Figure
3: The two eddy covariance measurement
setups deployed on and around the Romaine-2 reservoir. Raft station
(left, photo taken looking west) and shore station (right, photo taken
looking north) with the following instruments: (a) net radiometer, (b)
air temperature probe, (c) accelerometer, (d) sonic anemometer and
infrared gas analyzer, and (e) propeller anemometer. Photos were
provided by Hydro-Québec and taken on 13 June 2019, at approximately 2 m
below the maximum reservoir level.
A complete year-long net radiation time series was created using the
following strategy. We used the net radiation that was measured on the
raft when it was deployed (June−October). When ice was present on the
reservoir, it was typically covered in snow. We therefore assumed that
the emitted/reflected radiation measured at the shore station during
that time was equivalent to what would have been measured on the
reservoir. During the transition periods, we estimated the reflected
radiation on the reservoir with a simple albedo formula based on that by
Patel and Rix (2019). The longwave radiation emitted during the
transition periods was estimated from the Stefan−Boltzmann law. This was
done by taking an emissivity of 0.995 and extrapolating the water
temperature profile in the top first meter of water to estimate the
water skin temperature for periods when no direct measurements were
available.