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The predominant climatological wind regime in summer over the Greek Seas and especially over the Aegean Sea is undoubtedly the Etesian winds system, very well known since the time of the ancient Greeks, who first identified and described its main characteristics. The Etesian winds have been under continuous and intensive research since early 1900s, and numerous papers have been published, which have revealed all the secrets associated with the physical mechanisms responsible for their creation and maintenance. The ordinary synoptic situation, which is closely associated with the appearance of spells of Etesian winds outbreaks over the Aegean Sea, refers to cases in which the Subtropical Jet Stream (SJS) is situated over the Greek mainland. Then the frontal surfaces associated with the Polar Jet Stream (PJS), or a polar jet streak, passing through Greece from the north can cause severe weather in northern Greece as far south as Larisa (39.39° N, 22.26° E). Precipitation does not usually occur south of Larisa, because the SJS constitutes a barrier to the southward extension of the upper half of the frontal surface. In this case, cold advection occurs in the lower troposphere, resulting in a drop in temperatures even in southern Greece, due to the establishment of an Etesian winds outbreak. Thereafter, these north-easterly winds persist for a long time, weakening gradually, following the variation of the pressure gradient due to the combination of the mobile dynamic anticyclone positioned over the Balkans, after the passage of the cold front and the permanent Cyprus surface low. The main goal of this article is to investigate how much the case of a time period around 9 July 2022 differs from the conceptual model mentioned above, as deep convection occurred over all of Greece over three successive days, breaking the Etesian winds regime and defeating the low tropospheric stability usually accompanying this wind regime. [ABSTRACT FROM AUTHOR]

The Pedersen process is an alumina production process, which combines pyrometallurgical and hydrometallurgical methods. In the pyrometallurgical stage, limestone is calcined and CO2 is generated. This off-gas can be captured with a high CO2 concentration. At the end of the hydrometallurgical process, aluminum hydroxides, like bayerite, are precipitated using CO2. In this paper, experimental work on precipitation of aluminum hydroxides through the addition of a mixture of CO2, O2 and N2 is presented. The parameters varied, as were the percentages of each gas and the temperature. The indicators measured were the time until the beginning of precipitation and the time that the precipitation lasts. These tests simulate the use of a smelter furnace off-gas in the precipitation stage of the Pedersen process and have shown promising results. [ABSTRACT FROM AUTHOR]

At the end of surface mining activities, the remnant voids are of great concern regarding rehabilitating the final open pits. The investigation of the sustainability of pit lakes in post-mining regions constitutes a challenging research problem. This paper aims to highlight the effectiveness of pit lakes as a rehabilitation factor. In this framework, several cases worldwide and in Greece were examined in detail and evaluated. The results indicate that mine pit lakes must be evaluated as dynamic systems, natural or artificial, which demand rational mine water management to ensure their sustainability. Specifically in Greece, it is of great importance during the transition to the post-lignite era. [ABSTRACT FROM AUTHOR]

The Circular Economy set a frame to govern sustainable growth. Laspias river basin (Thrace) is characterized by various land and water uses and pressures posed directly and/or indirectly on the riverine system which acts as a burdened receptor. The aim is to prioritize threats in the basin and to further recognize the causality relationships in main elements affecting water management parameters that fall upon circular economy using enhanced DPSIR, Decision Making Trial and Evaluation Laboratory (DEMATEL) techniques. To assess the status quo, circular economy principles were adopted using a sustainable water management perspective embedded in DPSIR to link the causes and effects components. The key criteria based on the cause-factors were mined simplifying the multicriteria analysis of the effects. Findings highlight the multiplicity of pressures and origin of the impacts. This method proved as a valuable tool to track threats prior to stakeholder mapping for participatory management. [ABSTRACT FROM AUTHOR]

This review presents a mineralogical and physicochemical comparison of coal seams located in the regions of Northwest and Central Greece. The comparison extends to the fly ash derivatives from the coal combustion for energy production, in the cases where data are available. Coal occurrences from Northwest Greece tend to exhibit higher content of rare earth elements (REE) compared to those of Central Greece. Moreover, fly ash products show similar trends in Light-REE compared to their coal parent rocks. The observed REE distribution seems to be correlated with the occurrence of specific minerals such as allanite, monazite, as well as with Fe-contents. [ABSTRACT FROM AUTHOR]

