What Am I Doing Here VI – Meteorology

One of my last scientific tasks from around here. If I exclude fixing toasters, changing light bulbs or vacuum keyboards, from a scientific standpoint, my work is summed to this.
Meteorology is something that uses a lot of time and resources. There’s someone here dedicated to the task for 5 days a week but unfortunately this job requires 18 hours of daily dedication, including weekends, holidays, Christmas, New Year or even Easter.
What does it consists actually? Well, its several tasks actually. The two constant ones, that is, that need to be performed 365 days per year, are the meteorological observations (synops, as in synoptic observation) and the balloon launch, with a meteorological sonde attached to it. Between those we still do instrument calibrations, that ideally should be daily too, and ozone measurements, but only when the Sun is high enough above the horizon for it.
Synops are made every 3 hours, from 9h00 up to midnight, 365 days a year. The weather balloon with the meteorologic sonde is thrown every day around 10h30 and the ozone measurements depend mostly on the time of the year. From April to September we simply don’t do them. The Sun is too low in the horizon or simply its not around. From October to March, the schedule of this measurements progress as the Sun gets longer above the horizon line. In October or February we can do as little as 3 observations around lunch time, when the sun is higher in the sky, but in the middle of the Austral Summer (during December) we do measurements from 9 A.M to midnight and in certain periods we do them hourly.
Our regime is quite simple: the atmospheric scientist does the usual 40 hours in the week – synops from 9h00 to 18h00, sonde launch in the morning, any ozone measurements during that period and any instrument calibration if necessary. After 18h00 we still need to do the 21h00 and midnight synops and any ozone measurements if it is Summer. Those normally go to another member of the science team and we rotate them weekly.
Who is the science team then? Well, around here these are the elements that deal with the science projects and with any resulting data. So that’s me, the other electronics engineer (yes, we have two of those around here), the data manager and of course, the atmospheric scientist. The week nights and weekends are distributed among us four to avoid institutionalize the atmospheric scientist.
Its a simple job and it gets easier the more you do it, but it is extremely repetitive… and important. I, as one of the members that spends a lot of time in the field, am quite dependent of the weather forecasts to plan my trips. Last thing that I need is get out of the station for a day to do field work and have to turn around after a few hours later, or get stuck in the middle of nowhere because a storm was brewing behind my back. Antarctic weather is very unpredictable and dangerous. A day may dawn all blue, sunny and pretty and end up completely covered in clouds, snow and 85 km/h winds that screws all visibility. A good weather forecast is key for the success of most of out work here and for that we need to provide good data to the right people.
Synops are done directly in a Web page. It is basically a weather profile of the area around the station and has to be filled up every 3 hours. The bulk of the information, like temperature, pressure, wind speed and direction is automatically retrieved from the AWS (Automatic Weather Station). But other stuff, like the coverage and types of clouds in the sky, visibility and a couple of weather phenomena (mirages, solar halos, precipitation, etc..) are not yet automatic and need someone to literally look at the sky and code them. At first I would take a good 10 minutos to do a synop but nowadays I’m so used to it that I can do them in my head while I walk to the computer.
The ozone measurements are done with a Dobson spectrometer, a very old but still reliable instrument.
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Historic fact: the Dobson spectrometer that I’m using today, named Daphne by some reason, is the same one that Jonathan Shanklin, Joe Farman and Brian Gardiner used during the 80’s when they discovered the hole in the ozone layer over Antarctica and that triggered the worldwide prohibition in CFC use, the components that causes the destruction of the atmospheric ozone. To learn how to operate the Dobson spectrometer by none but John Shanklin himself, while I was still in Cambridge, a few months before going South, was without doubt on of the high points of my life.
This instrument measures the difference between the quantity of light received for two types of radiation: UVA and UVB. UVB is a type that, even though it belongs to the evil ultraviolet, is not that harmful. Besides, the ozone layer doesn’t absorb much of it to begin with. But the UVA is a different animal. This radiation os way more energetic and its the one responsible for the beach burns and a few melanomas here and there. Fortunately we have a layer full of ozone that absorbs huge quantities of this radiation and save us from getting our skin like crackling. If there’s ozone in the atmosphere, than the detected UVA quantity is going to be small. The UVB quantity on the other hand is always constant since the ozone barely touches it. But if we have a big hole on it above us then the detected quantities of these radiations are going to be similar. An that’s how, by measuring both radiations ratios, this device can tell us how much ozone we have above us.
