Applied Scientific Research 59: 89–110, 1998. © 1998 Kluwer Academic Publishers. Printed in the Netherlands. 89 Report on Turbulence and Mixing in Geophysical Flows II J.M. REDONDO Departamento de Física Aplicada, Universidad Politecnica de Catalunya, Campus Nord B5, 08034 Barcelona, Spain P.F. LINDEN Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, U.K. Abstract. We describe the presentations at the international meeting/workshop on Mixing in Geo- physical Flows that took place at Vilanova i la Geltru, near Barcelona during the 20, 21 and 22nd of March 1997. There were more than 100 participants from 20 countries with 66 oral and poster presentations covering experimental and theoretical aspects of rotating and stratified fluids as well as field observations. The main topics discussed at the workshop were stratified flows, rotating stratified flows, gravity waves, instabilities and mixing, convection, experiments and numerical simulations of Geophysical flows and turbulent mixing. The papers are summarised in this report giving a state-of-the-art overview of present research in geophysical turbulent mixing. Key words: turbulent mixing, stratified flows, geophysical flows. 1. Introduction Flows where both the velocity and density vary with height arise naturally. Un- derstanding both the fundamental processes which trigger transition to turbulence and also the mixing properties of the ensuing turbulence itself is essential to the parameterization of the redistribution of important quantities such as moisture, heat, momentum and pollutants within geophysical flows. The workshop addressed a wide range of geophysical mixing processes through 8 invited talks, 30 oral contributions and 28 posters. Approximately one third of the papers discussed experimental research, one quarter dealt with theoretical matters and a further quarter discussed numerical studies while the remainder of the contri- butions were related to geophysical observations. This mix of approaches provided a broad spectrum of mixing processes and a nice balance of the methods used to address the problems associated with them. Topics were discussed in contributed papers mainly falling under categories determined by an invited review paper. The conference opened with a discussion of mixing processes in stably stratified fluids where the mixing is produced by some imposed turbulence. These processes