The level of innovativeness within the higher education systems of east and southeast Europe and their graduates is still assessed as modest or moderate. Besides the general socio–economic context and the inherited institutional management types, this deficiency stems from a lack of generic skills crucial for increasing the innovation capacity of the universities. TrainESEE v.2 project suggests that significant changes should be already put in place within the applied teaching methodology, but also highlights the importance of developing project development and management skills, innovation, entrepreneurial skills, and finally competences needed to strengthen science to business cooperation. [ABSTRACT FROM AUTHOR]

Wildfires stand as significant contributors to atmospheric aerosols, exerting a substantial influence on air quality and radiative forcing. In our research, we utilized the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) to delve into the repercussions of wildfires on aerosol pollution and meteorological interactions. Our study centered on Greece, serving as a poignant test case. We focus on the summer of 2021, a period marked by intense wildfire occurrences within the nation. [ABSTRACT FROM AUTHOR]

Carbon monoxide, XCO, and methane, XCH4, column-averaged dry-air mole fractions (DMFs), observed by the TROPOspheric Monitoring Instrument (TROPOMI) on board Sentinel-5P (S-5P), are validated against those obtained from a Bruker ground-based low-resolution Fourier transform spectrometer, EM27/SUN, operating in the framework and according to requirements of the Collaborative Carbon Column Observing Network (COCCON), in Thessaloniki, Greece, on a mid-latitude urban site. The current operational S5P/TROPOMI observations show very good agreement with the respective FTIR measurements and capture both their seasonal variability and pollution episodes. XCO reported the highest concentrations during the fire episodes in summer 2021, when its daily mean value reached a maximum of 0.134 ± 0.015 ppm. XCH4 shows a slight annual increase of 0.02 ppm, with the highest concentrations during early 2022 (approximately 1.92 ppm). The satellite CH4 and CO products have been recently reprocessed with updated CH4, CO and H2O cross-sections, among other improvements, bringing noticeable changes in the pre-existing biases of S5P products against the FTIR ground-based data. We report that, for this mid-latitude station, mean biases and standard deviations fall well within mission requirements for XCH4 and XCO (-0.01 ± 0.6% and 0.62 ± 4.2% for XCH4 and XCO, respectively), underlying the significance of satellite measurements as a valuable supplement to ground-based data for the purpose of greenhouse gas monitoring. The results presented in this work for the Thessaloniki FTIR instrument are in strong agreement with FTIR locations in the middle latitudes. [ABSTRACT FROM AUTHOR]

Extreme weather events are identified as a major area of interest, and further consideration is demanded. This study investigates the synoptic and dynamic aspects of a storm system, named "Athina", that affected most of Greece in early October 2021. This system is synoptically attributed to a low surface pressure generated in the Gulf of Genoa, linked to a mid-tropospheric, almost neutral tilted trough, over central Europe. "Athina" brought heavy rain and strong winds to many parts of Greece, causing flooding and landslides in several areas and caused travel disruptions, with ferries and flights cancelled due to the adverse weather conditions. The worst-hit regions were the northwestern part of the country and Evia. Synoptic maps for upper and lower troposphere, observations from Hellenic National Meteorological Service's network, and satellite imagery were usedfor the analysis of this weather event. The results from a regional numerical weather prediction model are also presented. [ABSTRACT FROM AUTHOR]

Water leakages in urban water supply networks are a major cause of non-revenue water (NRW) and pose significant challenges for water management. To address this issue, the Municipal Enterprise for Water and Wastewater of Aigialeia (DEYA Aigialeias), the Institutionalized Research Laboratory of Smart Technologies, Renewable Energy Sources and Quality of UNIWA (STRESQ), and the Laboratory of Climatology and Atmospheric Environment (LACAE, NKUA) are collaborating on a project titled "Smart system for Leak Detection for water supply Network of Aigio". By installing sensors and implementing a SCADA system with PLC controllers, critical parameters such as water supply, pressure, and quality will be monitored. This project aims to reduce water leakage, which currently accounts for approximately 48% of the town's total water supply, ultimately saving around 600,000 m² of water annually. [ABSTRACT FROM AUTHOR]

