After several days of bad weather and remotely checking some of the instruments' functions at the best, the team was finally able to return to the Ridge Lab after lunch today. Even though visibility was still poor, due to continuous light snow, the road was clear since Ron and Dave had been working hard on it all morning. Yesterday's strong winds slowed down during the previous night and almost ceased completely at the Eureka weather station in the evening, so that conditions were perfect for ozonesonde launch scheduled for 6:15 pm each day.
Erik and Sébastien removed the cover from the Bruker 125HR chiller to see if it had been damaged during Sunday's temperature drop to -2℃. They discovered that several pipe elbows had cracks. Pierre used a clamp to narrow the cracks and Epoxy to seal them. The repair seemed to be effective but the team had to head back to the weather station. Eric and Sébastien intend to further test the chiller to see if the seals can sustain through longer periods tomorrow if weather permits. Finally the CaF2 beamsplitter has been installed into the instrument and it is thus ready to take near infrared measurements.
At the Ridge Lab, winds were still too strong to work on the roof, but it was clear that the PEARL-GBS dome had frozen over. It is most likely that the tracker itself is frozen too, causing the errors observed during the weekend. The PEARL-GBS CCD seems to have suffered from the cold as well. One of its gain settings is not working properly. Kristof is facing further testing to find the exact source of the error, and to see how to fix it.
Ellen arrived at the Ridge Lab to find PARIS-IR totally functional. The instrument is, in general, very robust so no harm was done by yesterday's low temperatures in the IR lab. Ellen set the globar up for background measurements to test PARIS-IR further and the instrument ran smoothly for approximately half an hour, taking 5 measurements, before Ellen had to shut it down to join the rest of the team on their ride back to sea level. The PARIS-IR data archives were successfully mounted to the CANDAC server the previous day.
The 13 March 2016 UTC measurements by the CRL contained many of the same types of clouds as we saw during the end of the previous day. All were below about 4500 m altitude, where there were some small clouds which completely extinguished the lidar beam. By far, most of today's clouds were concentrated below 2000 m altitude and were much less attenuating than those at higher altitudes. The winds were still fairly high today, hovering between 10 and 15 knots. There is a gap in data between 01:00 and 05:00 UTC which results from 21 knot winds requiring the lidar's hatch to be closed.
Yesterday's strong winds, blowing snow and blocked roads didn't allow for Ghazal to go up to the Ridge Lab, so no DIAL measurements were taken during the night from 13 to 14 March.
Today's Raven ozonesonde launch went smoothly. Since the wind speed had dropped down to close to zero, the Raven made it only 62 km southwest of Eureka, after taking a slight 20 km detour to the northwest. It's terminal altitude was 32743 m to which it rose at an ascent rate of 194 m/minute.