General
This eight-day module will start Monday 19 April at 9.00 and finish Wednesday
28 April at 13.00. Timetable
Short descriptions of the main lectures are given below.
Atmospheric waves
As a basis for other lectures in atmospheric dynamics and numerical prediction,
this module investigates the types of wave motion described by linearized
atmospheric prediction equations. Study of the dynamics of these waves
and the identification of their mechanisms enables the filtering and isolation
of wave types, and an appreciation to be gained of the various simplifications
and approximations made in the study of atmospheric motion at different
scales.
Numerical methods for weather prediction
With the increasing use of numerical models to understand and simulate
the behaviour of the atmosphere, it is important that meteorologists are
aware of the various techniques available for the numerical solution of
a set of partial differential equations. This module provides an introduction
to the finite difference, finite element and spectral techniques by examining
their use for solving the advection, diffusion and gravity wave equations.
Emphasis is placed on the accuracy and stability of these schemes and
their relative merits. Other topics discussed include splitting methods,
staggering, non-linear instability and the semi-Lagrangian technique.
Governing equations/adiabatic formulation of large-scale models of the
atmosphere
These lectures illustrate how the adiabatic part of large-scale models
of the atmosphere is formulated. The design of the ECMWF forecast model
used since 1979 will play a central part in the lectures but other schemes
and formulations will also be described. The following areas will be covered:
- The primitive equations and shallow water equations
- Coordinate systems
- Horizontal discretization
- Vertical discretization
- Time-differencing, semi-Lagrangian schemes and diffusion
- Limited-area modelling and boundary conditions.
Ocean wave modelling
An overview of the state-of-the-art of ocean wave modelling is given.
The basic evolution equation of the wave spectrum, the energy balance
equation, is derived. The practice of wave modelling is discussed and
it is shown that in particular from validation studies using satellite
and buoy data that present-day wave models are reliable. From experience
it is known that wave results depend in a sensitive manner on the quality
of the driving surface winds. For this reason ocean wave forecasting has
certain benefits for atmospheric modelling. Examples of these benefits
are given.
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