Sunrise or Sunset - Seeing Even More Gravity Wave Clouds

#2521 "Singleton Sunrise Morning Cloud"

Perhaps my years of paddling and walking on shorelines, not to mention "sitting on the rocks of the bay", have paid off in many more ways than just the enjoyment of the moment. You can learn a lot by watching waves. Gravity waves are the ultimate tool because they are absolutely perpendicular to the atmospheric frame of reference wind. I painted gravity waves in the above skyscape and this Blog will explain those as well as the patterns in August sunrise at Killbear that initiated this series of Blogs on Creative Scene Investigation. Please read on... 

Early satellite imagery of the weather from the seventies was the other key inspiration for me. I saw that atmosphere as an ocean of air very much like the lakes that I paddled on.  That statement is not a big stretch because it is true. The different air masses are also individual pools in that larger ocean. We just happen to live at the bottom of those air oceans. 

I applied the concepts of the different types of water gravity waves to the atmospheric fluid of air so that I could better appreciate the satellite imagery. There may be seven different types of ocean waves but I found it most helpful to keep it simple and just consider wind waves and swells. 

Wind-driven waves are created by the friction between wind and the surface water. As wind blows across the fetch of the water, the continual disturbance creates a wave crest. Gravity takes over from the wave crest and digs the trough. Wave height and wavelength both increase with the wind speed. 

Swells may originate as wind waves but continue propagating far from the original energy source of the strong winds. Shorter wavelength swells carry less energy and dissipate faster. Swells that are observable some distance from the source tend to be longer wavelengths. 

In my graphic for #2535 "Sunrise on Killbear Light", I conveniently labelled the main, large bands of cloud as simply gravity waves. I did not call them "swells" or mention the fine structure of the clouds within those atmospheric swells.  Let me explain... 

Swell Gravity Waves at a distance
from the strong wind source region

Atmospheric wind waves are generated where the atmospheric relative winds are strongest - between the companion swirls. This is also the local maximum in the jet stream. Atmospheric wind waves can be seen in the cirrus. As in the ocean, atmospheric swells propagate outward from this source. The shortest wavelength swells decay fastest. The longer wavelength swells travel great distances before "crashing" on the shore of the air mass at the deformation zone. If you can imagine the atmosphere in these terms, much of the science of oceanography can be transferred to the atmosphere. It all started when I first really began  to appreciate satellite imagery. 

In Sunrise or Sunset - Seeing Gravity Wave Clouds, I was actually describing atmospheric swells. What I did not describe were the details within those swells and how they got there. The CSI fun really starts with superimposing smaller scale wind waves on to the atmospheric swells. The signatures that result can be applied to really understand the weather. I constructed the following graphics to better explain these patterns thinking that each image might be worth a thousand words. 

Adding Wind Gravity Waves to Swells

Atmospheric gravity waves are most easily observed when the layer of moisture in the stable layer is rather thin. The crest of the wave associated with ascent and cooling air is more likely to be cloudy - condensed water droplets or ice crystals. The lowest point of a wave or trough associated with descending and warming air will be the thinnest. The best case is when the lifted condensation level in the atmosphere is near the midpoint between the crest and trough so that bands of cloud are separated by blue sky. Waves are occurring all of the time in the atmosphere but those motions are typically shrouded in cloud. 

There are many interesting situations that superimpose wind gravity waves on top of swells. The warm conveyor belt is probably the most interesting and informative about the weather. The system relative winds associated with the warm conveyor belt are best described by the deformation zone conceptual model but I will save most of those details for the next Blog and focus instead on the gravity of the situation. 

The wavelength of the wind waves is determined by the wind speed – stronger wind gives a longer wavelength.  The spacing of different portions of the wind wave are best described by differences in the wind speed which translate to differences in the wavelength. The simpler approach is to imagine that the stronger winds along the confluent asymptotes are simply tipping the gravity waves as depicted in the above graphic. That simplification is not correct. 

