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This study presents an updated assessment of the projected climate change over Greece in the near future (2021–2050) and at the end of the 21st century (2071–2100) (EOC), relative to the reference period 1971–2000, and focusing on seasonal crop-specific climatic indices. The indices include days (d) with: a maximum daily near-surface temperature (TASMAX) > 30 °C in Spring, a TASMAX > 35 °C in Summer (hot days), a minimum daily near-surface temperature (TASMIN) < 0 °C (frost days) in Spring, a TASMIN > 20 °C (tropical nights) in Spring–Summer and the daily precipitation (PR) > 1 mm (wet days) in Spring and Summer covering the critical periods in which wheat, tomatoes, cotton, potato, grapes, rice and olive are more sensitive to water and/or temperature stress. The analysis is based on an ensemble of 11 EURO-CORDEX regional climate model simulations under the influence of a strong, a moderate, and a no mitigation Representative Concentration Pathway (RCP2.6, RCP4.5 and RCP8.5, respectively). The indices related to TASMAX are expected to increase by up to 11 days in Spring and 40 days in Summer, tropical nights to rise by up to 50 days, frost days to decrease by up to 20 days, and wet days to decline by up to 9 days in Spring and Summer, at the EOC with an RCP8.5. The increased heat stress and water deficit are expected to have negative crop impacts, in contrast to the positive effects anticipated by the decrease in frost days. This study constitutes a further step towards identifying the commodities and/or regions in Greece which, under climate change, are or will be significantly impacted.

The spatial distribution, radiative forcing, and climatic effects of tropospheric ozone in China during summer were investigated by using the regional climate model RegCM4. The results revealed that the tropospheric ozone column concentration was high in East China, Central China, North China, and the Sichuan basin during summer. The increase in tropospheric ozone levels since the industrialization era produced clear-sky shortwave and clear-sky longwave radiative forcing of 0.18 and 0.71 W m–2, respectively, which increased the average surface air temperature by 0.06 K and the average precipitation by 0.22 mm day–1 over eastern China during summer. In addition, tropospheric ozone increased the land–sea thermal contrast, leading to an enhancement of East Asian summer monsoon circulation over southern China and a weakening over northern China. The notable increase in surface air temperature in northwestern China, East China, and North China could be attributed to the absorption of longwave radiation by ozone, negative cloud amount anomaly, and corresponding positive shortwave radiation anomaly. There was a substantial increase in precipitation in the middle and lower reaches of the Yangtze River. It was related to the enhanced upward motion and the increased water vapor brought by strengthened southerly winds in the lower troposphere.

This study aims at assessing the differences induced in the Global Horizontal Irradiance (GHI) predictions by the mesoscale atmospheric Weather Research and Forecasting (WRF) model when using different shortwave radiation. Model predictions are compared with GHI measurements at 12 stations of the Hellenic Network of Solar Energy (HNSE) for January, April, July and October 2013. The shortwave radiation schemes that were evaluated are: the Dudhia, the updated Rapid Radiative Transfer Model (RRTMG), the updated Goddard and the Goddard Fluid Dynamics Laboratory (GFDL) schemes. All schemes perform better under cloudless conditions due to limited ability of the WRF model to simulate cloudy conditions. The Dudhia scheme performs best with mean relative difference of 2.2 ± 15% for clear-skies, while the differences for the other schemes range between 5 and 12% with similar standard deviations. For all-skies, the model-derived hourly GHI is overestimated for all schemes (∼40–70%). For the daily averages, the model predictions are in better agreement with the measurements, mainly under all-sky conditions, with deviations of about half those of the hourly data and smaller standard deviations. There are strong indications that the differences of the model predictions from the measurements depend on the solar zenith angle and the amount of aerosols at each station.

This article investigates the commonality in risk factors and sector biases in managed volatility equity strategies (both active and passive). A unique aspect of this article is that it is written from the perspective of a user of the strategies. Unlike all other past studies it considerers several versions of low volatility strategies—from different managers with different investment approaches and risk models. The findings here are therefore more general and not specific to a particular implementation or risk model. We will explore both actively managed volatility strategies as well as an index strategy.

This study explores the ideas of Greek prospective primary teachers about the anthropogenic greenhouse effect, particularly about its causes, consequences and cures. For this purpose, a survey was conducted: 265 prospective teachers completed a closed-form questionnaire. The results showed serious misconceptions in all areas (causes, consequences and cures). The most prominent misconception found by this survey is the conflation between the greenhouse effect and the ozone layer depletion, which is widely reported in the literature. There is also the notion that ‘good things’ (like clean beaches) can help ameliorate the greenhouse effect, whereas ‘bad things’ (like insecticides) can enhance it. One of the secondary results of the survey is that prospective teachers’ main source of information about the greenhouse effect is school. This calls for educational interventions to fight misconceptions at the source. Some suggestions are presented in this paper. The results of this study are compared with the results of two similar studies conducted in the UK and in Turkey.

