OVERVIEW OF CORDEX DOWNSCALING EXPERIMENTS OVER SOUTH AMERICA FOR REGIONAL CLIMATE CHANGE ASSESSMENT

SILVINA A SOLMAN

Denver

Conferencia; SCENARIOS FORUM 2019; 2019

University of Denver

The COordinated Regional Downscaling EXperiment (CORDEX), implemented under the auspices of the World Climate Research Program (WCRP), aims to improve downscaling techniques and their use in the provision of robust regional climate information for application in vulnerability, impacts and adaptation. As such, under the CORDEX Phase 1, a common modeling framework was implemented. This initiative has provided an unprecedented opportunity for climate change assessment studies in the South American (SA) domain owing to the invaluable ensemble covering various forcing scenarios (RCPs), Regional Climate Models (RCMs) and driving Global Climate Models (GCMs). Up to date, the RCP-RCM- GCM matrix available for the SA domain is uneven, with most of the simulations performed under the 4.5 and 8.5 RCPs, with only few simulations available for the RCP2.6. Several studies based on sub-sets of these simulations have assessed the climate change signal on various climatic features, such as the seasonal mean temperature and precipitation, winds, extreme events, regional circulation features, among others. These studies also allowed assessing the range of uncertainties in regional climate change associated with varying forcing from GCM simulations and greenhouse gas (GHG) concentration scenarios and different RCMs. Most of these studies were based on the 50km resolution simulations.Next CORDEX generation (CORDEX Phase 2) is now focused on providing greater homogeneity of multi-model ensemble information across regions and for increased resolution of continental-scale information, through two different approaches: 1) The CORDEX-CORE and 2) the CORDEX Flagship Pilot Studies (FPS). For the CORDEX-CORE framework, a core set of RCMs downscales a core set of GCMs over all or most CORDEX domains at 20 km resolution under two extreme RCPs: 8.5 and 2.6 allowing to cover the widest range of scenario uncertainty. The FPS aim at more targeted studies addressing specific scientific questions of methodological and regional relevance based on very high-resolution simulations. Some results from these set of products under the CORDEX Phase 2 are already available for the SA-CORDEX domain. Results from these updated simulations will be discussed with a focus on assessing the scenario uncertainty and based on lessons learned from the CORDEX Phase 1 for the SA domain.