Environmental Sciences Proceedings

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. Full article

Wildfires are one of the strongest drivers of degradation of Mediterranean ecosystems, while weather and climate are among the main factors influencing fire potential. From this perspective, we attempt to assess the future forest fire risk in Crete in the near (2046–2065) and distant future (2081–2100), under the Representative Concentration Pathways (RCPs) of RCP2.6, RCP4.5, and RCP8.5. A risk assessment model was developed according to the conceptual framework of the “impact chain”, as defined by the Intergovernmental Panel on Climate Change (IPCC), aiming at the formulation of a final composite risk index. The multicriteria spatial analysis, which was implemented with GIS techniques, highlighted the areas that are expected to be heavily affected in the future. It was found that the forest fire risk for the tourism sector increases with the higher emissions scenarios and towards the end of the century, with the south and central parts of the island exhibiting ‘very high’ risk. The effectiveness of this method is underlined, both in terms of implementing the necessary preventive measures against the adverse effects of climate change and of strengthening adaptation planning. Full article

Heating and Cooling Degree Days (HDD, CDD) are indicative of the energy needs of buildings and also are associated with agriculturalism, tourism and other outdoor activities. Under the changing climate, future modifications of HDD and CDD are of primary importance. In the present work, monthly and annual HDD and CDD are computed and analyzed for the present and near future climate conditions. Elevation and sea proximity were found to be crucial in the formulation of energy requirements. Summer energy needs for cooling are expected to increase due to global warming while winter needs for heating are expected to decrease. Full article

This work explores the impact of thermal stress on natural-cause mortality in the nine Office of National Statistics regions of England using the thermal index Apparent Temperature as the exposure indicator. A standard time-series Poisson regression analysis for over-dispersed data was used, along with distributed lag non-linear models, setting a lag period of 21 days to account for the delayed effects of temperature. Regional differences in the exposure–response relationships were revealed. On the whole, the results demonstrated that the population in England is more vulnerable to cold effects and highlighted the dominant health impact of moderately low temperatures. Full article

Background: During the 2019 coronavirus disease (COVID-19) pandemic, lockdown was implemented, which likely reduced maternal 25(OH)D levels in pregnancy due to reduced sun exposure from social distancing measures and confinement at home. At the same time, however, due to the lockdown and the ban on the free movement of vehicles, the emissions of many atmospheric pollutants also decreased. We know that air pollution and low ground level ultraviolet B radiation (UVB; 290–315) can deteriorate the body’s vitamin D status in healthy women living in a polluted area, which plays a significant independent role in vitamin D deficiency (VDD) and, hence, residence can be one of the main reasons of vitamin D status in women. The reduction in air pollution likely produced positive changes in maternal 25(OH)D levels. Methods: We studied serum 25(OH)D in mothers who came for delivery, with stratified random sampling, from 27 September 2019 to April 14, 2021. We divided our sample into the pre-COVID period and the post-COVID period. Quantitative results of 25(OH)D vitamin levels on the mother were converted to qualitative variables assessing lack of 25(OH)D, adequacy, deficiency, and severe deficiency of maternal concentrations and, thus, defined. The results of 25(OH)D are presented as means ± standard deviations or by frequencies and percentages. The Chi-square test was used to find an association between maternal 25(OH)D concentrations within the COVID-19 period. Results: The results of our study showed a paradox. The mean values of 25(OH)D levels of the mothers were statistically significantly higher during the COVID-19 period compared to the pre-COVID-19 period. Conclusions: In conclusion, pregnant women should be encouraged to lead a healthier lifestyle, avoid being outside during rush hours, take nature walks, not smoke, exercise, take leisurely morning walks in the sun, and taking take their vitamin D supplements, which are recommended according to the gestational age, imitating all that they did during the pandemic, in order to avoid VDD. Full article

This work focuses on examining the contribution of passenger cars to CO₂, NO_X, CO, PM₁₀, and NMVOC emissions, as well as the changes in future emissions resulting from the usage of different types of vehicles. Initially, the importance of the road transport sector is discussed, followed by a presentation of data regarding the vehicle fleet. Subsequently, a methodology for forecasting the fleet, and calculating emissions, is introduced. Finally, the results are presented, focusing on the release of gaseous pollutants under different possible scenarios regarding the extent of electric vehicle penetration into the passenger vehicle fleet, for the year 2030. Full article

Greece in the period July–August 2021 was affected by two heat waves characterized by very high temperatures. The result was the occurrence of fires in various regions of the country, with Attica being one of the most affected regions of Greece. The atmospheric burden was very high, and the smoke covered the Attica sky at times, affecting the sunshine and by extension the incoming solar radiation. In this study, we examine whether the reduction in solar UV radiation synergistically with the increase in atmospheric particulate pollution was related to the spread of COVID-19 in Attica in the summer of 2021. Full article

