The team's day began well: temperatures at the PEARL Ridge Lab have risen to -26°C and there has been very little wind. Compared to Eureka's -43°C, this felt warm! The sun now rises while we eat breakfast, and sets shortly after we finish dinner. It's a welcome return to a more familiar rhythm of light and dark. Albeit one which is temporary at this latitude. Soon enough, there will be few hours of darkness.
The Polar Vortex has moved towards Russia; its center is now above the Laptev Sea. Eureka is now beneath the edge of the vortex. Our solar-viewing instruments are likely sampling air partially in, and partially outside of the vortex.
In the PEARL Ridge Lab's IR lab, Dan took 45 MIR measurements with the Bruker in the morning. Before lunch, Sebastien changed the beamsplitter and began NIR measurements. The sun is now high enough for TCCON measurements midday, and the weather looked good. After lunch, Joseph took over Bruker operations remotely. 28 NIR measurements were acquired before Joseph had to abort measurements due to heavy clouds which rolled in mid-afternoon.
Dan also updated his "Guide to being the ACE Validation Campaign Webmaster" document. He has been writing the daily reports and updating the campaign website since 2012. He hopes the document will be a useful resource for people who take on this role in the years to come.
As the sun climbs higher Jonathan continues to monitor the observed solar line shifts in the Bruker measurements. Thanks to Stephanie Conway's quick retrieval of the recent data (back in Toronto), Jonathan is able to see the emergence of the expected daily trend. During the extended phase of the campaign we will begin the process of fine-tuning the alignment of the tracker.
Sebastien took 40 measurements with PARIS today. Some of the later measurements may be adversely affected by the clouds, however.
This morning, Xiaoyi, Paul, and Dan performed active tracking tests with the PEARL-GBS tracker. Xiaoyi and Paul worked on the Ridge Lab roof, while Dan controlled the tracker from inside and monitored the tracker camera image. Xiaoyi borrowed two pieces of welder's glass from the Bruker. (They are used to check the alignment of sunlight on the internal Bruker aperture and to check the sun for interference from clouds.) The relatively weak glass did not reduce the sunlight sufficiently to avoid saturation of the tracker's camera. When Xiaoyi inserted the second (stronger) glass, Dan re-cropped and centered the image of the sun, and was able to find an iris setting which avoided camera saturation but allowed enough sunlight for a good signal. Nonetheless, Trax6.3 failed to work on active mode for longer than a few seconds. The team received further instructions from Jonathan about a re-calibration procedure which could help. Dan also expressed concern that the glass was not the ideal strength ñ there was a very narrow iris range between saturation and near-complete loss of signal. Given that the PEARL-GBS needs its filter wheel to be repaired before active tracking is useful for measurements, completing the remaining tasks on to enable PEARL-GBS active tracking will wait for now.
During the process of testing active tracking, Xiaoyi also adjusted the PEARL-GBS pick-off mirrors once again. They are now well-aligned for both the instrument and the tracker camera.
Except for the period of time this morning when the PEARL-GBS was down for the active tracking tests, the PEARL-GBS, UT-GBS, and SAOZ are operating nominally.
This afternoon, Xiaoyi also modified the labview code running UT-GBS. Its spectra have been saturating during MAX-DOAS measurements. The code fix worked well this afternoon and should avoid the saturation issue moving forward.
Paul made exciting news today: a local Saskatoon paper, The Star Phoenix, published an interview with him. In it, Paul talks about the three distinct threads he has woven into an interesting life: science, photography, and farming. We've added a link to the article on the campaign's media page. You can also find it linked here! In the morning, Paul also cleared frost from the SPS window. SPS continues to operate nominally.
Just a quick reminder: ACE ozonesonde flights concluded Saturday evening.
With all the instruments dutifully taking atmospheric measurements, the team headed out of the lab and into the "warm" Arctic weather for a couple hours of hiking this afternoon. Paul, Dan, Xiaoyi, and Sebastien headed north from the Ridge Lab. Back in 2013 the team discovered a picturesque vista we've returned to every year. We made record time, arriving in a little under an hour. We admired the view over Eureka Sound for a few minutes in the silence only remote wilderness can offer. While clouds had covered the sky to the south by the time we arrived, the northward view was wonderfully clear. Paul and Dan took photos of the scenery and their team mates. Upon returning to the Ridge Lab and completing their tasks for the day, the team departed for Eureka. Mike had returned to the Ridge Lab to do tasks for Alexey, and left in the CANDAC truck at the same time.
On the trip back to Eureka, we spotted a herd of muskox a moderately close distance from the road. Paul had been hoping to see Muskox! The two trucks stopped at a valley a short distance from Upper Paradise. The Muskox were in between the road and fjord Paul, Mike, Dan, Xiaoyi, and Sebastien then walked quietly along the valley, and a short distance up the side of a hill. There they had a reasonably good view of the herd. The clouds and sun hanging above the Muskox herd made for a memorable Arctic scene.