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In the framework of planning and designing resilient housing under a changing climate, the present study constitutes a comprehensive literature review exploring climate-proofing solutions for the built environment concerning energy supply and water availability. This study delved into a multitude of sources that included scientific papers and reports and European Union guidelines and tools. The identified solutions covered building, urban, and territorial scales. The hazards of interest included heatwaves, heavy precipitation, droughts, earthquakes, wildfires, and storms. Several types of solutions were found (e.g., nature-based, education/capacity-building, engineering/built environment, etc.) with different times of application and timescales of action (e.g., defensive measures, short-term solutions, long-term adaptive, etc.). The maturity of the identified solutions was assessed based on the Technology Readiness Level (TRL) and Societal Readiness Level (SRL). Moreover, each solution's contribution to climate mitigation was investigated. The solutions were assessed in terms of self-sustainability and other key criteria, namely, effectiveness, contribution to resilience maturity and climate change mitigation, adaptive nature, financing access, risk reduction, and social cohesion. In total, 85 energy and water solutions were determined from the desk review analysis and 67 (30 for the energy sector and 37 for the water sector) solutions were finally retained and proposed. [ABSTRACT FROM AUTHOR]

As warmer and drier conditions associated with global warming are projected to increase in southern Europe, the Mediterranean countries are currently the most prone to wildfire danger. In the present study, we investigated the statistical relationship between drought and fire weather risks in the context of climate change using drought index and fire weather-related indicators. We focused on the vulnerable and long-suffering area of the Attica region using high-resolution gridded climate datasets. Concerning fire weather components and fire hazard days, the majority of Attica consistently produced values that were moderately to highly anti-correlated (−0.5 to −0.9). This suggests that drier circumstances raise the risk of fires. Additionally, it was shown that the spatial dependence of each variable on the 6-months scale Standardized Precipitation Evapotranspiration Index (SPEI6), varied based on the period and climate scenario. Under both scenarios, an increasing rate of change between the drought index and fire indicators was calculated over future periods versus the historical period. In the case of mean and 95th percentiles of FWI with SPEI6, abrupt changes in linear regression slope values were observed, shifting from lower in the past to higher values in the future periods. Finally, the fire indicators' future projections demonstrated a tendency towards an increasing fire weather risk for the region's non-urban (forested and agricultural) areas. This increase was evident from the probability distributions shifting to higher mean and even more extreme values in future periods and scenarios. The study demonstrated the region's growing vulnerability to future fire incidents in the context of climate change. [ABSTRACT FROM AUTHOR]

This study investigates the origins and the atmospheric circulation patterns that led to the occurrence of Wet-Cold compound events (WCCEs) recorded by the Hellenic National Meteorological Service (HNMS) between 1980 and 2004. The study employed two methods to provide insights into the issue. The first method involved identifying clusters from backward trajectories (BTs) at three heights above the arrival point (500, 1500 and 5500 m). The second method aimed at detecting weather patterns (WPs) that result from the clustering of atmospheric pressure at sea level (SLP) and the geopotential height (GH500) at 500 hPa using ERA5 reanalysis data. To detect clusters for both methods, k-means clustering was applied. The analysis of backward trajectories produced seven clusters of BTs at each height level. Most of these clusters originated from the northwest or north, with medium, short, and long-distance clusters observed at the heights of 500 m, 1500 m and 5500 m, respectively. Despite analysing the temporal data, no clear connection was established between the clusters and months. From the cluster of GH500 and SLP variables for 94 different dates, we derived three main weather patterns. All weather patterns showed high GH500 values in Western Europe and lower GH500 values in Eastern Europe. Although SLP values differed significantly among the clusters, they helped to identify distinct weather patterns. Finally, we found that on 7 out of a total of 94 different dates with WCCEs, large amounts of moisture are transported through the atmosphere to Greece over long distances by atmospheric rivers (ARs). [ABSTRACT FROM AUTHOR]

