When the team arrived at the Ridge Lab shortly before 9:00 AM on March 4, there were still several clouds on the horizon. However, the strong wind of the previous days had died down and the temperature at PEARL was rather pleasant at slightly below -30°C. The total time of sunlight amounted to 7:20 hours. The team proceeded to get their instruments ready for the day and a brief glimpse of the early Arctic spring Sun provided some hope. Shortly after lunch the wait was over. The clouds finally disappeared allowing a clear view of the Sun for several hours. After a successful and productive day, the team headed back to the weather station for dinner at 5 PM.
In the morning, there was a layer of cloud hanging over the fiord and solar measurements were not possible yet. Beatriz and Tyler took the time to reinstall the PTU30T at the Ridge Lab near the Bruker 125HR and ensured that their codes were logging the data properly. They then ran some tests using the long intake tube for the pressure sensor to see if it would register a pressure difference when changing the height of the tube to be above or below the sensor itself. They found that the sensor does not register a change in pressure if the end of the tube is at a lower elevation than the sensor itself, but does so when raising it above the height of the sensor. Accordingly, the PTU30T should register a pressure difference if they raise the end of the tube up to the level of the Sun tracker dome. Around noon, the Sun began to rise above the clouds so they began taking solar measurements with the Bruker 125HR and the EM27/SUN. By mid afternoon, the clouds had mostly disappeared, and they were able to collect a large number of high quality solar spectra. By the end of the day, they had collected a total of 30 solar measurements with the Bruker 125HR across all of the 7 spectral filters. They encountered some issues with the sun tracker which had difficulties keeping the Sun centered in the field of view, but they were able to overcome this by manually adjusting the tracker pointing. Overall, it was a very successful day for the FTIR's.
With favourable wind levels throughout the day, Kristof and Ramina were finally able to head up to the roof of the Ridge Lab to start troubleshooting the PEARL-GBS tracker issue. While the issue is not yet resolved, they spent the day ruling out the motor and the motor cable components of the setup as possible causes. If favourable weather conditions persist, they will continue troubleshooting with a focus on other components such as the motor controller.
Due to clouds, Ali wasn't able to make any measurements with the DIAL during the night of Tuesday, March 3, to Wednesday, March 4. Since the conditions improved significantly during the day of March 4, he is optimistic for upcoming measurements.
The CRL made 24 hours of measurements on March 3, again with the uncalibrated depolarization.
The team is enthused by the excellent afternoon weather conditions. They hope conditions will continue to be good enough to work on the roof as needed and take more solar measurments for the rest if their stay.
Cheers,
Ellen Eckert
[on behalf of the 2020 Canadian Arctic ACE/OSIRIS Validation Campaign]