On the first morning of the campaign, Saturday 22 February, the team was treated to a delicious breakfast. The temperature at the weather station went from close to -40°C (-50°C with the windchill) in the morning to -36°C in the evening (-47° with the windchill).
Despite non-ideal weather conditions, most of the team took off to the PEARL Ridge Lab around 8:30 am where spent a very productive day. Rather strong winds made working on the roof non-advisable and visibility became increasingly worse during the course of the day. However, the team had plenty of work to do inside.
Ellen remained at the weather station to assist ABB field technician Guillaume Gamache with his work on the E-AERI. On her way to 0PAL, she encountered musk ox Manfred who has been frequently spotted lingering around the station frequently. Manfred is known to be notoriously unimpressed by humans, but the team and weather station staff prefer to keep their distance regardless.
Sunday is only half a working day for the team with brunch being served at 11 AM. Since the weather had significantly improved from the previous day, the team was eager to head out to the Ridge Lab at noon. They seized the chance to take a few pictures on the roof where first-timers Ramina and Beatriz got their first impressions of the breath-taking scenery. The team then proceeded to work on their instruments. On their way back to the weather station shortly after 4 PM, they were able to capture several photos of the stunning Arctic twilight colours.

On Saturday, Beatriz and Tyler started off the day by cleaning the dust and old grease off of the panels and O-rings of the Bruker 125HR. They then re-applied new vacuum grease to the O-rings to ensure that the instrument has a good seal. Afterwards, they ran an N₂O background measurement and cell-test measurement, which will be processed in LineFit to check the alignment of the instrument. Lastly, they set up the logging of the pressure data from the Vaisala PTB330 pressure sensor on the Raspberry Pi, which will be relocated to the suntracker dome in the next few days. A missing screw on the right side of the suntracker dome caused a bracket to get stuck, preventing the dome from opening as it should. A fix was prepared, but they had to await better weather conditions to implement it.
Sunday's favourable weather conditions allowed Tyler and Beatriz to start solar measurements with the Bruker 125HR. The solar intensity was low but they were able to obtain 5 measurements, namely two measurements for filter 6 and three measurements for filter 3. They cleaned the scanner rods and fixed the problem with the dome by replacing the missing screw, so the dome now opens and closes as usual again. They also unpacked and set up the EM27/SUN and checked the general status of the instrument. However, they were not able to align the instrument yet because the solar signal was too weak. They analyzed the N₂O cell measurements from the previous day using LineFit and the results look good in general, even though they differ slightly from the former two cell test. When time permits, they would like to re-do the procedure to confirm their findings. They continued working with the pressure sensor to identify the best way and place to set up the sensor and the Raspberry Pi on the dome.

On the first day of the campaign, Kristof gave a tour of the PEARL Ridge lab to newcomer Ramina. They then spent some time resolving the UT-GBS tracker issues and restarted measurements. The PEARL-GBS tracker continues to show errors and will be investigated further on the rooftop when wind conditions stabilize. Kristof and Ramina then spent the afternoon assembling the indoor components of Environment and Climate Change Canada's Pandora instrument. Due to the challenging weather conditions they postponed assembling the outdoor components of the Pandora instrument.
On Sunday, Kristof and Ramina headed to the rooftop of the PEARL Ridge Lab to finish the installation of the Pandora instrument with the help of Pierre Fogal. After completing the assembly, Kristof and Ramina ran tests to ensure the trackers were working. The team was accompanied by a great rooftop view of the sun close to the horizon as they installed the instrument.

On Saturday, Ali went up to the PEARL Ridge Lab with rest of the team. Alexey gave him a tour of the DIAL and showed him the different parts of the system. Then, Ali set up Remote Desktop on his laptop to allow him to remotely control the DIAL from the Weather Station. Ali dedicated a significant amount of time and effort to troubleshooting some communication issues between the windows machine of the DIAL and his laptop which is running OSX. Ali and Alexey started collecting measurements around 7 PM. After about one hour, a layer of clouds formed at around 2.5 km and the wind blew snow onto the mirror. Therefore they had to stop measurements.
Alexey made good progress on the CRL and started running test measurements with the 532 nm laser.

The campaign started off well for Tom and the SunPhotoSpectrometer (SPS), which arrived in excellent condition. Within a few hours the packing case was emptied and the sun tracker was set for testing in the lab. The SPS itself checked out and was ready to make measurements of ozone and nitrogen dioxide. By lunchtime on Saturday, the instrument and tracker were both ready to be mounted outside on the roof of the lab but low temperatures and high winds made this an unattractive option. It was decided to wait until Sunday and hope to see more favourable conditions for outside work.
On Sunday, Tom and John took the SPS back to the roof where they mounted it successfully. After alignment the SPS will be ready to take measurements again.

On Saturday morning, Ellen assisted Guillaume on the E-AERI cooler replacement. They removed the cover around the black bodies outside of 0PAL so Guillaume can install a third black body over the course of the following days. They also worked on the connector of the cooler replacement part. On Sunday afternoon, Guillaume installed the new cooler on the E-AERI and is planning to calibrate the instrument tomorrow.

The team is looking forward to the upcoming days when most of the instruments will take their first measurements of this year's campaign.

Cheers,
Ellen Eckert
[on behalf of the 2020 Canadian Arctic ACE/OSIRIS Validation Campaign]