After five days of clouds, the sky finally cleared up on Thursday. Eager to seize these weather conditions, the team got to the Ridge Lab by 9:00 am and got started on their instruments immediately. With a sun rise at around 8:00 am and about 9:45 hours of daylight, the clear sky conditions posed perfect conditions for measurements.
Solar mid-infrared measurements with the Bruker 125HR started later than expected today for Sébastien and Erik due to communication issues between the tracker computer, sun-tracker dome and tracker motors. With the assistance of Pierre, the dome was opened manually from the roof, but could still not be controlled by the tracker computer. They began to try and diagnose the errors by checking the serial connections and power supplies but could not find the cause. They eventually were able to run the dome and sun-tracker by switching from the tracker computer's ethernet IP to wireless IP. For the remainder of the day, the sun-tracker and dome ran without error allowing for a total of 50 measurements before shutting down remotely from the weather station. Sébastien and Erik returned to the lab after dinner to further test the sun-tracker and dome and found that they were running normally.
Kristof spent the day debugging code. The camera adjustments made by the tracker code confuse the LabVIEW code used by the GBSs to record spectra. Until this communication error is resolved, some functions of the tracker code cannot be used. Fortunately this does not affect the measurements.
Pierre and Ellen moved on to even more drastic measures and took PARIS-IR apart, down to its bare hard drive. Connecting it to Pierre's computer, they found that its file system was corrupted. This issue, however, could be resolved. After putting everything back together, PARIS-IR came back to life after 5 days of being out of order. The control software didn't show any issues and Ellen was even able to recover the last 6 measurements PARIS-IR had taken before going down on 5 March. She then seized the last minutes of daylight to perform 19 solar measurements with the instrument and, after shutting it down properly, converted one into an interferogram and further into a spectrum to see if there were any peculiarities. Both the interferogram and the spectrum looked reasonable.
On the 9th of March UTC, Emily measured for 24 hours with the CRL. The clouds over the weather station and 0PAL were so optically thick that they completely extinguished the CRL's beam by about 3 km altitude.
After days of waiting, the sky finally cleared up at 8:00 p.m on 9 March. Emily and Ghazal went to the Ridge Lab and successfully finished the realignment of the laser. The lidar operated nominally from 9:30 p.m to 6:00 am local time.
Today's ozonesonde - again a Raven - was launched with the assistance of handy person Shawna, who brightens up our daily life at Eureka with her delicious cooking and uplifting spirit. Due to calm atmospheric conditions, the sonde stayed fairly close, as it just travelled to 97 km southeast of Eureka. It climbed as high as 33267 m, rising 195 m/minute.