Distribution of trace metals in the sediments of Elefsis Gulf

The present work examines the temporal evolution of industrial contamination in sediments caused by trace metals in the Elefsis Gulf, Greece. The current state of contamination as well as the related sources can be obtained from the study of the sediments. Trace metals, namely Ni, Cu, Fe, and Mn, were collected during 1984-2003 by the local monitoring network. The statistical analysis of the data and the contaminants isopleths patterns support the following conclusions: There is a strong correlation between the nearby coastal industrial activities and the distribution of the trace metals’ concentration in sediments. There is no seasonal or annual variation of the distribution. The sediments’ concentration of Mn in all sampling points and Cu in the center of the Gulf has decreased during the last years

An Operational System For Monitoring Oil Spills In The Mediterranean Sea: The PROMED System

The primary objective of this work was the development of an operational system for early detection of oil-spills, monitoring of their evolution, and provision of support to responsible Public Authorities during cleanup operations, based on Remote Sensing and GIS technologies. In case of emergency, the principal characteristics of the oil spill are defined with the aid of a space-borne synthetic aperture radar (SAR). The transport, spreading and dispersion of the oil spill is subsequently simulated on the basis of wind forecasts of the area. The use of thematic maps of protected, fishing and urban areas, and regions of high tourism allows the better assessment of the impact of an oil spill on the areas to be affected in terms of environmental sensitivity. Finally, reports are generated notifying port authorities, the media, and local organizations to be potentially affected by the presence of the oil spill. The pilot site for testing the PROMED System in Greece is the island of Crete

Application of sodar and lidar techniques in air pollution monitoring: A report on the EURASAP 90 international meeting

The European Association for the Science of Air Pollution (EURASAP) 90 International meeting was held in Crakow from 26 to 28 September 1990. Eighteen participants from 14 countries were present. Papers were presented on: (1) various approaches to classify and digitize the facsimile records of Acoustic Sounders (henceforth AS); (2) use of AS systems for mesoscale and microscale studies; (3) determination of the mixing depth; (4) parameterization of the convective boundary layer based on AS observations; (5) lidar and RASS recent applications and comparisons with meteorological masts; (6) air pollution forecast systems which incorporate AS systems. The analytical discussions which followed led to agreement about how best to use and relate the various techniques for obtaining better results with the individual systems, the possible combination of the different systems to construct a complete profilometer for the measurement of wind, temperature and their associated statistics covering both short (10 m) and long (1000 m) ranges as well as the determination of the Atmospheric Boundary Layer (ABL) depth incorporating the different systems

Acoustic remote sensing and associated techniques of the atmosphere and oceans

The 6th International Symposium on Acoustic Remote Sensing and Associated Techniques of the Atmosphere and Oceans (6th ISARS) was held in Athens, Greece from 26 to 29 May 1992. It was organized by the National Observatory of Athens, the University of Athens and the European Association for the Science of Air Pollution (EURASAP). Sixty participants from 21 countries were present including some of the pioneers in acoustic remote sensing. Papers were presented on: 1. (1) Acoustic sensing techniques; 2. (2) Acoustic instrumentation; 3. (3) RASS and lidar; 4. (4) Applications of remote sensing to air pollution studies; 5. (5) Boundary layer studies. The detailed discussion which followed each presentation as well as the round table discussion which was organized in the last session led to agreement about how best to proceed in both the development and use of the various remote sensing techniques for obtaining better results with the individual systems. Special attention was given to the intercomparison between the different techniques and on the possible design of a complete profilometer system which will combine the various instrument performance and will achieve better accuracy and resolution, covering at the same time a wide range of heights. The 7th ISARS international meeting will be held after two years in Boulder, CO, U.S.A. and will be organized by the WPL-NOAA

Individual seasonality index of rainfall regimes in Greece

The study of rainfall seasonality in different geographical areas in Greece using an individual seasonality index was the purpose of the present work. The correlation of the seasonality index (S̄I, sum of the absolute deviation of mean monthly rainfall from the overall monthly mean divided by the mean annual rainfall) with the mean individual seasonality index (S̄I, average of SI, for each year i) was initially determined. A regression analysis of S̄I with geographical latitude resulted in a statistically significant inverse linear correlation. The time series trend of the SI, was examined to verify that no significant change in rainfall seasonality occurred. © Inter-Research 2005

Recent advances on atmospheric acoustic sounding

Acoustic sounder design characteristics and operating parameters are described. Emphasis is given to the recent miniature construction of the high resolution, high frequency, acoustic sounders and examples of modern applications are presented. Various atmospheric features recorded by the systems, including thermal plumes, temperature inversions and waves are given. Also typical examples of quantitative measurements are shown with emphasis to wind statistics. © 1994 Taylor & Francis Ltd

On the determination of the thermal comfort conditions of a metropolitan city underground railway

Although the indoor thermal comfort concept has received increasing research attention, the vast majority of published work has been focused on the building environment, such as offices, residential and non-residential buildings. The present study aims to investigate the thermal comfort conditions in the unique and complex underground railway environment. Field measurements of air temperature, air humidity, air velocity, globe temperature and the number of passengers were conducted in the modern underground railway of Athens, Greece. Environmental monitoring was performed in the interior of two types of trains (air-conditioned and forced air ventilation cabins) and on selected platforms during the summer period. The thermal comfort was estimated using the PMV (predicted mean vote) and the PPD (predicted percentage dissatisfied) scales. The results reveal that the recommended thermal comfort requirements, although at relatively low percentages are met only in air-conditioned cabins. It is found that only 33% of the PPD values in air-conditioned cabins can be classified in the less restrictive comfort class C, as proposed by ISO-7730. The thermal environment is "slightly warm" in air-conditioned cabins and "warm" in forced air ventilation cabins. In addition, differences of the thermal comfort conditions on the platforms are shown to be associated with the depth and the design characteristics of the stations. The average PMV at the station with small depth is 0.9 scale points higher than that of the station with great depth. The number of passengers who are waiting at the platforms during daytime reveals a U-shaped pattern for a deep level station and an inverted course of PMV for a small depth station. Further, preliminary observations are made on the distribution of air velocity on the platforms and on the impact of air velocity on the thermal comfort conditions. © 2016 Elsevier B.V

On the atmospheric water vapor transmission function for solar radiation models

A new expression for the integral transmission of atmospheric water vapor has been developed. This expression is based on the latest known water vapor spectral absorption data, on a new vertical atmospheric profile and finally, on the Neckel and Labs model (1981; 1984), incorporating the most recent corrections of the extraterrestrial solar spectrum. The proposed expression can be easily used by solar radiation models in order to predict the beam, diffuse, and global solar radiation, especially in regions where the vertical atmospheric profile is similar to that in Athens. © 1994

The total solar radiation time series simulation in Athens, using neural networks

The present study describes a neural network approach for modeling and making short-term predictions on the total solar radiation time series. The future hourly values of total solar radiation for several years are predicted, by extracting knowledge from their past values, using feedforward backpropagation neural networks. The results are tested using various sets of non training measurements, the findings are very encouraging and the model is found able to simulate the future values of total solar radiation time series based on their past values. 'Multilag' output predictions are performed using the predicted values to the input database in order to model future total solar radiation values with sufficient accuracy. Furthermore, an autoregressive model is developed for analysing and representing the total solar radiation time series. The predicted values of solar radiation are compared with the observed data series and it was found that the neural network approach leads to better predictions than the AR model