Introduction to Data
Assimilation
and Applications to Atmospheric Data Analysis
Department of Atmospheric and Oceanic Sciences
McGill
University
Author: Pierre Gauthier
Table of contents
195-616B Topics in Geophysical Fluid Dynamics
Department
of Atmospheric and Oceanic Sciences McGill University
Prerequisites
Nature of the observations and their use
Observations used in the operational data
assimilation
system of the Canadian Meteorological Centre
Data coverage for radiosondes at 00 UTC and 12
UTC
Aircraft data (AMDAR)
Surface and ship data coverage (SYNOP)
Buoys (fixed and drifting)
Observation usage at CMC: satellite data
Horizontal coverage of ATOVS radiance data (over
6-h)
Wind data derived from cloud motion (SATOB,
SATWINDS)
Estimation problem
History of assimilation methods
Schematics of the method of direct insertion
Difficulties of data assimilation
Statistical estimation: univariate case
Best Linear Unbiased Estimate (BLUE)
Statistical interpolation (or Gauss-Markov
method)
(Gandin, 1963; Rutherford, 1973; Schlatter,1977; Daley, 1991)
Diapositive PPT
Wind and geopotential analysis corrections
obtained
in response to a single observation of the zonal wind component located
at 265 hPa in the Northern extra-Tropics (45N-60W) (Gauthier et al.,
1998)
Observation operators
Data assimilation cycle
Diapositive PPT
4D variational data assimilation (4D-Var)
Advantages of the temporal dimension
Other formulations
Applications of data assimilation
Diapositive PPT
Other references