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15 pages, 1921 KiB

Open AccessArticle

Extreme Precipitation Events in Serbia: Defining the Threshold Criteria for Emergency Preparedness

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Atmosphere 2018, 9(5), 188; https://doi.org/10.3390/atmos9050188 - 15 May 2018

Cited by 12 | Viewed by 4335

Abstract

Considering recent weather events in Serbia (especially the floods in 2014), a need has arisen for research that would help in identifying extreme weather phenomena. Therefore, the aim of this paper is to determine the thresholds above which intense precipitation can be considered [...] Read more.

Considering recent weather events in Serbia (especially the floods in 2014), a need has arisen for research that would help in identifying extreme weather phenomena. Therefore, the aim of this paper is to determine the thresholds above which intense precipitation can be considered as extreme precipitation events in Serbia. In this study, we determined the frequency of precipitation occurring at an intensity above the threshold of an extreme phenomenon (1961–2015), as well as the frequency of precipitation occurring at or above the absolute daily maximum in the reference period (1961–1990). The study sample included daily rainfall observations from 28 stations from the national meteorological network in Serbia. Applying a decile method, all the stations recording precipitation above the threshold of dangerous phenomena on the same day are classified into the corresponding decile. The threshold value was determined as the average value of the extreme annual precipitation in the analyzed period. The cases that are due to the high prevalence listed in the last decile are considered extreme. The results showed that the critical number of observation points above which an event is considered extreme precipitation event is 6.21, and a warning of the danger could be ensured only in the case of neighboring stations in the network. The threshold of extreme precipitation events for the individual stations ranges up to 130 mm. The obtained results might be used to mitigate the effects of extreme precipitation events in Serbia in the future. Full article

(This article belongs to the Special Issue Advances in Atmospheric Physics: Selected Papers from CEST2017)

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17 pages, 12066 KiB

Open AccessArticle

Atmospheric Emissions from Oil and Gas Extraction and Production in Greece

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Georgios Papailias

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Ilias Mavroidis

Atmosphere 2018, 9(4), 152; https://doi.org/10.3390/atmos9040152 - 18 Apr 2018

Cited by 11 | Viewed by 8744

Abstract

This paper addresses the atmospheric emissions of CO₂, SO₂, H₂S, NOx, and volatile organic compounds (VOCs) from oil and gas extraction and production in the Gulf of Kavala. This is currently the only location of oil and [...] Read more.

This paper addresses the atmospheric emissions of CO₂, SO₂, H₂S, NOx, and volatile organic compounds (VOCs) from oil and gas extraction and production in the Gulf of Kavala. This is currently the only location of oil and gas production in Greece. Facilities are located both offshore (Kappa and Delta platforms) and onshore (Sigma plant), producing sweet gas, sour gas, and sour crude oil. This study presents the characteristics of atmospheric emissions, including emission measurements, emission inventories, and concentration measurements, from a central monitoring station and twelve total sulfation stations, the latter aiming to assess the effects of atmospheric emissions to air quality. During the development of the monitoring system, special attention was placed to sulfur compounds, since the existence of sour gas and sour crude oil was expected to lead to increased amounts of H₂S and SO₂. One of the main findings of the present study is that if the prevailing wind direction is considered (i.e., from N–NE), then the central monitoring station is not located downwind of the onshore and offshore facilities; therefore, its position should be re-examined. The emission inventories showed that flaring at the offshore facilities is the main source of SO₂ emissions, while SO₂ emissions and ambient concentrations were well below the relevant standards. Furthermore, CO₂ emissions were lower by 67.73% as compared to 2008, when emissions reached a maximum. This was attributed to more energy demanding activities during that period, and mainly to the operation of turbines between 2007 and 2009. Since it is expected that the exploitation of hydrocarbons as well as oil and gas extraction and production will increase in the future in Greece, appropriate measures should be taken to ensure environmental protection, such as the use of up-to-date emission control technologies and a flare gas recovery system. Full article

(This article belongs to the Special Issue Advances in Atmospheric Physics: Selected Papers from CEST2017)

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27 pages, 1724 KiB

Open AccessArticle

A Statistical Investigation of the Impact of the Indian Monsoon on the Eastern Mediterranean Circulation

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Atmosphere 2018, 9(3), 90; https://doi.org/10.3390/atmos9030090 - 01 Mar 2018

Cited by 17 | Viewed by 3957

Abstract

The Indian summer monsoon (ISM) is a prominent feature of the summer circulation in the Northern Hemisphere (NH) and has been found to modulate the weather and climate conditions in many remote regions. This study investigates the most recurrent patterns of summertime midlatitude [...] Read more.

