Klemens Barfus

1 Introduction The Arabian Peninsula (AP) is an arid region situated in the southwestern corner of the Asian continent, characterised by low rainfall, limited freshwater resources, exceptionally high summer temperatures, and elevated evaporation rates (Almazroui 2011; Almazroui et al. 2012; Varikoden et al. 2016). Furthermore, groundwater resources in this region are extensively exploited (Alsaaran and Alghamdi 2022).

1 Introduction According to IPCC (2021), the global average surface temperature for 2011–2020 has increased by 1.09°C compared to 1850–1900 and is expected to reach values of ∼3–5°C by the end of the century in the worst case scenario, as described by the Representative Concentration Pathway (RCP) 8.5, from the Coupled Model Intercomparison Project Phase 5 (CMIP5, Taylor et al., 2012).

As a contribution to an Integrated Water Resources Management (IWRM) project in Distrito Federal, Brazil, we address several aspects for a credible downscaling of near-surface air temperature and precipitation using the Statistical DownScaling Model (SDSM4.2). For instance, we apply a detailed screening of predictors, consider the end user needs in the validation procedure, assess the added value of the downscaling model and include several sources of uncertainties until the downscaling step.