a visual proxy for some other phenomenon that correlates with temperature.
One idea I have is that the real driver of winds are temperature gradients, not absolute temperatures. That means that if for instance all temperatures on the planet rises by one Celsius, the threshold for feeding hurricanes and thunderstorms would also rise from 27° to 28°.
Any thoughts on that?
/Jan
I am not sure if this is quite true. Yes thunderstorms are born on hotspots, and usually the warmest, because of greater upwelling in that spot, but they don’t move to the hottest part over the life of the storm. As they grow they move with the prevailing winds, with the upwelling action, now strong enough to encourage even more upwelling even if the spot is slightly cooler (though still warm) than where the thunderstorm originated.
Also frequently the storms greatest power, as felt on earth is in the late afternoon, when the earth starts cooling, because a large amount of the rainfall comes from the collapse of the thunderhead.
marque2 February 16, 2018 at 5:18 am
Thanks, marque2. Actually, over their lifespans thunderstorms do move to nearby hot spots.
Why? Well, because as you point out, they follow the winds … and the warm air over the hot spots is less dense than the cold air under the thunderstorm, so some wind flows (as it always does) from cold to hot. This tends to move the thunderstorm away from nearby cool areas and towards nearby warm areas.
w.
The purveyors of ‘climate models’ have become very guarded about the details of their mathematical modelling in recent years. Nonetheless, I was able to learn that the grids used to represent air temperature, pressure, etc. have always been far too coarse to allow accurate representation of even large cyclones, let alone thunderheads or dust devils. In short, the entire phenomenon of atmospheric convection, known to thermodynamics through the adiabatic lapse rate as the SINGLE most important factor influencing temperature distribution in the atmosphere, is completely beyond the computational reach of global scale climate modelling.
“Like many such emergent climate phenomena, dust devils are driven…”
I don’t think dust devils should be characterized as a “climate” phenomena; they have nothing to do with “climate change” and have been around forever, for all we know (note the comment about the need to monitor every one of them (in order to increase the accuracy of long term weather forecasting) referenced above from the *1970s*). Don’t know if that was unintentional (or if that was not the intended meaning), but dust devils surely have nothing to do with CO2 levels or with changes to the “average” surface temperature. IOW, these are a “weather, not climate,” phenomena, even though (like all weather) they form a component part of the aggregate of weather that *is* “climate.”
In my brief time in Washington state (mid to late ’90s), I witnessed my share of them – and of dust *storms*, when you just went inside and hunkered down until they were over, unless you enjoyed being sandblasted. Just didn’t want people to get the (wrong) impression that dust devils are “new” or that they are a “result” of “climate change.”
AGW is not Science February 16, 2018 at 8:40 am
Actually, they do have a lot to do with the “average” surface temperature. Imagine if they did not exist. The warmer areas of the planet would get much warmer than they are today because the hot-spots would not receive the cooling effect of the dust devils.
However, I’m equally happy if you want call them “weather phenomena”, despite their clear effect on the long-term termperature.
w.
Here’s one from a bit further afield:
The picture is a bit clipped but this one was taken in 2016 by the NASA Opportunity rover in 2016!
Or is it the opposite, hot spots chasing the thunderstorms? Most of the energy supplied to the warm area around Indonesia is LW, released latent heat, which is both feeding the thunderstorms and heating the surface.
A similar effect can be seen in Egypt. Some years ago, after the last of the Egyptian-Israeli wars, I had occasion to spend some time in Port Said, in high summer. Port Said was seriously damaged in the war. (How serious? Just outside my hotel the street lamps were perforated by bullet holes. I had plenty of time to reflect upon the intensity of the fighting that produced such an effect!). There were no communications between Port Said and the outside world, so to contact my office I had to take a taxi from Port Said to Cairo, speak with the boss, be spoken to and then return to Port Said. I made this journey quite often. The road was, on the whole, very lightly used and when the ancient taxis (those large, WWII generation American cars, massive engines, no AC) overheated and perforce we had to wait a while in the desert road, I used to observe the dust devils that would suddenly form seemingly out of nothing and wander across the desert. I was particularly interested in what happened when one reached “our” road. It just collapsed. In the absence of any information to the contrary, I figured out that the cause of the collapse was the difference in the temperatures, road v desert.
