@InProceedings{GrimmNato:2006:MeFiVa,
author = "Grimm, Alice Marlene and Natori, Angela Akie",
affiliation = "Universidade Federal do Paran{\'a}, Departamento de
F{\'{\i}}sica and Caixa Postal 19044. 81531-990 Curitiba, PR,
Brazil. (Grimm and Natori)",
title = "Impacts of climate change in South America: mean fields and
variability",
booktitle = "Proceedings...",
year = "2006",
editor = "Vera, Carolina and Nobre, Carlos",
pages = "269--274",
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 America, precipitation, temperature,
variability.",
abstract = "This paper examines the differences between climatological
seasonal fields of precipitation and temperature over South
America for present conditions (1961-1990) and under SRES A2 and
B2 scenarios forcing conditions (2071-2100), as well as the
changes in interannual variability of these fields. The data are
produced by six low-resolution (longitudinal spacing more than 2.5
degrees) and one high-resolution atmosphere-ocean general
circulation models, and two high-resolution atmosphere general
circulation models (longitudinal spacing less than 1.875 degrees)
driven by sea surface temperature output from a low-resolution
coupled model. On average, the best present climatology is
provided by Max Planck Institute and Hadley Center models. The
differences between the mean fields obtained from the six
low-resolution coupled models for the two periods show
considerable discrepancies. The most similar responses are from
ECHAM4/OPYC3 and HadCM3 models. For instance, in spring these two
models indicate decreasing rainfall in north, center and southeast
of Brazil and increasing rainfall in southern Brazil. Other three
models indicate negligible impact over these regions and the sixth
model shows changes of opposite sign. Similar discrepancies do
occur in the other seasons as well. The changes in temperature
agree with respect to a general warming, but the magnitude and
location of the centers of maximum change are also discrepant
among different models. The high resolution and low-resolution
models with similar physical basis do also present great
differences in their indication of climate change. The differences
are smaller when the high-resolution model uses the SST produced
by the coupled low-resolution model as boundary condition. The
interannual variability of spring and summer precipitation and its
relationship with SST was analyzed using the output of
ECHAM5/MPI-OM higher resolution coupled model for the A2 emission
scenario. The first mode of variability, both in spring and
summer, is associated with El Niņo-Southern Oscillation (ENSO). In
both seasons it features a dipole of anomalies between northern
and southern Brazil. For present conditions (1961-1990) the
centers of these dipoles are shifted with respect to their
observational counterparts and in summer the anomalies in southern
Brazil are overestimated. The correlation between the principal
components series and SST reproduces reasonably the ENSO pattern.
For future scenario (2071-2100), the southern centre of the
precipitation dipole weakens and the northern centre extends
southward. In spring, the correlation pattern with SST weakens
considerably in eastern equatorial Pacific, as well as in the
subtropics, which is consistent with smaller precipitation
anomalies in southern Brazil. The correlation also weakens in
eastern equatorial Pacific in summer, although correlation
coefficients in the subtropics are stronger. There are also other
changes in variability, related with the tropical Atlantic SST and
northeastern Brazil precipitation. The relationship between ENSO
events and precipitation variability in Brazil weakens for the A2
scenario, both in spring and winter, mainly in the eastern
equatorial Pacific and especially in spring, which is presently
the season with strongest ENSO-related impact. This suggests that
either ENSO events will weaken or their relationships with
southern Brazil precipitation will weaken due to differences in
the atmospheric basic state, at least in the analyzed period..",
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/2005/10.31.22.22",
url = "http://urlib.net/ibi/cptec.inpe.br/adm_conf/2005/10.31.22.22",
targetfile = "269-274.pdf",
type = "Climate change in the SH",
urlaccessdate = "29 jun. 2024"
}