Author(s): Juan Jose Rosa-Canovas; Matilde Garcia-Valdecasas Ojeda; Emilio Romero-Jimenez; Patricio Yeste; Cesar Quishpe-Vasquez; Sonia R. Gamiz-Fortis; Yolanda Castro-Diez; Maria Jesus Esteban-Parra

Linked Author(s): Juan José Rosa-Cánovas, Emilio Romero-jiménez, Yolanda Castro-Díez, María Jesús Esteban-Parra

Keywords: Drought; Iberian Peninsula; Decadal climate prediction; Weather Research and Forecasting model; Decadal Prediction Large Ensemble

Abstract: Drought is one of the natural hazards with a major impact on society, environment and economic activities. Previous studies analysing the drought variability in the last decades of the 20th century have detected a trend towards drier conditions in the Mediterranean area. The extra heat content added to the climate system by global warming may lead to longer and more intense drought episodes in the future, thus the development of reliable tools and services to monitor drought at different time scales could help to prevent the potential losses related to this kind of events. The aim of this study is to assess the predictive skill of drought with regionalised decadal climate prediction experiments in the Iberian Peninsula (IP). A mesoscale numerical weather prediction system, the Weather Research and Forecasting (WRF) model, has been used to dynamically downscale a global decadal prediction product to generate decadal climate information at high resolution over the IP. The Decadal Prediction Large Ensemble (DPLE) has been selected to provide the initial and boundary data to run the regional model. The DPLE is a set of decadal experiments initialised every year from 1954 to 2015 carried out with the Community Earth System Model (CESM) at NCAR. For each initial date, an ensemble of 40 members was generated by randomly perturbing the initial atmospheric conditions. The downscaling simulations have been performed using two nested domains: the EUROCORDEX domain, with a resolution of approximately 50 km, and another finer domain covering the IP, with a resolution of nearly 10 km. The dynamically-downscaled product encompasses 13 decadal experiments initialised every year from 1987 to 1999 for three members of the ensemble. Several drought indices, such as the Standardized Precipitation Evapotranspiration Index (SPEI), have been calculated in order to evaluate against observational data in which extent the regionalised decadal climate predictions are suitable to reproduce drought variability. Results from this study might help to better understand the processes underlying drought modeling in the decadal climate prediction. In addition, they may provide resources to contribute to the development of adequate adaptation and mitigation strategies to the impact of the near-term climate change on water resources in the IP. Acknowledgments: J. J. Rosa-Cánovas acknowledges the Spanish Ministry of Science, Innovation and Universities for the predoctoral fellowship (grant code: PRE2018-083921). This research has been carried out in the framework of the projects CGL2017-89836-R, funded by the Spanish Ministry of Economy and Competitiveness with additional FEDER funds, and B-RNM-336-UGR18, funded by FEDER / Junta de Andalucía - Ministry of Economy and Knowledge.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022929

Year: 2022