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Tombrou M.,National and Kapodistrian University of Athens | Bossioli E.,National and Kapodistrian University of Athens | Kalogiros J.,Institute of Environmental Research and Sustainable Development | Allan J.D.,University of Manchester | And 11 more authors.
Science of the Total Environment | Year: 2015

High-resolution measurements of gas and aerosols' chemical composition along with meteorological and turbulence parameters were performed over the Aegean Sea (AS) during an Etesian outbreak in the framework of the Aegean-GAME airborne campaign. This study focuses on two distinct Etesian patterns, with similarities inside the Marine Atmospheric Boundary Layer (MABL) and differences at higher levels. Under long-range transport and subsidence the pollution load is enhanced (by 17% for CO, 11% for O3, 28% for sulfate, 62% for organic mass, 47% for elemental carbon), compared to the pattern with a weaker synoptic system. Sea surface temperature (SST) was a critical parameter for the MABL structure, turbulent fluxes and pollutants' distribution at lower levels. The MABL height was below 500m asl over the eastern AS (favoring higher accumulation), and deeper over the western AS. The most abundant components of total PM1 were sulfate (40-50%) and organics (30-45%). Higher average concentrations measured over the eastern AS (131±76 ppbv for CO, 62.5±4.1 ppbv for O3, 5.0±1.1 μg m-3 for sulfate, 4.7±0.9μg m-3 for organic mass and 0.5±0.2 μg m-3 for elemental carbon). Under the weaker synoptic system, cleaner but more acidic air masses prevailed over the eastern part, while distinct aerosol layers of different signature were observed over the western part. The Aitken and accumulation modes contributed equally during the long-range transport, while the Aitken modes dominated during local or medium range transport. © 2014 Elsevier B.V.


PubMed | Institute of Environmental Research & Sustainable Development, Technical University of Delft, CzechGlobe, University of Manchester and 2 more.
Type: | Journal: The Science of the total environment | Year: 2014

High-resolution measurements of gas and aerosols chemical composition along with meteorological and turbulence parameters were performed over the Aegean Sea (AS) during an Etesian outbreak in the framework of the Aegean-GAME airborne campaign. This study focuses on two distinct Etesian patterns, with similarities inside the Marine Atmospheric Boundary Layer (MABL) and differences at higher levels. Under long-range transport and subsidence the pollution load is enhanced (by 17% for CO, 11% for O3, 28% for sulfate, 62% for organic mass, 47% for elemental carbon), compared to the pattern with a weaker synoptic system. Sea surface temperature (SST) was a critical parameter for the MABL structure, turbulent fluxes and pollutants distribution at lower levels. The MABL height was below 500 m asl over the eastern AS (favoring higher accumulation), and deeper over the western AS. The most abundant components of total PM1 were sulfate (40-50%) and organics (30-45%). Higher average concentrations measured over the eastern AS (131 76 ppbv for CO, 62.5 4.1 ppbv for O3, 5.0 1.1 g m(-3) for sulfate, 4.7 0.9 g m(-3) for organic mass and 0.5 0.2 g m(-3) for elemental carbon). Under the weaker synoptic system, cleaner but more acidic air masses prevailed over the eastern part, while distinct aerosol layers of different signature were observed over the western part. The Aitken and accumulation modes contributed equally during the long-range transport, while the Aitken modes dominated during local or medium range transport.


Darenova E.,CzechGlobe | Pavelka M.,CzechGlobe | Janous D.,CzechGlobe
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis | Year: 2011

Respiration of stems contributes approximately 8 to 13 % to the total respiration of forest ecosystem, which is not negligible, and it has to be included in carbon flux estimates. The aim of this study was to determine dynamics of stem CO 2 efflux during the growing season in Norway spruce stand and factors affecting this efflux. Continuous measurements of stem CO 2 efflux were carried out by an automated system during the growing season in 2006-2009. Further measured characteristics were stem temperature, stem increment and precipitations. Stem CO 2 efflux was in tight relationship with changes in temperature with the mean coefficient of determination of 0.76. This infers that temperature was the main factor driving changes in CO 2 efflux during the season. To eliminate effect of temperature and determine other factors influencing stem CO 2 efflux, CO 2 efflux was normalized for temperature of 10 °C (R 10). Basic seasonal course of R 10 followed the pattern of stem growth rate with its maxima in June and July. The other factor effect, which was possible to determine, was presence of rainfall. Rainfall strong enough caused mostly increase in R 10. This effect was the most significant when the R 10 course had a decreasing trend in the second part of the growing season.

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