Increased interest is demonstrated recently in the emergence of prosumer schemes for the residential sector on the basis of combined RES and storage configurations. Primarily, such schemes aim to increase energy autonomy for end users. Despite providing an alternative supply solution that may secure end users from volatile energy prices, RES-battery configurations also suggest costly and, in most cases, capital-intensive solutions. As such, exploring the generation of additional revenue through market participation is an exercise worth undertaking, noting at the same time that decongestion management services may also be provided to the local grid. In this context, the current study introduces an operational framework for the market participation of RES-battery prosumer schemes, seeking to determine the optimal balance between self-consumption and market integration. For that purpose, we use typical demand patterns and perform an extensive parametrical analysis concerning system size, spot price levels and degree of market integration in the context of the Greek electricity market, with our results indicating areas of optimum balance for the minimization of similar schemes' levelized cost of electricity. [ABSTRACT FROM AUTHOR]

The synoptic-meso-a scale study of a convective line shows that the latter was favored by the vertical superposition of the passage of an ULFnt onto a low-level convergence line. [ABSTRACT FROM AUTHOR]

This pilot study aims to evaluate the impact of climate change on the critical stages of crop growth. Data from agricultural stations in Greece were analyzed to assess the effects of climate change on the country's agriculture, focusing on areas vulnerable to frost, as identified by the Hellenic Agricultural Insurance Organization. The study examined the differences in climate patterns between continental and coastal agricultural regions to determine which areas are more resilient to local climate change. The frequencies of frost events and government subsidies were analyzed. The significance of early spring temperatures and their potential consequences for plant growth and vegetation, if followed by late-frost incidents, was emphasized. The severity and impact of frost events vary depending on the location, vegetation type, and growth stage. The economic importance of frost-sensitive crops, like deciduous fruit trees, citrus, and vines, in Greek agriculture has been highlighted. Given the increasing frequency of adverse weather conditions, the study underscores the need for a resilient and sustainable approach to agriculture, focusing on prevention and adaptation to climate variations. [ABSTRACT FROM AUTHOR]

This study aims to provide insight regarding the future evolution of a series of important agroclimatic indicators for a specific farming area of viticulture in Stimagka, Greece. The calculated indicators cover various aspects of the climate and its impact on agriculture and can be categorized into four broad categories: temperature-, precipitation-, drought-, and animal comfort-related indicators. An ensemble of state-of-the-art regional climate model simulations with a spatial resolution of 12 km are used to calculate the indicators for the period 1986-2055. For the period 2006-2055, two scenarios of possible future evolution of anthropogenic greenhouse gases are used: rcp4.5 and rcp8.5. Results indicate a clear future increase in temperature-related indicators in the region and also more persistent drought conditions. [ABSTRACT FROM AUTHOR]

Climate variation in temperature describes the fluctuations that occur above or below the average temperature over time. This study focuses on the analysis of various approaches for calculating the average temperature to better capture and represent the true average temperature over the course of a day. As the conventional approach often fails to integrate significant behaviors of temperature variations, nine mathematical formulas are employed with a different number of daily observations. Specifically, this study inserts the geometric and harmonic mean and their variations for the estimation of the average temperature. Furthermore, the application of the formulas to the time series of temperature recordings for three station locations in Greece is analyzed. For the evaluation of the results, six widely used statistical indices for quantifying errors are applied, and their relative effects are also discussed. Finally, as a practical application of the impact of the formula used for the averaging of daily temperature, the various approaches are introduced on the same observation dataset for the estimation of the heating degree-days, an index that can have significant climatological and economic implications over a region. [ABSTRACT FROM AUTHOR]

The preservation of historical buildings, as well as museum exhibition facilities, is critical under the changing environmental conditions. Since the potential outdoor climate changes may affect the recommended environmental conditions within the museum microenvironment, there is an urgent need for further research into the relationship between the outdoor and indoor climate and how future changes could affect it. This study investigated the relationship between the indoor and outdoor climate conditions in museums and historical buildings located in Greece. The main goal of this work was to assess the suitability of the indoor microclimate by applying the heritage microclimate risk (HMR) and the predicted risk of damage (PRD) indices. In order to achieve a detailed assessment of the present temperature and relative humidity (RH) outdoor conditions over the specific case studies, data from three different sources were incorporated in the study (observed, reanalysis, and model data). The model data were derived from the regional climate model RegCM4 with a fine spatial resolution of 10 x 10 km. The indoor environmental parameters were collected both from the museums and the historical buildings in the two case studies. In cases where indoor environmental data were not available, monitoring sensors were installed. The findings indicate that in cases where there is no control over climate conditions, the indoor climate is predominantly influenced by the outdoor climate. As a result, these spaces exhibit a heightened sensitivity to potential future temperature increases. [ABSTRACT FROM AUTHOR]

