Issue 2 [June]( Issue on Air Pollution and Atmospheric Processes )Editorial Estimation of pollution dispersion patterns of a power plant plume in complex terrainDeligiorgi D. Philippopoulos K. Karvounis G., Pages:227-240 DOI: https://doi.org/10.30955/gnj.000955Paper Topic: General Issue: Issue 2Get Full Paper AbstractThis study aims to identify the pollutant dispersion patterns in complex terrain under various meteorological conditions. The study area is situated at Chania plain on the island of Crete, Greece, where the topography is fairly complex. Thus, the local meteorology is expected to be deeply affected by this complex morphology. The main source of air pollution in the region is a diesel power generating plant. The daily averaged ground level distributions of sulfur dioxide, emitted from the power plant, were predicted using the AERMOD modeling system. In order to assess the meteorological conditions in the wider region, a meteorological monitoring network with six stations was installed and operated for two years. A detailed spatial and temporal analysis of the meteorological parameters is performed in order to determine their ability to characterize the transport and dispersion conditions in the area of concern. The model was applied for days with well established wind flows and the case studies indicate that such a model is capable of predicting the general pattern of ground-level concentrations of sulphur dioxide in the area of the power plant. Analyzing the basic meteorological aspects of a particulate air pollution episode over the industrial area of Northwestern Greece during the November of 2009Karagiannidis A.F. Triantafyllou A.G. Karacostas T.S., Pages:241-253 DOI: https://doi.org/10.30955/gnj.001015Paper Topic: General Issue: Issue 2Get Full Paper AbstractThe complex terrain basin of Amyntaio – Ptolemais – Kozani in Western Macedonia of Greece is an area characterized by increased industrial activity and therefore it demands continuous and assiduous environmental monitoring. A prolonged particulate matter air pollution episode was recorded in the area during November 2009. Basic meteorological aspects are analyzed, during the episode period. Daily and hourly PM10 and PM2.5 concentration measurements were used along with surface and lower atmosphere hourly meteorological parameters from 13 measuring stations. The observational data were supported by data produced by the meteorological component of an air pollution model. The overall analysis showed that the episode was primarily the result of the synoptic setting of the middle and lower troposphere. An Omega blocking pattern which gradually transformed to a high-over-low pattern prevailed over central and southern Europe during the episode’s period. The examination of the vertical wind field in the lower troposphere and appropriate stability indices, revealed a continuous absence of significant convection. The weak horizontal wind field near the surface and the reduced mixing height combined with the lack of synoptic forcing resulted in the trapping of the pollutants in the lower troposphere and the recording of increased airborne particulate matter concentrations. The radical change of the synoptic setting in the first days of December marked the end of the episode. Bioclimatic conditions under different ground cover types in the greater Athens area, GreeceKamoutsis A.P. Matsoukis A.S. Chronopoulos K.I., Pages:254-260 DOI: https://doi.org/10.30955/gnj.000966Paper Topic: General Issue: Issue 2Get Full Paper AbstractThis research aims to investigate the bioclimatic conditions in different ground cover types in the greater Athens area, Greece: a major street with heavy traffic (MS), an adjacent pedestrian street (PS) with irrigated plants and an urban park. Four sites were selected: one in each of the streets, and two in the park (one of which is covered by irrigated plants (IPS) while the other is covered by non-irrigated plants (NIPS). Air temperature and relative humidity were monitored in each site during the periods of July-August and September-October of the years 2009 and 2010. These parameters were used for the calculation of the thermohygrometric index based on which bioclimatic conditions were evaluated. The “Hot” class prevailed at all sites during the July-August period while similar bioclimatic conditions detected at all environments with irrigated plants at the aforementioned period. During autumn, the “Comfortable” class prevailed at the PS and the urban park compared to the MS. The findings of our study could provide useful information for the design of outdoor spaces with irrigated vegetation as well as for the plantation and irrigation of plant species on city roads with heavy traffic. Local scale simulation of air temperature by a two-step hybrid downscaling approach using regional climate modeling and artificial neural networksPhilippopoulos K. Yiannikopoulou I. Deligiorgi D. Flocas H., Pages:261-270 DOI: https://doi.org/10.30955/gnj.000967Paper Topic: General Issue: Issue 2Get Full Paper AbstractThe influence of microscale and mesoscale meteorology on the local scale variation of air temperature cannot be correctly simulated by the coarse resolution Global Climate Models. The scope of this work is to develop a hybrid dynamic-statistical downscaling procedure and quantify its predictive ability to estimate air temperature variability at finer spatial scales. The study focuses on the warm period of the year (June – August) and the method is applied to eight sites located in Greece with different topographical characteristics. The two-step methodology initially involves the dynamic downscaling of coarse resolution climate data via the RegCM4 regional climate model and subsequently the statistical downscaling of the modeled outputs by training site-specific artificial neural networks (ANN). The RegCM4 model is employed to enhance the representativity of the dataset, while the ANNs are used as function approximators to model the relationship between a number of atmospheric predictor variables and the observed air temperature time series. An insight of the ANN transfer function is obtained by examining the relative contribution of each input variable. The performance of the methodology is evaluated and the results indicate significant improvement from the inclusion of the ANN models in downscaling air temperature. Pages« first ‹ previous 1 2