Many modern frameworks for community resilience and emergency management in the face of extreme hydrometeorological and climate events rely on scenario building. These scenarios typically cover multiple hazards and assess the likelihood of their occurrence. They are quantified by their main characteristics, including likelihood of occurrence, intensity, duration, and spatial extent. However, most studies in the literature focus only on the first two characteristics, neglecting to incorporate the internal hazard dynamics and their persistence over time. In this study, we propose a multidimensional approach to construct extreme event scenarios for multiple hazards, such as heat waves, cold spells, extreme precipitation and snowfall, and wind speed. We consider the intensity, duration, and return period (IDRP) triptych for a specific location. We demonstrate the effectiveness of this approach by developing pertinent scenarios for eight locations in Greece with diverse geographical characteristics and dominant extreme hazards. We also address how climate change impacts the scenario characteristics. [ABSTRACT FROM AUTHOR]

South European and Mediterranean countries traditionally suffer from water scarcity, especially the regions around the Mediterranean. In Cyclades, the effects of drought have historically been observed and tackled with small-scale applications, with the most efficient method being rainwater harvesting (RWH). RWH is an inherent aspect of the local population's culture and architecture, since most houses have built-in water tanks and flat roofs to harvest as much rainwater as possible. In recent decades, the increase in local population and tourism have added additional stress to the limited water resources of the Cycladic islands. To overcome water shortages, most of the islands are equipped with desalination plants. Despite the use of these plants, RWH is still a vital source of water that is free and has zero carbon footprint. Thus, it is important to compare, assess and quantify the performance of this traditional water conserving method as a key water source for the islands' water resources management, today and for the coming decades. In this research, we investigate and quantify the future performance of rainwater harvesting applications and their contribution to continuous, sustainable, and climate-resilient water supply. The results show a decrease in rainwater harvesting potential in most of the islands, as well as the negative effect of touristic activity on per capita water availability on the islands. [ABSTRACT FROM AUTHOR]

Future fire weather conditions under climate change were investigated based on the Fire Weather Index (FWI), Initial Spread Index (ISI) and threshold-specific indicators in Greece. The indices were calculated from climate datasets derived from high-resolution validated simulations of 5 km. The dynamical downscaled simulations with the WRF model were driven by EC-Earth output for historical (1980–2004) and future periods, under two Representative Concentration Pathways (RCPs), RCP4.5 and 8.5. The analysis showed that the FWI is expected to increase substantially, particularly in the southern parts with extreme values found above 100. In addition, the number of days with an FWI above the 90th percentile is projected to increase considerably (above 30 days), under both scenarios. Over the eastern and northern mainland, the increase is estimated with more than 70 days under RCP4.5, in the near future (2025–2049). Moreover, central and north-eastern parts of the country will be affected with 30 or more extreme consecutive days of prolonged fire weather, under RCP4.5, in the near future and under RCP8.5 in the far future (2075–2099). Finally, the expected rate of fire spread is more spatially extended all over the country and particularly from southern to northern parts compared to the historical state. [ABSTRACT FROM AUTHOR]

This work presents the methodological approach followed for the study of the interaction of natural stone monuments with the local microclimate (exposure to RH, temperature alterations, wind, marine aerosol). This was implemented with the documentation of the associated weathering phenomena and the study of historic climate data of the area. The paper is focused on the main weathering mechanisms of the marly limestone at the Hellenistic theater of Zea in Piraeus, Greece. Based on the weathering phenomena identified, the development of the appropriate mitigation strategy was based on the physical, chemical and mechanical characterization of the natural stones, along with the evaluation of different conservation treatments, considering the characteristics of the coastal environment. Considering the mineralogy of marly limestones, silane-based materials were selected for providing both consolidation and water repellency effects. The evaluation of the conservation treatments was based on the modification of microstructural and water-related properties of natural stone samples, along with their consequent effect on their durability against accelerated aging tests. The results indicated that the design of migration actions proved to be multivariable parameter, depending on the intrinsic stone properties, the environmental parameters and the conservation efficacy of the treatments. [ABSTRACT FROM AUTHOR]

