The team woke up to low hanging clouds on Tuesday, March 3. They made their way up to the Ridge Lab at 8:30 AM but it soon became clear that no solar measurements would be possible today. Visibility decreased quickly and the team decided to head back to the weather station for lunch at noon. Both Eureka and PEARL saw temperatures at or slightly above -30°C throughout the day with moderately high wind speeds. Even though obstructed by thick clouds, the Sun was above the horizon for 7 hours.
Due to the thick clouds solar measurements with the Bruker 125HR and EM27 were not possible. Tyler and Beatriz set up the Vaisala PTU30T pressure sensor at the weather station and continued to take side-by-side measurements with the well-calibrated Environment and Climate Change Canada PTB330 pressure sensor at the weather station. They quantitatively compared both data sets and found that the PTU30T was biased high by a very small amount relative to the PTB330. Nevertheless the two sensors present good agreement in general and track similar pressure trends. Tyler and Beatriz will collect more side-by-side measurements to establish the PTU30T bias. They will also use the PTU30T to check the calibration of the Setra pressure sensor of the PEARL weather station at the Ridge Lab.
In the morning, Ramina and Kristof processed the results of last night's dark current measurements for the UT-GBS. With the last of the lab tests completed, they replaced the input optics in the hatch, and restarted measurements. The winds were still too strong to work on the roof, so in preparation for troubleshooting the PEARL-GBS tracker, Ramina and Kristof assembled the backup tracker parts into a functional setup that will be used to test individual components of the PEARL-GBS tracker.
Since heavy clouds obstructed the sky during the night of Monday, March 2, to Tuesday, March 3, Ali couldn't make any measurements with the DIAL.
The CRL made 12 hours of measurements on Monday, March 2, and measurements are continuing into March 3. The weather has still not cooperated for a start delay depolarization calibration, but are otherwise going very well, with lots of signal from snowy clouds.
Pierre found the SPS frozen and not pointing in the right direction. He rebooted the SPS computer and that fixed the problem. The SPS is now back to nominal operations.
The team is patiently waiting for clear skies and sunny weather while making sure that everything is ready once conditions improve.
Cheers,
Ellen Eckert
[on behalf of the 2020 Canadian Arctic ACE/OSIRIS Validation Campaign]