As a home study assignment, drop a pebble in a pond or your bathtub to really learn about dispersive swell waves. All of the energy in that first wave is supplied by the stone. The waves disperse in all directions from that source and significant ripples survive long distances before dissipating. … with no additional energy supplied. These are really swell swells! The direction of motion of dispersive swells like in your tub, might be diagnosed by the decay in amplitude, the arc shape of the swell or in the atmosphere, the direction of cloud drift.

We should not be surprised to see smaller and shorter wind waves superimposed on swells. They happen all the time in the atmospheric ocean.

Remember that nature's solutions to the laws of physics is always correct. Nature also constructs more accurate and beautiful graphics than I can. The next Blog will further explain gravity waves (both wind driven and swells) within the context of the deformation zone conceptual model. Stay tuned, looking at clouds is about to get even more exciting. I am sittin' on the very edge of that rock of the bay.. Otis Redding would be pleased. 

Keep you paddle in the water and warmest regards... 

Phil the Forecaster Chadwick

Sunrise or Sunset - Seeing Gravity Wave Clouds

#2535 "Sunrise on Killbear Light"

This is the next step in applying Creative Scene Investigation (CSI-ing) to "Sunrise on the Killbear Jumping Rocks". The first step explained the colour of the light in Sunrise or Sunset - Seeing Red. The second step explained the clouds. The next step will investigate the gravity waves in those clouds using #2535 "Sunrise on Killbear Light" since that painting includes that portion of the sky depicts the same sunrise, . 

#2534 "Sunrise on the Killbear Jumping Rocks"

Every line in the clouds has a story to tell. The large scale banding in these clouds are gravity waves and they reveal the system relative winds in the free atmosphere away from friction and complicating interactions with the surface of the Earth.  The larger the wavelengths of the gravity waves, the stronger the wind. The system relative wind direction must be perpendicular to those waves. The cloud itself is probably drifting in the same direction as those winds but one cannot discern that motion in a painting. 

The sky in #2535 "Sunrise on Killbear Light" is the same as in
#2534 "Sunrise on the Killbear Jumping Rocks" but I
included more of the clouds in that painting ... so the weather
can be better understood. 

Gravity waves in the sky are exactly like gravity waves on a lake. The wind is blowing perpendicular to those lines. The layer is fairly stable. Waves increase in size and wavelength with the wind. Parcels of air or water deflected upward are pulled back down by gravity. These parcels have momentum and overshoot the average level on their way down. The sinking parcels reach equilibrium and then rise buoyantly. The parcels once again gain momentum and overshoot the average only to be pulled down again by gravity. The process gets repeated again and again and again...

The fact that there are clouds at all tips the balance in favour of that being a southerly wind with moisture from the tropics. If there is not much cloud, then it is likely that the winds are from the north were moisture is more limited. 

The gravity waves also reveal the relatively stable layer in the atmosphere. Parcels displaced from the stable level, always try to return home again. These stable layers can be frontal surfaces typically associated with a southerly flow and more cloud - a warm front in this case. Subsidence inversions are stable layers that typically occur with sinking air and are typical with dry northerly flows. 

Dry northerly flow with gravity waves. A sunset
view looking west over Singleton Lake. 

But there is much more to CSI in this painting … I also see deformation zones and smaller scale gravity waves but will save those for the next day.

Keep you paddle in the water and warmest regards... 

Phil the Forecaster Chadwick

Sunrise or Sunset - Seeing Clouds

This is the next step in applying Creative Scene Investigation (CSI-ing) to "Sunrise on the Killbear Jumping Rocks". The first step explained the colour of the light in Sunrise or Sunset - Seeing Red. 

2518 "Sunset Weather Story"
Another sky with lots of cloud...