The Indian summer monsoon (ISM) is a prominent feature of the summer circulation in the Northern Hemisphere (NH) and has been found to modulate the weather and climate conditions in many remote regions. This study investigates the most recurrent patterns of summertime midlatitude circulation, over the eastern Mediterranean (EM) and also globally, that are most associated with the ISM. Monthly data of 44 summers from the ERA40 dataset are used and two multidimensional statistical methods, the Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA), are implemented. The ISM is found to be related to subsidence anomalies in the middle and more extendedly in the upper troposphere over the central and eastern Mediterranean and with an Etesian-like pattern regarding the field of the lower troposphere winds. An equatorial Rossby wave pattern, extending westward from an ISM heat source up to EM and N. Africa, was identified to be associated with the variability of ISM. The observed relationship between the ISM and the EM circulation features can be attributed to this equatorial Rossby wave response to the monsoon forcing. CCA implementation revealed the interconnection of the aforementioned PCA results with an ISM action center over the northern Arabian Sea and the monsoon trough region. Full article

(This article belongs to the Special Issue Advances in Atmospheric Physics: Selected Papers from CEST2017)

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14 pages, 3156 KiB

Open AccessArticle

Indoor Air Quality and Thermal Conditions in a Primary School with a Green Roof System

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Nikolaos Barmparesos

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Margarita Niki Assimakopoulos

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Vasiliki D. Assimakopoulos

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Nikolaos Loumos

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Maria Aliki Sotiriou

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Athanasios Koukoumtzis

Atmosphere 2018, 9(2), 75; https://doi.org/10.3390/atmos9020075 - 20 Feb 2018

Cited by 16 | Viewed by 4604 | Correction

Abstract

This paper presents experimental results from a typical school building in Athens, equipped partly with a green roof system (GRS). Environmental monitoring took place in six classrooms located both under the concrete roof and the GRS sectors as well as in the immediate [...] Read more.

This paper presents experimental results from a typical school building in Athens, equipped partly with a green roof system (GRS). Environmental monitoring took place in six classrooms located both under the concrete roof and the GRS sectors as well as in the immediate external environment during the warm and cold periods of a school year. Daily measurements of pollutants CO₂, TVOCs (Total Volatile Organic Compound), PM₁, PM_2.5, and PM₁₀ were performed in selected classes. Moreover, indoor ambient temperature (T) and relative humidity (RH) measurements were implemented in order to estimate the absolute humidity (AH) and assess the indoor environmental conditions. The results highlight that during summer, the GRS reduces temperature in a classroom on the top floor by about 2.8 °C, in comparison with the respective classroom under the concrete roof and that AH remained relatively stable for both classrooms. Amid winter, a reverse behavior occurs only for temperature. Moreover, air exchange rates (AER) were calculated by using the CO₂ decay method for all of the classrooms. The results demonstrated insufficient ventilation for all experimental sights. Finally, concentrations of PM₁, PM_2.5 and PM₁₀, were found to be relatively decreased, with average values of 0.79, 3.39, and 27.80 μg m⁻³. Levels of CO₂ and TVOCs were elevated during class hours ranging from 469 to 779 ppm and from 6.63 ppm to 13.33 ppm, respectively, but generally within the respective limits of exposure. The examination of the indoor/outdoor (I/O) ratio of air pollutants, demonstrated that the outdoor meteorology affects only PM₁ and PM_2.5, as PM₁₀ and TVOCs are strongly affected by internal sources and the activities of pupils. Full article

(This article belongs to the Special Issue Advances in Atmospheric Physics: Selected Papers from CEST2017)

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15 pages, 3831 KiB

Open AccessArticle

Atmospheric Dispersion Modelling and Spatial Analysis to Evaluate Population Exposure to Pesticides from Farming Processes

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Atmosphere 2018, 9(2), 38; https://doi.org/10.3390/atmos9020038 - 24 Jan 2018

Cited by 10 | Viewed by 5437

Abstract

This work originates from an epidemiological study aimed to assess the correlation between population exposure to pesticides used in agriculture and adverse health effects. In support of the population exposure evaluation two models implemented by the authors were applied: a GIS-based proximity model [...] Read more.