This paper aims to study wet–cold compound events (WCCEs) in Greece for the wet and cold season November–April since these events may affect directly human activities for short or longer periods, as no similar research has been conducted for the country studying the past and future development of these compound events. WCCEs are divided into two different daily compound events, maximum temperature– (TX) accumulated precipitation (RR) and minimum temperature– (TN) accumulated precipitation (RR), using fixed thresholds (RR over 20 mm d -1 and temperature under 0 ∘ C). Observational data from the Hellenic National Meteorology Service (HNMS) and simulation data from reanalysis and EURO-CORDEX models were used in the study for the historical period 1980–2004. The ensemble mean of the simulation datasets from projection models was employed for the near future period (2025–2049) to study the impact of climate change on the occurrence of WCCEs under the Representative Concentration Pathways (RCPs) 4.5 and 8.5 scenarios. Following data processing and validation of the models, the potential changes in the distribution of WCCEs in the future were investigated based on the projected and historical simulations. WCCEs determined by fixed thresholds were mostly found over high altitudes with TN–RR events exhibiting a future tendency to reduce particularly under the RCP 8.5 scenario and TX–RR exhibiting similar reduction of probabilities for both scenarios. [ABSTRACT FROM AUTHOR]

Future changes in drought characteristics in Greece were investigated using dynamically downscaled high-resolution simulations of 5 km. The Weather Research and Forecasting model simulations were driven by EC-EARTH output for historical and future periods, under Representative Concentration Pathways 4.5 and 8.5. For the drought analysis, the standardized precipitation index (SPI) and the standardized precipitation-evapotranspiration index (SPEI) were calculated. This work contributed to achieve an improved characterization of the expected high-resolution changes of drought in Greece. Overall, the results indicate that Greece will face severe drought conditions in the upcoming years, particularly under RCP8.5, up to 8/5 y of severity change signal. The results of 6-month timescale indices suggest that more severe and prolonged drought events are expected with an increase of 4 months/5 y, particularly in areas of central and eastern part of the country in near future, and areas of the western parts in far future. The indices obtained in a 12-month timescale for the period 2075–2099 and under RCP8.5 have shown an increase in the mean duration of drought events along the entire country. Drought conditions will be more severe in lowland areas of agricultural interest (e.g., Thessaly and Crete). [ABSTRACT FROM AUTHOR]

This paper aims to study wet-cold compound events (WCCEs) over Greece for the wet and cold season November-April. WCCEs are divided in two different compound events (TX-RR) and (TN10 RR) and two different approaches using fixed (RR over 20 mm/day and Temperature under 0 oC) and percentile (RR over 95th and Temperature under 5th) thresholds. Observational data from the Hellenic National Meteorology Service (HNMS) and simulation data from reanalysis and EUROCORDEX models were used in the study for the historical period 1980-2004. Simulation datasets from projection models were employed for the near future period (2025-2049) to study the impact of climate change on the occurrence of WCCEs under RCP 4.5 and 8.5 scenarios. Following data processing and validation of the models, the potential changes in the distribution of WCCEs in the future were investigated based on the projected and historical simulations. WCCEs determined by fixed thresholds were mostly found over high altitudes with a future tendency to reduce particularly under RCP 8.5. On the other hand, WCCEs obtained with percentile thresholds, were distributed mostly in Eastern Greece and Crete while their changes differed significantly among models. [ABSTRACT FROM AUTHOR]

This paper aims to study wet-cold compound events (WCCEs) over Greece for the wet and cold season November-April. WCCEs are divided in two different compound events (TX-RR) and (TN-RR) and two different approaches using fixed (RR over 20 mm/day and Temperature under 0 °C) and percentile (RR over 95th and Temperature under 5th) thresholds. Observational data from the Hellenic National Meteorology Service (HNMS) and simulation data from reanalysis and EUROCORDEX models were used in the study for the historical period 1980-2004. Simulation datasets from projection models were employed for the near future period (2025-2049) to study the impact of climate change on the occurrence of WCCEs under RCP 4.5 and 8.5 scenarios. Following data processing and validation of the models, the potential changes in the distribution of WCCEs in the future were investigated based the projected and historical simulations. WCCEs determined by fixed thresholds were mostly found over high altitudes with a future tendency to reduce particularly under RCP 8.5. On the other hand, WCCEs obtained with percentile thresholds, were distributed mostly in Eastern Greece and Crete while their changes differed significantly among models. [ABSTRACT FROM AUTHOR]

