An alternative parameterization of eddy diffusivity in the Gulf of Finland based on kinetic energy of high frequency internal wave band

In July 1998, Three time series of shear microstructure measurements (duration 13, 24 and 14 h respectively) were performed in 3 different wind forcing regimes as well as in 3 different background density stratification and current velocity shear situations at the entrance to the Gulf of Finland. We compared the ¿measured¿ eddy diffusivities with the diffusivities parameterized using the Richardson number, the Brunt-Väisäla frequency and with the diffusivities simulated using the two equation k-e turbulence closure. Summing up the discrepancy of all three time series the methods applied resulted in a remarkable and consistent bias against the measured eddy diffusivity. Contrary to this result, the calculations with the new suggested parameterization scheme, which accounts for the internal wave kinetic energy of the super-inertial frequency band, fitted well for all three time series. Similarly, the modified k-e simulations accounting for the super-inertial internal wave energy matched better the measured profiles.

LILOVER Madis;  STIPS Adolf; 

2011-05-11

FINNISH ENVIRONMENT INST

JRC62569

1239-6095,   

http://www.borenv.net/BER/pdfs/ber16/ber16A-103.pdf,    https://publications.jrc.ec.europa.eu/repository/handle/JRC62569,