Why The Gigantic Rain Clouds Appears Grey?
Why are Rain Clouds Grey?
The reason why overcast days are so dismal
To understand why clouds can appear grey, you first need to know why they also appear white. It’s all to do with the reflection of light. Clouds are created when air and water vapour near the ground warms up and rises. As it gets uplifted, the water vapour condenses, and the droplets join together to make clouds. The more condensation there is, the more droplets there are and the bigger the clouds become. When light from the Sun passes through these large aggregations of water vapour, the droplets scatter the light in all directions. The droplets are tiny and spread out enough to scatter the entire spectrum of light, which means that they will appear white.
As more water droplets accumulate and the clouds get larger,
less light is able to penetrate through the cloud. What we see from the
ground seems grey because less light is being scattered to our eyes.
As the water droplets inside the cloud get larger, this effect is
enhanced, which is why clouds appear much darker just before it rains.
Super-cold brine from the sea ice above kick-starts
the production of this deathly marine icicle
What are Brinicles?
These so-called ‘ice fingers of death’ are a chilling phenomena
Found in both the Arctic and Antarctic seas, brinicles are formed when conditions are both calm and very cold. Usually occurring as winter sets in, these stalactite-like icy pillars grow downwards into the water from the sea ice.
As new sea ice forms, water freezes, and salt and other ions are forced out, creating
salty brine. This fluid leaks through cracks and pores in the ice until it finds its way out.
The brine is much denser and colder than the seawater underneath the sea ice, which is usually around -1.9 degrees Celsius. As it hits the seawater, the brine begins to settle and the water around it freezes instantly. A brittle tube – or brinicle – is formed, and through this more brine trickles and freezes. Providing that sea conditions are calm, and no wildlife cruises past to knock it down, this process can continue until the brinicle reaches the seabed. Then it can spread out in a deadly frozen web, killing everything in its path. Scientists have reported seeing ‘black pools of death’ near brinicle formation, as the descending frozen brine has encased every nearby organism in ice.
Light and clouds
How sunlight changes how we see the weather
1) Clouds build
2) Grey clouds
Less light penetrates thick clouds, making them appear grey from underneath.
3) Rainfall
The grey effect intensifies as the clouds grow larger, just before it rains.
The small droplets that first form a cloud reflect the entire spectrum of light, making it look white.
5) Sunlight
Light from the Sun shines into the cloud, which is formed as water vapour cool and condenses.
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