This Tuesday turned out to be another day with perfectly clear skies and 6:45 hours of daylight. The outside temperature at PEARL stayed close to -25℃ during the day and the strong nightly winds slowed down. The team made it to the Ridge Lab by shortly after 9 am without any problems on the road and started their daily routines.
Another sunny day allowed Sébastien and Erik to perform mid-infrared measurements with the Bruker 125HR for a third consecutive day. Today 66 measurements were made in total matching yesterday's number. They also noticed increasing signal intensity of the measurements in each filter due to the gradually increasing solar elevation angle. This was also noticed in the solar tracking as Sébastien and Erik had an easier time locating the position of the Sun with the solar-tracker at start-up. They hope to achieve a larger number of measurements in the coming days as weather permits. After yesterday's test of the vacuum of the Bruker, Sébastien and Erik have decided to keep the pump running overnight to allow for faster start-up in the morning to maximize the number of measurements.
Kristof spent the morning finishing the lamp and stray light tests for the PEARL-GBS. Afterwards, he proceeded to troubleshooting the PEARL-GBS sun-tracker with Pierre and Peter. They were able to rule out several potential issues, and the search for errors has been narrowed down to the components in the sun-tracker dome. The cables and motor controllers will have to be be tested whenever weather permits them to work on the roof. Kristof has also set up the PEARL-GBS to take dark current measurements overnight.
Ellen continued operational measurements with PARIS-IR today. She took 36 measurements with the instrument between 10:27 am and 3:28 pm. There were no complications. In addition to working on the website, Ellen started to convert the measurements taken during the weekend to interferograms yesterday and continued with the processing of Monday's measurements today.
Since SPS was having some issues, Pierre went on the roof this morning and found that the cable to it was loose. After tightening it, the instrument seemed to work fine for a while but at some point it seemed to have difficulties again. MAESTRO is running smoothly, but since SPS is controlling the tracker its number of measurements might be increased once Zahra's attempt to let MAESTRO control the tracker succeeds. Pierre also scraped some frost of the window.
The CRL ran for 22.84 hours on 29 Feb (UTC). It required a restart once, but otherwise ran smoothly. Later in the day, the clear skies were invaded by some clouds which came in from the South with increased wind speeds. Emily was able to spend much of the day processing the raw data from the first days of the campaign and producing some initial lidar plots to compare with other instruments.
Due to strong winds, Ghazal wasn't able to perform measurements with the DIAL at the night from 29 February to 1 March.
As on the previous day, an ozonesonde was launched at 6:15 pm local time. This one was successful and made it to 34194 m. It ended its flight approximately 170 km southeast of Eureka. Today's balloon was a 1200 g model, set up with a 1.5 kg lift, that rose at approximately 240 m/minute.