The Hub Huddle: Clouds in the Big Sky

News, info, thoughts and links from Lordship Hub, Lordship Rec and Central Tottenham

20th June 2020

Lordship Hub Cafe

Now open every day from 11-4pm as a takeaway only. Pay us a visit when you are in the Rec. Sadly, we are not able to open the toilets to the public yet, but it is a start!

CLOUDS IN THE BIG SKY

One of the many fantastic things about Lordship Rec is the “big sky”. It is a great place to see the sky and the amazing patterns and colours of clouds, sunsets, rainbows and the mists of winter and autumn.

Have you ever looked up at the changing spectacle and wondered what it could tell you about the weather?

TOTTENHAM’S ONLY BLUE PLAQUE

Luke Howard (1772 – 1864) is known as the Namer of Clouds and the Father of meteorology for his detailed observations over many years of the weather and cloud formations in Tottenham. At a house that he lived in, at 7 Bruce Grove, he is commemorated with the only English Heritage Blue Plaque in Tottenham.

From an early age, his observing eye began to notice the appearances of the sky and forms of clouds. He was fascinated by the violent volcanic eruptions at Laki in Iceland which resulted in sunsets blazing through clouds, and overcast skies which led to the unusually cold winters in Britain from 1783-1785. He would have been aware of the summer hailstorm in 1788 which destroyed crops and resulted in serious food shortages and a rise in the price of bread the following Spring.

Luke Howard published a short essay called, “On the Modification of Clouds” in 1803, in which he proposed his classification and nomenclature of the clouds, a system that is still in use today.

From their home on Tottenham Green Luke Howard and his wife, Mariabella made daily recordings of the weather. Using the data obtained from the instruments in the garden in 1818 – 1820 he published “The Climate of London” in two volumes updating it with a revised edition in 1833. His daily barometric pressure readings are among the earliest consistent scientific observations recorded.
for more information see: www.tottenhamclouds.org.uk/

CLOUD TYPES

The diagram below names the variety of clouds in different heights in the sky.

A cloud is a visible mass of minute droplets of water, ice crystals, or both, suspended in the air. Though they vary in shape and size, all clouds are basically formed in the same way through the warm air and water vapour rising from the earth and sea which cools and turns into tiny droplets of water or ice that form on tiny particles in the atmosphere like dust. The higher the temperature or air pressure the more water vapour the air can hold. If the temperature or the air pressure falls then the vapour turns to liquid or ice and clouds form. If the water droplets in the clouds mass together and get too heavy then they fall as rain. The large droplets of water make the clouds look grey as they block out the sun.

HIGH LEVEL CLOUDS
Cirrus is one of the most common types of clouds that can be seen at any time of the year. They are thin and wispy and always made of ice crystals. Besides the filament appearance, cirrus clouds are often coloured in bright yellow or red before sunrise and after sunset. Cirrus clouds light up long before other clouds and fade out much later.

Cirrocumulus usually form at about 5 km above the surface with small white fluff patterns that spread out for miles across the sky. They’re sometimes called ‘mackerel skies’ because they can sometimes have a grayish color and look a bit like fish scales. Cirrocumulus can look similar altocumulus clouds but does not have shading like altocumulus where some parts can be darker than others. Cirrocumulus never generates rainfall though can mean cold weather and they don’t mix up with other kind of clouds.

Cirrostratus have a sheet-like appearance across the sky. They’re quite translucent and vary in colour from light grey to white and the bands can vary widely in thickness. Cirrostratus clouds can turn into altostratus clouds if they descend to a lower altitude. They almost always move in a westerly direction and the sight of them usually means rainfall is imminent in the next 24 hours.

MID LEVEL CLOUDS
Altocumulus clouds form at a lower altitude so they’re largely made of water droplets though they may retain ice crystals when forming higher up.  They usually appear between lower stratus clouds and higher cirrus clouds, and normally precede altostratus if a warm frontal system is advancing. When altocumulus appears with another cloud type at the same time, a storm could follow. The amount of rainfall from altocumulus is projected from light to moderate.

Altostratus can spread over thousands of square miles and are linked to light rain or snow. While they don’t produce heavy rain they can morph into nimbostratus clouds which are packed with moisture and can deliver a heavy downpour. They are uniformly grey and featureless.

