precious bay science

- 36^oC and science still goes on at Halley!

A project to look at the chemistry of the lower atmosphere has begun at Precious Bay, down at the coast some 17km away from Halley station. During springtime, chemical reactions occur on ice surfaces that associated with newly-forming sea ice (e.g. frost flowers, concentrated brines on new sea ice). These reactions generate reactive bromine compounds which are released into the atmosphere. Here they react rapidly with ozone and cause massive loss in ozone at ground level. These ozone depletion events have been studies at the Halley CASLab, but now we are trying to study them in situ. To do this a mini-max DOAS (Differential Optical Absorption Spectroscopy, which measures bromine monoxide) and an ozone monitor have been set up at Precious Bay to monitor the chemistry as the air arrives off the sea ice zone. The instruments have to run autonomously, and are supplied with power from a mixture of solar panels and wind turbines. We hope to run this experiment continuously over the next few months. The system was set up and the experiment started as temperatures reached –36^oC. The lucky two carrying out the work were Neil Brough (atmospheric chemist) and Thomas Speiss (UAV meteorologist) and made possible with a lot of effort and help from the Halley base.

Day 1...after arriving at the site by skidoo it was time to put the P tent up, get the caboose warm and settle in. It was still only about 25oC, and so it was fairly warm in comparison to what it is now (-42oC). The caboose or wooden/metal hut sleeps four and that is a squeeze but there were only two of us this time, me and tom, so it was comfortable. It has a heater, a stove and a tilly lamp for light, 4 beds, a table and a collection of cosmopolitan

Day2....not a great sleep in the sleeping bags but another day with more cups of tea. Put up most of the poles for the generators and solar panels. Able to work with thin gloves on due to the warm weather. Man food (bagged and freeze dried food) was for lunch but a frozen food parcel from the chef was waiting for us for the evening meal. Wet clothes hung around to dry and warm up.

Day3... woke up and felt the cold for the first time since arriving, the blow that was predicted has arrived and we have to sit it out for most of the day. It was a gusty 25-30 but we were safely inside our sleeping bags waiting for the storm to pass. Only two things needed to get up for, tea and pee....a day of reading

Day 4..set up the rest of the equipment. The temperature has dropped to -36. we are having to warm our hands in the caboose as well as run around the perimeter to keep the feet warm. The breathing causes lots of condensation at night and the cold is a discomfort and a disturbance to my sleep. The good thing is that the stars are crystal clear although star gazing is brief.

Day 5...outside temperature -36, inside temperature -25...we are having a few minor problems getting the caboose upto temperature and so we decide to head back this day since it is a clear sky. We pack up, roll the sledge over and spend 30 minutes getting it back up and reach the warmth of base an hour later. It is such a comfort to find the warmth again. More trips to precious bay are planned to check on the instruments and download the data. The fun we have....