This paper introduces a climatic multi-hazard risk assessment for Greece, as the first-ever attempt to enhance scientific knowledge for the identification and definition of hazards, a critical element of risk-informed decision making. Building on an extensively validated climate database with a very high spatial resolution (5 × 5 km2), a detailed assessment of key climatic hazards is performed that allows for: (a) the analysis of hazard dynamics and their evolution due to climate change and (b) direct comparisons and spatial prioritization across Greece. The high geographical complexity of Greece requires that a large number of diverse hazards (heatwaves—TX, cold spells—TN, torrential rainfall—RR, snowstorms, and windstorms), need to be considered in order to correctly capture the country's susceptibility to climate extremes. The current key findings include the dominance of cold-temperature extremes in mountainous regions and warm extremes over the coasts and plains. Extreme rainfall has been observed in the eastern mainland coasts and windstorms over Crete and the Aegean and Ionian Seas. Projections of the near future reveal more warm extremes in northern areas becoming more dominant all over the country by the end of the century. [ABSTRACT FROM AUTHOR]

Climate change is set to affect extreme climate and meteorological events. The combination of interacting physical processes (climate drivers) across various spatial and temporal scales resulting to an extreme event is referred to as compound event. The complex geography and topography of Greece forms a variety of regions with different local climate conditions affecting the daily minimum temperature and precipitation distributions and subsequently the distribution of compound events of low temperature and high precipitation values. The aim of our study in this work is to identify these wet–cold events based on observational data from the Hellenic National Meteorological Service (HNMS) stations, which are divided into five different geographical categories, in the period 1980–2004 and coldest months of the year (November-April) on monthly basis. Two available reanalysis products, that of ERA-Interim downscaled with the Weather Research and Forecasting (WRF) model at 5km horizontal resolution (WRF_5), and the coarser resolution (∼30 km) ERA5 Reanalysis dataset from European Centre for Medium-Range Weather Forecasts (ECMWF), are adopted to derive a gridded monthly spatial distribution of wet–cold compound events, after performing a comparison with the observations. The results yield that the monthly maximum HNMS probabilities range from 0.07 % in April to 0.85 % in February, ERA5 range from 0.4 % in April to 2.97 % in February and WRF_5 from 10.4 % in November to 25.04 % in February. The results also displayed that February, January and December, are in this order, the months with the highest WCCEs. [ABSTRACT FROM AUTHOR]

Wind technology is projected to play a key role in mitigating climate change effects and contributing to the reduction of CO2 emissions, but its sustainability critically depends on current and future climate conditions. In this study, the climate change impacts on wind resources and wind energy potential in Greece are assessed, yielding a wealth of information that could be used by stakeholders. A detailed evaluation of future wind characteristics over Greece is carried out using EURO-CORDEX RCA4 model data with a horizontal resolution of ∼12 km, taking into consideration future RCP scenarios for the short term decadal climatology of 2040, which is the expected end-life of installed wind turbines. The RCA4 model demonstrated accurate performance when compared to actual observational data from the HNMS network, thus allowing higher confidence in assessments of future periods. Future projections revealed changes in the mean wind speed of the order of ±5% that did not vary significantly for the different RCP scenarios, although on a monthly basis that variability could reach ±20%. Decadal changes in the mean wind potential were of the order of ±15% for the two RCPs (2.6 and 8.5). Wind gusts exceeding 52 m/s, linked to the wind turbine structural integrity and robust performance, appeared more frequently in RCP 8.5 by about 2–4 times per decade, affecting mostly the South Ionian Sea. The findings also indicate a tendency for calming of the "Etesians" winds over the Aegean Sea in future summers. [ABSTRACT FROM AUTHOR]

The contribution of different anthropogenic source-sectors on ozone mixing ratios and PM2.5 concentrations over Europe is assessed for a summer month (July 2006) using the US Environmental Protection Agency's (EPA's) Models-3 framework and the Netherlands Organization for Applied Scientific Research (TNO) anthropogenic emissions for 2006. Anthropogenic emission sources have been classified into 10 different Standard Nomenclature for Air Pollution (SNAP) categories. The road transport category, which is mainly responsible for NOX emissions, is estimated to have the major impact on Max8hrO3 mixing ratio suggesting an increase of 6.8% on average over Europe, while locally it is more than 20%. Power generation category is estimated to have the major impact on PM2.5 concentrations since it is the major source of SO2 emissions, suggesting an increase of 22.9% on average over Europe, while locally it is more than 60%. Agriculture category is also contributing significantly on PM2.5 concentrations, since agricultural activities are the major source of NH3 emissions, suggesting an increased by 16.1% on average over Europe, while in regions with elevated NH3 emissions the increase is up to 40%. [ABSTRACT FROM AUTHOR]