Lastly, the weather sonde launch is fairly trivial. Around 10h00 we calibrate one of these little boxes full of sensors. These are single use and come in sealed bags to protect them from moisture.
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In fact, if we could get them back after a launch, they may be used again. But the majority ends up in the ocean or several hundred kilometers from the base. When a 250g plastic box, and white on top of it, can go all the way up to 30 kilometer in altitude and with all sort of weird winds in all sorts of directions, its almost impossible to get them back afterwards.
The sonde is calibrated with a proper instrument and a computer.
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The process is mostly automatic. Once the sonde is ready, we stick a box with a couple of batteries on the back, pick up a balloon and go to the caboose where we keep the helium canisters.
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Then all whats left is too fill up the balloon until it resembles a small morbidly obese person, attach the sonde to the bottom of it and throw it out of the shack.
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The software that we use to calibrate the sonde is the same one that receives and processes that data. This sonde gets us a somewhat vertical profile of the area, specifically, the temperature, atmospheric pressure, speed and direction of the wind and humidity in the 30 or so kilometers above our heads.
A typical Met day, as many of my Saturdays and Sunday when I was rudely interrupted from my drooling session by the alarm clock, is something like:
– Get myself awake and with a properly washed face by 9:00, just in time for the first synop and ozone measurement if the sun is around for that.
– Mornings are excellent for ozone measurements. The second one comes at 10:00. Until then I normally use the hour for breakfast.
– At 10:30 its time to start preparing the met sonde. Once the 10:00 Dobson is done, I’ll grab the sonde almost immediately.
– The sonde takes about 15 minutes to be ready, more or less. When it gets ready, I just stuck a box with batteries on its back, grab a balloon, put something warmer on top and go for a 50 meter walk to BART, the booth where we keep the helium canisters. (Yes, that’s a reference to Bart Simpson. A bit of weird antarctic humor)
– The balloon takes a good 5 to 10 minutes to get full enough. I then stuck the sonde to its bottom and simply open my hand out side and free the poor fellow. After that all its left is to wait for it to blow, which takes a good 3 hours at least.
– Since I’m already outside, I normally take the chance to do a temperature calibration. About another 50 meters from BART is a set of meteorological junk, which includes a Stevenson screen, which is nothing more than 4 old school mercury thermometers on a tic tack toe pattern.
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The temperature that we get around the station is normally obtained from electronic sensors. These are cheaper, easier to use and makes us look all high tech and such, but the sad truth is that they aren’t as precise as a good old tube with a few drops of mercury inside of it. Since walking out 100 meters from the station whenever we what to know the temperature, we only use these ones once a day as a calibration for the cheaper ones.
– If all goes well, I’m back on base by 11:00 (sometimes the met sondes go all stupid on me and stop sending data midway to their flight. Normally we try to launch another one as soon as possible) where I do the last touches in the sonde calibration and temperature sensors.
– And now I have a whole hour until mid-day, when the next synop is due.
– After the last one, the next annoying bit happens only if there’s Sun around. If that’s the case, I have another ozone measurement at 13:30, which cuts right through my lunch time.
– Between 13:30 and 14:00 I have to check on the balloon every once a while to see if it has popped. When it does (you can see the altitude going down instead, which means that the sonde is in meteorite mode), I need to prepare the data and send it to the guys at the WMO. (World Meteorological Organization)
– The worst of this day end around here. Its a lot going on on a Saturday or Sunday morning. In the beginning there was always something that got forgotten. Once the data from the sonde is done, all its left is a synop and maybe an ozone measurement at 15:00 and then its easier from that point on.
– 18:00, another synop and an ozone one, if it is doable. Since I have 3 hours since the last one, I normally take the chance to compensate the fact that I had to be awake before lunch on a Saturday with an afternoon nap. With any luck I can also do a quick hop to the gym, but I tend to stay an snore for a few more minutes.
– 21:00, the story goes on. Another synop and, in case we are almost, almost in Summer, another ozone measurement.
– Midnight. End of the work day. Last synop and, for a few weeks during the peak of Summer, when the Sun is really, really high, even at mid night, one last ozone measurement.
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Its truly a long day. But after lunch and, after a good nap, its more of the same all the way up to midnight. Yes, it is boring as hell, specially after the 37th early Saturday, but I rather have that than get surprised by 90 km/h winds in the middle of nowhere when the forecast was predicting a 30 degree day..
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