CR 68:169-182 (2016)  -  DOI: https://doi.org/10.3354/cr01388

ABSTRACT: The La Plata Basin (LPB) is an important region for social and economic sectors of South America, mainly as a source of water and for agriculture. Regional models are used to analyze changes in precipitation over South America in order to provide more details of the projected changes in specific regions. Results of regional models from the CLARIS-LPB project are analyzed to assess changes and uncertainties in future projections for the LPB compared to the base period. Results from several models are taken into account in order to assess uncertainties. The models agree in projecting more precipitation in the whole basin and in an increased frequency of extreme wet austral summers. The majority of models agree in projections of drier conditions in the upper LPB and an increase in the frequency of extreme dry austral winters and springs. However, in the lower LPB the projections indicate an increase in the frequency of extreme wet winters and springs. In austral autumn the uncertainties are high in the upper LPB. The uncertainties are low regarding increases in the frequency of rainy days in the middle and lower LPB and in the maximum number of consecutive dry days in the upper LPB. The projected patterns of austral summer anomaly precipitation variability obtained from empirical orthogonal function analysis display the same dipole between southern LPB and the South Atlantic Convergence Zone as in the base period, but increased anomalies in the northern center. In the austral winter the only anomaly signal simulated in the base period remains in the future projections, but the maximum variability is displaced southwards.

KEY WORDS: Precipitation extremes · Regional models · La Plata Basin · Climate change · Frequency of extremes · Precipitation variability · Precipitation indices