The Green Flash
This is perhaps the most elusive of all atmospheric optics, sort of the Loch Ness Monster of weather. It’s so rare, in fact, that I’ve never met anyone who has ever seen it himself, and many meteorologists and active sky-watchers live a lifetime without seeing one. I never fail to look for the green flash when I can see the horizon at sunset.
Just as the sun’s disk drops below the horizon, the blue light of the sky is mostly scattered, permitting green light to shine through. However, we usually can’t see the green light—the sun’s reddish light is so bright it “cancels out” the green. But if conditions are such that the green light is magnified—in very hot weather, for example— the green light will flash out for a second or so.
Sky-watchers who are pilots are particularly lucky. We have the best seat in the house for seeing the spectacular light show the atmosphere puts on every day.
The aurora borealis of the North Pole (and its South Pole counterpart, the aurora australis) is an atmospheric light show that is born in space. The sun casts off tiny particles called the solar wind, some of which are swept up by the earth’s magnetic field. When they all crowd together at the poles, they are heated up and emit bright ribbons of fight that typically can be seen only by people close to the poles. SomebYnes, though, they wander to the temperate latitudes (where they generate thousands of panicky 911 calls).
The newfound appreciation for weather is one of the greatest side benefits of learning to fly or becoming a close follower of aviation. Pilots look at the sky not as something far away but as a place they’ve visited and will return to soon. They don’t see clouds as faraway places, but, as awe-inspiring works of nature that are almost as stunning from the inside as from the outside. Even raging storms take on a new aspect of strange beauty. The more we learn about the sky above us, the more enjoyable flying becomes.
The Least You Need to Know
^ Atmospheric optics are not only awe-inspiring, they are accurate indicators of how the sky is behaving.
>■ Though the simple result of the sun striking the spinning earth, weather’s complexity is unending.
>* With a few simple categories in mind, anyone can become an expert cloud – spotter.
V Turbulence, either from heat or wind, holds dangerous potential that can cause damage and injuries.
Thunderstorms hold dangerous secrets that can endanger a flight.
Weather experts can help pilots interpret the weather, but many flyers enjoy doing their own forecasting.