Willis,
A similar effect can be seen in Egypt. Some years ago, after the last of the Egyptian-Israeli wars, I had occasion to spend some time in Port Said, in high summer. Port Said was seriously damaged in the war. (How serious? Just outside my hotel the street lamps were perforated by bullet holes. I had plenty of time to reflect upon the intensity of the fighting that produced such an effect!). There were no communications between Port Said and the outside world, so to contact my office I had to take a taxi from Port Said to Cairo, speak with the boss, be spoken to and then return to Port Said. I made this journey quite often. The road was, on the whole, very lightly used and when the ancient taxis (those large, wonderful, WWII generation American cars, massive engines, no AC) overheated and perforce we had to wait a while in the desert road, I used to observe the dust devils that would suddenly form seemingly out of nothing and wander across the desert. I was particularly interested in what happened when one reached “our” road. It just collapsed. In the absence of any information to the contrary, I figured out that the cause of the collapse was the difference in the temperatures, road v desert.
Willis wrote: “With that as prologue, let me say that one of the reasons I greatly enjoy writing for the web is the immediate feedback that I get. The most valuable feedback is when someone points out something that I’ve done wrong. I can’t begin to calculate how many years of wasted effort I’ve been saved by someone saying “Um, dude … did you notice that you totally went off the rails right here?” … or more likely, something equally correct but much less pleasant. Fortunately, even unpleasant corrections are gold, they keep me out of blind alleys.”
Um, dude: Did you remember that tiny convective dust devils and massive convective thunderstorms in the Western Pacific depend on the existence of a unstable lapse rate? They can’t be driven indefinitely by surface temperature alone! The heat convected aloft must go somewhere (to space or horizontally) as fast as it arrives or convection will cease. One needs more than a surface energy balance perspective.
Um, dude: Did you notice that daily surface warming occurs only over land (including larger tropical islands), but not over the bulk of the ocean? Your thermostat hypothesis is correctly based on your experience on tropical islands, but it applies only to a small fraction of the planet and only during the rainy season.
Frank February 16, 2018 at 3:54 pm Edit
Yes, I did remember that it depends on the existence of an unstable lapse rate. It also depends on the presence of an atmosphere, and gravity. Your point is totally unclear here.
Say what? You clearly haven’t done enough surfing and sailing in the tropical ocean. That is absolutely not true. Daily surface warming absolutely occurs over the open ocean. I’ve discussed this at length in a number of posts about the TAO buoys, q.v.
Again, absolutely not true. It applies not only in the tropics, both ocean and land, as well as in monsoon areas. I’ve even seen it in operation in England.
And its operation in the tropics is central to the regulation of the climate, because half of the energy striking the surface occurs in the tropics.
Thanks for the polite manner,
w.
Convection carries latent heat aloft and releases it as clouds form, raising the local temperature in the upper atmosphere. That converts an unstable lapse rate into a stable one, ending convection – unless some mechanism exists to remove that heat as fast as it arrives. Your posts on the thermostat tend to focus on what is happening at the surface and IIRC don’t usually deal with the ultimate fate of that heat.
Due to the high heat capacity of water, the Western Pacific Warm Pool can send a great deal of latent heat upward with cooling SST, but it doesn’t take much latent heat to warm the thin upper troposphere. The cloud and thunderstorms over this unusually warm water can persist without a mechanism to remove the heat they release high in the atmosphere.
In the long run, convection can only remove as much heat from the surface as is escaping from the upper atmosphere to space as radiation. As best I can tell, your thermostat hypothesis focuses on the surface becoming too hot and doesn’t worry about the upper atmosphere remaining cold enough to create an unstable lapse rate.
Respectfully, Frank
Wills: I haven’t time to work this out tonight, but your glider pilot comments mind me of the fact that we SHOULD be able to calculate the “net energy radiated to space” from the TS’s. Making some sort of distribution curve for this (to represent the varying magnitude of the storms), taking some of your various data sets (about the number and duration of the storms), it seems we SHOULD be able to get an ESTIMATE of the “addition” to pure radiation from the “grey gas” which is the simplistic analysis being done by much of the Gorebull warming crowd. AND checking variations in this aggregates, may show that you are very correct in TS’s being the “thermostat” of the Earth. Got time for analysis?
Sorry, dropped the second “i” from Willis. Typing too fasttttt!!!
@Willis: ” Nor does a thermal generally take off and wander around the landscape.”
This is incorrect – which is why sometimes you’ll have to abandon a thermal when trying to push upwind.
Powered hang gliders, light aircraft and float planes don’t do much soaring flight, and “flown a sailplane” might not make you an expert (I’m not, but I know people who are).
My suggestion was a genuine tip, offered in good faith, because often “Eureka” moments happen at the boundaries of subjects.
Kind regards…