After the stormy weekend the team was finally able to return to the PEARL Ridge Lab on Monday, March 2. Sunday's icy winds had taken their toll on the lab and driven the indoor temperatures down quite a bit. The outside temperature had increased compared to the weekend and remained close to -26°C (around -40°C with the windchill). The winds had also calmed down, both at the Ridge Lab and at the Eureka Weather Station. The team got back to work on their instruments shortly after 9 AM and adapted well to the challenging indoor environment throughout the day. Even though visibility had significantly improved compared to previous days, clouds prevented solar measurements. The team returned to the weather station at around 4:15 PM.

Beatriz and Tyler worked on installing the new Vaisala PTU30T pressure sensor used for the Bruker 125HR next to the Bruker PC. The data outputted from the sensor was formatted differently compared to the previous pressure sensor, so some modifications were required to make it compliant with the pressure logging codes. Once the PTU30T was set up, they let it collect data for a few hours to ensure it and the codes were working properly. At the end of the day, Beatriz and Tyler brought the sensor down to the Eureka Weather Station to compare its output with a well-calibrated Environment and Climate Change Canada pressure sensor. This will help identify potential systematic biases in their sensor.

Kristof and Ramina performed the UT-GBS lab tests today. They started with removing the input optics from the tracker hatch. They then performed the resolution tests, and the results confirmed that the UT-GBS CCD won't need realignment. The stray light and polarization tests both yielded results similar to previous years. To finish the tests, the UT-GBS was left to take dark current measurements overnight.

Since the weather conditions remained challenging during the night of Sunday, March 1, to Monday, March 2, Ali and Alexey could not operate the DIAL.

The CRL remained closed on March 1. Alexey took the opportunity and topped up the cooling water in the lasers. Measurements began again this morning, Monday March 2, as soon as the winds abated.

A regular ozonesonde was launched by the weather station staff at 6:15 PM. It reached a final altitude of 15754 m (81.9 hPa).

The team is looking forward to improving conditions and warmer temperatures inside the Ridge Lab.

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