On Wednesday February 28th the weather at the Eureka weather station hovered around -24 degrees throughout the day, while up at the PEARL Ridge Lab it steadily rose from about -24 degrees in the morning to about -20 degrees in the evening. Unfortunately, the overcast weather from the past few days held fast, and the 6 hours and 10 minutes of sunlight was mostly obscured by the thick clouds. But once again the team remained optimistic about the conditions improving soon and performed a variety of tests on their instruments to prepare for the next opportunity to make solar measurements.
Erik and Sébastien installed the alignment kit on the Bruker FTIR. For this, a HeNe laser replaces the solar beam and a telescope is used to view the interference pattern. Pictures of the fringes were taken at various positions of the mobile mirror, but no adjustments were attempted to the Bruker. Before going back to the weather station Erik and Sébastien started a second channeling test with a different filter. Kristof was again prevented from working on the roof due to continued high winds. He performed the resolution, stray-light, and polarization tests on the UT-GBS today, and left the instrument to take dark current measurements overnight.
Regular measurements were made overnight under cloudy skies with the CRL. This morning Emily and Peter topped up the laser water, and discussed the filter replacement that Peter will likely do for the CRL later in the year. Emily installed a new lamp which points up into the hatch, which will be helpful in verifying whether the hatch is open or closed, even when it's dark during polar night. The motors which adjust the laser frequency doubling were reinstalled in the lidar, and were realigned. Regular measurements began again in the afternoon.
Once again SPS was found to be operating as expected overnight, and further preliminary analysis of the data was performed by Tom throughout the day. In the afternoon, Tom trained Paul to operate SPS, as Paul will be taking over from him this weekend for the rest of the intensive phase of the campaign.
In addition to the operations overview of SPS provided by Tom, Paul ensured that the various instruments under his purview, including SAOZ, continue to operate as expected.
Xin took his first snow profile samples from the far end of the Eureka airport runway today. Before lunch, he managed to analyze salinity for the snow samples he collected yesterday from near the Ridge Lab and on the fjord. Xin found some interesting results from this, particularly that the surface snow salinity near the Ridge lab is several times higher than in lower layers. In the afternoon, two more vertical snow profiles were taken at the same sea ice and Ridge lab sites as yesterday. Additionally, further surface snow samples were collected for salinity analysis.
As with yesterday, due to the persistently overcast weather DIAL did not operate last night. It is fully operational and Ghazal and Alexey are waiting for clear sky.
Finally in the evening, some of the campaign team braved the cold for a few minutes to watch one of the meteorological technicians launch the first ozonesonde of the campaign.
Cheers,
Paul Jeffery
[On Behalf of the 2018 Canadian ACE/OSIRIS Arctic Validation Campaign Team]