@InProceedings{CintraCock:2014:LoEnTr,
author = "Cintra, Rosangela Saher Correa and Cocke, Steven",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Florida
State University}",
title = "A Local Ensemble Transform Kalman Filter Data Assimilation System
for the FSU Global Atmospheric Model",
booktitle = "Anais...",
year = "2014",
organization = "Uncertainties 2014.",
keywords = "Data assimilation, Kalman filter, numerical weather prediction,
global atmospheric model.",
abstract = "Projections of future climate or weather are produced using
complex atmospheric general circulation models (AGCMs). Due to the
inherent uncertainty of our knowledge of the weather/climate
system it is inevitable that there exists model errors. Data
assimilation is the process by which measurements and model
predictions are combined to obtain an accurate representation of
the state of the modeled system. Data assimilation is recognized
as essential in weather prediction and climate analysis. All data
assimilation systems require reasonable estimates of the initial
condition (analysis) to run AGCMs considering the errors of the
model, the observations and the analysis. In this work, a data
assimilation system, the local ensemble transform Kalman filter
(LETKF) was implemented. By local we mean that the analysis can be
carried out independently at each grid point with the use of only
local observations. Uncertainty is represented not by a covariance
matrix, but by an ensemble of estimates in state space. The
ensemble is evolved in time through the full model, which
eliminates any need for a linear hypothesis as to the temporal
evolution. The LETKF assimilation scheme was tested with Florida
State University Global Spectral Model (FSUGSM). The model is a
multilevel (27 vertical levels) spectral primitive equation model
with a vertical \σ-coordinate. All variables are expanded
horizontally in a truncated series of spherical harmonic functions
(at resolution T63) and a transform technique is applied to
calculate the physical processes in real space. The LETKF data
assimilation uses the synthetic conventional observations and
satellite data (surface pressure, absolute temperature, zonal
component wind, meridional component wind and humidity). The
observations are localized at every other grid point of the model.
The ensemble forecast size is 20 members, which run parallel (one
single model member per computer node simultaneously) and the
assimilation scheme is parallelized via MPI. The numerical
experiment has a one-month assimilation cycle, for the period
01/01/2001 to 31/01/2001 at (00, 06, 12 and 18 GMT) for each day.
An important source of information for the evaluation of the
quality of any data assimilation is the observation-minus-forecast
(OMF) and the observationminus- analysis (OMA) statistics. The
histogram of OMF and OMA for a range of spatial and temporal
scales is calculated, and the results are consistent. The results
showing the analysis from the assimilation of the observations
will be presented.",
conference-location = "Rouen, France",
conference-year = "2014",
label = "lattes: 8185155301349092 1 CintraCock:2014:LoEnTr",
language = "pt",
targetfile = "Cintra_local.pdf",
url = "http://uncertainties2014.insa-rouen.fr/",
urlaccessdate = "26 abr. 2024"
}