The team went up to the Ridge Lab on March 10 after breakfast and stayed there until just before dinnertime. Weather conditions were sunny with ice crystals and –32.5°C (–44°C with windchill).

Petra and Pierre started the day by diagnosing and correcting the technical issues with the FTIR Suntracker system from the previous day, which turned out to be a network problem. With the sun properly pointed into the FTIR spectrometer, Petra recorded near-infrared spectra while she and Pierre prepared equipment for mid-infrared spectra.

To make mid-infrared measurements, Petra changed out the beamsplitter, the key component that permits different spectral regions to be recorded. She then used liquid nitrogen to cool the detectors that convert incoming photons to electrons that create the signal. These measurements were recorded until sunset. Due to network connection issues with the Suntracker, FTIR measurements were not possible on March 11 and 12.

Kevin took inventory of spare parts for the two GBS instruments. Then, he and Darby connected to a network webcam that will be installed on the roof of the Ridge Lab to monitor the domes that cover the optical equipment that directs light toward each GBS detector. Darby also digitized selected pages from archival lab books.

On March 11, the mat-track truck underwent maintenance to ensure safe travels on upcoming trips to and from the Ridge Lab, so the team spent the day working from the Eureka Weather Station. In the afternoon, Darby, Kevin, and Petra walked over to 0PAL to connect a new network webcam, intended to monitor local conditions. At 18:15, the team watched the meteorological team launch an ozonesonde carried by a large Raven balloon filled with hydrogen, also a part of the ACE/OSIRIS validation campaign, and captured the launch on camera. This was potentially the last launch at this station ever using a Raven balloon, as Totex balloons are normally used. Weather conditions were sunny with ice crystals and –32.5°C (–44°C with windchill).

Darby and Kevin went to 0PAL on March 12 to test and organize equipment. The weather was sunny with ice crystals and –35.5°C (–49°C with windchill). The team wound down in the evening with card games and Pierre and Petra taught Kevin and Darby how to play cribbage.

The Pandora instrument operated nominally.

Cheers,
Darby Bates
[on behalf of the 2025 Canadian Arctic ACE/OSIRIS Validation Campaign team]