When the team got to the Ridge Lab at around 9:00 am, visibility was poor due to blowing snow and a thin layer of high clouds. These conditions persisted until close to noon, when the wind speed dropped slightly and the sun finally reappeared from behind the cloud cover. Erik and Ellen seized the chance to go for a walk around the lab and enjoyed the bright sunlight after several days with overcast skies. Unfortunately, these favourable measurement conditions didn't last for long. The team headed back to the weather station for dinner at around 4:45 pm. The evening skies were again rather clear.
Bruker 125HR operations started this morning with Sébastien performing a second HCl cell test using the repaired chiller. The cell test was completed with only a minor leak from the chiller which will be fixed using an Epoxy solution. At the end of the cell tests, the clouds at PEARL cleared and Erik prepared the instrument for mid-infrared solar measurements by switching to the KBr beam splitter. Sébastien and Erik then cooled the detectors and started measurements, although shortly after the clouds reappeared limiting the number of measurements made to 13.
Kristof spent the day testing the PEARL-GBS CCD. The cold caused a temporary glitch, pushing the CCD dark current to several times its normal value. After the CCD was off for the majority of the last 3 days, everything seems to have returned to normal. The PEARL-GBS sun-tracker is working as well, but the dome is still covered with frost from the weekend storm.
Due to the weather conditions in the morning, Ellen decided to perform globar measurements with PARIS-IR using the HBr gas cell. These ran from 9:26 to 11:43 am. Since the conditions improved around noon, she switched over to atmospheric observations and took measurements from 11:57 am to 3:48 pm, when the sun-tracker was shut down as thin clouds were obscuring the sun again. Ellen took 44 measurements in total today.
The CRL measured for 24h on the 14th March 2016 UTC. It was cloudy all day, and was snowing by the end of the measurement. Emily and Ludovick took a look at the MMCR, FIRR and Lidar data together this morning, and interesting differences exist in several of the clouds. For example, the clouds at 06:00 and at 23:00 UTC, both at about 4 to 5 km altitude.
Today was a rather difficult day for the DIAL. Some internal parts of the laser were damaged due to the water leakage during Sunday's extremely low temperatures at the Ridge Lab. Pierre, Emily, Peter, and Ghazal started an intensive attempt to asses the damage. More updates on the issue will be provided shortly.
During the intensive phase of the campaign, ozonesondes were launched on a daily a basis, until today, when ozonesonde launches will now be made on a weekly basis.