The sky near the horizon was filled with streaks of heavy clouds this morning, and throughout the day. Luckily, the Sun was positioned between bands of thick clouds for a few hours mid-day, allowing enough sunlight to reach the instruments for measurements. Joseph and Dan took 23 mid-infrared measurements with the Bruker, and focused on filters measuring parts of the spectrum where CH4, N2O, HCl, HF and O3 can be retrieved. The light was too dim to take data using other filters. Debora performed 18 measurements with PARIS. Her data will be analyzed to examine O3, N2O, HCl, HF and HNO3.
This morning, Pierre finished building the new sun tracker dome, for which Xiaoyi is very thankful! In the afternoon, Pierre, Dan and Xiaoyi installed the tracker on the roof. The temperature outside at PEARL was -21 °C throughout the afternoon, but felt considerably colder due to 30 km/hr winds (gusting up to 43 km/hr). Dan took a few great photos of this process to share with you on our daily album.
Xiaoyi's UT-GBS and SAOZ continue to function normally. His work troubleshooting the PEARL-GBS continues. Thankfully, the PEARL-GBS completed its dark current measurements successfully last night. Progress at last. Xiaoyi now suspects the UPD sub-vi is causing the problems. He tried a series of potential solutions today, and believes he has a fix. He will continue following this thread tomorrow. With help from Joseph, Xiaoyi moved the PEARL-GBS back to the mezzanine. It has been taking zenith-sky measurements. Xiaoyi almost has all three of his instruments running now!
Volodya finished testing Brewer 021. Volodya and Dan carried it back up to the roof and Volodya re-installed it. He will monitor its performance for the next few days. If the micrometer cleaning was enough to make it happy, he will install Brewer 192 at the weather station. Both the SPS and MAESTRO continue to work fine and collect data.
At Eureka, the temperature has stayed near -40 °C this afternoon. At the nearby 0PAL, the CRL operated for 24 hours, and took measurements in all channels. Water vapour measurements were taken only during hours of darkness. Emily also worked on calibrating and processing depolarization channel data. For her, the weather has been helpful in one sense: The clear sky one day followed by ice clouds the next is helpful in this lidar calibration process!
Today's ACE ozonesonde flight was launched at 18:15 and reached an altitude of 30,622 m and 8.0 millibars.
It appears the Polar Vortex is beginning to dissipate.
We had the first wildlife sighting of the trip: while driving up to PEARL the team saw an Arctic Fox running along a nearby hillside. We tried to catch a photo, but it was too quick for much success.
In the evening, Emily and Dan watched the launch of a radiosonde balloon. While he had looked at data collected from them before, Dan had never seen one!