Sunday, August 05, 2007


Science Never Sleeps

It's Sunday morning. I'm duty weather girl.

The majority of base members might be enjoying a lie in, but science never sleeps.

There are three of us in the Halley met team and we take turns to work the weekend shifts.


As I make my way to work at nine, there's already a glow over the misty horizon.

There's just one week to go until sun up.


After entering my 9am weather observation into the computer which sends it straight to the UK met office, I take my place in the Halley met office.

It looks so similar to any old office back home, if I wasn't going outside every hour I could easily forget I was 12000 miles away.

The friendly office penguin sits over my desk, alongside photos of green, sunny, hilly places to help me remember that it's not flat and white everywhere.

At about half ten get dressed up again and make for BART, a shipping container on stilts, to fill the daily weather balloon with helium gas ready for launch.

When it's full, the balloon's about the same size as me (height not width, even Ant's amazing food hasn't done me that much damage, not yet at least!). I tie a radiosonde onto the neck of the balloon before releasing it. That's a little plastic box carrying temperature, pressure and humidity sensors and a GPS antenna (you can work out wind speed and direction if you know how the positions changes with height), which hangs on a long string beneath the balloon and transmits data back our receivers every second.

The balloon can travel up to 25km and expand to the size of a double decker bus before bursting!


On my way back to the office after lunch the light was as bright as a bedside lamp with a hangover. The morning mist had cleared and the daylight totally caught me by surprise. The past few weeks went something like this: it was dark all the time, then a few days of blizzard, then suddenly the skies cleared and we got days back again! I mean, I still had to use night mode on my camera to take this photo, the light only lasts a couple of hours and it's probably still dark enough to turn street lights on back home, but after three months it comes as a welcome change, that's for sure.

4 comments:

Paul Capewell said...

Hi Tamsin, hope you don't mind me asking - when the radiosonde comes down again, do you retrieve it to use again? I assume thats why it has a GPS inside?

Also, the balloon expanding... Might be a silly question, but would that happen anywhere, or is it to do with the cold?

Akio said...

Hi, my name is Leighton, and I'm with PBS (public television) in the United States. I love your blog and would love to lend it a wider audience. Please email me when you have a chance: lwoodhouse@kcet.org. Thanks!

Tamsin Gray said...

Hi Paul,
Thanks for your questions. Here goes:

The answer to your first question is a definitive no. We don't retrieve the sondes because it would be logistically impossible as well as unsafe and even if we could retrieve them, they would almost certainly be too badly damaged by the fall for reuse.
The GPS is used to track the movement of the balloon so that wind speed and direction can be calculated.

The expansion of the balloon would happen anywhere, not just in the cold. As you move up through the atmosphere anywhere in the world, the pressure drops with height. By the time the balloon has risen 15km the pressure will have fallen to around a tenth of its value at surface level. Effectively, there is less air pushing on the balloon from the outside, so the gas inside expands outwards until eventually the balloon cannot stretch any further and pops.

I hope that answers your questions, if you would like any more details drop me an email: tgray@bas.ac.uk

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