Microplastics are a ubiquitous environmental pollutant that can potentially pose a threat to both aquatic organisms and to human health. Prevention methods are pivotal to microplastic mitigation, and new trends are emerging, that include a growing industry of alternative materials. Bioplastics and biodegradable products are emerging as a possible solution to mitigate pollution from petroleum-based single-use and limited-use items. The paper presents findings on the occurrence of plastics and microplastics in aquatic systems, on the composition and biodegradability of bioplastics, and on the potential of bioplastics to provide a solution to plastic pollution. Full article

Climate change raises concerns over the sustainability of the outdoor thermal environment and its impacts on societies. This study aims to examine the thermal conditions in Athens metropolitan area, Greece. Hourly data from 15 stations of the Automatic Weather Station Network of the National Observatory of Athens (2010–2021) were used to estimate the Net Effective Temperature (NET) and the Universal Thermal Climate Index (UTCI). The NET and UTCI were higher within the Athens basin (NET: mean ± sd = 15.3 ± 7.1 °C; UTCI: mean ± sd = 18.9 ± 10.4 °C) than in the surrounding area (NET: mean ± sd = 11.2 ± 9.3 °C; UTCI: mean ± sd = 13.4 ± 13.4 °C; p < 0.001). The highest numbers of hours with unfavorable warm conditions were found in Faliro (28.6%, NET; 27.7%, UTCI), Neos Kosmos (28.6%, NET; 27.4%, UTCI) and Patissia (28.6%, NET; 27.2%, UTCI). With respect to unfavorable cool conditions, the highest number was in Spata (65.1%, NET; 28.4%, UTCI). Full article

Thermal comfort is a key aspect of optimal conditions in urban public spaces. Air temperature, relative humidity, wind speed, and globe temperature measurements are critical components of bioclimatic research in the broader scientific field of urban space quality assessment. The evaluation of thermal comfort in public spaces frequently requires field measurements over long periods and at multiple sites at the same time. This can be challenging on a qualitative and quantitative level. Finding the most accurate way to collect such data in an accessible and manageable way is crucial in the context of an urban field study. Data from various instruments were evaluated and statistically compared in order to assess possible instrument synergy or even similarities that would allow a transition to a simplified way of measuring these determinants of thermal comfort. Full article

Surface solar radiation (SSR) is a crucial parameter for both the Earth’s climate and human activities, and it consists of two components: the direct beam from the sun and diffuse radiation, with the latter being scattered by atmospheric molecules, aerosols, or clouds. The multidecadal variations of SSR, known as Global Dimming and Brightening (GDB), should also arise from a corresponding variability of either the direct or the diffuse radiation. Thus, the determination of the trends of both the direct and the diffuse radiation is important for showing the causes of GDB. In the present study, we estimate the trends of global and diffuse radiation on a global scale during the period 1984–2018, using worldwide reference ground-based measurements from the Global Energy Balance Archive (GEBA) and the Baseline Surface Radiation Network (BSRN). An increasing tendency of SSR is observed over most locations on our planet, while a decreasing trend occurs in India. On the other hand, the diffuse radiation has decreased over Europe and parts of Asia, whereas it has increased over the USA, India, and East Asia. Full article

The objective of this study is the evaluation of the physical processes responsible for the genesis and evolution of an explosive cyclone in the central Mediterranean with the aid of the surface pressure tendency equation. For this reason, the equation is solved numerically, providing the opportunity to quantitatively specify the relative significance of the diabatic processes in Mediterranean explosive cyclogenesis, contrary to the qualitative approach of previous studies. Our approach allows for the first time a direct comparison of the physical mechanisms between the cyclogenesis over the northern and the southern part of the central Mediterranean. The results demonstrate that the interaction between the upper level baroclinic and low-level diabatic processes triggered the development of the explosive cyclone, but low-level baroclinicity and diabatic processes prevailed during the cyclone evolution. Full article

The overarching objective of the present study is to assess the quality of the CALIOP–CALIPSO aerosol retrievals towards understanding their advantages and deficiencies. Such analysis is a prerequisite prior to their utilization in a radiation transfer model (RMT) for estimating the clear-sky shortwave (SW) aerosol-induced direct radiative effects (DREs) within the Earth–Atmosphere system. The study region encompasses North Africa, the Middle East, and Europe (NAMEE domain), and the period of interest ranges from 2007 to 2020. A holistic approach has been adopted involving spaceborne retrievals (CALIOP–CALIPSO and MODIS-Aqua) and ground-based measurements (AERONET). Overall, CALIOP underestimates columnar aerosol optical depth (AOD), particularly in dust-rich areas, attributed to various factors (e.g., lidar ratio). In order to demonstrate the significance of an appropriate definition of the lidar ratio, focusing on DREs, three example dust cases are investigated. The CALIPSO dust extinction coefficient profiles are used as inputs to the libRadtran Radiative Transfer Model (RTM) along with other crucial parameters. For each study case, two RTM runs are performed using the default (CALIPSO) and an updated (DeliAn) dust lidar ratio. Our results indicate remarkable differences (up to ~22%) on the surface and atmospheric DREs while varying from 17% to 27% at TOA. Full article

