On Wednesday March 6th, the temperature at the Eureka Weather Station was around -35 degrees C, with a calm wind of 1.6 knots (3 km/h) giving a windchill temperature of -39 degrees C. At the PEARL Ridge Lab, temperatures were approximately -28 degrees C, with winds of 8.7 knots (16.2 km/h), bringing the windchill index down to -40 degrees C. The weather today was characterized by light snowfall in the morning and a consistent dusting of ice crystals in the afternoon (visually distinguishable from snow by the formation of “halos” from reflected and refracted sunlight). Today we had a total of 8 hours and 35 minutes of sunlight.
The morning was mostly cloudy. However, the sun briefly rose above the low-hanging layer of cloud, and Tyler managed to record a few spectra with the Bruker 125HR and the EM27/SUN before the sun disappeared again. While the realignment of the 125HR resulted in excellent lineshapes, the signal levels with one of the internal sources are lower than expected. Tyler and Pierre will try to increase the signal-to-noise ratio by fine-tuning the alignment of the internal source optics on the next cloudy day.
Kristof lost connection to the UT-GBS CCD last evening, and he wasn't able to revive it remotely. In the morning, he found that the CCD controller unit appeared to be off. After taking a closer look, Pierre determined that the built-in power supply in the controller was dead. A replacement was quickly ordered with help from down south, and the new power supply should arrive on the plane that will carry the rest of campaign’s intensive phase team home. Pierre (who will stay for the extended phase) will try to repair the CCD controller once the power supply arrives; the UT-GBS will remain offline until then. The PEARL-GBS continued the MAX-DOAS measurements today, and the Pandora was switched to regular measurement mode as well.
In the morning, with help from Peter, Xin collected snow samples from all of his sampling sites, including a snow core sample on the sea ice down to a depth of ~28 cm. In the afternoon, Xin worked at 0PAL to measure snow density for those snow samples collected from the sea ice. This afternoon we observed a sundog around the sun at Eureka and the tray mounted on outside of 0PAL successfully collected a thin layer of diamond dust for chemical analysis.
Ali continues to work with DIAL data from earlier in the campaign, as well as some old sample data from 2004 which is archived in the system. He aims to compare the older data processing method with his new optimal estimation scheme, using radiosonde temperature profiles as a baseline. He spent much of the afternoon working on code to read in the older DIAL data and do the comparisons, as the older data is in a different format than the new DIAL data. Additionally, he did his usual checks on the SPS data, and noted that the instrument continues to operate nominally.
Emily continues to run the CRL from down south, and it has been has making measurements continuously with both the green and UV lasers during all times that the winds are gusting less than 20 knots at 0PAL. So far, she has measurements 24 h/day for 25 - 28 February, then for partial days on each of 1 - 5 March (with a minimum 9.75 h each day), and again for 24 h on 6 March. These measurements continue at present. Based on initial data assessments, the CRL measurements appear to be of good quality.
At the end of the day, a few of the campaign team members went for a 3 km walk towards the Eureka airport, and through the hills behind the Weather Station. After dinner, they gathered outside to watch the launch of a Raven balloon carrying an ozonesonde.
Cheers,
Tyler Wizenberg
[On Behalf of the 2019 Canadian Arctic ACE/OSIRIS
Validation Campaign team]
* Instrument Status *
Bruker FTIR: Nominal operations
EM/27 SUN FTIR: Nominal operations