Sussex Sun Halo

I was hanging the laundry out this morning when I looked up and a sun halo:

22-degree sun halo in Sussex

This particular beauty is a 22° degree halo which is formed when sunlight is refracted by ice crystals in the barely-visible cirrus clouds. While not rare as such, it is certainly unusual to see such a complete example in the UK. I am using the bird-feeder to eclipse the sun so that the sensor on my camera wasn't too flooded with light from the sun (I was in point-and-shoot mode).

Optical effects are probably my favourite thing to see in the sky. Antarctica was great for them as the cold atmosphere means they appear more frequently. Seeing this gave me a spring in my step all day! If you are lucky enough to spot one, view it wearing sunglasses and use your hand to block the sun to avoid damaging your eyes.

In other news, the strawberries are progressing well, and I think I'll have my first strawberry any day now!

Met Office Mk2 Strawberry Gauge

Met Office Mk2 Strawberry Gauge

A few years ago, when I worked for The Environment Agency, I used to visit and maintain various rain gauges around the West Midlands. We looked after them on behalf of the Met Office, who used the data to calibrate their radar images of rain fall. We had some automatic tipping bucket gauges, some monthly storage gauges and some daily or '5-inch' rain gauges. These are the classic Met Office rain gauges which were invented in something like 1872*, updated to the Mk2 in 1875, and haven't changed since. They are a thing of beauty.

Periodically rain gauges would need to be replaced if they failed inspection, and I rehomed a couple with vague ideas of using them in the garden for plants or something sculptural. They have sat at the bottom of Daddy's garden ever since, but during a recent conversation with friends about using copper tape to slug-proof strawberry plants, I realised I had the perfect solution - I give you the Met Office Mk2 Strawberry Gauge!

The main body of this one already had a slit in one side after a nasty incident with a grounds-keeper and a ride-on lawn-mower (final score: Lawn-mower 1 - Rain gauge 0). I lengthened the slit and tidied the edge up with a metal file, then drilled a line of holes on the other side and used a hacksaw blade to make another slit. I hammered the top of the slit inwards, and used pliers to persuade the bottom half outwards. I didn't manage to make the hole very big and had to sort-of post the stem/leaves through from the inside, but it worked. I also drilled several holes in the bottom of it to allow for drainage. The lid of the rain gauge was used as-is with no modifications, as it has an internal funnel which allows it to drain.

Overall I am pretty pleased with how it came out, although doing the metal work was far harder than I had anticipated. I have another base, and several internal cans, but I think the neighbours deserve a break from banging, thumping and drilling for a few days - my arm muscles certainly do!

I'll have to wait a few months to see quite how slug-proof they are, but I am looking forward to fresh strawberries for breakfast enormously!

*That's a total stab in the dark. I remember from university that it was pretty old (18-something), but don't quote me on the exact date. Do let me know if you know though!

Czech It Out!

 I might not be in Antarctica any longer, but that's no excuse not to do fun stuff in fun places. I've spent this last week at Hradec Králové in the Czech Republic at a workshop organised by the World Meteorological Organization. The aim was for different countries to come together to discuss how to improve and re-evaluate the data collected from Dobson spectrophotometers. Dobsonmeters measure atmospheric ozone by looking at the difference in absorption of different wavelengths of UV light. The occurrence of severe ozone depletion (The Ozone Hole) over the South Pole was discovered by measurements from a Dobsonmeter at Halley Research Station in Antarctica.

We had a visit to the Czech Republic's Solar and Ozone Observatory, and a dinner and some talks from the Ministry For The Environment which were very interesting.

The town was very pretty and extremely well-provisioned with bars and restaurants, of which we fully availed ourselves. There was an excellent selection of traditional Czech food and the service was very good.
A few photos:

Fishy Business

Tide gauge

The Proudman Oceanographic Laboratory (POL) maintain a network of sensors around the UK and the South Atlantic to monitor tidal elevation. Rothera's well house (built as the intake for our reverse osmosis plant which provides our drinking water) is an ideal site for a tide sensor as it is directly connected to the sea by an underground pipe, so the level is the well is always the same as the current sea level.

As part of my job, I carry out calibration water level dips for POL so that they can check that their automated equipment is doing what it should be. In summer this involves walking to the well house, jumping up onto the roof (it is about waist-high), lifting the lid and climbing down the ladder inside. After six months of winter it is a slightly different game, as first I have to spend half an hour digging through the snow to find the lid, clearing enough snow to be able to lift the lid and give myself somewhere to stand so that I can open it, and then try to climb into it safely.

Once inside it is not too unpleasant though, as there is a heater which stops the damp affecting the electrics used to run the monitoring equipment, and it is out of the wind and snow.