This work originates from an epidemiological study aimed to assess the correlation between population exposure to pesticides used in agriculture and adverse health effects. In support of the population exposure evaluation two models implemented by the authors were applied: a GIS-based proximity model and the CAREA atmospheric dispersion model. In this work, the results of the two models are presented and compared. Despite the proximity analysis is widely used for these kinds of studies, it was investigated how meteorology could affect the exposure assessment. Both models were applied to pesticides emitted by 1519 agricultural fields and considering 2584 receptors distributed over an area of 8430 km². CAREA output shows a considerable enhancement in the percentage of exposed receptors, from the 4% of the proximity model to the 54% of the CAREA model. Moreover, the spatial analysis of the results on a specific test site showed that the effects of meteorology considered by CAREA led to an anisotropic exposure distribution that differs considerably from the symmetric distribution resulting by the proximity model. In addition, the results of a field campaign for the definition and planning of ground measurement of concentration for the validation of CAREA are presented. The preliminary results showed how, during treatments, pesticide concentrations distant from the fields are significantly higher than background values. Full article

(This article belongs to the Special Issue Advances in Atmospheric Physics: Selected Papers from CEST2017)

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15 pages, 10316 KiB

Open AccessArticle

Observations of Local Meteorological Variability under Large-Scale Circulation Patterns over Athens, Greece

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Christos H. Halios

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Helena A. Flocas

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Costas G. Helmis

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Dimosthenis N. Asimakopoulos

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Panagiotis G. Mouschouras

Atmosphere 2018, 9(1), 25; https://doi.org/10.3390/atmos9010025 - 23 Jan 2018

Cited by 3 | Viewed by 2976

Abstract

Linking synoptic circulation patterns to specific environmental problems is of significance in the Eastern Mediterranean region, which is characterized by increased seasonal climatic variability and a wealth of distinct weather patterns. This study aims to discuss the links between synoptic scale circulation, intra-day [...] Read more.

Linking synoptic circulation patterns to specific environmental problems is of significance in the Eastern Mediterranean region, which is characterized by increased seasonal climatic variability and a wealth of distinct weather patterns. This study aims to discuss the links between synoptic scale circulation, intra-day variability and sub-hourly temperature changes over Athens. Diurnal cycles of surface atmospheric variability were examined by applying Principal Component Analysis and Integral Quantities Analysis to a four months data set with surface meteorological elements. Sub-hourly temperature changes were identified by applying a simple linear technique. Principal Components, Integral Quantities and temperature change rates (geometric structures) were related with synoptic circulation categories. It was found that the presence of a Closed Low over the area results in intense along-mountain flows, whilst, after the passage of a trough, when a strong northwesterly flow is established over the area, surface recirculation flows develop. On 64% of the days, geometric structures were observed in the hourly temperature time-series, and they were found to occur across all synoptic situations. Cliff—ramps was the most common geometric structure, and step changes were found to be related with recirculation flows. Full article

(This article belongs to the Special Issue Advances in Atmospheric Physics: Selected Papers from CEST2017)

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12 pages, 6376 KiB

Open AccessArticle

Estimating the Biogenic Non-Methane Hydrocarbon Emissions over Greece

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Ermioni Dimitropoulou

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Vasiliki D. Assimakopoulos

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Kyriaki M. Fameli

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Helena A. Flocas

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Panagiotis Kosmopoulos

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Stelios Kazadzis

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Kostas Lagouvardos

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Elizabeth Bossioli

Atmosphere 2018, 9(1), 14; https://doi.org/10.3390/atmos9010014 - 09 Jan 2018

Cited by 2 | Viewed by 3856

Abstract

Biogenic emissions affect the urban air quality as they are ozone and secondary organic aerosol (SOA) precursors and should be taken into account when applying photochemical pollution models. The present study presents an estimation of the magnitude of non-methane volatile organic compounds (BNMVOCs) [...] Read more.

Biogenic emissions affect the urban air quality as they are ozone and secondary organic aerosol (SOA) precursors and should be taken into account when applying photochemical pollution models. The present study presents an estimation of the magnitude of non-methane volatile organic compounds (BNMVOCs) emitted by vegetation over Greece. The methodology is based on computation developed with the aid of a Geographic Information System (GIS) and theoretical equations in order to produce an emission inventory on a 6 × 6 km² spatial resolution, in a temporal resolution of 1 h covering one year (2016). For this purpose, a variety of input data was used: updated satellite land-use data, land-use specific emission potentials, foliar biomass densities, temperature, and solar radiation data. Hourly, daily, and annual isoprene, monoterpenes, and other volatile organic compounds (OVOCs) were estimated. In the area under study, the annual biogenic emissions were estimated up to 472 kt, consisting of 46.6% isoprene, 28% monoterpenes, and 25.4% OVOCs. Results delineate an annual cycle with increasing values from March to April, while maximum emissions were observed from May to September, followed by a decrease from October to January. Full article

(This article belongs to the Special Issue Advances in Atmospheric Physics: Selected Papers from CEST2017)

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