The wettest drought on record - the weather of 2012

A public lecture at Bangor University presented by Professor Geraint Vaughan in the Main Arts Lecture Theatre on Monday 24th June 2013, at 6.30pm.

Professor Geraint Vaughan will be giving his re-scheduled public lecture for the Science Festival Week. The event is sponsored by the Royal  Meteorological Society and the Climate Change Consortium of Wales.  Entry is free of charge, includes a wine reception and is open to all members of the general public.

2012 began with predictions of drought and with hose pipe bans  beginning as early as March in some parts of the UK. The 3-month  outlook released by the Met Office UK originally forecast: “…average  UK rainfall slightly favours drier than average conditions for  April-May-June as a whole, and also slightly favours April being the  driest of the 3 months. With this forecast, the water resources  situation in southern, eastern and central England is likely to  deteriorate further during the April-May-June period”. However, April  and June ended up being the wettest months recorded, since records began in 1910.

Clearly, predicting month to month variations in rainfall at long-lead  times remains very difficult. There are a number of factors  influencing the climate system and our weather. Sea ice cover in the Arctic Ocean can act as a mirror reflecting heat back into the atmosphere but as it melts, the dark ocean becomes a heat sink for the sun’s rays, warming the earth’s surface. The position of the jetstream  – the atmospheric circulation that drives our prevailing west to east  flow of weather systems - appears to have been a major contributing factor behind the high rainfall last year. Evidence suggests that during March and April there appeared to be a ‘blocking pattern’ in the jetstream’s path – causing its deviation to the north and south of  its usual eastward progress.

What is the science behind the extensive high rainfall and extreme  flooding events during 2012? Come and find out from one of the world’s  leading experts - Professor Geraint Vaughan. Professor Vaughan is a  native of north Wales and Welsh language speaker. He gained his BA from Cambridge University and DPhil from Oxford University. Geraint  started his research career in the Meteorological Office, initially on  rocket-borne measurements of mesospheric ozone, then on airborne  measurements of stratosphere-troposphere exchange. In 1984 he joined  the Physics department at the University of Wales Aberystwyth, moving  to University of Manchester as Professor of Atmospheric Science in January 2005.

Limpets and the stone age rock shelter

Above Pont Garreg Hylldrem, where the road from Llanfrothen turns a leftwards right angle towards Beddgelert, there’s an overhanging cliff popular with climbers. It was popular with stone age hunters too, not for climbing but for the welcome shelter of the overhang on a platform about ten metres up from the sea or estuary below.

Local resident Clive Hudson was climbing there on Christmas Day 2007 (I didn’t ask why or whether it was before or after lunch) when he spotted a limpet shell wedged within a crevice. How had it got there?

Subsequent excavation, under the supervision of Bangor University, has uncovered several hearths and many shells: oysters, cockles and winkles as well as limpets. Mixed in were pieces of bone, probably deer, and so far 42 pieces of worked flint. Three limpets from different parts of the site have been carbon dated as being from 7379, 9281 and 9349 years ago.

Under normal soil conditions the high levels of acidity in north Wales would have caused the shells and bones to disintegrate but lime, seeping out of the overhanging rocks, has altered the chemistry thereby preserving these relics. Just a short distance beyond the overhang and normal acidity returns. 

Dr Gary Robinson, lecturer in archaeology at Bangor, describes the site as a hunting camp used on a regular basis for a few days at a time before returning to the home base. ‘It might have been for three or four hunters out on an expedition, maybe pursuing deer or spawning salmon on their way upstream. ‘

The low volume of shellfish remains suggest that these were snacks as opposed to the main diet of the hunters. Strangely one of the mussel shells is a species never before found in Wales but present in the Mediterranean. Was the sea warmer all those years ago?

Towards the end of the dig, in April 2012, a flint arrowhead was discovered, probably dating back to the bronze age. If that's the case, then this rock shelter was used for 5000 years. 

Mammal Society – the day we went to Bangor

It’s normal to hold meetings in London but this autumn (17th November) the society experimented with collaborating on a regional seminar.  The venue was Bangor, ‘dinas dysgu’ or ‘city of learning’, in the Brambell Building with its natural history museum making an excellent area for serving refreshments. On the ground local organisation was by the Snowdonia Mammal Group and more than 120 people attended the conference from all over UK.  

Derek Yalden (President) gave the first talk, an update on our knowledge of brown hares and how they are faring. It seems not so well. Surveys at the beginning and end of the 1990s showed a disappointing decline despite the introduction of ‘set aside’. I think Derek said he used to see 2 or 3 a day on average in the 1980s but nowadays it’s down to just 1.

