High-resolution decadal climate prediction of maximum and minimum temperatures in the Iberian Peninsula

The Mediterranean regions are expected to experience an increase in temperature under the climate change scenario along the ongoing 21st century. Thus, the development of instruments to predict the evolution of this field is crucial to adequately assess the challenges we are called to face in the upcoming decades. Decadal climate predictions (DCPs), alongside seasonal predictions, play a fundamental role at time scales in which this kind of information is being actively requested by institutions and governments.

This study aims at assessing the prediction skill of maximum and minimum temperatures in the Iberian Peninsula (IP) by using DCPs at a very high resolution. The experiments have been conducted by following a dynamical downscaling (DD) approach with the Weather Research and Forecasting model (WRF) version 3.9.1.1 as the regional model, and the Decadal Prediction Large Ensemble (DPLE) providing the initial and boundary conditions. The DPLE encompasses a set of decadal experiments initialized every year in November from 1954 to 2017. For each initialization date, an ensemble composed of 40 members generated by randomly perturbing the initial atmospheric conditions. In this study, the DD simulations have been performed for a subensemble of 4 members and 13 initialization dates (from 1987 to 1999). Two nested domains have been considered: one, coarser, covering the EUROCORDEX region at a resolution of 50 km approximately, and another, finer, spanning the IP at a resolution of about 10 km. The prediction skill has been assessed for different forecast ranges to analyze the dependence of the skill on the lead time along the decade.

The results of this study will contribute to the collective efforts of the scientific community in the development of mitigation and adaptation strategies to climate change. This is particularly relevant in the IP, where the consequences of the increase in temperature, such as an increment in droughts and heat waves frequency and intensity, are already causing human, environmental and economic losses.

 

Keywords: maximum temperature, minimum temperature, Weather Research and Forecasting Model, Iberian Peninsula, Decadal Prediction Large Ensemble.

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 P20_00035, funded by FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades, CGL2017-89836-R, funded by the Spanish Ministry of Economy and Competitiveness with additional FEDER funds, the project LifeWatch-2019-10-UGR-01 co-funded by the Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014-2020 (POPE), LifeWatch-ERIC action line, and the project PID2021-126401OB-I00 funded by MCIN/AEI/ 10.13039/501100011033/FEDER Una manera de hacer Europa.