We
couldn't have asked for a more perfect observing day today. Not a cloud
in the sky (and just a little bit of very thin haze right near the
surface). Temperatures at the lab went from about -14 to -11 through
the day, with the morning's winds dying to nothing by early afternoon.
We arrived at the lab after breakfast to find everything as we hoped -
the PEARL-GBS, SAOZ, SPS and MAESTRO were all working happily, and the
DA8 booted up and found alignment without a problem. Everyone
went to it with a smile.
Mareile and Clive worked on optimizing MAESTRO and SPS through the day,
while Cristen continued with the UT-GBS testing and refocusing. Tom
investigated the meteorological data and found that there had been a
sudden stratospheric warming (as forecasted) while we were hankered
down in Resolute (on the 21st). The minimum temperatures inside the
vortex jumped by about 8 degrees - though note that the vortex is not
over us at the moment, and stratospheric temperatures over us are much
warmer than inside. The dynamical activity of the polar vortex plays a
crucial role in the way that the ozone story develops in any given
Arctic spring, so following its progress is essential for the
interpretation of our data.
In the FTS lab, the three instruments made the most of the perfect
observing conditions between sunrise (~11am) and sunset (~2:45pm). As
in previous years, PARIS has approximately 1/3 of the solar beam,
allowing it to measure continuously, while the rest was sent to the
Bruker and DA8 alternately. Measurements were made with all of the
filters on both of the larger instruments, giving us a total of 9 and
10 measurements for the DA8 and Bruker, and 27 for PARIS.
After dinner, several of us walked up to the runway and back (about 2
miles), enjoying the lack of wind and clear skies. It was much colder
(~-30) at the weather station than at PEARL - or indeed the runway. It
was interesting to actually feel the temperature inversion as we walked
down into it. As we settled down to watch the Academy Awards, the lidar
team packed up for another night of observing. Last night had been very
productive for them, and they were expecting another great night up at
the lab. Let's hope these clouds stay away!