Interaction between a bubble plume and the near field in a stratified lake

A steady state bubble‐plume model is evaluated using full‐scale temperature, salinity, and dissolved oxygen data collected in a Swiss lake. The data revealed a plume‐generated near‐field environment that differed significantly from the ambient far‐field water column properties. A near‐field torus of reduced stratification developed around the plume, the extent of which is on the same lateral scale as the horizontal dislocations generated by persistent first‐mode seiching. The plume fallback water was found to penetrate much deeper than expected, thereby maintaining reduced vertical gradients in the near‐field torus. The plume entrains a portion of the fallback water leading to short‐circuiting, which generates a complex plume‐lake interaction and reduces far‐field downwelling relative to the upward plume flow. As the integral plume model incorporates the entrainment hypothesis, it is highly sensitive to the near‐field environmental conditions. After identifying appropriate near‐field boundary conditions the plume model predictions agree well with the field observations.