The second day of the campaign was busy and productive. Nearly all instruments are taking routine measurements, which we are feeling good about!
It was another chilly day in Eureka, with temperatures near -43°C near the weather station. As happened yesterday, PEARL was a relatively warm -35°C but it felt more like -53°C with the wind. The team took care while working on the roof today, as the wind speeds were moderately quick, around 45 km/hr. Our instruments enjoyed sunlight from around 10 AM until around 4 PM; however, clouds and plenty of haze on the horizon limited solar measurements at times.
In the PEARL Ridge Lab's IR lab, Joseph and Dan took 49 MIR measurements with the Bruker. Dan took 29 measurements with PARIS, whose GPS finally locked this morning. They spent time discussing the suntracker and its code with Jonathan (in Halifax), who has been very helpful. He walked them through modifications to the code that better reflect conditions in the High Arctic, and helped them experiment with different camera focus parameters. Hopefully, the changes will enable the new tracker to work on active mode (using the camera's image of the sun). The tracker has been run on passive mode so far. Joseph and Dan hit an unexpected snag when they tried to correct the computer's time and date (it's a Ubuntu Linux OS). They haven't been able to fix it yet. This will be their first task tomorrow morning.
Over in the UV-Vis Lab, Sophie worked on focusing the UT-GBS's light onto the CCD perfectly. She will continue to work on this tomorrow. It takes plenty of patience to get the GBSs working perfectly.
Tom and Zahra tested the SPS and MAESTRO one last time inside the UV-Vis lab before moving them to the roof with Paul's help. The SPS instrument needed to be insulated before exposing it to the low temperatures outside. They covered it with insulating foam boards. The MAESTRO instrument does not need to be insulated. It works fine in low temperatures.
With help from Paul, Tom and Zahra moved SPS, MAESTRO, and their suntracker up to the roof and installed them. Sophie came along to watch, and Dan took a few photos of the process. The power cable and data cables were bundled together and attached to the sun tracker to stop them from twisting around the instruments and being cut off when the tracker moves. Using plastic zip ties to do that is difficult because they break in the very low temperatures at PEARL, so instead they used rope.
Back inside the UV-Vis lab again Tom and Zahra hooked up the data cables running down from the roof to the SPS and MAESTRO computers and powered up the instruments. They are working well and made zenith sky measurements. The software running the instruments will automatically perform measurements as long as the computer does not freeze. One reason to run the instruments 24 hours a day is to keep them warm. If they are turned off, especially in the case of the SPS, they might stop working.
Down at 0PAL's lidar lab, Emily and Sham measured overnight in all UV and Visible CRL channels for 12 hours. In the morning, they placed glassine sheets over the primary mirror of the telescope to depolarize the incoming backscattered laser light. Emily and Sham measured like this for 4 hours for depolarization calibration. Then, they performed a polarized lamp calibration for several hours. After supper, they started the lidar for regular measurements in all UV and Vis channels overnight.
While Zen isn't here in person, he keeps a watchful eye on 0PAL's E-AERI remotely from Toronto. All is well with the E-AERI, and it continues to faithfully take measurements continuously.
ACE ozonesonde flights begin tomorrow (March 1).
This evening, Paul, Emily, Sham, Dan, Sophie, and Zahra went for a walk much of the way to the Eureka runway and back. It's always a good idea to get outside! Afterwards, Paul, Emily and Dan took photos of the CRL, whose laser beam was shining particularly bright due to the high number of ice crystals in the air tonight.
Tomorrow begins the weekend, but the team will be back in the lab and working hard to collect more scientific data about the high Arctic atmosphere!