TURBULENCE CLOSURE IN BOUNDARY-LAYER THEORY - AN INVITATION TO DEBATE

Turbulence in the Planetary Boundary Layer has been a topic of researc h for a long time. Its theory, however, is hampered by the fact that w e have fewer fundamental equations than unknowns when dealing with tur bulent motions. The search for additional ''laws'' to match the number of equations with the number of unknowns in turbulence theory, is com monly labelled the turbulent closure problem. Despite considerable eff ort, this problem has not been solved. There is a variety of approache s available. However, these have not converged towards a commonly acce pted PBL theory, like the Monin-Obukhov similarity for the surface lay er. The Working Group on Boundary Layer Dynamics and Air-Sea Interacti on of ICDM/IAMAP therefore invites the scientific community to discuss these problems and possible solutions. The present paper intends to s timulate such a discussion.