Things worked out well for the team on Friday, March 6. Eureka saw a total of 8 hours of sunlight which was made good use of by the team. Since all instruments are currently running smoothly, the increased wind speeds at the Ridge Lab didn't cause any major delays. Temperatures at PEARL were rather low, around -36°C (well below -50°C with the windchill), but there was still quite some activity in and around the lab. Shortly after arriving, the team spotted a herd of musk oxen on the ridge across from the lab. The herd was moving fast and the team was wondering if they were being chased by the wolf pack that lives in the area. A bit later, Eureka SPM Scott, SPM-in-training Andrew and MetTech Cole stopped by at the lab and the team showed them around, and explained their research and their instruments to the curious visitors. After another successful day, the team wrapped up at 4:30 PM and headed back to the weather station for dinner.

Tyler and Beatriz began solar measurements around 9:30am, shortly after arriving at the Ridge Lab. The wind speeds were too high to work on the roof, so they weren't able continue working on the pressure sensor. However, they continued to monitor the data from the sensor now that the tube is installed in the suntracker dome. They also performed some tests by disconnecting the tube from the sensor to confirm that it was registering a pressure difference. In total, they collected 107 mid-infrared solar measurements with the Bruker 125HR across all seven spectral filters, and around 3000 interferograms with the EM27/SUN.

Kristof and Ramina's daily instrument check showed that all UV-Vis instruments were operating nominally. The PEARL-GBS took MAX-DOAS measurements on March 6, and the Pandora continues its regular measurement schedule. As the Sun gets higher and the hours of sunlight increases daily, the measurement window increases as well. While the instruments were running, Kristof and Ramina were catching up on some research and coursework.

The night from Thursday, March 5, to Friday, March 6, was another good night for the DIAL. The weather was clear and calm. Observations were collected between 9 PM on Thursday to 6 AM the following day. Ali and Alexey assumed that the optics might need a clean-up but this didn't turn out to be necessary.

The CRL measured 24h of calibrated measurements on March 5.

Another successful "Raven" launch happened on March 6 at 6:15 PM. It reached 20678 m (35.0 hPa) before communication with the sonde was lost.

While most things have become routine now and measurements are running smoothly, the team is hoping for the winds to calm down a bit to be able to work on the roof again and maybe go for a hike the following days as the views are stunning.

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