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The IPCC 1.5 °C report argues for a 50% cut of global greenhouse gas emissions by 2030. Dangerous gaps lie between what is required to reach the 1.5 °C objective, what governments have pledged and what is happening in reality. Here, we develop 'climate policy gap' graphics for Portugal, Spain and Morocco to help reveal this divide and quantify the under-reaction between diagnosis and action, through layers of political intended and unintended miscommunication, insufficient action and the power of the fossil fuels industries. The climate policy gaps for the three nations reveal overshoots on even the most ambitious levels of emissions reductions pledged when compared with trajectories compatible with 1.5 °C or even 2 °C limits. This research suggests that there is a built-in feature of under-reaction in climate policy, which staves off any emission pathways compatible with stopping a temperature rise above 1.5 °C by 2100. It shows that the climate policy gap is a political and methodological tool that reveals systemic shortcomings of government climate action. Its visibility identifies benchmarks and sectors that should be activated to close these gaps in response to the growing popular demands for climate justice. [ABSTRACT FROM AUTHOR]

The Land Use and Climate Across Scales Flagship Pilot Study (LUCAS FPS) is a coordinated community effort to improve the integration of land use change (LUC) in regional climate models (RCMs) and to quantify the biogeophysical effects of LUC on local to regional climate in Europe. In the first phase of LUCAS, nine RCMs are used to explore the biogeophysical impacts of re-/afforestation over Europe: two idealized experiments representing respectively a non-forested and a maximally forested Europe are compared in order to quantify spatial and temporal variations in the regional climate sensitivity to forestation. We find some robust features in the simulated response to forestation. In particular, all models indicate a year-round decrease in surface albedo, which is most pronounced in winter and spring at high latitudes. This results in a winter warming effect, with values ranging from +0.2 to +1 K on average over Scandinavia depending on models. However, there are also a number of strongly diverging responses. For instance, there is no agreement on the sign of temperature changes in summer with some RCMs predicting a widespread cooling from forestation (well below -2 K in most regions), a widespread warming (around +2 K or above in most regions) or a mixed response. A large part of the inter-model spread is attributed to the representation of land processes. In particular, differences in the partitioning of sensible and latent heat are identified as a key source of uncertainty in summer. Atmospheric processes, such as changes in incoming radiation due to cloud cover feedbacks, also influence the simulated response in most seasons. In conclusion, the multi-model approach we use here has the potential to deliver more robust and reliable information to stakeholders involved in land use planning, as compared to results based on single models. However, given the contradictory responses identified, our results also show that there are still fundamental uncertainties that need to be tackled to better anticipate the possible intended or unintended consequences of LUC on regional climates. [ABSTRACT FROM AUTHOR]

Land‐atmosphere coupling plays a crucial role in determining the evolution of weather and climate. In the current study, the full ensemble of CORDEX‐Africa climate change simulations is used to understand how strong and weak coupling regions in Africa will evolve in the future. The ability of the regional climate models to capture the coupling signal relies on a reasonable representation of near surface air temperature, precipitation, surface fluxes, and soil moisture. A thorough model evaluation reveals typical shortcomings in the representation of the African climate, in particular seasonal precipitation. The multimodel ensemble mean outperforms the individual models and is therefore used for the investigation of the land‐atmosphere coupling. This ensemble mean shows a widespread warming in Africa and changes in precipitation, such as a decrease in the Sahel during summer and an increase in western Africa during summer and autumn. The coupling analysis relies on surface fluxes, the related evaporative fraction and their correlations as well as the correlation between evaporative fraction and soil moisture. Overall, water‐limited regions that exhibit a strong land‐atmosphere coupling are projected to expand further southward in West Africa and further northward in southern Africa. This is particularly true over the Sahel during spring and summer, when the strong coupling region shifts southward, indicating a potential expansion of the semiarid and arid regions. A transition of energy limited regimes, with weak coupling, to water‐limited regimes where soil moisture plays a more important role, is projected for the end of the 21st century as drying continues. Key Points: The projections for the African future climate indicate significant changes of the precipitation patterns and a warming up to 7°Regions with strong and weak land‐atmosphere coupling regimes can experience relevant changes as indicated by a CORDEX‐Africa RCM ensembleWater‐limited regions, with a strong land‐atmosphere coupling, will expand southward in West Africa and northward in southern Africa [ABSTRACT FROM AUTHOR]

