Meteorology Section

Société Jersiaise

Meteorology Section

Notes following a meeting held on Wednesday 11th January 2017 at 8pm

Present: Darlene Hewitt, Eileen Lerche-Thomesen, Frank Le Blancq, Jennie Holley, Margaret Cabot, Roger Long, Sheila Mallet, Sue Hardy, Dorothy Vincent, Richard Perchard, Caroline Leach, Christine Vibert (first visit).

Apologies: Averil Arthur, Chris Sutton, Georgia Le Maistre, Paul Aked and Rosemary Bett.

Admin: The Chairman reminded members that Société subscriptions are due and early payment would be appreciated by the Office.

Discussion: 1) The Chairman passed around a news cutting, announcing the now old news that the BBC were to dispense with the services of the UK Met Office as their supplier of weather information. At the time a new supplier had not been chosen, which seemed odd. A Dutch based company MeteoGroup has since been chosen and will take over this spring – I can’t find an exact date. After initial comments that most of the current presenters would transfer to the new company, JH commented that she understood this is not now the case.

2) In December the chairman attended a Royal Met Society meeting on ‘Chaos theory’ in London and showed an example of a product that can result and how it can be of use to a forecaster. On a non-weather note he also highly recommended a visit to the Wildlife Photography exhibition at the Natural History Museum which runs until September.

3) During the autumn, a retired seismologist from Strasbourg University visited Jersey and visited the seismological station at Maison St. Louis. In 1934 the new Director of the Observatory was Père Rey, who had worked with a seismograph in Madagascar and presumably asked to loan one for St Louis. On his return to France, our visitor sent a brief history of the Mainka seismograph confirming from the identification plate that it had been first sent to Grenoble in 1923, later returned to Strasbourg and then loaned out to Jersey in 1935.

Members Contributions CL – mentioned moon bows. These are formed in a similar manner to rainbows, but as the water droplets are much smaller than rain drops and light from the moon is less intense than the sun, they tend to be white in colour, though occasionally weak colours can be seen.

MC – showed a couple of photographs of a rather unusual cumulonimbus cloud seen in Cambodia, with a narrow but long thin anvil, the whole being reminiscent of an open mouthed alligator. SM – explained the origin of Halcyon Days, which comes from Greek mythology. The goddess Halcyon, daughter of Aeolus, ruler of the winds, insulted Zeus and was turned into a bird (kingfisher). Out of pity, she was allowed 14 days of calm mid- winter weather spanning the solstice (the Halcyon Days) in which to lay her eggs. Recent studies of 43 Greek plays (reported in Weather journal, 2014) identified such quiet calm days between mid-January and mid-February, when Athenians would watch plays in the open air. This allows an association of the quiet weather with anticyclonic conditions and consequently implications for the Greek climate in ancient times. RL pointed out that while the use of ‘Halcyon Days’ now refers to any time period but this is incorrect use of the words.

SH – contributed to various discussions. She also offered to sort out some photos of sea-swept and iced up lighthouses for a future meeting. She mentioned a 1600’s map showing coastal areas inundated at Anne Port, Beaumont and at L'Etacq, as well as St Ouen’s pond - long before the 20th century sea defences.

More discussion 1) The Chairman noted a recent JEP letter concerning climate change written by Mr Derek Bernard. The letter was littered with inaccurate, false and contentious statements, none substantiated, yet written in a manner which made them appear authoritative and to which a (personal) reply was felt necessary. The Chairman was pleased to see two supporting letters, one written by a practicing scientist, refuting most of Mr Barnard’s comments. This prompted general discussion which later focused more specifically on the likely effects of climate warming in Jersey, of which the effects of sea level rise are the most pressing. Sea walls, shingle banks and sand dunes as defenses were all mentioned. ELT noted a recent instance of a shingle bank which had built up quickly by about 6 feet last year at Grêve d’Azette and which had been moved by the following spring tide. Other instances of substantial beach movements were recalled and RP mentioned the situation near Gorey. SH reminded us that some years ago there was discussion of ‘managed retreat’ of the coastline. If a breach occurred in St. Ouen’s sea wall, would it be rebuilt? In times past there was no road along the bay, only tracks leading down to the beach from inland.

2) A chart was shown of the remarkably steady decrease in mean wind speed from a peak of 50 knots down to 2 knots over 24 hours, following the storm on the 21st and 22nd November.

3) The Chairman handed out details of the local autumn and December climate issued by Jersey Met. Discussion concentrated on the weather events in December which were remarkable in two respects. First, it was the second driest December at Maison St. Louis since 1894, with a rain total of 22.6mm; only 1905 with 21.8mm was drier. However, research stretching back to 1862 reveals 1879 was also very dry with 22.2mm. Overall therefore, December 2016 was probably the third driest since 1862, a span of 154 years. In mid-December, the island was near absolute drought conditions, a most unusual position in December. Pressure is not something we can sense, but it was remarkably high all month. The mean was 1028mb, with the highest reading of 1044mb recorded on the 27th.

4) Finally a series of photographs was passed round, including a set of interesting and unusual wind vanes seen last summer in the Baltic States. Next meeting date: Wednesday 12th April in the Meeting Room at 8pm.

Thanks to everyone who attended and apologies for any omissions or errors.

The photograph below was taken on Noirmont Common on 11th December. It shows a spider’s web hanging vertically on a gorse bush and exposed to a light southeast breeze. At the time a thick fog, with visibility of about 100 meters, covered the Common. Fog consists of minute water droplets, about 1000 times smaller than a rain drop and as the droplets passed through the web some adhered to it. As further droplets coalesced, some of them grew in size and a careful look at the droplets, shows quite a wide range of sizes. They are sufficiently small that surface tension keeps them spherical.

Frank Le Blancq Chairman – SJ Meteorology Section 17 January 2017