Tuesday, September 29, 2015

Supermoon Makes Waves

Littlehampton - Monday 28th September 2015
See my Water and Art blog for the series of sketches I did in the area around the East Pier.

A combo of astronomical events meant that the suite of spring tides at the end of September could  be particularly high: 

Spring tide – full moon with the Sun, Earth and Moon in line
Supermoon – i.e. full moon at its closest point to Earth in its elliptical orbit (perigee)
Full moon a few days after the autumnal equinox.

The Sunday night was clear, the full moon indeed very bright. This so-called supermoon, a bit bigger and brighter than an average full moon, was the first full moon after the autumnal equinox , and a Blood Moon, with a total lunar eclipse coinciding with the supermoon (perigee). Full moon  02:52 GMT 28/09/15.
The timings of supermoons, lunar eclipses and predicted tide heights follow a roughly nineteen year (18.6y) cycle governed by the elliptical orbit of the Moon around the Earth and its position in the plane of the ecliptic, the Earth's orbit around the Sun. This goes some way to explaining the run of high spring tides during the past two years which have made for some good Severn Bores and high tidal ranges around the UK coast. However, the weather makes a big difference. This two year period has included some storms and tidal surges leading to widespread coastal flooding. Most notably: December 5th 2013 (North Sea), early January and February 2014 (both mainly affecting western coasts facing towards the Atlantic. All these episodes involved deep low pressure systems with less air pressing down on the sea making for a higher tide and strong winds. This time, the EA had a few precautionary flood alerts out for low lying and exposed areas of coast around England and Wales, along with the tidal  Severn, Wye and Thames. The potential for tidal trouble, however, was very much moderated by high pressure over the UK and Scandinavia, a steady 1035 millibars on Sunday and Monday where we were in south Hampshire. Higher atmospheric pressure pressing down on the sea would reduce the tide height from that predicted, 20cm for 1035 millibars (Port of Southampton tide tables). Anticyclones, too make for light winds or still conditions. 

Given the calm weather / high pressure, I'd expected a calm day like the one I'd had along our local coast the day before. I came then,  with a 40cm x 30cm folder-cum-board of loose watercolour papers prepared over the weekend with loose collage, along with  watercolour, some acrylic ink, pens / pencils. Also a new A5 lightweight paperback sketchbook for quick drawings.   When I was here last month (17th August) I mentioned bringing right materials for the conditions, especially when I go my more regular painting / sketching spots with a view to tackling a particularly subject, invariably, too assuming particular weather. 
As it was an equinoctial spring tide,  I expected it to be rough at the Arun mouth when I arrived at Littlehampton East Beach around 11:00am, about an hour before high tide (12:04h BST), with the flood tide and currents running at full pelt. However, I hadn't expected the large breaking waves and swells, all amplified in the narrow harbour entrance making it look even rougher than usual. A red Fire and rescue motorboat, thankfully as far as I knew, not needed. No yachts attempting to sail in or out of the harbour. I've often seen yachtsmen rising to the challenge of the fast flowing choppy water between the piers on the rising tide. 
I’d say the waves in narrow harbour entrance were well over 1m crest-trough. Some were nearer 2m and splashing over pier wall, splashing gawpers on the East Pier, of which there were quite a few. 

 Apart from having to watch my folder of papers in case it blew away, I wished I’d brought the proper camera. Though the camera on my new phone is relatively good as mobile cameras go, it was designed for much gentler conditions than those before now. The case got in the way, I couldn’t see the screen in polarising sunglasses and I was nervous about it getting splashed and dropping it over the side of the pier.  With the sun shining in a virtually clear sky and south facing coast during the middle of the day, the light was dazzling. Hence the wonky horizons in the photos here, and video shoot panning down to my feet and a stray finger. (Link to YouTube).

For drawing I made do with quick pencil scribbles my lightweight sketchbook. I coloured them later in the beach shelter behind the coastguard tower as I ate my sandwiches. I sheltered there as much from the dazzling sun as the northeasterly.

Another drawing on the East Pier around 2pm, the tide by then ebbing. Now things had calmed down and the splash hazard had abated, it was easier. I was no longer straight into sun.  The harbour entrance between the piers was still full of waves, with the strong ebbing large waves, standing waves.   An interesting interplay of wave forms and subtle patterns on water as it caught light, the strong currents now running against them. 


After a coffee in town, I returned to the East Beach around 4pm. The tide was now well out, well clear of shingle and breakwaters, revealing a broad, flat beach of mainly sand and the low wall along the river downstream of the East Pier. People were walking out onto beach. The wind now light, it felt reasonably warm.
I finally made use of one of my pieces of prepared paper: on the East Pier for about an hour as the tide continued to recede. Because of train timings (I had to head home by 6pm / not so many after that) I had to leave the shore about half an hour before low water (18:00h BST). Even by then,  the water had receded almost out to beacon on the east side of the harbour entrance. A lone figure at far end of sandbank.



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