Monday, 15 December 2014

Works are going on

We are not only busy with instruments directly at the station. We also went to the automatic weather station a few hundred meters to the East of the station in order to maintain it. Its data logger was partly damaged in mid-June during heavy winds (up to 26 m/s). We had a new one with us and replaced the old one with the new one. Parts of the measurements of that automatic weather station are temperature sensors in the ice for a vertical temperature profile. As there is every year some snow accumulation (some years more, some less, with a high variability), these sensors are not anymore at their original depth and therefore new ones are placed. If possible, the old ones can stay connected to the data logger. Another important piece of information for the interpretation of snow accumulation comes from snow profiles, i.e., the digging of a pit/hole of around 1.5m depth. One determines the different layers of snow (e.g., hardness, crystal size, form), measures temperature, ice crystal habits, and takes measures for deriving the water equivalent in mm of the different layers. Quentin and I went to dig such a snow pit on a calm sunny day and the views one has are really beautiful. The snow knife is necessary to cut out the cylinder for the water equivalent measures out of the surrounding ice.
We also continued the trials and repairs to get the laser instrument for measuring the size distribution of particles and the sunphotometer back to operation. Very likely, the sunphotometer has an issue with its motorized robot system and somehow the delicate system of gears and pins to detect zero and other pre-defined positions has been de-routed. It is still not working and we get a bit desperate on it. On the other side, we managed finally to get the laser instrument back to work. It took quite a few emails with the manufacturer and trials/repairs on the internal cabling of the electronic steering boards. It appeared that its internal pc was broken. We had to connect an external pc via a serial cable to the electronics of the instruments, got the software from the company, and after some typical trial and error work on the serial connection, the instrument measures since Sunday noon again. This is very good news. The data of this instrument are also very important for interpretation of the cloud condensation nuclei counter. So, in the evening we granted ourselves one or two glasses of fine whiskey.
In addition to this and the routine work on the other 10 instruments we launched every day a radiosonde with a balloon. If there is not much wind, it is no problem to hold the Helium-filled balloon until the radiosonde is ready (i.e. until the receiving signal of the GPS is stable). But during stronger winds, the balloon is bouncing in every direction behind our place of a container and it looks like a fight man against balloon :-)
Now we are already in our last week at Princess Elisabeth station. The schedule foresees that we leave the station on Friday or Saturday, probably Friday. This means to prepare all instruments in a way that the engineers and technicians remaining at the station can easily handle or check them.

No comments:

Post a Comment