The North African Coastal Low-Level Jet (NACLLJ) is a semi-permanent feature offshore the north western African coast, linked to the cold nearshore upwelling of the Canary Eastern Boundary Current system. Its main synoptic drivers are the Azores Anticyclone over the ocean and the inland Sahara thermal low. The coastal jet events occur in one of the world's most productive fisheries region, thus the evaluation of the effects of global warming in its properties is imperative. This study proposes an analysis of the annual and intra-annual attributes of the NACLLJ for two time periods 1976–2005 (historical) and 2070–2199 (future), resorting to coupled and uncoupled atmosphere–ocean simulations with the ROM model, as well as near surface offshore wind speed from the CORDEX-Africa ensemble. The future simulations follow the RCP8.5 greenhouse gas emissions scenario. Overall, the ROM coupled simulation presents the best performance in reproducing the present-climate near surface wind speed, offshore northwest Africa, compared to the remaining RCM simulations. The higher SST resolution in the coupled simulations favours much localised colder upwelling strips near the coast and consequently stronger jets. In future climate, a small increase in the surface wind speed is projected, mainly linked to the regions of coastal jet presence. The NACLLJ is projected to be more frequent and intense, encompassing larger areas. An increase of the jet seasonal frequencies of occurrence is projected for all seasons, which is larger from spring to autumn (up to 15, 16 and 22% more frequent, respectively). However, in some offshore areas the winter NACLLJ persistency is likely to double, relatively to present-climate. Higher inter-annual variability is also projected for the future NACLLJ seasonal frequencies. The strengthening of the coastal jet speeds is also significant, between 5 and 12% in all seasons. Additionally, the jet's diurnal cycle shows an increase in jet occurrence across the day, particularly in the mid and late afternoon. [ABSTRACT FROM AUTHOR]

The strong coastal upwelling associated to the Benguela eastern boundary upwelling system makes the ocean along coast of this current one of the most productive ecosystems in the world. The Benguela Coastal Low‐Level Jet (BCLLJ) is one of the most important mesoscale feature that shape the climate of this region. The main synoptic forcing of the BCLLJ is the Angola thermal low over land and the St. Helen anticyclone over the ocean, resulting in southwesterly winds along the coast. This study investigates how the BCLLJ might change due to climate warming, with the help of uncoupled and coupled simulations from a 25‐km horizontal resolution regional climate model (ROM). In general, the coupled simulation displays the best performance in representing the present time near‐surface wind speed, with a decrease on the known warm bias of sea surface temperature in the Benguela eastern boundary upwelling system region. The analysis of the projected changes of the BCLLJ climate toward the end of the 21st century (2070–2099), following the RCP8.5 emissions scenario, shows an increase in the frequency of the BCLLJ occurrence along the southern area with higher changes in the coupled simulation (between 6% and 8%). These changes are related to a southerly shift of the St. Helen High, which intensifies the flow offshore the west coast of South Africa and causes a sharpening of the land‐sea thermal contrasts. However, during spring, associated with the decrease in near‐surface wind speed due to higher sea surface temperatures, the future frequency and intensity of the BCLLJ are lower. Key Points: At the end of the 21st century, the warming climate will impact significantly the frequency and intensity of the Benguela coastal jetAn increase in frequency and intensity of the Benguela jet is projected in southern area due to stronger thermal and pressure contrastsDue to a decrease in thermal gradient, the Benguela jet frequency and intensity is expected to decrease during spring in the northern area [ABSTRACT FROM AUTHOR]

