Fathalla Rihan, United Arab Emirates
A Basis for Improving Numerical Weather Prediction by Assimilating Doppler Radar Radial Winds
Coauthors
M. N. Anwar, H. Al-Sakaji Abstract:
Numerical Weather Prediction (NWP) is considered as
an initial-boundary value problem: given an estimate of
the present state of the atmosphere, the model simulates
(forecasts) its evolution. Specification of proper initial
conditions and boundary conditions for numerical dynamical
models is essential in order to have a well-posed
problem and subsequently a good forecast model (A
well-posed initial/boundary problem has a unique solution
that depends continuously on the initial/boundary
conditions). The goal of data assimilation is to construct
the best possible initial and boundary conditions, known
as the analysis, from which to integrate the NWP model
forward in time.
In this paper, we describe
an approach to assimilate Doppler radar radial winds into a high resolution NWP model using 3D-Var system. We discuss the types of errors that occur in radar radial
winds. Some related problems such as nonlinearity and sensitivity of the forecast to possible small errors in
initial conditions, random observation errors, and the background states are also considered. The technique
can be used to improve the model forecasts, in the Gulf area, at the local scale and under high aerosol
(dust/sand/pollution) conditions.