GOTM, a model for simulating dissipation measurements in estuaries and open ocean
M.R. Villarreal1, H. Burchard2, K. Bolding3 and P.P. Mathieu3
1Grupo de F'sica Non Lineal. Universidade de Santiago de Compostela. 15706 Santiago de Compostela. SPAIN
2
Institut für Meereskunde der Universität Hamburg Troplowitzstr. 7, D-22529 Hamburg, GERMANY.
3
Joint Research Centre, Space Applications Institute, Marine Environment Unit I-21020 Ispra (VA), ITALY.
ABSTRACT
GOTM, General Ocean Turbulence Model [1] is a one-dimensional water column model that allows for different combinations of momentum and tracer equations and a choice between some standard turbulence parametrizations (including k-e and Mellor-Yamada two equation models [2] with different sets of stability functions). Different test cases have been prepared and implemented to be run with GOTM, including some situations where direct measurements of turbulence dissipation rate were available (EU financed MASTIII project PHASE campaigns in Knebel Vig and Ooster Scheldte [1] and the Irish Sea measurements of Simpson et al. [3]). The actual forcings in the site are estimated from measurements (moored current meters, meteorological station data,…), and the model is relaxed to temperature and salinity data, so that turbulent magnitudes are prognosed, which allows to a direct comparison with the available dissipation rate measurements. The effect on the results of the chosing of the turbulence model, of the set of stability functions chosen and of the different parametrizations of internal wave breaking and shear instability mixing will be discussed.
Figure 1
REFERENCES
[1] Burchard, H., K. Bolding, M. R. Villarreal, 1999. GOTM, a General Ocean Turbulence Model. Theory, implementation and test cases, report of the European Communities EUR, 18745.
[2] Burchard, H., O. Petersen, 1999. Models of turbulence in the marine environment - A comparative study of two-equation turbulence models. J. Marine Systems., 21, 29-53.
[3] J.H. Simpson, W.R. Crawford, T.P. Rippeth, A.R Campbell and J.V.S Cheok, 1996 The vertical structure of turbulent dissipation in shelf seas, J. Phys. Ocenogr. 26, 1579-1590.
NOTE: GOTM is a freeware code available under the GNU license in http://www.gotm.net