The Benguela coastal low‐level jet (CLLJ) is characterized by intense winds that occur around 400 m above sea level, within or at the top of the marine atmospheric boundary layer. The semipermanent St. Helen high‐pressure system, over the South Atlantic Ocean, and the inland thermal low‐pressure system, over the Namib Desert, are the synoptic forcing behind the Benguela CLLJ. This coastal jet is an important mesoscale feature in the Namibia and Angola coastal areas, since it is present virtually all year round, with a marked seasonal cycle. This study investigates the climatology of the frequency and the intensity of the Benguela CLLJ and its relationship with synoptic and local forcing's, using high‐resolution modeling. An uncoupled ROM (REMO‐OASIS‐MPIOM) hindcast simulation, with 25‐km horizontal resolution, for the period 1980–2014, is used to analyze the features of the Benguela CLLJ. It is shown that Benguela CLLJ is characterized by two local maxima of frequency of occurrence at around 26°S and 17.5°S. During austral summer, the jet has a frequency of occurrence of about 60% and it is in its southern core. During autumn and winter, the frequency of occurrence decreases to nearly half and migrates equatorward. During spring, the jet has a frequency of occurrence of 45% and is found at the northern core. The jet wind speed is higher in the south core but is found at higher altitudes in the north core. The seasonal cycle of horizontal momentum budget defines the seasonality of Benguela CLLJ frequency of occurrence. Key Points: Seasonal variability of the frequency of Benguela jet occurrence is strong linked to the seasonal cycle of the horizontal momentum budgetThe Benguela coastal jet is present all year round, and it is characterized by two local maxima of frequency of occurrenceThe vertical structure of the coastal jet has a well‐mixed maritime boundary layer and strong subsidence at the jet core [ABSTRACT FROM AUTHOR]

We present a detailed evaluation of wind energy density (WED) over Portugal, based on the EURO-CORDEX database of high-resolution regional climate model (RCM) simulations. Most RCMs showed reasonable accuracy in reproducing the observed near-surface wind speed. The climatological patterns of WED displayed large sub-regional heterogeneity, with higher values over coastal regions and steep orography. Subsequently, we investigated the future changes of WED throughout the twenty-first century, considering mid- and end-century periods, and two emission scenarios (RCP4.5 and RCP8.5). On the yearly average, the multi-model ensemble WED changes were below 10% (15%) under RCP4.5 (RCP8.5). However, the projected WED anomalies displayed strong seasonality, dominated by low positive values in summer (< 10% for both scenarios), negative values in winter and spring (up to − 10% (− 20%) under RCP4.5 (RCP8.5)), and stronger negative anomalies in autumn (up to − 25% (− 35%) under RCP4.5 (RCP8.5)). These projected WED anomalies displayed large sub-regional variability. The largest reductions (and lowest increases) are linked to the northern and central-eastern elevated terrain, and the southwestern coast. In contrast, the largest increases (and lowest reductions) are linked to the central-western orographic features of moderate elevation. The projections also showed changes in inter-annual variability of WED, with small increases for annual averages, but with distinct behavior when considering year-to-year variability over a specific season: small increases in winter, larger increases in summer, slight decrease in autumn, and no relevant change in spring. The changes in inter-annual variability also displayed strong dependence on the underlying terrain. Finally, we found significant model spread in the magnitude of projected WED anomalies and inter-annual variability, affecting even the signal of the changes. [ABSTRACT FROM AUTHOR]

