Assessment of climate change impacts on precipitation and temperature over Subtropical Chile based on South America CORDEX-CORE regional simulations

In this study, we analyze the projected changes in mean and extreme precipitation and temperature over subtropical Chile, based on simulations of 3 Regional Climate Models (RCMs) (RegCM4-7, REMO2015, and ETA) from South-America CORDEX-CORE, each one driven by three different CMIP5 GCMs. The RCM’s performance for the present climate is evaluated against the CR2MET (~5km) dataset.

The changes for the end (2070-2099) of the century for the RCP8.5 scenario are assessed with respect to the historical period (1976-2005). Extreme events are expressed in terms of 30-yrs return values, estimated from the GEV distribution fitted to seasonal extremes for extended austral winter and summer.

Accordingly, to GCMs projections, robust mean drying conditions are found among RCMs between 35ºS-40ºS in winter and 35ºS-45ºS in summer over the continental Chile and adjacent ocean. North of 30ºS REMO2015 and ETA show a statistically significant increase of mean winter precipitation over mountain regions. Another robust signal among the RCMs consists in an increase of extreme winter precipitation north of 35ºS over the mountain area. Increases in the maximum and minimum temperatures are significant over all domain for the 3 RCMs, but it is prominent to the north of 35°S (30°S) for REMO2015 and RegCM4-7 for winter (summer), especially over the mountain leeward, while ETA depicts the higher heating in the south of 30°S. The changes are mainly associated with a positive displacement of distribution (changes in location parameter) for temperatures and the amplification of interannual variability (positive changes in scale parameter) for precipitation. The physical processes responsible for these changes are discussed.