African Conference on Research in Computer Science and Applied Mathematics (CARI2012)

REGISTRATION DEADLINE: 15th of September (English/French)

Abstract:
The ocean and the atmosphere, coupled with other components (continent, and ice) are building blocks of the earth system. Recent events have raised questions on social and economic implications of anthropic alterations of the earth system, i.e. both its long-term evolution and extreme events. A better understanding of these systems is a key ingredient for improving our prediction of such implications. In particular, the coastal zone is now subject to extensive surveys as this interface between the continent and the ocean is identified as a prime area for environmental impacts. A strong knowledge of coastal and marine submesoscale dynamics is required in various environmental topics, e.g. marine biogeochemistry, marine pollution, fisheries, coastal erosion, regional climate. The same applies to the atmosphere component where high resolution weather forecasts are required for several applications: extreme events, agriculture, air pollution, forestry ? Numerical models are essential tools to understand key processes, simulate and forecast events of various space and time scales. The continuous increase of computing power and the availability of global forcing products allows the production on limited areas of forecasts on nowadays personal computers.

The objective of the tutorial is to give the attendees sufficient knowledge to be able to run limited area marine or weather forecasts using state of the art realistic numerical models. The tutorial starts with an overview of the set of equations and underlying physics of the ocean and atmosphere systems. The usual physical simplifications used to make the computational cost affordable are also addressed (e.g. hydrostatic/non hydrostatic, Boussinesq, compressibility). The most important numerical choices (e.g. horizontal grid and vertical coordinates systems, time stepping and advection-diffusion algorithms, separation in slow and fast modes) are introduced in the light of the underlying physic. The attendees will then be able to exercise on realistic experiments using the Regional Ocean Modeling system (ROMS) and the Weather Research and Forecasting model (WRF). Both models have a set of pre- and post-processing tools that allows the fast set-up of a numerical simulation and the analysis of their outputs.

Programme (Details):
Day1: Presentation of the equations of numerical ocean and weather models and their numerical discretization, forcings.
Day 2: Practice: Ocean Modeling using the Regional Ocean Modeling System (ROMS)
Day 3: Practice: Weather Modeling using the Weather Research and Forecasting model (WRF)

During day 2 and day 3, the attendees will learn how to prepare a realistic configuration (preparation of the domain configurations and acquirement of external forcings data), how to run the models, and how to diagnose its outputs.

Open source software:
WRF (http://www.wrf-model.org ), ROMS ( http://www.romsagrif.org ), Fortran Compiler (Gnu Fortran), Octave