Under-ice circulation in an Arctic lake : observations from two field seasons in Lake Kilpisjärvi, Finland ...

• Main Author: Graves, Kelly Elise
• Format: Text
• Language: English
• Published: University of British Columbia 2015
• Subjects: Arctic; Kilpisjärvi
• Online Access: https://dx.doi.org/10.14288/1.0166136; https://doi.library.ubc.ca/10.14288/1.0166136

High spatial resolution CTD profiles and Acoustic Doppler Current Profiler velocity measurements show significant rotational basin-wide, under-ice circulation in May of 2013 and 2014 at Lake Kilpisjärvi, Finland (69°01'N, 20°49'E), a seasonally ice-covered, Arctic lake with negligible through-flow. In 2013, a high-pressure horizontal density anomaly with vertically paired rotating circulations was observed. The estimated maximum cyclonic and anti-cyclonic azimuthal velocities magnitudes were 0.03 and 0.02 m s-¹. The Rossby radius (Rri), horizontal length scale at which rotational effects become as important as pressure effects, was estimated to be ∼ 160 m and the Rossby number(R⃘⃘⃘⃘⃘ ), the ratio of the centripetal acceleration to the Coriolis acceleration, ∼ 0.2. It is hypothesized that this circulation was driven by heat flux at the shorelines from warm incoming streams causing a density flow down the slopes to the centre of the lake where the flow converged. This flow was balanced with a shoreward flow ...