After extensive efforts over the course of a decade, convective-scale weather forecasts with horizontal grid spacings of 1-5 km are now operational at national weather services around the world, accompanied by ensemble prediction systems (EPSs). However, though already operational, the capacity of forecasts for this scale is still to be fully exploited by overcoming the fundamental difficulty in prediction: the fully three-dimensional and turbulent nature of the atmosphere. The prediction of this scale is totally different from that of the synoptic scale (103 km), with slowly evolving semigeostrophic dynamics and relatively long predictability on the order of a few days. Even theoretically, very little is understood about the convective scale compared to our extensive knowledge of the synoptic-scale weather regime as a partial differential equation system, as well as in terms of the fluid mechanics, predictability, uncertainties, and stochasticity. Furthermore, there is a requirement for a drastic modification of data assimilation methodologies, physics (e.g., microphysics), and parameterizations, as well as the numerics for use at the convective scale. We need to focus on more fundamental theoretical issues—the Liouville principle and Bayesian probability for probabilistic forecasts—and more fundamental turbulence research to provide robust numerics for the full variety of turbulent flows. The present essay reviews those basic theoretical challenges as comprehensibly as possible. The breadth of the problems that we face is a challenge in itself: an attempt to reduce these into a single critical agenda should be avoided. [ABSTRACT FROM AUTHOR]

Regional climate models (RCMs) are used with increasing resolutions seeking to represent in an improved way regional to local-scale atmospheric phenomena. The EURO-CORDEX simulations at 0.11° and simulations exploiting finer grid spacing approaching the convective-permitting regimes are representative examples. These climate runs are computationally very demanding and do not always show improvements, which depend on the region, variable and object of study. The gains or losses associated with the use of higher resolution in relation to the forcing model (global climate model or reanalysis), or to different resolution RCM simulations, are widely known as added value. Its characterization is a long-standing issue, and many different added-value measures have been proposed. In the current study, a new method is proposed to assess the added value of finer-resolution simulations, in comparison to its forcing data or coarser-resolution counterparts. This approach builds on a probability density function (PDF) matching score, giving a normalized measure of the difference between diverse resolution PDFs, mediated by the observational ones. The distribution added value (DAV) is an objective added-value measure that can be applied to any variable, region or temporal scale, from hindcast or historical (non-synchronous) simulations. The DAVs metric and its application to the EURO-CORDEX hindcast daily precipitation data are presented here. Generally, the EURO-CORDEX simulations at both resolutions (0.44° and 0.11°) display a clear added value in relation to ERA-Interim, with maximum values around 30% in summer and 20% in the intermediate seasons. When both RCM resolutions are directly compared, only three of five models (0.11°) show added value, with a maximum of ∼10%. The regions with the larger DAVs are areas where convection is relevant, e.g. Alps and Iberia. When looking at the extreme PDF tail, the higher-resolution improvement is generally greater than the low resolution for seasons and regions. [ABSTRACT FROM AUTHOR]

Global reanalyses are powerful tools to study the recent climate. They are built by combining forecast models with observations through data assimilation, which provide complete spatial and temporal information of observable and unobservable parameters. The reanalyses constitute very valuable threedimensional data of the atmosphere, which make it possible to investigate a panoply of atmospheric processes, such as coastal low-level jets (CLLJs). In the present study, three global reanalyses, the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim), the Japanese 55-year Reanalysis (JRA-55), and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), are used to build an ensemble of reanalyses for a period encompassing 1980-2016 with 6-hourly output. A detailed global climatology of CLLJs is presented based on this ensemble of reanalyses. This reanalysis ensemble makes it possible to explore the ability of reanalysis to represent the CLLJs mitigating its uncertainty and adding robustness. The annual and diurnal cycle as well as the interannual variability are analyzed in order to evaluate the temporal variability of frequency of occurrence of CLLJ. The ensemble mean displays a good representation of the seasonal spatial variability of frequency of occurrence of coastal jets. The Oman and Benguela CLLJs show, respectively, a decrease and increase of frequency of occurrence in the studied period, which are statistically significant during boreal summer and austral spring. The coastal jets have higher mean frequencies of occurrences during late afternoon and early evening. During the season where each CLLJ has higher mean frequency of occurrence, the Oman CLLJ is the most intense and occurs at higher altitudes. [ABSTRACT FROM AUTHOR]

