Our last official station of on-ice activities included albedo measurements with Don Perovich. The skies were clear and sunny with only a slight wind. Balmy compared to the previous day!
“It feels like Seattle,” Jinlun cheerfully commented as we walked onto the ice.
Looking up at the blue skies and coastline, I admitted that it *almost* felt like a summer day by the beach. But I pointed out that we were wearing quite a lot of winter-weather gear. Jinlun paused. Indeed we were! We laughed and continued on, enjoying the fine weather.
Yellow Team set up another straight line, along which we made albedo measurements every 5 m. One person slipped on a backpack with the ASD device inside and slung a tray around his/her neck to carry the laptop. A second person maneuvered the cosine collector arm and cued their partner to take a measure with the ASD when the arm was level. Following closely on their heels was another person who took notes on surface conditions and documented each measured point photographically.
When we finished the line of measurements, some scuttling clouds had rolled in. The clouds, we learned, could introduce some more noise into the measurements. Fortunately, we had finished. We now had to download the data and do some analysis!
Clear skies at the start of measurements
Setting up the ASD
Laura knee-deep in melt!
Scuttling clouds at the end of measurements
Day 3 was spent with Jackie Richter-Menge learning how to make snow and ice thickness measurements. We were lucky that the recalcitrant EM31 had started to work again; ‘lucky’ given that the first two groups still took the instrument out just to get a feel for using the EM31 even though no data was logged. Jackie had us put the Magna Probe and EM31 together in the Theatre beforehand (no sense spending more time out in the cold than required). After assembling the instruments, we walked them out onto the ice.
The next order of business was to set up a straight line along which to take measurements. Jackie showed us how to do this using nothing more than a thickness tape, 3 stakes, and a pair of eyes. But the strong winds made this task more difficult. The tape kept curving away from us and snagging on chunks of ice. After struggling with the wind, we managed to set up a straight 200 m line. This line would guide our measurements.
Jinlun volunteered to wear the EM31 first, which appears below as the instrument shown with long white arms. It was a awkward to carry. But each of us patiently bore it out for an easy 50 m stretch, then handed it off to someone else on our team. We could only imagine what it must be like to do a 9 km line (!) in the winter time on one’s own–something that Jackie has done in the past.
We all took turns with each of the instruments. One person would handle the EM31, another would take measures with the Magna Probe, a third person would take notes on surface conditions alongside Magna Probe measures, and a fourth would drill holes with a hand auger to get ice thickness that the EM31 measures could be checked against.
“Now back up, Jinlun… Don’t hit the stake…”
Laura with the Magna Probe
Handing off instruments
We did it!