Krissie's Blog - 5

Apr 20, 03:27 PM

Before I officially had this job, I knew that part of my responsibilities would be to release weather balloons. The good people at the National Weather Service in Mount Joy, IA, let me visit for a couple of days and watch what they do. The equipment down here is the next generation from what they had at the NWS, so it takes much less time to prepare a balloon – about 15-20 minutes, as opposed to an hour. But there are some balloon things that are unique to the South Pole; the first being our balloon oven.

The balloon inflation room at the Balloon Inflation Facility (BIF) is kept at 55°. We store the balloons in this room, so they get kind of brickish – not quite frozen but very stiff. We always have two 600g latex balloons in the oven – one for use that day and a backup in case the balloon pops early and we have to launch a second one. The bigger balloon on the top shelf is a NOAA balloon, which is 1500g. It’s bigger because it carries a heavier payload.

This is a picture of the room. Our balloons (and especially NOAA’s balloons) get to be quite large, so the ceiling has to be high enough for them. All of those cardboard boxes on the shelves are our 600g latex and 3000g plastic balloons. The big, white compressor on the left of the picture is used by the firefighters. It can refill their SCBA tanks and, in the summer, they use it to charge the aircraft firefighting vehicle.

You’re not supposed to touch the balloon. The oils from your skin can potentially cause the balloon to pop early. Handling it by the neck, we roll out the balloon, insert the fill nozzle, clamp it closed, attach the fill weight, and clip it to the table so it doesn’t float away. Then we turn on the helium. When the 500g weight is pulled off the table, the balloon is full.

Now it’s time to prepare the radiosonde, which is the name of the instrument we attach to the balloon. The cabinet behind me is full of them. In this picture I’m just opening up the package.

The radiosonde is a radio transmitter. The silver stem on the top right of it measures temperature, pressure, and relative humidity. Sondes that also measure wind are called rawinsondes. But ours are tracked by GPS, so that’s how our wind data is derived. Hypothetically we could go out and retrieve the sondes because of GPS, but it would take too much fuel to go get them. So we just let them crash to the ground and get buried in the snow. Don’t worry, they don’t harm anything by being out there. They only go about 70ish km away, which is still nowhere near an ecosystem. Back in the States, radiosondes have parachutes on them and also have a prepaid mailing package inside, so that if you find one, you’re supposed to send it back so quality control can be run on it and possibly have it reconditioned and used again. We put the sonde in the cradle you see next to the computer, and we recalibrate the sensors through it. The recalibration takes about 5 minutes. This is when I start the battery and go sweep/shovel the deck outside.

You’ve heard of a dry-cell battery. Well, this is a wet-cell battery. We activate it by soaking it in water for at least 4 minutes. It can stay on the shelf for years, since it’s inactive until it gets wet. I check on the balloon every few minutes, but it’s usually ready about the time I’m done sweeping the deck.

So the weight is off the table now. I’m logging how much helium I used.

We use two two-foot long strings. The first one seals the balloon. Then we fold the neck of the balloon upward and tie it, creating a loop that supports the hook of our sonde’s payout reel. Now it’s time to check on the sonde.

We do a ground check, which gives us data from inside the office. This way we know it’s working. Then we give it data from the outside: air pressure, air temperature, relative humidity, wind speed, and wind direction. Once that’s done, we drain the battery, dry it off as best we can, connect it to the sonde, and seal the package.

Once all the data on the screen goes from ——- to //////, we know the sonde is transmitting and we can launch. See that reel that looks like kite string? That hook on the top is what we thread through the folded balloon neck. Here’s my firefighter friend Marty doing it. I think everybody should launch a balloon at the South Pole, so you’ll see various people in my shots, after I’ve done the “hard” work.

Then we open the giant door. The 600g balloon is small enough that we only need one door open. One hand goes around the balloon neck and spool, and the other hand holds the sonde. Then I cut the balloon loose and walk outside.

We wait outside with the sonde for about a minute, so it can get its bearings. Another method is to set the sonde outside to let it acclimate, bring it back inside to attach it to the balloon, and then walk outside and immediately let it go. But I think it all evens out in the end.

This is me and my boss on my very first on-the-job balloon launch. We’re waiting for it to acclimate. The BIF is 1/8 mile from the Station. That’s Summer Camp in the background. In the summer, we have to call COMMS for permission to launch because there’s almost always an inbound flight right around the time we’re launching. So we have to get the pilot’s permission sometimes.

This is Dr. Ella’s turn. You let go of the balloon first and then the sonde. This is a nice action shot I took, if I do say so myself. About the time it takes to close the giant door and walk back into the office is the amount of time it takes for the satellites to lock onto the sonde. Data will then start streaming in. We get data for every two seconds of flight.
The balloon rises around 13 ft per second. It reaches an altitude around 100,000 ft. and expands to many times its beginning size. These days they take 1.5 hours to reach maximum height, around 36 mb. In the summer, a flight lasts up to 2.5 hours and gets up to around 4 mb. When the balloon pops and the sonde starts to fall, the computer program recognizes it and tells you that the flight has been terminated. So then we process the data and send it to Charleston, SC, where they make a forecast out of it.
In the winter, the cold pops the balloons early, so as of this week, we and NOAA have started using plastic balloons, which are like giant jellyfish/trash bags. We launch our 3,000g plastics every three days and do the 600g rubber balloons on the days in between. The US never gets cold enough for plastics. In the summer we launch two balloons a day, for 00Z and 12Z. After the last plane leaves the continent in February, we only do a 00Z balloon per day. UTC/GMT/Zulu time is the same around the world. And all around the world, meteorologists are launching balloons at exactly the same time. World Peace through weather balloons!
We measure the atmospheric conditions I mentioned before, in order to create a profile of the atmosphere. Every Thursday we do a dual-launch with NOAA, when they launch their 19,000g plastic balloon. They send up ozonesondes to measure ozone levels as the hole forms in the winter. We hitch a ride with them when they do this, and they benefit by getting our pressure and GPS data.

That’s their last 1500g latex balloon of the season, which is big enough to need both doors open. Their ozonesonde is the Styrofoam box with orange tape. My radiosonde is hanging just below it. The orange thing is a parachute, but they don’t retrieve their sondes either. I’m guessing it’s to slow the descent. This picture was taken last week, that’s why it’s so dark outside. It’s still not completely the dark of night yet, but more stars are appearing every day and the auroras are getting brighter.

This is how high they go – high enough to see the beginning of Space. This isn’t Antarctica. That would just look white. These are the Rocky Mountains. You can also see some pretty tall clouds in the background. A camera was sent up with a balloon and was retrieved after balloon burst. Next week I’ll show you a few plastic balloon pictures. Bye for now.

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