Blocking occurrence and its impacts on European temperature have been studied in the last decade. However, most previous studies on blocking impacts have focused on winter only, disregarding its fingerprint in summer and differences with other synoptic patterns that also trigger temperature extremes. In this work, we provide a clear distinction between high-latitude blocking and sub-tropical ridges occurring in three sectors of the Euro-Atlantic region, describing their climatology and consequent impacts on European temperature during both winter and summer. Winter blocks (ridges) are generally associated to colder (warmer) than average conditions over large regions of Europe, in some areas with anomalies larger than 5 °C, particularly for the patterns occurring in the Atlantic and Central European sectors. During summer, there is a more regional response characterized by above average temperature for both blocking and ridge patterns, especially those occurring in continental areas, although negative temperature anomalies persist in southernmost areas during blocking. An objective analysis of the different forcing mechanisms associated to each considered weather regime has been performed, quantifying the importance of the following processes in causing the temperature anomalies: horizontal advection, vertical advection and diabatic heating. While during winter advection processes tend to be more relevant to explain temperature responses, in summer radiative heating under enhanced insolation plays a crucial role for both blocking and ridges. Finally, the changes in the distributions of seasonal temperature and in the frequencies of extreme temperature indices were also examined for specific areas of Europe. Winter blocking and ridge patterns are key drivers in the occurrence of regional cold and warm extreme temperatures, respectively. In summer, they are associated with substantial changes in the frequency of extremely warm days, but with different signatures in southern Europe. We conclude that there has been some misusage of the traditional blocking definition in the attribution of extreme events. [ABSTRACT FROM AUTHOR]

In this work we performed an analysis on the impacts of blocking episodes on seasonal and annual European precipitation and the associated physical mechanisms. Distinct domains were considered in detail taking into account different blocking center positions spanning between the Atlantic and western Russia. Significant positive precipitation anomalies are found for southernmost areas while generalized negative anomalies (up to 75 % in some areas) occur in large areas of central and northern Europe. This dipole of anomalies is reversed when compared to that observed during episodes of strong zonal flow conditions. We illustrate that the location of the maximum precipitation anomalies follows quite well the longitudinal positioning of the blocking centers and discuss regional and seasonal differences in the precipitation responses. To better understand the precipitation anomalies, we explore the blocking influence on cyclonic activity. The results indicate a split of the storm-tracks north and south of blocking systems, leading to an almost complete reduction of cyclonic centers in northern and central Europe and increases in southern areas, where cyclone frequency doubles during blocking episodes. However, the underlying processes conductive to the precipitation anomalies are distinct between northern and southern European regions, with a significant role of atmospheric instability in southern Europe, and moisture availability as the major driver at higher latitudes. This distinctive underlying process is coherent with the characteristic patterns of latent heat release from the ocean associated with blocked and strong zonal flow patterns. We also analyzed changes in the full range of the precipitation distribution of several regional sectors during blocked and zonal days. Results show that precipitation reductions in the areas under direct blocking influence are driven by a substantial drop in the frequency of moderate rainfall classes. Contrarily, southwards of blocking systems, frequency increases in moderate to extreme rainfall classes largely determine the precipitation anomaly in the accumulated totals. In this context, we show the close relationship between the more intrinsic torrential nature of Mediterranean precipitation regimes and the role of blocking systems in increasing the probability of extreme events. [ABSTRACT FROM AUTHOR]

ABSTRACT The summer time cloud diurnal cycle over western Iberia is analysed here using a satellite climate data record of fractional cloud cover based on 9 years of Meteosat Second Generation observations which is distributed by the EUMETSAT's Climate Monitoring Satellite Applications Facility. These observations were complemented with a corresponding mean cloud diurnal cycle using SYNOP reports on six locations over the studied domain. It is shown that the main coastal mountain range separates regions that are characterized by two very different cloud regimes: stratocumulus-topped boundary layer convection dominates the region towards the coast and continental cumulus convection dominates the region to the east of these mountains. To explain the observed variability, a long-term regional climate model [Weather Research and Forecasting model ( WRF)] simulation over Iberia was used. A comparison of the observations against model output for the common period between observations and simulation shows that although the model generally underestimates cloudiness, it is able to represent the diurnal cycle in a realistic manner. It is shown that the observed cloud diurnal evolution is linked to the thermal circulations generated by the land-sea contrast and orography. The extent to which the cloud deck penetrates inland is closely related to the coastal orography: although smaller hills tend to enhance cloudiness, larger mountains block the progression of the marine boundary layer further inland, as it behaves as a density current. Larger mountains also produce katabatic flow and a rather strong subsidence aloft during the night. The warming due to this subsidence helps the blocking of the cloud deck as it is partially responsible for evaporating clouds, as shown by a potential temperature budget analysis. [ABSTRACT FROM AUTHOR]