Air moves like most everything else following the path of least resistance. Air can move along constant energy surfaces in the atmosphere for free… meteorologists call them isentropic surfaces. These isentropic surfaces slope upward from the equator toward the poles. For air headed northward (in the northern hemisphere), the parcels of air rise for free along those sloped surfaces. These parcels of air from the lower levels of the tropics are loaded with moisture. Clouds form as the air rises and cools. For someone in the mid latitudes, the high level cirrus arrives first to be followed by the mid level altostatus and eventually the low cloud nimbostratus if it is raining. More on clouds in a later Blog... 

The air originating from the Arctic tends to be dry and cold as the parcels start of their southward journey. These parcels become warmer and drier as they descent along the downward sloping isentropic surfaces. Typically not much cloud to see in those southbound flows. For more on isentropic science see 'Isentropic Surfaces - Science and Art Merges'.

You might imagine yourself as a kid with your arms extended along the slope of the isentropic surfaces. With your right hand down and your left hand up, the slope of your arms would be the same as the slope of the isentropic surfaces if you are looking east. You can even make noises and imagine you are an airplane... 

2534 "Sunrise on the Killbear Jumping Rocks"

There is a lot of cloud in this painting. Ice crystal cirrus clouds are overhead with lower level altostratus on the right side horizon. This cloud was painted in more detail in #2536 "Killbear Cirrus Sunrise" . Applying what we just learned, the rising southerly flow full of cloud must be originating from the south. Pointing my right hand down and to the south means that you must be looking eastward in the painting. Those cloudy air parcels are rising on the isentropic surfaces as though they were riding up your extended arms. I saw the sun so it must be dawn and that yellow ball of light was rising. 

But there is much more to CSI in this painting … for another day.

Keep you paddle in the water and warmest regards... 

Phil the Forecaster Chadwick

Sunrise or Sunset

#2516 "Singleton Dry Cold Front Sunset"

Sometimes it is a challenge to determine which rays of sunlight inspired a work of art. This explains why I typically include the answer in the name of the painting (like above). But there are ways to decipher the puzzle and this is the first in the series of Creative Scene Investigative methods that I employ. I will keep these brief. 

Colour is king. Humans can see maybe up to a million colours. Our brain takes that information and make sense out of it - perception. We perceive things automatically which is why many people thought my sunrise painting below was actually a sunset. They saw "red" and instinctively knew what that meant. 

#2534 "Sunrise on the Killbear Jumping Rocks"

Typically sunset are more colourful than sunrises. Dust and particles raised by stronger daytime winds and convective thermals created when the sun heats the earth, are efficient at scattering the shorter wavelengths of light out of the direct white beam originating from the sun. Removing the shorter blue, and green light leaves more orange and red to be viewed. Therefore it is automatic to think that red skies must be sunset skies. 

Vertically Integrated Smoke Plume July 20th, 2021

The skies have been especially colourful this past year. Forest fires over the Rockies and throughout the Boreal forest are now much more common - a result of climate change. This smoke has spread throughout eastern North America and is the reason my sunrise sky was remarkable for its hues of red and orange. Colourful skies are the new normal. 

Red skies have been painted before. Tom Thomson's skyscapes starting in the fall of 1915 were especially colourful. His friends in the Group of Seven thought he was taking too much artistic license and exaggerating those hues. Tom painted what he saw and in this case, he was seeing the volcanic dust and the aerosols from the eruption of Lassen Peak in California. Norwegian artist Edvard Munch painted what became known as "The Scream" in 1893 possibly remembering the colour of the skies after Krakatoa exploded a decade earlier in 1883-84.  Some refer to this as the scream of nature and I would not disagree. Nature is screaming now as well. 

There are other clues painted in those oils of Killbear that reveal the eastward looking view. Those will be revealed in time... 

Keep you paddle in the water and warmest regards... 

Phil the Forecaster Chadwick

Creative Scene Investigation

 My Professor recently asked me a question: "I notice that the title is "sunrise". Interesting. A meteorological question for you. Can an ordinary person or even a professional meteorologist discern sunset from sunrise in art? And if so, how? To me, this is a 'perfect' sunset painting."

