Wednesday 14 November 2012

Rainbows... Sunsets and Clouds...


One thing I really miss while I am staying in Christchurch
is the sunrises and sunsets that I love so much.
I am too much enclosed by close-by houses... I hate being shut inside...
Perhaps that's one of the reasons I choose to live in a house-bus
and my favourite place to be is at the beach with wide open spaces.


But the other day while staying at my Dad's house...
I caught this rainbow. It wasn't raining where I was
but obviously was somewhere.
It was an amazing rainbow stretching across the whole sky...
With a distinct primary bow...
Which is formed by light rays undergoing a single reflection in  raindrops which brighten the sky inside it...
And a secondary bow...
 Rays reflected twice are deviated to form the second bow and brighten the sky outside it.
Raindrops along lines of sight between the two bows
cannot send light to your eye and so the sky is darker there...
Known as the 'Alexander Dark Band'...
First described by Alexander Aphiodisias in 200AD
The colours were delicate but very distinct as you can see.

It had been Nor'west for a short while...
Creating one of the rareties of the skies...
Distinctive Altocumulus clouds forming the
Nor'west or Canterbury Arch.
It's peculiar to the South Island east coast... Warm moist air from over the
Tasman Sea is pushed up by the Southern Alps causing it to cool rapidly
and much of the moisture is dumped on the West Coast.
As the air passes over the Alps the water vapour remaining becomes
visible in a band of cloud over the mountains at the top of each air wave.
To the viewer on the east side this appears as an arch of cloud.
It can be seen from Amberley in the north to Central Otago in the south
but is most prominent over the Canterbury Plains.

The atmosphere is quite oppressive... Heavy dark clouds...
The Nor'west can have a deep psychological effect on many people...
It's linked to increases in suicide and domestic violence...
Caused by a significant build up of positive ions...
This strong electric field
upsets the melatonin/seratonic balance
Another phenomenon of nature - read about it here.

Spectacular...

And what I could see of the sunset through the trees.
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