Sunday evening was quiet for the most part. Kristof and Paul again watched the ozonesonde launch, Erik and Sébastien returned to the Ridge Lab for a few hours to finish the Bruker's alignment, and some of the team packed their personal gear in preparation for leaving tomorrow morning. Eventually most of the team ended up watching television with weather station staff and visitors to the station.
Monday morning started off pleasantly warm, with a temperature of -30 degrees (the warmest it's been during this campaign) and ice crystals making the horizon hazy. The team set off for the PEARL Ridge Lab hoping that the 10 hours and 38 minutes of sun up, coupled with the rapidly clearing sky, would permit for a full day of measurements. At noon the team joined together in the PEARL Ridge Lab common area for a teleconference, with Emily doing one of the presentations involved in that, before returning to our separate projects. While the temperature continued to warm up all the way to -25 degrees, this was followed by an increase in cloud cover and blowing snow. Shortly after the teleconference the sun became fully obscured by clouds and blowing snow, and solar measurements had to be abandoned. Half the team departed the Ridge Lab for the last time around 14:30, and the remainder of the team departed PEARL near 17:00.
Paul spent the first half of the day making solar measurements with PARIS-IR, managing to take 26 of these before the sun became obscured. Afterwards he processed the new data into interferograms and raw spectra and backed it all up onto external drives. Finally Paul finished cleaning the area around PARIS of equipment no longer needed during the extended portion of the campaign.
In the morning Kristof was able to calibrate the active solar tracking for the PEARL-GBS. Since both GBS instruments continue to operate normally, the last day passed without any excitement.
With DIAL shut down for the season, Ghazal spent the day catching up on other projects.
To follow up on the instrument alignemnt, Erik and Sébastien did HCl and N2O cell tests Sunday evening and Monday morning. In the afternoon they packed the alignment kit and left the instrument with the CaF2 beamsplitter installed in order to start another HCl test remotely.
Gurpreet checked the performance of SPS and continued to make measurements with the instrument.
Finally at 0PAL, CRL made 12 hours of measurements with both lasers on March 12th, spanning 00:00-3:00UTC and 15:13-23:59UTC. Snow in the evening accumulated on the hatch window and obstructed measurements, so the hatch had to be closed for the remainder of the night. It was opened again in the morning. While weather forecasts continued to show "light snow" by morning it was no longer the wetter snowstorm-type snow of the night before, and could barely be seen. Measurements continued into March 13th until the evening when gusts of wind and blowing snow forced the lidar to close the hatch. Measurements will recommence on March 16th after Emily has returned home.