Our 2^nd speaker was Penny Lewns with a ‘reasons to be cheerful’ talk about badgers and an overview of the work she and her partner have done by way of badger mitigation. There were some interesting photos of artificial setts under construction with an analysis of how successful they had been.

Before our excellent lunch amongst the skeletons in the museum we split into 5 workshops and I joined the ‘wildlife film making’ workshop with Geoff Garside. There’s a lot more to it than point and click with a camcorder. I walked away feeling very inspired (brilliant footage of stoats playing on the Conwy estuary, more photogenic than meerkats!) but a bit in awe of how good you’ve got to be. The sad conclusion was the comparative lack of producer or investor  interest in UK as opposed to exotic species. I’m told the other workshops were also good.

The afternoon session was opened by Jack Grasse and his totally black slide – it had something to do with our collective knowledge of dormice not so long ago. It’s not just about surveying hazel nuts and broadleaf. Jack gave a graphic (great facial expressions) description of how to age an old nutshell. What do they eat in conifers? Is it sap and invertebrates? We just don’t know yet, but maybe the MISE project will help.

Anita Glover from Leeds University described the arrival of Alcathoe’s Bat in the UK. In April 2010 it was confirmed in Sussex and 350 km away in Yorkshire. It was first described in Greece in 2001. Alcathoe? She was a young woman in Greek mythology who ... ‘while the other women and maidens were revelling and ranging over the mountains in Bacchic joy, these two sisters alone remained at home, devoting themselves to their usual occupations, and thus profaning the days sacred to the god. Dionysus punished them by changing them into bats’. How widespread are they in UK and when did they really arrive?

Kate Williamson described how she, Chris Hall and Sam Dyer had piloted hedgehog survey techniques with tracking tunnels. In the middle of the tunnel is an ‘inkpad’ to cover the soles of the feet and make tracks.  The team found that black powder paint (not easy to find these days) mixed with oil was successful, maintaining tackiness for about 6 days. Hot dogs were used to entice subjects into the tunnel and a motion detector camera showed that the local cat was very partial to these! The pilot seems to have worked well but be prepared for cattle to disrupt tunnels.

Chris Hall spoke about surveying for coastal otters across the coastline of Llŷn and Snowdonia. 22 locations of 1 km² were chosen, each with a flow of freshwater. All showed positive in the course of 12 months when surveys in September and May were combined. Working with volunteers can be very successful but you need to control them! Bill and Mandi Taylor (the unsung heroes) were commended for outstanding contributions to these and other surveys.

Pete Turner from Waterford Institute gave the final talk about the use of DNA analysis to identify individual otters. At the time of his talk DNA patterns had been taken from 86 of the 123 spraints from the Llŷn coastal otter survey in 2011. Of these spraints 79 were from females and 7 (8%) were from males.  Do females mark more than males? Analysis so far, from out of the above, has identified 19 different individual otters.

And finally it was the raffle. A great day out and I was particularly pleased that 3 of the delegates signed up to become direct debit subscribers of Natur Cymru! And here are 30 seconds from the day:

Sticky Stuff

Sandbanks provide natural defences, reducing coastal erosion, and behave in ever changing but predictable ways. Scientists can run models which will plot the size and location of sandbanks as sea levels rise in response to climate change and this is useful to inform planning decisions. The trouble is that sand and pure sandbanks are only part of the story – much of the sediment on earth is not sand but mud or a mix of mud and sand.   

Mud and sand

Where the sediment is sand you get a rippled effect and the length and height of the ripples reflects the flow and the amount of energy passing over that bit of the seabed. These patterns of sediment are called ‘bedforms’. Where the sediment is mud, or a mix with sand, the bedforms are much more flat and less mobile.

Sand is firm to walk on whilst mud is clawing and squelchy. Mud is sticky or cohesive whilst sand is non-cohesive. What makes mud so sticky is the volume of negatively charged particles of clay and the degree and types of excretion by many different creatures.

Dr Jaco Baas

The £1m COHBED (COHesive BEDforms) project has been set up by NERC to fill the gap in our understanding, and improve our ability to model and plan for the future. Bangor University are 1 of the 5 universities working on the project. 

If you’d like to know more about this project you should listen in to Radio Wales Country Focus, sometime in November, when Dr Jaco Baas will explain the finer points of ‘sticky stuff’.