SF6 and PFC are being used as state-of-the-art tracers in tracer-technology programmes aimed at efficient oil recovery in the North Sea. This study aimed at specifying sources of leakage and quantifying emission levels of such gases and at evaluating their effect on global warming. To satisfy these goals, quantification of SF6 and PFC combustion by-products under different realistic flame/temperature conditions (turbine, refinery, power plant, households and car engine) has been performed. The PFC compounds studied were PMCP (CF3C5F9), PMCH (CF3C6F11) and 1, 2-PDMCH ((CF3)2C6F10). Three-dimensional transport atmospheric modelling has been carried out using UAM-AERO for four different tracers' emissions scenarios (Base scenario, one including maximum emissions of tracers and two scenarios including overestimated emissions during loading processes and distribution over the land of Norway). The results showed a significant increase in the background concentrations of SF6 and PFC in the last two mentioned scenarios up to 6 km height approximately. These concentration profiles have been used as input to radiative models. In addition to SF6 spectral data obtained from HITRAN2K complemented with new band measurements, newly obtained data with quantitative spectral analysis for the specific PFC have been used in the line-by-line (GENLN2) and broadband models. [ABSTRACT FROM AUTHOR]

This study concentrated on the effects of Biogenic Volatile Organic Compounds (BVOC) emissions on ozone (O3) in an area of the Eastern Spain on June 12, 1997, a day characterised by sea breeze. Simulation of meteorology was performed with the three-dimensional model ADREA-I. Comparisons of the model results with observations have revealed overall a good agreement in temperature and wind velocity. Two runs were performed with UAM-IV for the photochemical calculations. The first simulated the effects of the anthropogenic emissions only (run A) and the second the combined effects of anthropogenic and biogenic emissions, (run B). Comparisons of the model O3 concentrations with measurements showed a general agreement with the experimental data. Discrepancies between the calculated results and the observations during the early morning hours could be attributed to inaccuracies in nitrogen oxides (NOx) from the anthropogenic emissions inventory. Comparisons between runs A and B yielded differences up to 30% in the morning, over inland areas. It was deduced that the inclusion of BVOC in total emissions could result in an increase or decrease of tropospheric O3, depending on the available amounts of anthropogenic emissions. [ABSTRACT FROM AUTHOR]

Safety in touristic destinations is of utmost importance since tourists' preferences change frequently in response to emerging threats. Natural hazards are a significant risk and, as such, they need to be considered in the effort for safe tourism. Services and systems monitoring and predicting extreme natural phenomena and disasters in sites of special tourist and cultural interest can lead to more effective risk management and incident response. This paper presents Xenios, a system under development in Greece that provides early warning and risk communication services via web-based and mobile phone applications. We present the user requirements analysis contacted, which led to the design of a modular system architecture through a formal Business Process Model procedure. Currently, early warning systems for wildfire, floods, and extreme weather events are offered, based on a fusion of information from satellite imagery, meteorological forecasts, and risk estimation models. Moreover, visitors' dispersion monitoring via unmanned aerial vehicles (UAVs) and Wi-Fi connection signals is also offered, along with emergency response planning and ticketing system's interfacing. The system is built around a modular architecture that permits the easy integration of new subsystems or other danger forecasting modules, depending on the site's actual needs and limitations. Xenios also provides a mobile app for site visitors, which establishes a communication link for sending alarms, but also serves them with useful tourist information, so that they are encouraged to download and use the app. Finally, the opportunities for supporting a viable business model are also discussed. The results of this study could prove useful in designing other natural risk management systems for sites of cultural and natural interest. [ABSTRACT FROM AUTHOR]