The Iberian viticultural regions are convened according to the Denomination of Origin (DO) and present different climates, soils, topography and management practices. All these elements influence the vegetative growth of different varieties throughout the peninsula, and are tied to grape quality and wine type. In the current study, an integrated analysis of climate, soil, topography and vegetative growth was performed for the Iberian DO regions, using state-of-the-art datasets. For climatic assessment, a categorized index, accounting for phenological/thermal development, water availability and grape ripening conditions was computed. Soil textural classes were established to distinguish soil types. Elevation and aspect (orientation) were also taken into account, as the leading topographic elements. A spectral vegetation index was used to assess grapevine vegetative growth and an integrated analysis of all variables was performed. The results showed that the integrated climate-soil-topography influence on vine performance is evident. Most Iberian vineyards are grown in temperate dry climates with loamy soils, presenting low vegetative growth. Vineyards in temperate humid conditions tend to show higher vegetative growth. Conversely, in cooler/warmer climates, lower vigour vineyards prevail and other factors, such as soil type and precipitation acquire more important roles in driving vigour. Vines in prevailing loamy soils are grown over a wide climatic diversity, suggesting that precipitation is the primary factor influencing vigour. The present assessment of terroir characteristics allows direct comparison among wine regions and may have great value to viticulturists, particularly under a changing climate. [ABSTRACT FROM AUTHOR]

Coastal low-level jets (CLLJ) are a low-tropospheric wind feature driven by the pressure gradient produced by a sharp contrast between high temperatures over land and lower temperatures over the sea. This contrast between the cold ocean and the warm land in the summer is intensified by the impact of the coastal parallel winds on the ocean generating upwelling currents, sharpening the temperature gradient close to the coast and giving rise to strong baroclinic structures at the coast. During summertime, the Iberian Peninsula is often under the effect of the Azores High and of a thermal low pressure system inland, leading to a seasonal wind, in the west coast, called the Nortada (northerly wind). This study presents a regional climatology of the CLLJ off the west coast of the Iberian Peninsula, based on a 9km resolution downscaling dataset, produced using the Weather Research and Forecasting (WRF) mesoscale model, forced by 19 years of ERA-Interim reanalysis (1989-2007). The simulation results show that the jet hourly frequency of occurrence in the summer is above 30% and decreases to about 10% during spring and autumn. The monthly frequencies of occurrence can reach higher values, around 40% in summer months, and reveal large inter-annual variability in all three seasons. In the summer, at a daily base, the CLLJ is present in almost 70% of the days. The CLLJ wind direction is mostly from north-northeasterly and occurs more persistently in three areas where the interaction of the jet flow with local capes and headlands is more pronounced. The coastal jets in this area occur at heights between 300 and 400 m, and its speed has a mean around 15 m/s, reaching maximum speeds of 25 m/s. [ABSTRACT FROM AUTHOR]

