Dynamical and statistical downscaling: intercomparison in three extreme temperature events in southern South America

BALMACEDA HUARTE, R; FITA BORRELL L; ZANINELLI P; BETTOLLI MARIA LAURA

Beijing

Conferencia; ICRC-CORDEX 2019; 2019

CORDEX

Global Climate Models are the main tools used to generate weather and climate predictions atdifferent time scales. However, it is well recognized that these models are unable to provideinformation at the spatial scale required by many stakeholders. Hence, dynamical and statisticaldownscaling (RCMandESD)approachesarenecessaryforadaptingtheglobalmodelpredictionstosmaller spatial scales, providing suitable products for a range of applications. Despite of the largenumberofworksthatappliedthesetechniques,inSouthAmericathecomparisonofstrengthsandweaknessesofESDandRCMhasnotcomprehensivelybeenperformedyet,especiallyinthe simulationofextremeevents.Inthiscontext,theaimofthisworkistocompareESDandRCMinrepresentingextremetemperatureeventsincentral-easternArgentina.Tothisend,threehotsummersinwhichrecordheatwaveeventsoccurredwereselected:2002-2003,2013-2014and2015-2016.Forthecomparisonofthetwodownscalingmethodologies,theWRFRCMwasusedwithtwodifferentconfigurations, in which the soil physics were altered. Jointly three ESD models based on linearregressionandanalogueswereconsidered.AllmodelsweredrivenbyERAInterim.Also,totraintheESDmodelsandtoevaluatethedownscalingapproaches,dailystationdatafromArgentinawasused.Two different bioclimatic indices based on the wet bulb temperature were also simulated andcompared.Theresultsshowthatbothapproachesareabletoreproducethepersistenceandspatialdistributionsoftheextremeeventsaswellastheseasonalcharacteristicsofeachhotsummer.Thespreadinthesimulationoftheintensitiesoftheheatwavesvariesdependingontheparticularevent,theregionandthesimulationconsidered.Theyalsoshowedagoodperformanceinsimulatingthebioclimaticindices highlighting the importance of the generation of detailed climate information for impactassessment.