Eureka's weather took an interesting turn this weekend. Temperatures were -41°C near the weather station, and around -25°C at the Ridge Lab. Mid-day Saturday a thick fog filled the fjord and surrounding low-lying areas. John MacIver, the Eureka Weather Station's Station Program Manager, says a lead (large crack in the ice) likely opened nearby, creating a source of humidity. The difference in temperature and humidity quickly forms fog. The Ridge Lab was situated above it, and had a great view.
Dan, Paul, and Sophie took a break mid-afternoon to walk a short ways along the ridge and take photos. You can see two on the CREATEArcticSci Instagram page here and here. Eureka is somewhere in the middle of the second photo, beneath the fog.
Despite the thick fog below, the sky at the Ridge Lab was mostly clear on Saturday. Sunday, however, was mostly cloudy. The fog had dissipated by Sunday afternoon.
In the PEARL Ridge Lab's IR lab, Joseph and Dan took 61 MIR measurements with the Bruker on Saturday, and 10 on Sunday. Dan took 37 measurements with PARIS on Saturday and 4 on Sunday. They also continued to test controlling the suntracker computer and Bruker computer using a remote connection, informed by the IR Lab's webcam.
Over in the UV-Vis Lab, Sophie monitored the UT-GBS, PEARL-GBS, and SAOZ on Saturday. They all behaved well and took measurements. She started updating manuals to be used during the extended campaign phase. The cloudy conditions on Sunday gave her a good opportunity to perform tests on the PEARL-GBS. During a resolution test the instrument stopped responding. Sophie discovered the problem originated from the CCD controller. She re-started it and was able to finish the test. The UT-GBS output weird spectra during a test, but this was resolved by a simple restart of the instrument.
Down at 0PAL, the CRL took 24 hours of measurements in both UV and Visible channels on Saturday. Both parallel and perpendicular channels observed higher rates than usual due to the fog event. Sunday saw the CRL completing its 4th day of continuous measurements. Sham plans to continue routine measurements throughout the coming week.
Saturday's ACE ozonesonde flight failed once it reached an altitude of 300 meters. The cause is unknown. Sunday's ozonesonde flight was launched at 6:15 PM (local time) and reached an altitude of 32 644 meters (6.7 hPa). It used a regular 1200 gram totex balloon instead of a Raven balloon because of winds.