The soil moisture-temperature coupling represents a determinant role in the evolution of weather and climate, as these interactions are of utmost importance for extreme phenomena. For this study, daily data taken from all CORDEX-Africa simulations are considered. Two periods were selected, a historical (1971-2000) and a future (2071-2100) period which features two Intergovernmental Panel for Climate Change Representative Concentration Pathways (IPCC-RCP) scenarios: the RCP 8.5 and the RCP 4.5. A throughout assessment of the ability of the models to express the coupling signal in current climate is performed. A multi-model ensemble mean is built. The ensemble mean outperforms individual models in almost all situations, representing the best estimate for both current and future climates. The soil moisture-temperature coupling strength is assessed with the evaporative fraction, correlations with 10 days of non-overlapping means between soil moisture and evaporative fraction and between latent and sensible heat fluxes. In general, individual models are consistent in representing the weak, no-coupling and strong coupling regions, corresponding to the humid, arid and semi-arid or Mediterranean environments, as identified by the evaporative fraction. However, some inter-model variability is found regarding the intensity of each regime. In desert areas such as Sahara and Namib deserts, where precipitation is overestimated, and over large areas of central Africa, characterized by an overall dry bias, both induce an overestimation of the coupling strength. For future conditions, the increase of the surface energy budget and changes in precipitation regimes, hints towards an expansion of the arid climates. On the other hand, the intensification of the coupling strength over humid and semi-humid areas, suggest a shift of the strong coupling regions. The increase of the available surface energy and changes in coupling regimes, projected for the end of the 21st century, reveal an overall increase of sensible heating and a consequently widespread warming of up to 7 oC, for the worst-case scenario.AcknowledgementsThe authors wish to acknowledge project SOLAR (PTDC/GEOMET/7078/2014) and FCT - project UID/GEO/50019/ 2019 - Instituto Dom Luiz [ABSTRACT FROM AUTHOR]

In the framework of EURO-CORDEX, the largest regional climate model (RCM) set of simulations for climate change assessment was produced. This set included simulations at 0.44 and 0.11° spatial resolutions covering the full European domain. Very recently, the Flagship Pilot Study - Convective phenomena at high resolution over Europe and the Mediterranean – promoted a new set of simulations exploiting finer grid spacing at the convective-permitting resolution (~0.03°), covering a smaller central European domain. These climate runs are computationally very demanding and do not always show improvements. The latter depend on the region, variable and object of study. The gains or losses associated with the use of higher resolution in relation to the forcing model (global climate model or reanalysis), or to different resolution RCM simulations, is known as added value. Its characterization is a long-standing issue, and many different added-value measures have been proposed.In the current work, a recently proposed method is applied to assess the added value of finer resolution simulations, in comparison to its forcing data or coarser resolution counterparts. This approach builds on a probability density function (PDF) matching score, giving a normalised measure of the difference between diverse resolution PDFs, mediated by the observational ones. The distribution added value (DAV) is an objective added value measure that can be applied to any variable, region or temporal scale, from hindcast or historical (non-synchronous) simulations. The DAVs metric and an application to the EURO-CORDEX simulations, at 0.44°, 0.11° and 0.03° resolutions, for precipitation, are here presented. The EURO-CORDEX first set of simulations at resolutions, 0.44o and 0.11o, display a clear added value in relation to ERA-Interim, with values around 30% in summer and 20% in the intermediate seasons. When both RCM resolutions are directly compared the added value is smaller. The regions with the larger precipitation DAVs are areas where convection is relevant, e.g. Alps and Iberia. When looking at the extreme precipitation PDF tail, the higher resolution improvement is generally greater than the low resolution for seasons and regions. The convective permitting runs also reveal added value when compared with the coarser resolution grid, especially for extreme precipitation. However, the DAVs spatial analysis shows large added value heterogeneity.AcknowledgmentsThe authors wish to acknowledge SOLAR (PTDC/GEOMET/7078/2014) and FCT UID/GEO/50019/2019 - Instituto Dom Luiz projects. [ABSTRACT FROM AUTHOR]

