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Science/nature/environment

Dark mornings (and afternoons)

(10 Posts)
Elegran Sat 14-Dec-13 11:32:24

I've not seen in the press this year any suggestions that we should keep the clocks set an hour early all year. In previous years there have been some (south-eastern) opinions expressed that Scottish and northern opposition to the idea should be ignored as "a few dairy farmers in Shetland might have to get up in the dark for milking"

A spot of Googling yesterday (as though I don't have enough to do at the moment) found some figures for sunrise, sunset and day length for December 20th. In brief, the further north you go the shorter the day is, and the further west the later the daylight begins. Penzance is the most southerly town or city on the mainland, Thurso the most northerly. Lowestoft is the most easterly, Kilchoan the most westerly.

(In order of sunrise time. Format is - place, co-ordinates, sunrise, sunset, day length)

Lowestoft, 52°29' N 01° 46 E, 08.00, 15.44, 7hr 44min.
London, 51°30′ N 00°07′ W, 08.03, 15.43, 7hr 49min
Brighton/Hove, 50°49' N 00°07' W, 08.00 15:56, 7hr 56min
Birmingham, 52°29' N 01°52' W, 08.16 16.55, 7hr 39min
Penzance, 50°07' N 05°33' W, 08.18, 16.21, 8hr 03min
York, 53°57' N 01°05' W, 08.21 14,43, 7hr 23min
Liverpool, 53°25' N 03°00' W, 08.25 15.24, 7hr 29min
Newcastle, 54°58' N 01°36' W, 08.29 15.39, 7hr 10min
Edinburgh, 55°57' N 03°11' W, 08.41, 15.40, 6hr 59min
Glasgow, 55°50' N 04°15' W, 08.45 15.44, 6hr 58min
Aberdeen, 57°09' N 02°09' W, 08.46 15.26, 6hr 40min
Inverness, 57°28′ N 04°14′ W, 08.57 15.32, 6hr 35min
Kilchoan, 56°41' N 06°07' W, 08.50, 15.44, 6hr 54min
Thurso, 58°35' N 03°31' W, 09.03, 15.21, 6hr 18min

These places are on the mainland. The Northern and Western Isles are:-

Stornaway Isle of Lewis, 58°12′N 06°23′W, 09.11, 15.35, 06hr 24min
Lerwick Shetland, 60°9' N 01°09' W, 09.08, 14.57, 05hr 49min

(Times are from here and co-ordinates from various places, so may vary in accuracy.)

Add into this the lower potential radiation as you travel north, due to the curvature of the earth. The sun's rays strike at a lower angle, and have to penetrate further through the atmosphere. It is estimated here that in winter while Penzance receives about 8 megajoules of solar radiation per sq metre per day, Newcastle receives about 5 MJ and Shetland about 2MJ.

Plus, cloud cover is affected by geographical position, so the Scottish Highlands receive about half the sunshine that Essex is blessed with.

So if you suffer from SAD, the further south you are, the happier you will be – and the lighter it will be when you have to get out of bed in the morning.

Granny23 Sat 14-Dec-13 18:47:40

Fascinating stuff Elegran. Well it is to me anyway but then I HAVE been classified today as an Analytical Thinker blush.

The problem with using standardised GMT throughout Britain has more to do with longitude than latitude. There is nothing we can do that will alter the shortness of the days in the north (except to take full advantage of the LONGER days in the summertime). However if the chosen meridian had been centred on a line through, say, Edinburgh rather than Greenwich then most parts of the country would be more than 10 minutes different from solar time. Our weather maps tend to show the British Isles as being quite 'upright' when in reality they slope to the west and because Greenwich is to the east of the land mass, everywhere else has their 'real' time behind clock time, by up to 25 mins in the most westerly parts. Which is why we see in the chart, sunset in Penzance occurring 25mins behind Brighton although they are on much the same Latitude.

Elegran Sat 14-Dec-13 18:58:13

Yes, most of the country is to the West of London, if you look at the map at the right angle.

What bugs me a little is that noon at the Greenwich meridien is the marker from which the co-ordinates, datelines and time zones of the whole world are fixed, yet every year we get this chorus that we should abandon our own time zone so as to be in line with an area where noon is at least an hour earlier.

Elegran Sat 14-Dec-13 19:02:12

The lower light levels and shorter winter days at more northern latitudes go a long way to explain the northern love of firewater, from the Water of Life to Vodka, and also the Scandinavian winter suicide rate and the stereotypical dour Scot.

janerowena Sat 14-Dec-13 20:40:34

I made a graph years ago to show all that, for gardening purposes. I still live my life to aummer time unless I am socialising, as I no longer have school runs this year to worry about and can eat when I please. I feel far happier for it. I do suffer from SAD and really need that extra hour of daylight at the end of the day, not first thing in the morning when it is too cold for me to get out in it.

newist Sat 14-Dec-13 21:35:45

Thanks for the information Elegran I do not get up till its light in the winter, by the time a few jobs have been done its about 3.15 then it starts to get dark again, My favourite day is the 21st of December, Then I tell myself its much lighter on the 22nd. There is not a lot of daylight in the Hebrides in the winter. A Vodka or two does help

Elegran Sat 14-Dec-13 22:08:32

After the winter solstice it all starts getting brighter. You can understand why people have been holding ceremonies for thousands of years to make sure that the sun does come back. It must have been pretty scary when they did not know what was causing it to rise later and set earlier each day.

I wonder whether the webcam at Maes Howe will be working this year?

Elegran Sun 15-Dec-13 15:11:33

I had to put on the lights at three pm this afternoon. Really dreary.

newist Sun 15-Dec-13 15:56:15

The very nearly full moon, is shining brightly and its only 10 to 4,

FlicketyB Sun 15-Dec-13 16:17:35

I love the short days of winter as much as the long days of summer. I love shutting the curtains as the evening draws in, even if it is not long after 3.00pm. It is usually cold outsight and the warmth and lights on in the house make me feel so secure, like hibernating hedgehog.

While I understand the quite specific problems of those suffering from SAD, I think the rest of us need to learn to enjoy each season for itself whether, long or short days, rain, sunlight or snow. None of these different day lengths or weather conditions last long. Each has its own particular beauty. Enjoy it.