Nimbostratus clouds are the heavy rain bearers, forming thick and dark layers of clouds that can completely block out the sun. Though they belong to the middle-level category, they may sometimes descend to lower altitudes.

LOW LEVEL CLOUDS
Stratus clouds are composed of thin layers of clouds covering a large area of the sky. You can easily distinguish a stratus cloud by the long horizontal layers of cloud which have a fog-like appearance. These can produce light showers or even light snow if the temperatures fall below freezing. However, if enough moisture is retained at the ground level, the cloud can transform into a nimbostratus. Stratus clouds are most common in coastal and mountainous regions.

Cumulus is the most recognisable of all the types of clouds. These fluffy cotton wool clouds form a large mass with a well-defined rounded edge. Cumulus clouds are a sign of fair weather, though they may mean a light shower sometimes.

Cumulonimbus is fluffy and white like cumulus but much larger. It’s a vertical developing type of cloud whose base grows from eight kilometers, hence it’s commonly called a tower cloud. For the same reason, cumulonimbus is both a low-level and high-level type of cloud. At the low-altitude base, the cloud is mostly made of water droplets but the high-altitude summit is dominated by ice crystals. It produces intermittent rain but when it does, it can be heavy. When you see a cumulonimbus, you know there’s a thunderstorm waiting to happen somewhere.

Stratocumulus clouds look like a thick white blanket resembling cumulus clouds but much bigger. The base is well defined and flat but the upper part of the cloud is ragged.  Depending on the thickness of the cloud, a stratocumulus will have light to dark grey hues and look ominous but rarely produce rain.

Clouds may also form in contact with the ground surface, too. Such a cloud is known as fog, ice fog, or mist.

THE CLOUD APPRECIATION SOCIETY

If you are fascinated by clouds there is a society devoted to them, the Cloud Appreciation Society. They have a manifesto and here is some of what they stand for:

  • We think that they are Nature’s poetry, and the most egalitarian of her displays, since everyone can have a fantastic view of them.
  • We seek to remind people that clouds are expressions of the atmosphere’s moods, and can be read like those of a person’s countenance.
  • We believe that clouds are for dreamers and their contemplation benefits the soul. Indeed, all who consider the shapes they see in them will save money on psychoanalysis bills.

And so we say to all who’ll listen:
Look up, marvel at the ephemeral beauty, and always remember to live life with your head in the clouds!
See: cloudappreciationsociety.org/

BEAUTIFUL SUNSETS

One of the many stunning sunsets looking west from the Hub in Lordship Rec taken by Wendy Charlton

Why do clouds turn red during sunset
If you look at light through a prism you will see lots of colours. Each colour is a light wave with a different wavelength. Within the small range of wavelengths (or colours) that we are able to see, the shorter waves are blue and the longer ones are red. Colours such as green, yellow, and orange lie between the blue and red ends of the visible spectrum.

All these light waves of different wavelengths travel through empty space from the Sun. When they reach Earth’s atmosphere, the light waves interact with particles in the air like dust, water droplets and ice crystals and also interact with the tiny gas molecules that make up the air. The light waves bounce off these particles and scatter in lots of different directions. How light waves get scattered depends on the size of the particle compared with the wavelength of the light. Particles that are small compared with the light wavelength scatter blue light so the tiny gas molecules that make up our Earth’s atmosphere scatter the blue portion of sunlight in all directions, creating an effect that we see as a blue sky.

Red light waves are scattered more slowly by atmospheric gas molecules. At sunset when the sun is lower in the sky, the sunlight travels a longer diagonal path through the atmosphere to reach our eyes, the blue light has been mostly removed, leaving mostly red and yellow light. The result is that the sunlight takes on an orange or red cast, which we can see reflected from clouds or other objects as a red sky. Small particles of dust and pollution in the air can enhance these colours, but the primary cause of a blue sky or orange/red sunsets or sunrises is the scattering by the gas molecules in our atmosphere.

Cloud droplets are much larger than visible light waves, so they scatter light without much colour variation. This is why light scattered by clouds takes on the same colour as the incoming light. For example, clouds will appear white or grey at midday and orange or red at sunrise or sunset and are a canvas on which light’s colours are painted. This is why sunsets or sunrises are so much prettier in cloudy skies.

RAINBOWS
When it rains, and if the sun is at the right angle in the sky, you can often see a rainbow from Lordship Hub arching over Broadwater Farm Estate.