I use a tape measure on a reel which has a sensor on the end (a 'dipper') to measure from a datum point on the grating inside the well house down to the surface of the water. When the sensor touches the water it beeps, and I read the tape measure. I take one dip every five minutes, for around an hour each side of low and high tide. Audio books and knitting help to fill in the intervening four minutes between dips! We aim to do 30 calibrations per year, at a mix of high and low tides, and try to select tides which have at least 1m (3ft) difference between the high and the low. As Rothera has a strange double-tide, sometimes there is only 30cm (1ft) difference between the highs and lows; this can mean dipping at unsociable hours to get a useful tide! The folks at POL are very appreciative of our work though, as it helps to improve their tide modelling and prediction systems for the whole of the Atlantic. It has also helped other organisations with tsunami modelling, as the 2004 Indian Ocean tsunami was detected by the tide sensor at Rothera, and earlier this year the recent earthquake in Chile caused a 20cm jump in the tide trace, and we could see that it took several days for the tide to settle back to normal. For those interested, Rothera's live tidal information can be seen here.

Mr Fish

As barely a fortnight can pass between birthdays, and on the theme of the sea, I present to you Mr Fish, the latest in a long line of creative birthday cakes. Mr Fish is for one of our GAs who, in the real world, is a keen fly-fisherman. Down here he contents himself with spending his evenings making flies and dreaming of trout-fishing in New Zealand.

Ice Ice Baby: Two Cold Photographs

Two recent photos of what happens when you have a few days at around -20°C (-6°F).

Rothera Point surrounded by sea ice as far as you can see. In Hangar Cove at the bottom left of the photo the ice is so thick now that it is almost indistinguishable from land.

Up at the ski area we had retreated to the caboose for a cup of tea. I swilled my mug out with some more hot water and threw it out the door. The chippy suddenly got very excited as he had noticed that as my hot water met the cold air, it froze and created a cloud. Everyone ran back into the caboose to get more mugs of boiling water to throw in the air.

I've shamelessly cut and pasted from the internet, as they have worded it better than I could:

First, the near-boiling water is already close to becoming steam when it is thrown into the air, which means that the water molecules are much closer to evaporating into the vapor state than they would be if the water were cold.

Second, the act of throwing the water into the air causes it to break up into tiny droplets. The water that was contained in the cup (which originally had a relatively small surface exposed to the air) now experiences a tremendous increase in the total surface area exposed to the air. This situation helps to speed up the evaporation process (evaporation is the process of turning from a liquid to a vapor).

Finally, very cold air typically has a low humidity level (that is, a low amount of water vapor present). This is yet another factor aiding the transition from liquid water, to water vapor, to ice crystals. At sufficiently low temperatures, this process seems to occur almost instantaneously. 

Cold water is more viscous than hot water, so doesn't separate and spread out as efficiently as boiling water does, which is why it doesn't happen with cold water.

'It's Like A Rave In The Sky'

Today we were very fortunate to be treated to a display of rather amazing clouds. Nacreous (or Polar Stratospheric) clouds form during the polar winter at an altitude of between 15,000 and 25,000 metres. Due to their height, they are illuminated for a long time before sunrise and after sunset and are highly iridescent. Some of the clouds, especially the electric blue ones, were so bright that I couldn't look directly at them.

Iridescence occurs as light is diffracted by water droplets or ice crystals, and can be seen in other clouds around the world. I have seen it many times in the UK, especially in Alto cumulus clouds in Autumn, but never as bright as it was in nacreous clouds.

Most people on base came to look and take photos and it was fun to hear people's reactions and description. Our electrician, who has clearly had a far more active social life than I have, said, 'It's like a rave in the sky where all the clouds are taking LSD and tripping out'. Quite.

Skiing and Sun Pillars

My plans for an extended Sunday morning slumber were shattered by the wail of the fire alarm. After pulling on my overalls and grabbing my emergency bag I headed over to muster at Bransfield House, to be greeted by the smell of burnt toast. Courtesy of the chef. He can cook an eight-course meal for 22 people on Midwinter's Day, but making toast? Not so much.

It was 08:30, so rather than go back to bed I headed to the kitchen to make some Chelsea buns in anticipation of a skiing trip after lunch. They were good fun to make with pummelling the dough and rolling them up, but they took about 5 hours rise, so they had to go straight from the oven into a box to take with us, without time for cooling.

The snow conditions at Vals were lovely so we spent several hours practicing turns, and trying to take photos of each other going over the jump that we had dug the day before. Things were also a little less eventful than the previous day, when someone let go of their snowboard at the top of the hill. I gave chase, swooping it up just before it collided with the caboose - a risky manoeuvre which could easily have ended with egg on my face, but instead I have now acquired a reputation as a superhero skier who wears her pants on the outside and a cape around her shoulders. How little they know.

Some folks went into the caboose to get the primuses going for tea, so I had a go on a snowboard. I've improved a lot since I first started, and can now fall over making both left- and right-hand turns, as well as backwards and forwards. We'll get there one day, but after one run down I decided that tea and cake was the better option. The Chelsea buns went down very well and fuelled us for our ski back down to base.

Monday's main excitement was my first decent sighting of a Sun Pillar. This is coded and entered into the synopic observations which are sent to the Met Office. It is a 99040, for those who care!