@InProceedings{VeraSilvLiebGonz:2006:InSHCi,
author = "Vera, Carolina S. and Silvestri, Gabriel E. and Liebmann, Brant
and Gonzalez, Paula",
affiliation = "CIMA/DCAO, University of Buenos Aires-CONICET (Vera, Silvestri,
Gonzalez) and NOAA/CIRES Climate Diagnostics Center, Boulder,
Colorado, USA (Liebmann)",
title = "Precipitation variability in South America from IPCC-AR4 models.
Part II: Influence of SH circulation leading patterns",
booktitle = "Proceedings...",
year = "2006",
editor = "Vera, Carolina and Nobre, Carlos",
pages = "477--485",
organization = "International Conference on Southern Hemisphere Meteorology and
Oceanography, 8. (ICSHMO).",
publisher = "American Meteorological Society (AMS)",
address = "45 Beacon Hill Road, Boston, MA, USA",
keywords = "climate change, South American climate, SH circulation,
precipitation.",
abstract = "The ability of the climate model simulations performed for the
IPCC Fourth Assessment Report (AR4) in reproducing the leading
patterns of atmospheric circulation in the Southern Hemisphere
(SH) and their influence on precipitation variability in South
America are discussed here, using the same subset of the climate
simulations of the 20th century (20c3m) described in Part I. CMAP
precipitation dataset and NCEP-NCAR reanalyses were used to
describe the observed patterns. The leading patterns of
circulation in the SH were identified through an analysis of the
Empirical Orthogonal Functions (EOFs) for the 500-hPa geopotential
height anomalies over the SH, southward of 20°S. Regression and
correlation maps were computed for observations and model
simulations. For those models that an ensemble of runs are
available, the maps were first computed per individual run and
then averaged over all runs available for each model. Results show
that models are able to reproduce some of the features of the
leading modes of SH circulation interannual variability
(particularly those associated with the 1st leading pattern known
as the Antarctic Oscillation, AAO). Although the simulated
anomalies exhibit different amplitude and are somewhat misplaced
than those observed. Furthermore, it was found that the ability of
the models in representing the 2nd and 3rd SH leading modes (known
as PSA1 and PSA2 respectively) is affected by the way that models
reproduce ENSO features and the mean circulation along the SH
subpolar regions. Observations show that the AAO is negatively
correlated with precipitation anomalies over southeastern South
America (SESA); PSA1 is related with the typical ENSO-induced
precipitation anomaly pattern with negative anomalies in the
tropical region and positive ones in SESA, while PSA2 correlates
with positive precipitation anomalies further south. Results show,
however that models have serious deficiencies to reproduce the
observed influence of the three leading patterns of SH circulation
onto precipitation variability in South America. Preliminary
results show that UKMO, GFDL and MPI are the models that better
depict the main features of the SH circulation anomalies
associated with precipitation variability in SESA. Nevertheless,
it will also be tested the ability of the multi-model ensemble
those climate features..",
conference-location = "Foz do Igua{\c{c}}u",
conference-year = "24-28 Apr. 2006",
language = "en",
organisation = "American Meteorological Society (AMS)",
ibi = "cptec.inpe.br/adm_conf/2005/10.26.16.31",
url = "http://urlib.net/ibi/cptec.inpe.br/adm_conf/2005/10.26.16.31",
targetfile = "477-486.pdf",
type = "Climate change in the SH",
urlaccessdate = "15 jun. 2024"
}