Soil loss by water is a major form of land degradation with environmental and economic consequences. In particular, erosion rates are sensitive to both climate and land cover changes. The present study investigates the temporal changes in soil loss rate over South Europe during the 1980–2018 period. To that end, the Revised Universal Soil Loss Equation (RUSLE) was applied by integrating information from freely available geospatial datasets to conduct a multi-decadal assessment. In this frame, the temporal variability of the two dynamic RUSLE factors, namely rainfall erosivity (R) and cover management (C), was explored. Specifically, the rainfall erosivity values per decade were acquired from a newly developed dataset from the European Soil Data Center (ESDAC), coupling the Rainfall Erosivity Database at European Scale (REDES) and UERRA regional reanalysis rainfall data. On the other hand, land cover data were retrieved from the CORINE dataset (CLC) through the Copernicus Land Monitoring Service for different reference years. The appropriate values were assigned to each CLC category per country according to the recent literature to determine the C-factor. In terms of the other three static RUSLE factors, namely soil erodibility (K), slope length and steepness (LS) and support practice (P), these were obtained from the ESDAC database by exploiting the results of previous pan-European assessments. The results indicate that the mean annual soil erosion rates in South Europe were 6.82, 4.90, 4.89 and 5.26 t/ha/year for the decades 1981–1990, 1991–2000, 2001–2010 and 2011–2018, respectively. Full article

Particulate matter (PM) is one of the major air pollutants that has adverse impacts on human health. The aim of this study is to present an alternative approach for retrieving fine PM (particles with an aerodynamic diameter less than 2.5 μm, PM_2.5) using artificial intelligence. Ground-based instruments, including a hand-held Microtops II sun photometer (for aerosol optical depth), a PurpleAir sensor (for PM_2.5), and Rotronic sensors (for temperature and relative humidity), are used for the machine learning algorithm training. The retrieved PM_2.5 reveals an adequate performance with an error of 0.08 μg m⁻³ and a Pearson correlation coefficient of 0.84. Full article

Unmanned aerial vehicles (UAVs) are increasingly being used in meteorology research due to their ability to overcome challenges such as difficult access to hazardous locations and the need for high-resolution and real-time data. UAVs provide accurate and precise high-resolution data that allows scientists to study small-scale weather phenomena in unprecedented detail. This survey highlights the different types of UAVs used in meteorology, including fixed-wing, rotary-wing, and hybrid UAVs, as well as the various payload options available, such as sensors for temperature, humidity, pressure, wind, and precipitation. Overall choosing the appropriate UAV for meteorological applications relies on meeting specific mission requirements, including various factors. Full article

The polar front jet and the subtropical jet, usually separated, are rarely superposed at the same latitude over the greater Mediterranean region, resulting in intense cyclogenesis. The objective of this study is to identify the superposition of the two jets over the Mediterranean on a climatological basis and the possible association with high-impact weather events with the aid of satellite-based indicators. The results show that, indeed, the satellite indicators help in better identifying the area of possible jet superposition. Furthermore, it was found that although jet stream superposition occurs very rarely, it is mostly associated with severe weather events in the surrounding areas. Full article

In this paper, research on the relationship between forest fires and meteorology is carried out using simple meteorological variables (temperature, wind, and precipitation) from a few well-selected Greek meteorological stations. The 5 years (1998, 2000, 2007, 2012, and 2021) which recorded burnt areas for more than the 25-year average (37,000 ha) had as a common characteristic, on the one hand, a much drier than usual two-month period (July–August) following a winter period with a shortage of rainfall, and on the other hand a number of days with very high temperatures higher than the average of the last 25 years. The latter implies that average temperatures in all three summer months were at least 1 °C above their normal value. In the years following, the burnt areas were below their average regardless of the precipitation and summer temperature patterns. However, when precipitation during the two-month period (July–August) was two or more times more than normal, fire seasons had, at most, one-third of the 25-year average of burned areas, regardless of the precipitation of the winter periods preceding and summer temperatures in those years. This is very important as already in the early days of each fire season it will be possible to make an estimation of its outcome and to prepare more appropriately when the accuracy of the long-term seasonal forecast of temperature and rainfall anomalies is improved. Full article

Quality-assured aerosol optical properties (AOP) with high spatiotemporal resolution are vital for the accurate estimation of direct aerosol radiative forcing and solar irradiance under clear skies. In this study, the sky information from an all-sky imager (ASI) is used with machine learning (ML) synergy to estimate aerosol optical depth (AOD) and the Ångström Exponent (AE). The retrieved AODs (AE) revealed good accuracy, with a dispersion error lower than 0.07 (0.15). The retrieved ML AOPs are used to estimate the DNI by applying radiative transfer modeling. The estimated ML DNI calculations revealed adequate accuracy to reproduce reference measurements with relatively low uncertainties. Full article