Climate change is an ongoing process with evident effects on local climates. Heritage management is vital for the protection of cultural heritage, with vulnerability assessment and mitigation-adaptation strategies. This research presents the pressure of local climate and the climate extremes on the ancient Greek theatre of Dodoni in North-Western Greece, which combines cultural, natural, tangible, and intangible heritage. The impact of local climate is analyzed by collecting climatological daily time series of ambient air temperature, humidity, and precipitation, acquired by the nearby meteorological station of Ioannina (Hellenic National Meteorological Service) for the period 1956-2022. This information is incorporated into heritage management for future protection. [ABSTRACT FROM AUTHOR]

Waterspout outbreaks are very impressive phenomena defined as multiple waterspouts successively forming in a specific area. This study presents the twelve largest waterspout outbreak cases that have occurred in the last two decades (2000-May 2023) in Greece. Synoptic data indicated a closed low (CLOSED) pattern prevailed during waterspout outbreaks over the Aegean and Ionian Seas. A variety of convective parameters were examined, including most unstable CAPE (MUCAPE), mixed-layer lifting condensation level (MLLCL), low-layer shear (LLS) and 0-1 storm-relative helicity (SRH). The Szilagyi Waterspout Index (SWI) is applied successfully and is suggested for further consideration and application in waterspout operational forecasting. [ABSTRACT FROM AUTHOR]

A network of low-cost sensors operates at six islands in the Aegean Sea (Lemnos, Lesvos, Chios, Samos, Syros and Rhodes) providing real-time PM2.5 concentrations to the public. In the present study, the effect of the prevailing meteorological conditions on the local air quality was examined. For this reason, data about wind direction, dry and wet temperature, wind speed and sunlight were provided by the Hellenic National Meteorological Service for the period from January to September 2022. The analysis of the hourly PM2.5 concentrations revealed different air quality patterns on each island, as well as seasonal changes for the same islands (e.g., higher concentrations in Samos during the cold period). Temperature was found to contribute significantly to the PM2.5 measurements since it affects the anthropogenic activities related to emissions. For instance, higher temperatures in winter result in limited residential heating needs. [ABSTRACT FROM AUTHOR]

Greece was hit by an extreme heat wave, with a significant impact on human health and natural ecosystems in the period between 28 July and 11 August 2021. After the end of this unusual warm period, a rare occasion of multiple supercell storms was observed on 11 August 2021 in northern and central Greece. The synoptic conditions indicated embedded short waves in a northwesterly flow and significant thermal instability across the regions of interest was evident. In conjunction with the strong vertical wind, shear organized convection was released. At least six long-track supercells were documented and the onset, evolution and specific characteristics of them are presented. All supercells moved from NW toward SE, accompanied by large hail, intense rainfall and destructive wind gusts, producing widespread damage along their track. [ABSTRACT FROM AUTHOR]

During the last few decades, there has been an increase in the number of natural disasters in Greece, triggering consequences and raising public awareness. This research highlights air masses trajectories during flash floods and meteorological disasters in Greece, registered in the Emergency Database EM-DAT. Registered disasters on the EM-DAT platform offer a relevant information base for vulnerability assessment and rational decision-making in disaster situations. In Greece, the time series of registered disasters covered 117 years between 1904 and 2021, and 146 disasters were registered; 100 and 46 events were classified, respectively, as natural and technological disasters. The period 1980-2021 records a total of 83 out of 100 natural disasters. The categories of natural disasters included in the database do not vary, but there has been a striking increase in the number of meteorological and hydrological ones during the period 1980-2021. Meteorological disasters (a total of 17, out of which 15 were registered after 1980) and hydrological ones (23, all of them registered after 1980). Meteorological and hydrological disasters are associated with the large-scale circulation of air masses, which favors the occurrence of such phenomena. In order to identify their characteristics, back-trajectories analysis was used. The results indicate that flash floods occur when air masses are moving above warm sea waters, while for the other meteorological disasters, air masses moved from North Africa or North Europe/Atlantic areas. [ABSTRACT FROM AUTHOR]