This work introduces a methodology for assessing near-future fire weather pattern changes based on the Canadian Fire Weather Index system components (Fire Weather Index (FWI), Initial Spread Index (ISI), Fire Severity Rating (FSR)), applied in touristic areas in Greece. Four series of daily raster-based datasets for the fire seasons (May–October), concerning a historic (2006 to 2015) and a future climatology period (2036–2045), were created for the areas under consideration, based on high-resolution climate modelling with the Representative Concentration Pathway (RCP), PCR 4.5 and RCP 8.5 scenarios. The climate model data were obtained from the European Coordinated Downscaling Experiment (EURO-CORDEX) climate database and consisted of atmospheric variables as required by the FWI system, at 12.5 km spatial resolution. The final datasets of the abovementioned variables used for the study were processed at 5 km spatial resolution for the domain of interest after applying regridding based on the nearest neighbour interpolating process. Geographic Information Systems (GIS) spatial operations, including spatial statistics and zonal analyses, were applied on the series of the derived daily raster maps in order to provide a number of output thematic layers. Moreover, historic FWI percentile values, which were estimated for Greece in the frame of a past research study of the Environmental Research Laboratory (EREL), were used as reference data for further evaluation of future fire weather changes. The straightforward methodology for the assessment of the evolution of spatial and temporal distribution of Fire weather Danger due to climate change presented herewith is an essential tool for enhancing the knowledge for the decision support process for forest fire prevention, planning and management policies in areas where the fire risk both in terms of fire hazard likelihood and expected impact is quite important due to human presence and cultural prestige, such as archaeological and tourist protected areas. [ABSTRACT FROM AUTHOR]

In the present study, the ability of the Advanced Weather Research and Forecasting numerical model (WRF-ARW) to perform climate regionalization studies in the topographically complex region of Greece, was examined in order to explore the possibility of a more reliable selection of physical schemes for the simulation of historical and future high resolution (5 km) climate model experiments to investigate the impact of climate change. This work is directly linked to a previous study investigating the performance of seven different model setups for one year, from which the need was derived for further examination of four different simulations to investigate the model sensitivity on the representation of surface variables statistics during a 5-year period. The results have been compared with observational data for maximum and minimum air temperature and daily precipitation through statistical analysis. Clear similarities were found in precipitation patterns among simulations and observations, yielding smoothly its inter-annual variability, especially during the wettest months and summer periods, with the lowest positive percentage BIAS calculated at about 19% for the selected combination of physics parameterizations (PP3). Regarding the maximum and minimum temperature, statistical analysis showed a high correlation above 0.9, and negative bias around 1−1.5 °C, and positive bias near 2 °C, respectively. [ABSTRACT FROM AUTHOR]

Fire occurrence and behaviour in Mediterranean-type ecosystems strongly depend on the air temperature and wind conditions, the amount of fuel load and the drought conditions that drastically increase flammability, particularly during the summer period. In order to study the fire danger due to climate change for these ecosystems, the meteorologically based Fire Weather Index (FWI) can be used. The Fire Weather Index (FWI) system, which is part of the Canadian Forest Fire Danger Rating System (CFFDRS), has been validated and recognized worldwide as one of the most trusted and important indicators for meteorological fire danger mapping. A number of FWI system components (Fire Weather Index, Drought Code, Initial Spread Index and Fire Severity Rating) were estimated and analysed in the current study for the Mediterranean area of France. Daily raster-based data-sets for the fire seasons (1st May–31st October) of a historic and a future time period were created for the study area based on representative concentration pathway (RCP) 4.5 and RCP 8.5 scenarios, outputs of CNRM-SMHI and MPI-SMHI climate models. GIS spatial analyses were applied on the series of the derived daily raster maps in order to provide a number of output maps for the study area. The results portray various levels of changes in fire danger, in the near future, according to the examined indices. Number of days with high and very high FWI values were found to be doubled compared to the historical period, in particular in areas of the Provence-Alpes-Côte d'Azur (PACA) region and Corsica. The areas with high Initial Spread Index and Seasonal Spread Index values increased as well, forming compact zones of high fire danger in the southern part of the study area, while the Drought Code index did not show remarkable changes. The current study on the evolution of spatial and temporal distribution of forest fire danger due to climate change can provide important knowledge to the decision support process for prevention and management policies of forest fires both at a national and EU level. [ABSTRACT FROM AUTHOR]