The mesoscale Weather Research and Forecasting (WRF) Model is used over the Iberian Peninsula to generate 60 years (1950–2010) of climate data, at 5 km resolution, in order to evaluate and characterize the incident shortwave downward radiation at the surface (SW ↓), in present climate. The simulated values of SW ↓ in the period 2000–2009 were compared with data measured in Spanish and Portuguese meteorological stations before and a statistical BIAS correction was applied using data from Clouds and the Earth's Radiant Energy System (CERES), on board four different satellites. The spatial and temporal comparison between WRF results and observations show a good agreement for the analyzed period, although the model overestimates observations. This overestimation has a mean normalized bias of about 7% after BIAS correction (or 17% for original WRF output). Additionally, the present simulation was confronted against another previously validated WRF simulation performed with different resolution and set of parametrizations, showing comparable results. WRF adequately reproduces the observational features of SW ↓ with correlation coefficients above 0.8 in annual and seasonal basis. 60 years of simulated SW ↓ over the Iberian Peninsula were produced, which showed annual mean values that range from 130 W/m 2 , in the northern regions, to a maximum of around 230 W/m 2 in the southeast of the Iberian Peninsula (IP). SW ↓ over IP shows a positive gradient from north to south and from west to east, with local effects influenced by topography and distance to the coast. The analysis of the simulated cloud fraction indicates that clear sky days are found in > 30% of the period at the southern area of IP, particularly in the Algarve (Portugal) and Andalusia (Spain), and this value increases significantly in the summer season for values above 80%. [ABSTRACT FROM AUTHOR]

In Southern Europe, droughts are one of the most relevant extreme weather events [1], causing severe socioeconomic losses and human health impacts. With recent global and regional warming [1,2], droughts in the Iberian Peninsula (IP) have become more frequent and severe [3,4], revealing significant vulnerability and exposure of ecosystems and humans [2]. Changes in the frequency and/or intensity of extreme weather and climate events are bound to impinge profound environmental and socio-economic impacts in the next decades [1].In this work, the regional climate change in the IP for time periods when the global mean temperature increased 1.5º and 2ºC when compared to pre-industrial conditions was assessed in terms of drought evaluation. To achieve the proposed goal drought changes have been investigated using two of the most widely used drought indicators, the Standardized Precipitation Index (SPI) and the Standardized Precipitation and Evapotranspiration Index (SPEI). Both indices were calculated for the IP territory at 0.11º resolution during 2006-2100, considering the RCP8.5 and RCP4.5 scenarios obtained through EURO-CORDEX [5]. Both drought indices were computed monthly at multiple time-scales, using the accumulation periods of 1-, 3-, 6-, 9-, 12-, 18- and 24-months. The temporal multi-scalar character of both indices constitutes a significant advantage, allowing the characterization of the phenomenon with different response times of different ecosystems to drought conditions.Based on EURO-CORDEX simulations we addressed the following questions in this study: (1) to what extent could the occurring risk of droughts be avoided if global warming is limited, and (2) are there new areas with higher risk of population exposure to droughts in the IP. The obtained results enable the responsible authorities to take action, allowing society to timely prevent, adapt and mitigate to a range of different climate scenarios. [1] Hov Ø et al., 2013. Extreme Weather Events in Europe: preparing for climate change adaptation. Norwegian Meteorological Institute, Oslo. [2] Fischer E.M. and Knutti R., 2015. Anthropogenic contribution to global occurrence of heavy-precipitation and high-temperature extremes, Nature Climate Change, 5(6), doi: 10.1038/NCLIMATE2617.[3] Coll J. et al., 2016. Drought variability and change across the Iberian Peninsula. Theor Appl Climatol. doi:10.1007/s00704-016-1926-3[4] Vicente-Serrano S.M. et al., 2014. Evidence of increasing drought severity caused by temperature rise in southern Europe. Environ. Res. Lett., 9, 044001.[5] Jacob D. et al., 2014. EURO-CORDEX: new high-resolution climate change projections for European impact research. Reg Environ Change, 14, 563. https://doi.org/10.1007/s10113-013-0499-2Acknowledgements: This work was partially supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under projects IMDROFLOOD (WaterJPI/0004/2014) and IMPECAF (PTDC/CTA-CLI/28902/2017). Ana Russo and Andreia Ribeiro thank FCT for grants SFRH/BPD/99757/2014 and PD/BD/114481/2016, respectively. [ABSTRACT FROM AUTHOR]