The short–term prediction of near surface ozone levels is very important due to the negative impacts of ozone on human health, climate and vegetation. The objective of this paper is to develop and test an analytical model that could be applied to predict next day's maximum ozone concentration for the first time in Tirana, Albania, where ozone's monitoring has been recently started. The relationship of the daily maximum hourly ozone values with meteorological variables, including near surface air temperature and relative humidity and with air pollution variables like the persistency of ozone levels and its seasonal variation is examined. The data analysis reveals that the pollution persistency and the near surface air temperature are the factors that mainly affect the peak ozone levels. Multiple linear regression analysis has been performed to establish the relationship between the above mentioned parameters and peak ozone concentration. The agreement between observed and predicted daily maximum hourly ozone values is very good, with a correlation coefficient (R) of 0.87. The model slightly under–predicts the ozone concentration while no significant mispredictions are observed. Additionally, the model’s ability to predict the exceedances of a specific ozone limit value is examined. The model successfully predicts the exceedances of 105 μg m −3 , a value that corresponds to the 75 th percentile, in the 86% of the cases applied.

Typical multi-asset-class portfolios can be dominated by equity risk, even when the allocation to equities is relatively modest. Achieving risk parity between equities and fixed income in an unlevered portfolio would require significant rebalancing towards fixed income. While such rebalancing can lead to a reduction in risk, portfolios with high fixed-income allocations have historically underperformed equity-dominated portfolios. However, achieving risk parity through leverage, while keeping the initial asset allocation constant, would typically require substantial levels of leverage and could lead to a significant increase in portfolio volatility. The authors combine rebalancing and leverage to construct risk parity portfolios that target the same expected return and the same portfolio risk as the initial asset allocation and examine the performance of these portfolios in different market conditions.

This paper provides a comprehensive overview of the actual knowledge on the atmospheric pollution sources, transport, transformation and levels in the East Mediterranean. It focuses both on the background atmosphere and on the similarities and differences between the urban areas that exhibited important urbanization the past years: the two megacities Istanbul, Cairo and the Athens extended area. Ground-based observations are combined with satellite data and atmospheric modeling. The overall evaluation pointed out that long and regional range transport of natural and anthropogenic pollution sources have about similar importance with local sources for the background air pollution levels in the area.

This article presents alternative methods for constructing factor-replicating portfolios, which include portfolios that have unit exposure to a target factor, zero exposure to other factors, and minimum portfolio risk. The authors provide empirical evidence that constrained factor portfolios, with a limited number of assets and relatively low turnover, tracked several Barra equity risk model pure factor returns reasonably well. They also illustrate how factor-mimicking portfolios could have been utilized in the past to enhance both passive and active investment strategies. Factor-mimicking portfolios can be used to hedge out the unintended factor exposures of conventional benchmarks, which are aimed at targeting a particular beta factor, and thus enable plan sponsors to better manage their optimal allocations to beta factor risks. Additionally, factor-mimicking portfolios can be utilized to hedge out the style exposures of active stock-picking strategies enabling active managers to capture pure alpha.

Modern European cities are characterized by high particulate matter (PM) concentrations. Unfortunately, the number of stations monitoring air pollution, especially PM, is never sufficient for the overall representation of the problem. In the present work, an inexpensive outdoor passive sampler (based on an indoor passive sampler) was developed and assembled in an effort to provide the means to extend current PM monitoring networks. The uncertainty of the sampler was tested in vitro and in vivo. Twenty such outdoor passive samplers were assembled and installed at specific locations in the Greater Thessaloniki Area and measurements of PM were carried out. The results were in good agreement with the official monitoring stations. In addition, they revealed the aggravated air quality in the center of the city and in the west suburbs.

This article shows that portfolios that aim to diversify across countries and across industries provide markedly better reward-to-risk ratios than the traditional asset allocation strategies that aim to select country positions and then index local broad market indexes. Country asset allocations are distinctly different under each strategy. The results hold across nationality of investors, across alternative benchmarks, and across alternative currency hedging strategies.

A statistical analysis of ozone and PM10 concentration levels in the area of Volos, a medium-sized Greek coastal city, was carried out for the period 2001-2003. The data analysis revealed that the Daily Maximum Hourly (DMH) value of ozone concentration reaches a maximum of 160 µg/m³ during summer; it is observed during afternoon hours and is associated usually with winds from southern directions. This is attributed to the impact of the sea breeze on pollution levels. Concerning PM10 concentration, it was found that its DMH values are quite high and that its Daily Average (DA) value exceeds the limit value of 50 µg/m³ for approximately 38% of the days. The daily cycle shows two maxima (morning-evening) and in these cases the wind is typically from north-northwest directions. The weekly and seasonal variance of DA values of PM10 concentration is not very significant.