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.