Tuesday, March 10, was the last regular day of the intensive phase of the campaign. The team has been lucky with the weather being consistently good after a long wait at the beginning of the campaign, and today was no exception to that. The skies were clear with low winds, and temperatures at the Ridge Lab remained around -32°C for the entire day. It was considerably colder at the weather station with temperatures close to -45°C, sometimes going down to -55°C with the windchill. While Ramina, Ali and Ellen went to see the icebergs in the morning, the rest of the team headed up to the Ridge Lab after breakfast. Ramina joined them shortly after lunch when SPM-in-training Andrew and mechanic John went up to the Ridge Lab. The team went back to the weather station for dinner just after 5 PM.

Tyler and Beatriz started mid-infrared measurements with the Bruker 125HR around 9 AM and near-infrared measurements with the EM27/SUN. At 11 AM, they stopped the measurements for around an hour to swap the Bruker 125HR beamsplitter from KBr to CaF₂ to perform near-infrared measurements, and also to set up the SPH10 Vaisala static pressure head inside of the dome. After the successful installation of the pressure head, they took near-infrared TCCON measurements with the Bruker 125HR. By the end of the day, they had collected 26 mid-infrared solar spectra and 50 near-infrared solar spectra with the Bruker 125HR and around 1700 near-infrared interferograms with the EM27/SUN.

Kristof spent the day writing up a standard operating procedure document for the Pandora instrument. He also had to troubleshoot some alignment issues, with remote help from the Pandora team. It appears that the alignment code is struggling to cope with the unusual movement of the high Arctic Sun. The measurements, however, were not affected. After the morning trip to the icebergs, Ramina spent the afternoon compiling a complete inventory of the GBS equipment and backup parts.

Ali and Alexey took measurements with the DIAL between 9 PM and 4:30 AM during the night of Sunday, March 9, to Monday, March 10. The lidar is operating nominally.

The CRL made 24 hours of measurements on March 9.

An ozonesonde was launched in the morning of March 10, at 6:17 AM, and reached a final altitude of 30313 m (7.0 hPa). Another ozonesonde was launched at the regular time, at 6:15 PM, which terminated at an altitude of 16786 m (69.8 hPa).

The team will head up to the Ridge Lab for the last time tomorrow, weather permitting, to wrap up and get the instruments and documentations ready to take over for Pierre and Andrew who will perform measurements during the extended phase of the campaign.

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