First Advent

The first Advent fits nicely in my schedule. Yesterday Erik and I installed the pyranometer (total solar irradiation) and the UV-A and UV-B sensors on the northern roof of the station. It has still to be raised higher up on a support in order to have a free field of view, but nevertheless, it takes already now observations as planned. With installing these instruments, all my instruments are operational and it only rests to supervise them and to do some maintenance and minor improvements of operation. Therefore, this Sunday I can do things in a rather relaxed way. Although Sunday, almost everybody got up as usual because the glaciologist team of the IceCon project (http://icecon2012.blogspot.com/) left at 8am for the coast. They will be in the field for around 16 days. A lot of preparations have been done, they were eager to leave finally for their field work, and we were up to say Goodbye to them and to wish them a good journey and expedition. The 8 scientists left together with Alain Hubert (expedition leader), Raphy (field guide) and Kristof (mechanic). They have 2 of the strong Prinoth tractors, many skidoos and several sledges with containers with them. On the image above one of the trucks is to be seen, with the little blue rescue and communication container, then the sleeping room, the kitchen and the bathroom container. The trip to the coast will take about 20 hours and the only stops will be done for refueling the tractors. There’s also the group photo of the glaciologist expedition team and then the two truck-trailers on their way towards the coast – now appearing quite tiny on the great white plain. 

At Utsteinen, there are not only scientists and station expedition team members present. The rocks and moutains are also inhabited by birds, white snow petrels. In austral summer they breed here. And their presence apparently attracts some skuas to come here (see images above). Skuas are predators, living normally near the coast, but which feed also on old/sick/or young snow petrels. These skuas seem to follow the snow petrels and also to be attracted by our presence, curious if there might be some left-overs (but there aren’t).

Back on track in Utsteinen

Our flight with the Ilyushin went like foreseen. Take-Off in Cape Town was on Wednesday at 2330 local time. Together with us were around 50 other scientists from the German, Finnish, British, Swedish, Indian and Norwegian stations. Around two hours before landing everybody takes on his polar clothing what creates a bit of a mess in the aircraft because you have to fetch your bag with the clothes at the rear of the seats, change somehow at your narrow seat or in the narrow gangway. Anyway, after changing, everybody is longing for the landing. 5 and half hours after departure we landed safely at Novo Air Base (see also the image above; the Ilyushin has a camera in its nose and the film is shown in the cargo cabin). It is a 3 km ice runway, usable by heavy cargo aircrafts like the Ilyushin. Once landed, the cargo is unloaded and everybody helps to separate the boxes and all other equipment to the individual piles of each station destination. Half of our group had the feeder flight (smaller Basler propeller aircrafts) to the Belgian station at 7am local time, 9am Belgian time. The other half had to wait for next day because we had so much cargo (volume and weight) that it had to be split. Luckily I was on the first feeder flight. After one and a half hour we landed (bit rough) at Utsteinen where we unloaded our equipment and had a breakfast.

Since then I benefited from the quiet, calm weather to set up quite a few of my instruments. The aethalometer, TEOM and nephelometer in the specific shelter are already operational. Yesterday I set up on the station’s roof the ozone spectrophotometer and the sun photometer. And they are running well. That is really satisfying. The total ozone values are on the high side, above 350 Dobson units. However, UV radiation is high and next will be to calculate the UV index. The forecast says that the next days weather stays quiet and rather sunny. The disadvantage is that if there is only little wind, energy falls fast short as a lot of work has to be done. Therefore, the generators are often on what I see immediately in my aerosol data. Surely, these data I do not want, but one can see it as test for my instruments because it is so contrasting data to the otherwise pure air. 

The Antarctic summer season has started

A new season has begun at the Princess Elisabeth station in East Antarctica. A week ago the first team arrived at the station. Have a look at their reports (www.antarcticstation.org). It is also time for me to re-activate the blog. I will be also this season at the Belgian station. There are again a lot of things to do. First, the three instruments which were measuring during the winter have to be checked and maintained. The particle number size distribution instrument, the aethalometer (mass of light-absorbing particles) and the TEOM-FDMS (total particle mass) measured during a good part of the Antarctic winter until end of August when the power in the shelter broke down due to a minor electronic control device. However, the main station remained on power and this is really good news. It means that it is possible to run the station un-manned with remote control. Besides the three already mentioned instruments, I will re-install the Brewer spectrophotometer (total atmospheric ozone amount and spectral UV radiation) and the sunphotometer (total atmospheric aerosol optical depth) on the station’s roof, and also the instruments for particle total number concentration and particle scattering in the shelter. On the station’s roof there will also be a new pyranometer (total solar irradiation) and two sensors for UV-A and UV-B irradiation installed. In addition, I’ll maintain the instruments of the Hydrant project (ees.kuleuven.be/hydrant/) and I plan to do some snow pits, snow profiles digging again. The current plan says that we will fly on Wednesday night to Antarctica, to the Russian air base at Novolazarevskaya. At the moment I am in Cape Town, together with the next team to arrive at Princess Elisabeth – a group of 10 people, internationally well mixed (Belgian, French, British, Japanese, Swiss, German), like usual for Belgian projects.

