Projeções dos impactos das mudanças climáticas sobre as bacias do hidrossistema Jaguaribe, Ceará, Brasil, utilizando informações do cordex do modelo climático regional RCA4

Abstract

The objective of this work was to analyze the projections of precipitation, temperature and streamflow fields over the Banabuiú, Castanhão and Orós Hydrographic Basins (HBs) from five models (CSIRO-Mk3-6-0, ICHEC-EC-EARTH, IPSL-CMSA-MR, HadGEM2-ES and NOAA-GFDL-ESM2M) participating in the Coordinated Regional Climate Downscaling Experiment. The methodology consisted in evaluating the representation of the present climate through seasonality and inter-annual variability and in analyzing the medians of anomalies and trends of variables. In general, the models showed good representation of the climatological average observed over the basins, especially in the driest months: August to October. Castanhão HB showed greater inter-annual variability in its observed rainfall pattern. In the analysis simulations of the future climate of precipitation and streamflow, the results indicated a distribution of projections in different directions among the analyzed periods, with a pattern of anomaly reductions for the first period (2006-2035) and of increase for the last 30-year cycle of the century(2066-2095) in the two scenarios and in all the basins. In the second period (2035-2065) and between the scenarios, a greater dispersion between the modules and the directions of the medians were observed. The annual temperature averages showed an increase throughout for 21st century for the RCP 4.5 and RCP 8.5 scenarios, with higher intensity in the latter. In the trend analysis, the CSIRO-Mk3-6-0 model projected the greatest impacts of increasing temperature and reducing streamflow and precipitation, while the IPSL-CMSA-MR model indicated the greatest positive trends of rain and streamflow.