Microplastics can enter waters from surface run-off and atmospheric deposition. An exploratory study was undertaken to assess microplastic pollution in the natural lake of Yliki, an auxiliary drinking water reservoir supplying the network of Athens, Greece. Samples taken over the ~25 km² area of the lake revealed the presence of fragments and fibers at three out of ten locations, possibly from agriculture in the surrounding area or fishing in the lake. The findings highlight the ubiquitous nature of plastics and the need for regulated assessment of water supplies for environmental and human health protection. [ABSTRACT FROM AUTHOR]

Utilizing an extension of Pearson's correlation in the case of random vectors, we improve the empirical dynamic modeling causal analysis of non-linear systems. To prove the effectiveness of the use of such an extension we analyze two real-world examples, the paramecium-didinium protozoan system and the influence of environmental variables on mosquito abundance in northern Greece. In both examples it is shown that the causal analysis based on the extended metric outperforms the usual method of measuring the correlation between observed and predicted values of a single vector component. [ABSTRACT FROM AUTHOR]

In this study, we present the preliminary results of our effort to construct a new high spatial resolution precipitation database (1 km x 1 km) over Greece, on an annual and monthly basis. A variety of spatial parameters (i.e., latitude, longitude, altitude, aspect, distance from water bodies, among others) and ERA5 reanalysis data were used as independent variables in an algorithm combined with the Regression Kriging with a Histogram-Based Gradient-Boosting Regression Tree. The dependent variable in the algorithm was the gauge data covering most of the area studied. Maps were constructed for the ERA5 reanalysis and the modelled mean precipitation totals on an annual and monthly basis for the 1980-2010 study period. The findings of the analysis show that the applied methodology improves the spatial resolution and distribution of the ERA5 reanalysis precipitation totals over Greece. Furthermore, when comparing the modelled high spatial resolution datasets against ERA5 datasets over the gauge precipitation totals, the model achieved an average R² improvement of 31.7%, with the largest improvement recorded on an annual basis, while the RMSE decreased by 16.6% on average and more than 40% on an annual basis. [ABSTRACT FROM AUTHOR]

Intense cyclones with tropical-like characteristics (also known as "medicanes") occasionally develop in the Mediterranean. They can cause extreme weather phenomena with catastrophic potential due to excessive precipitation, windstorms, and coastal flooding. In this work, the impact of air-sea interactions on the track and intensity of a Mediterranean cyclone is evaluated using an atmosphere-only configuration (WRF) and a two-way coupled ocean-atmosphere configuration (NEMO-WRF). As a case study, we focus on a medicane that evolved over the central Mediterranean basin during 15-20 September 2020 (named "Ianos"), causing severe damage to western Greece. The atmosphere-only simulations were carried out using constant initial SST throughout the model integration, while in the coupling setup, the SST was consistent with the air-sea fluxes and updated every 6 min by the ocean model. The results from the two modeling approaches highlight the importance of air-sea feedbacks for predicting Mediterranean cyclone intensity, along with the forecast initialization time. [ABSTRACT FROM AUTHOR]

This work presents an approach for wirelessly monitoring the indoor temperature, relative humidity, and carbon dioxide (CO2) concentration parameters affecting the microclimate of the Holy Cross hermitage, which extends into a small cave located in the Olympus area of Greece and maintains remarkable wall paintings dated back to 1339 A.D. The results indicate that the methodology applied was effective enough in maintaining a long-term monitoring process and, as a result, comprehending the ambient conditions of the hermitage with regard to its microclimate. In this context, it would be possible to identify any imminent hazards in time and therefore plan the required conservation actions. [ABSTRACT FROM AUTHOR]

The World Health Organization (WHO) has developed the AirQ+ software in order to estimate the magnitude of the impact of air pollution on health in a given population. In this study, the AirQ+ was applied to calculate the short-term effects attributed to PM2.5, NO2 and O3 in the Attica Region, Greece. Based on the health endpoints handled by the AirQ+ software, we evaluated the impact of air pollutants on hospitalizations and work days lost. In 2015, 69,460 and 48,972 patients were admitted to the hospitals in the Attica Region due to circulatory and respiratory diseases, respectively. For the estimation of the attributable burden, the time-series of PM2.5 NO2 and O3 concentrations for the year 2015 are used. The burden attributed to PM2.5 is 297 (55-546) and 441 (0-953) hospitalizations for circulatory and respiratory diseases, respectively. NO2 and O3 also contribute to the burden of hospitalizations for respiratory diseases. Specifically, 424 (271-576) and 381 (61-718) respiratory-related hospitalizations are attributed to NO2 and O3, respectively. An important effect of PM2.5 exposure also handled by the AirQ+ is work absenteeism. Based on health statistics for Greece, the number of self-reported work days lost per year due to illness are 14.7 days per employed person. The attributable burden of PM2.5 is 0.33 (0.28-0.38) work days lost (per employed person per year). In conclusion, the short-term effects of air pollution exposure has a great impact on human health. [ABSTRACT FROM AUTHOR]

