FACT OR FICTION: Haze/smoke makes vivid sunsets!
Hi everyone! Jeff here.
With all the wildfires burning around drought-stricken California this summer, there's a lot to be said about awful air quality. But, for photographers like us, it's much more than that.
Fact or fiction? Smoke makes the sunsets more vivid because of the haze in the air, which makes the sunset redder. (It often appears in news articles.)
Our take... this is FICTION. It's one of the big myths in sunset science. Those of you who have photographed the last few sunrises can easily attest to that.
The myth comes from a difference in perception between photographers and 'non-photographers': most people think a sun that looks like an orange circle setting through a layer of haze looks cool. And it does. But, as a photographer, it means weak light in your foreground (if any), and that the burn is likely to fail to ignite.
So, why does haze kill a sunset/sunrise?
Remember, from our article "What makes a sunset burn?":
* When you see a colorful sunset, what you are looking at is sunlight hitting the clouds from below.
* The two basic elements of having a colorful sunset are:
(1) having clouds where you are, and
(2) having an unobstructed path for the sun to light the clouds from the bottom.
Does haze/smoke cause a change in either (1) or (2)? We'll let you think about it for a minute.
OK, spoiler alert! Here's the answer.
(1) No change. Having haze in the area, whether from smoke or something else, doesn't do anything to change the fact that you either have clouds over your head, or you don't. The clouds don't go anywhere.
(2) AHA! Something changed here. When light rays pass through haze, they weaken. (This is due to increased scattering.) By the time the light reaches the bottoms of the clouds (and, of course, your eye), it is much less intense.
What does this mean for us? Well, if the light reaching the bottoms of the clouds is less intense, the light and colors we see on the clouds will be less intense. If the haze is dense or thick, we may see no light/color at all.
Some of you may have noticed that under certain conditions, hazy sunsets can look promising just before sunset, but then the light mysteriously fizzles at sunset, and little to no color is produced. If you're watching the sunset, you will often notice that the sun looks like an 'orange circle' instead of a bright, blinding sunstar. You could probably even look at it without squinting (though if you try it and go blind, don't sue us).
Let's have a look into why that happens.
Have a look at the diagrams above. In (2), we consider a regular sunset, with high clouds over your head and an open horizon for the light to come through. As we discussed in "What makes a sunset burn?", that sky will burn (you're looking at an 80/0, possibly even 100/0 with those high clouds).
In (1), we consider a smoke or haze-influenced sunset. Those of you who know our "What makes a sunset burn?" article may quickly recognize this as being very similar to the diagram with fog, except the smoke is often higher and thicker. We see that in this situation, some light makes it through right after sunset (when the sun is just below the horizon), but then it disappears into the smoke plume and the light dies.
A few questions for you to think about:
(a) What would happen if those were low or mid-level clouds, and not high clouds, in the same position? Would any light make it through?
(b) What if the smoke/haze were over your head instead? How about if it were behind you?
Those of you who saw the sunrises today and yesterday will have a big hint. There was a big smoke plume on the horizon on both mornings (just like in the diagram (1)). Today, there were mid-level clouds and there was no burn. Yesterday, there were wispy high clouds, and they showed no early/blue hour pre-glow, and finally went pink about 10 minutes before sunrise, much later than normal. On both days, the cloud setup was excellent, with no clouds past the horizon to block the light.
If there is haze out to sea, it'll be a similar setup to diagram (1), except instead of smoke, we just have haze. It blocks the light similar to thin clouds. That's why you can see the sun through haze/smoke, but it's very weak.
Well, that's smoke and haze in a nutshell for you.
One of our biggest areas of current research is a patent-pending method to make Escaype one of the world's first weather models to consider the true effects of smoke and haze on an observer, like you, the photographer. We're on it. But it won't happen overnight.
Until then, here's what you need to know:
* There are lots of wildfires burning in California and the West Coast, and their smoke will continue to affect us until the wet season comes. It'll probably be at least a few weeks, perhaps a month. This effect will be much less frequent in the winter months.
* The Escaype model raw data do not consider smoke and haze, as weather models do not forecast these. When we are able to properly analyze it, we will be among the first. Exciting news! Until then, however, we must manually update in the groups, and if we suspect that haze/smoke will be an issue (like for today's sunrise and sunset, and likely for tomorrow's sunrise), we will continue to let you know to ignore those 0% skunk scores in the app, because the skies will fail to burn with vivid, dramatic colors.
EDIT: SMOKE MAP IS AVAILABLE HERE: http://www.ospo.noaa.gov/data/land/fire/currenthms.jpg