Jeudi 26 mai - Lagrangian studies of atmosphere and ocean

Peter Haynes,

Professor at the University of Cambridge, Department of Applied Mathematics and Theoretical Physics

Title : Lagrangian studies of atmosphere and ocean

Abstract :

Many processes in the atmosphere and ocean are naturally studied from a Lagrangian viewpoint. Over the last 20 years or so it has become routine to calculate trajectories using velocity fields from large-scale atmospheric analysis and reanalysis datasets. These have proved extremely valuable, for example, in interpreting in-situ chemical observations taken from aircraft or balloons. Large-scale trajectory calculations can be used more broadly to study large-scale process and to give a new view of different features of the atmosphere. Examples given in this talk will include definition of the troposphere and the tropopause, the calculation of ozone depletion potentials for short-lived species (i.e. species that are not well-mixed in the troposphere) and study of the processes determining the concentrations of water vapour in the stratosphere.

The availability of large-scale datasets generated by high-resolution ocean models and of state estimates for the time evolving circulation in large regions of the ocean means that similar opportunities are now available for the ocean and indeed several papers reporting Lagrangian studies have been published in the last few years. Some preliminary results from a study of export from the Southern Ocean will be discussed in the talk.