#2534 "Sunrise on the Killbear Jumping Rocks"

I am honoured to provide an answer for my Professor and friend. I have thought about these things an inordinate amount of time. Perhaps I have always had my head in the clouds and for me, that has been a good thing. Nature and the real atmosphere have been valuable classrooms for me - as much as the fine  universities I have attended. When en plein air and surrounded by the everyday world, I simply observe and questions appear. Possible explanations drift through my consciousness and play like movies in my mind. 

I have compiled the answers to those questions into a body of work that I call Creative Scene Investigation. CSI is not to be confused with the TV show of a similar title. Nobody dies. The laws of science are something that you can put your faith in. They are not subject to the whims of humans. We are not moving at the speed of light so there is no need to invoke Einstein's Special or General Relativity Theories. 

I developed and validated these CSI concepts using my own paintings - fully aware of the time, location and direction of view of  each work. I have kept detailed records from the very start of my artistic journey in 1967. It is quite a library of art that now comprises 2559 paintings. My Fine Art America site includes about 2000 of those works. 

The Group of Seven
with Barker Fairley (fourth from left),
Arts and Letters Club, Toronto, 1920.

I then validated these CSI principles on an independent sample. Tom Thomson and the Group of Seven really loved to paint en plein air and they greatly inspired my artistic ramblings as well. Tom and the Group faithfully observed, recorded and interpreted the honesty of nature that inspired them.  They included enough clues in their work that I was able to apply CSI and appreciate the subjects that caught their eye. It was as if I was standing with them and appreciating the same views of nature while they painted. 

This effort morphed into a series of presentations that I started to give in the mid 1980's. The talks went by various names and have been presented across Canada whenever and wherever there was a group who was passionate about these artists, understanding the beauty of nature and wondering "why" they painted. Googling "Tom Thomson Was a Weatherman" will turn up the details of a few of those events. I wrote a book with that title but the publishers were not interested. 

CSI involves the close examination of the art and applying the appropriate bits of science to whatever might be included in the painting. The science might come from climatology, meteorology, atmospheric optics, astronomy, biology, geology - the list goes on and continues to grow. This is not to say that it is impossible to make a mistake – it is just that it helps to really investigate and think about what the artist was contemplating. The more facts that you have that point in a particular direction, the more confident you can be about your conclusion. You could still be wrong but you will learn from that mistake as well. 

CSI tries to answer the Five questions of any good story. 

• Who is it about?
• What happened?
• When did it take place?
• Where did it take place?
• Why did it happen?

The first question pretty obvious if we know anything about the artist. CSI really dives deep into answering what, when and where which often reduces to the time of day OR which way is north? Having answered the first four questions allows us to get into the mind of the artist to better understand "why". 

The complete body of work that comprises Creative Scene Investigation is much too long for a single Blog entry but I have decided to mix in more CSI details here. CSI entries will be mixed in with my ongoing Blogs on meteorology and material that did not get published before I officially retired on Groundhog Day in 2011. One never fully retires...

Here are a few of the CSI applications that I will explain in more detail. 

The clouds and weather are my favourite place to start CSI. What is the cloud type and height? Is the atmosphere stable or unstable? Are the clouds frontlit or backlit?  What is the wind direction at cloud height from the cloud shape? What is the relative wind speed? Where is the sun? What is the time? What is the season? What is the angle of view? There are many questions and each painting might ask a few more that are not included in the summary. 

Finally, I apply a bit of knowledge from how artists typically work. If the art is a plein air work, artists tend to paint the colourful side of a subject with the sun on their back. It simply feels good. Painting looking into the sun is hard on your eyes and one is viewing the shadowed side of the subject while developing cataracts. Typically not good. The angle of a plein air artist’s view can be very much like a sundial. 

#2522 "Singleton Sheared ???? Anvil"

This may not be rocket science, brain surgery or even rocket surgery but it is science… and it is fun... Much more to come. 

Keep you paddle in the water and warmest regards... 

Phil the Forecaster Chadwick