Rainbow over Broadwater Farm Esrate from the Roundway taken by Wendy Charlton

A rainbow is an arc of colour produced when the Sun shines through falling rain. For a rainbow to be seen, the Sun must be above the horizon and not be obscured by clouds, mountains, or other obstacles but has to be quite low in the sky. The air opposite the Sun, as seen from your position, must be filled with a large number of water droplets. Rainbows always appear in the sky opposite to the Sun. So, if you have your back to the Sun, the rainbow will arch across the sky in front of you.

How do Rainbows form?
Sunlight may appear white to us, but in fact it consists of all visible colours. As soon as a ray of sunlight enters a raindrop, it is split up into its components, causing its colours to fan out and become visible as a spectrum of colours.

Reflection: Water droplets act like little mirrors. When a ray of sunlight strikes one of these water spheres, most of the light bounces off its rear wall and is reflected back. During a rain shower, the air is full of water droplets acting together as a reflective surface made of millions of tiny mirrors casting the sunlight back at you.

Dispersion: Pure sunlight may appear white to us, but it consists of all visible colours. As soon as a ray of sunlight enters a droplet of rain, it is split up into its components, causing its colours to fan out and become visible as a spectrum of colours. This happens both when the ray enters the raindrop and when it leaves it again.

Refraction: As the ray of sunlight enters and leaves the raindrops, it is refracted (changes direction slightly). Each raindrop reflects all of the colours of the sunlight back but it reflects and refracts each colour at a slightly different angle. You only see the red light from droplets that are higher in the sky, and only the orange light from the droplets that are a little lower which is how the top two stripes of the rainbow are formed and the remaining coloured stripes of the rainbow are created in a similar way according to their angle of refraction.

Why Is a Rainbow Curved?
Technically, a rainbow is the upper half of a circle of light, which centres on a point directly opposite the Sun, as seen from your perspective. The lower half of the circle, however, is usually not visible since the water droplets hit the ground before it can form. It is however possible to see a circular rainbow from high up in an aeroplane.

GREAT “CLOUD” PAINTERS LINKED TO TOTTENHAM

John Mallord William TURNER depicted cloudscapes in all seasons and developed ways to paint luminous clouds and skies. One of the great patrons of Turner was BG Windus (1790-1867) who opened his collection of art to viewing by the public one day a week at his villa opposite Luke Howard’s house on Tottenham Green. During the lifetime of JMW Turner, the Windus collection was recognised as the best place in London to see his work.

John CONSTABLE who painted landscapes with fantastic cloudy skies informed by Luke Howard, spent over two weeks in 1806 at Markfield House, Tottenham. He made many Cloud studies.

THE CLOUD GARDEN

The land behind numbers 7 to 9 Bruce Grove, N17 has for a long time been designated as ‘Significant Local Open Land’. ​It does not have planning permission for development. The area to the south of Bruce Grove is an Area of Deficiency of access to nature, according to Haringey’s own planning documents. Providing a site rich in nature would help address that deficiency.
www.tottenhamclouds.org.uk/cloud-garden.html

There are lots of mature trees on the site and it is home to many birds, flowers and pollinators.  There is lots of scrub. Birds noted by members of Tottenham and Wood Green Friends of the Earth and Bruce Grove Residents Network include the Great Spotted Woodpecker, Blackcaps, Robins, Dunnocks, Blackbirds, Blue and Great Tits. A vision for the site could include planting more native tree and shrub species, perhaps some fruit trees, removing the Knotweed, creating a wildflower area, installing nest boxes and even a wildlife pond.

The previous owner of the house at No 7 did nothing with the property and apparently, due to non repayment of a loan. the bank repossessed it and put the land up for auction. The council were asked to intervene and make a bid themselves and much to everyone’s delight they were prepared to do this. However, a developer bought the land off-auction, the day before it would have taken place and for a much higher price. People have not been able to find out who the new owner is and are anxious that there could be plans to carry out an intense development on the site to recoup their outlay. There is a continuing to petition asking that the Council do a Compulsory Purchase, see the link below:
actionnetwork.org/petitions/save-the-cloud-garden-green-open-space-for-bruce-grove

And now, something to raise your spirits, after a long period of hard times, one of the best feel good, weather related songs of all time!