The short-term changes in micrometeorological and hydraulic attributes of burnt forest soils were evaluated under the influence of three types of post-fire restoration works (wattles, log barriers, and log dams). Comparisons between the two zones (erosion EZ and deposition DZ) formed at the area between two consecutive restoration work units were performed. The reflectance presents minor differences in the two zones, being slightly higher in the EZ, whereas cooler surface temperature and higher soil moisture were recorded in the DZ. The DZ can effectively infiltrate precipitation water with rates of about 150% higher compared to the EZ. [ABSTRACT FROM AUTHOR]

In August 2021, extreme wildfires burned wide areas in Greece. The most severe events took place in the region of Attica and significantly affected the air quality over the city of Athens. In the same period, southern winds transferred dust from the Sahara Desert to the city. We chose a day with high dust and smoke loads to test a new method for the determination of the individual components of the aerosol mixture, based on actinometric and radiometric measurements and radiative transfer modelling. Then, we estimated the radiative effect of each of the aerosol mixture components. Assuming that dust particles are coarse while all other particles are fine, coarse to fine mode ratios were estimated and were compared with the corresponding ratios from a CIMEL sun photometer, resulting in quite good agreement. [ABSTRACT FROM AUTHOR]

Based on the value of statistical life and the willingness to pay methods, we estimated the economic cost resulting from premature mortality associated with fine particulate matter and ground-level ozone exposure across Greece during 2004-2019 under a constant and changing income elasticity scenario. The spatiotemporal trends of the economic burden were also investigated. The total economic burden attributable to premature mortality due to exposure to PM2.5 and O3 for the 16-year period was estimated at EUR 66.34 billion under the constant scenario and at EUR 273.65 billion under the changing scenario. A dramatic decline of the mortality cost was observed from 2009 to 2019 in the changing scenario, as opposed to a less profound downward trend under the constant scenario, where the annual gross domestic product and the consumer price index were not taken into account. [ABSTRACT FROM AUTHOR]

Transient Luminous Events (TLEs) are rare electrical discharges occurring in the middle and upper atmosphere above thunderstorms. The results of systematic observations of TLEs in a region that includes Greece and its surrounding area during a 2-year period (September 2020-September 2022) are presented. This study provides a first insight about the frequency, the spatiotemporal distribution, and the variety of these events in that region. In total, 1632 TLEs were observed during these 2 years. Of these, 95.5% were red sprites. Most events occurred over the Ionian Sea, the southern Adriatic Sea, and western Greece. The most favorable period for TLEs in Greece and its surrounding area is from October to February. Noteworthy were two prolific nights, 15-16 October 2020 and 4-5 December 2021, over mesoscale convective systems at the Ionian Sea and the southeastern Aegean Sea, respectively, when hundreds of these events were observed. Observations of this kind are of great significance, not only because they are the first-ever conducted in the aforementioned region but also due to the fact that these events seem to exhibit a relatively high frequency of appearance there. [ABSTRACT FROM AUTHOR]

Diurnal Temperature Range (DTR), defined as the difference between the daily maximum (Tmax) and daily minimum (Tmin) air temperature, has received considerable attention as an important indicator of climate change. In the present study, we analyse long-term highly homogenized DTR data from 51 Greek stations and investigate their spatiotemporal changes. The long-term temporal changes of DTR revealed mixed patterns with both increasing and decreasing trends over the study period and distinct seasonal differentiations. DTR pattern in Athens has fluctuated since the beginning of the twentieth century, generally following warming and cooling air temperature trends. After the mid-1980s, DTR showed a pronounced decreasing trend at a rate of 0.47 °C/decade in summer (p < 0.01) due to higher warming rates of Tmin, suggesting the combined effects of regional warming and urbanization levels. [ABSTRACT FROM AUTHOR]