Being back and staying connected

It’s now already six weeks ago that I left Antarctica and that I am back in Belgium. Normal working life takes over rapidly. It has been time for debriefing meetings, for securing the data and to proceed to first preliminary data analysis, but also to think already what tasks have to be done during next season and what this means with respect to sending staff and cargo.

From the Belatmos instruments, three of them are still operational – the aethalometer, the TEOM-FDMS, and the laser aerosol spectrometer. The aethalometer and TEOM-FDMS are storing the data on their internal data storages and will be read out next season. Concerning the aerosol spectrometer – it is connected via an Ethernet cable to the internet. Therefore, I can regularly check the size distribution data and also download the current data. This also means that at this moment, the power supply of Princess Elisabeth station is still working. Let’s keep fingers crossed.

Above, I put some preliminary plots with examples of aerosol data. The top image shows the total scattering coefficient measured by the nephelometer at 635 nm for roughly two days (of 5min average data). These coefficients are given in units of Mm^-1 (or 1*10^-6 m). The scattering coefficient correlates well with the overall amount of ambient particles – the more particles there are, the higher the scattering coefficient. However, at the same time, aerosols do scatter and absorb, and the more scattering compared to absorbing they are, the higher the scattering coefficient will be. Values like shown in the graph represent low overall aerosol concentrations.

In the middle graph, the total number concentration detected by the condensation particle counter (CPC) is shown for two hours (1min averages) from the same period. The overall particle concentration was around 600 to 700 particles per cm-3. The few much higher peaks indicate very probably the measurement of the exhaust of skidoos or prinoths passing by nearby. However, this has to be analysed and confirmed in more detail. As mentioned in a former post, the usual concentration in sub-urban regions would be 10 to 100 times higher.

The bottom image gives the number size distribution over the two hours of the total number concentration of the middle graph. Although the laser aerosol spectrometer can only measure from a particle size of 90 nm onwards, the dominant size around 100 nm was within the measurement range. It also can be seen that there are hardly any particles larger than 1 micrometer. In a further analysis, I will combine the two measurements of total number concentration and of size distribution to define the concentration within the range 3 to 90 nm – as the CPC is measuring all particles from 3 nm onwards.

Last Days

Today is the last day for me at Princess Elisabeth station. Tomorrow we will fly to the Russian Novo Air Base and on Thursday then to Cape Town. The last days are filled with de-installing the instruments which have to go back to Belgium for calibration or adaption reasons, and to prepare the other instruments for winter operation. All my instruments have been measuring fine so far, so I am right away satisfied. There was a lot of sunny weather, and the ozone spectrophotometer and the sun photometer had done a lot of good measurements. Also the condensation particle counter (measuring the number of particles in the air) turned out to behave smoothly. Most of the time there are low particle concentrations of around 300 to 500 particles per cubic centimetres. If one would measure, e.g., in Brussels, the concentrations were 100 to 1000 times higher. Our instrument is really sensitive – detecting immediately if the station’s bulldozer, tractor or somebody smoking is passing nearby. The last days we take advantage of the calm weather for clearing the garage’s roof from the huge amount of snow/ice which has accumulated over the last winter. We were moving tons of snow/ice. One block of around 50x50x50 cm of this compacted snow weighs approximately 70 to 80 kg. On Sunday I also went with Denis from the Observatory to dig a 1 m snow profile in order to better understand the snow accumulation over the winter. These measurements are needed for the ‘Hydrant’ project of the KU Leuven, from whom nobody could come this season. At such a profile one measures the temperature profile, determines how many layers are distinguishable, and within these layers one describes the ice crystals size, form and the hardness of the snow. In addition, from the layers snow samples are taken in a normed cylinder and this is weighed. This weight is then converted in water equivalent and is then used to estimate the amount of precipitation over the accumulation period. On the images, the Utsteinen nunatak and the station on the small Utsteinen ridge can be seen. On Monday, we got a bit more wind and this was announced earlier by the forms the clouds form over the Romnoesfjellet peak towards north, around 60 km from Princess Elisabeth station.