On Saturday March 10th, the team woke up to clear skies and temperatures around -44 degrees at the Eureka weather station. Throughout day the temperature at the weather station bounced between -43 and -45 degrees, while up at the Ridge Lab it rose from -30 to -28 degrees. Approximately 9 hours and 40 minutes of sunlight was expected, and the team was able to make good use of it to record measurements.
The previous night was clear, permitting Ghazal to make the last DIAL measurements for the season. Saturday morning she joined the rest of the campaign team in heading up to the PEARL Ridge Lab, to shut down DIAL. With a little help from Pierre and Paul the end of season process went well and the system was “summer-ized” by the mid-afternoon.
Sebastien and Erik spent the day taking mid-infrared solar measurements with the Bruker FTIR. A total of 111 MIR measurements were taken.
With both the PEARL-GBS and UT-GBS working well, Kristof was able to focus his attention on data analysis. Looking at the data, Kristof found that bromine levels had returned to normal since the bromine explosion seen earlier in the week. Additionally, Kristof spent some time talking to Xin about how to best utilize the output of Xin's chemical transport model for analyzing the observed bromine explosions.
In the morning Paul cleaned the SPS window and verified that SPS and the tracker had functioned as expected overnight. Around 11:30 he reset the computer that controls SPS and its tracker. In the afternoon during a check of SPS Paul found that its control software had frozen, requiring a reset of the software, after which SPS continued making measurements normally. Periodic checks of SAOZ throughout the day found the instrument to continue operating as expected. SPS was left to run overnight.
John and Xin visited the site behind the Ridge Lab site for the last time. Afterward they discussed the snow sampling instructions Xin had prepared to allow for further sample collection during the extended phase of the campaign. In the afternoon, they visited the two sites 5 km to the west of the station, and then collected snow samples from atop the sea ice site in front of the station.
Saturday evening saw much of the campaign team watching the ozonesonde launch, followed by watching some hockey in the rec room. Overall it was an evening of rest after a long week of work.
On Sunday the 11th of March, the temperature at the weather station began around -40 degrees and warmed over the course of the day to -38 degrees. Up at the Ridge Lab the temperatures went in the opposite direction, beginning near -30 degrees and gradually cooling to -32. While the early morning was cloudy, by mid-morning the sky had cleared, and it remained clear for the rest of the day. About 9 hours and 55 minutes of sunlight were expected.
On the way up to the Ridge Lab the team saw a wolf, possibly the same one as they had on Friday, running atop the sea ice near the roadway. The team managed to get some great pictures of its trek, and they got lucky enough to see it stop and roll around in the snow for a bit. On the way back to the weather station in the evening they saw another wolf, following a similar path as the one in the morning. While the wildlife during the first part of the campaign was scarce this certainly has helped make up for it!
Kristof continued working on code to analyze the bromine data, both new data from this year’s campaign and that from previous campaigns. In particular he was looking at measurements that overlap with results from Xin’s model to allow for comparison.
Upon arriving at the Ridge Lab Paul checked the windows of both SPS and SAOZ to ensure they were clear, before checking on the operations of both instruments. Paul reset the SPS and tracker software around 1:30 in the afternoon, and continued monitoring SPS and SAOZ intermittently. SPS was left to run overnight.
On Sunday, Sébastien and Erik continued with mid-infrared solar measurements. A total of 56 MIR measurements were made. In the evening they went back to the lab with Pierre to check the aperture alignment of the instrument. They found that the front and rear apertures were not co-aligned. Sébastien and Erik aligned the apertures and are currently running a HCl cell test to check the result.
Sunday morning, Xin made his last visit to the site near the creek behind 0PAL and took a set of samples from there. In the afternoon, he and John went to the two sites west of the station, and then made their last visit to the runway site. The rest of the afternoon was spent packing up samples we in the 0PAL lab.
Sunday evening saw the team watch an ozonesonde launch, followed by each heading off to continue working on their own projects. With only two full days left up in Eureka, weather permitting of course, the team is trying to get everything in order before their departure.
Cheers,
Paul Jeffery
[On Behalf of the 2018 Canadian ACE/OSIRIS Arctic Validation Campaign Team]