After the previous days of high winds, calmer weather arrived on March 30, along with clear
skies, which made for favourable conditions for rooftop work and solar measurements at the
Ridge Lab.
After performing cell tests earlier in the campaign to verify the alignment of the Bruker FTIR,
Erik decided to prioritize solar measurements. On March 30, cloudy conditions in the morning at
the Ridge Lab prevented measurements from being made. The skies cleared by the afternoon
and Erik was able to record NIR solar measurements for the remainder of the day. The following
day, switched to MIR measurements after swapping the Bruker FTIR's beam splitter, and
cooling the detectors with liquid nitrogen.
In the afternoon on Friday March 31, clear skies and calm conditions allowed Erik and Pierre to
work on the Bruker FTIR’s sun-tracker on the roof of the Ridge Lab. They found that the sun-
tracker was slightly unlevelled and they spent some time to make adjustments to the sun-
tracker’s base to level it.
On Saturday April 1, Erik then began to reinitialize the sun-tracker’s software after the previous
days adjustments to the sun-tracker. This involved redefining the tracker’s initial position and
making small corrections to the azimuth and altitude positions of its mirrors to better pinpoint the
Sun’s portion. Active calibration was also performed by optimizing the tracker’s NetCam image
of the Sun. After the reinitialization of the tracker’s software, Erik then resumed MIR solar
measurements with the Bruker FTIR for the remainder of the weekend.
In the UV-vis lab on March 30-31, Ramina finalized the straylight tests & results for the UT-GBS
using both a halogen lamp light source, as well as zenith-sky sunlight. With the UT-GBs tests
completed and the instrument operating under optimal conditions, Ramina then sent some time
setting up the PEARL-GBS to in order to perform the resolution, straylight, polarization, and
dark current & bias tests in the coming days. Pierre and Ramina also replaced the PEARL-GBS
heater on the roof, as the previous one had stopped working which enabled the dome to begin
frosting up again. With the new heater in place, the dome is clear to perform optimal
measurements once the lab tests are complete.
The Pandora instrument continues to perform alignments to track the Sun and has required
some manual aligning of the setup on the rooftop by the team to ensure that the components
are levelled. In doing so, it can continue to track the Sun without interruption to establish a good
record of alignments in preparation for measurements.
Ramina Alwarda and Erik Lutsch
[On behalf of the 2023 Canadian Arctic ACE/OSIRIS Validation Campaign team]