The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Maria L. Salgueiro - One of the best experts on this subject based on the ideXlab platform.
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sulphur and nitrogen compounds in variable marine continental Air Masses at the southwest european coast
Atmospheric Environment, 1996Co-Authors: Casimiro Pio, Mário Cerqueira, Luís M. Castro, Maria L. SalgueiroAbstract:Measurements of atmospheric sulphur and nitrogen species were made on the west coast of Portugal, within the framework of BMCAPE project. Four research intensive campaigns took place between November 1993 and August 1994 and revealed pronounced seasonal cycles for DMS and MSA. Surprisingly high levels of DMS were detected during autumn (mean concentration: 776ngSm−3), possibly as a consequence of a later algae bloom or local marsh emissions. COS displayed a slight seasonal variation with mean concentrations ranging from 741 ng S m−3 in autumn up to 903 ng S m−3 in summer. On the basis of backward Air mass trajectories and local meteorological data, samples were assigned into different classes of Air Masses. The lowest concentrations of SO2, nssSO42−, NH3, NH4+, HNO3, N03− and NO2 were found in Air Masses transported over the Atlantic Ocean and were about 3–10 times lower than those recorded in Air Masses from continental origin. Nevertheless, for many of the species, the mean concentrations in maritime Air were still significantly higher than those previously recorded in remote marine sites, presumably owing to long-range transport of pollutants or contamination induced by mesoscale wind circulation.
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Sulphur and nitrogen compounds in variable marine/continental Air Masses at the southwest European coast
Atmospheric Environment, 1996Co-Authors: Casimiro Pio, Mário Cerqueira, Luís M. Castro, Maria L. SalgueiroAbstract:Measurements of atmospheric sulphur and nitrogen species were made on the west coast of Portugal, within the framework of BMCAPE project. Four research intensive campaigns took place between November 1993 and August 1994 and revealed pronounced seasonal cycles for DMS and MSA. Surprisingly high levels of DMS were detected during autumn (mean concentration: 776ngSm−3), possibly as a consequence of a later algae bloom or local marsh emissions. COS displayed a slight seasonal variation with mean concentrations ranging from 741 ng S m−3 in autumn up to 903 ng S m−3 in summer. On the basis of backward Air mass trajectories and local meteorological data, samples were assigned into different classes of Air Masses. The lowest concentrations of SO2, nssSO42−, NH3, NH4+, HNO3, N03− and NO2 were found in Air Masses transported over the Atlantic Ocean and were about 3–10 times lower than those recorded in Air Masses from continental origin. Nevertheless, for many of the species, the mean concentrations in maritime Air were still significantly higher than those previously recorded in remote marine sites, presumably owing to long-range transport of pollutants or contamination induced by mesoscale wind circulation.
Charles A. Doswell - One of the best experts on this subject based on the ideXlab platform.
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Tornadoes in the Central United States and the “Clash of Air Masses”
Bulletin of the American Meteorological Society, 2014Co-Authors: David M. Schultz, Yvette Richardson, Paul Markowski, Charles A. DoswellAbstract:After tornado outbreaks or individual violent tornadoes occur in the central United States, media stories often attribute the location, number, or intensity of tornadoes to the “clash of Air Masses” between warm tropical Air and cold polar Air. This article argues that such a characterization of tornadogenesis is oversimplified, outdated, and incorrect. Airmass boundaries and associated temperature gradients can be important in tornadogenesis, but not in the ways envisioned on the synoptic scale with the clash-of-Air-Masses conceptual model. In fact, excessively strong horizontal temperature gradients (either on the synoptic scale or associated with a storm's own cool outflow) may be detrimental to tornadogenesis. Where adjacent Air Masses are relevant is through their vertical distribution that produces the requisite instability for the convective storm, but that instability is not directly related to the formation of tornadoes. Therefore, this article recommends that a greater effort be made to communic...
Hanqing Kang - One of the best experts on this subject based on the ideXlab platform.
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Number size distribution of aerosols at Mt. Huang and Nanjing in the Yangtze River Delta, China: Effects of Air Masses and characteristics of new particle formation
Atmospheric Research, 2014Co-Authors: Honglei Wang, Bin Zhu, Lijuan Shen, Yan Yin, Hanqing KangAbstract:Aerosol number spectra in the range of 10 nm–10 μm were observed at Mt. Huang (Aug. 15–Sep. 15) and Nanjing (Oct. 13–Nov. 15) by a wide-range particle spectrometer (WPS) in 2011. Based on the backward trajectories obtained using the HYSPLIT model, the transport pathways of observed Air Masses during the study periods were classified into the following four groups: maritime Air mass, continental Air mass, marine–continental mixed Air mass and local Air mass. The variations in the aerosol number spectrum and the new particle formation (NPF) events for various types of Air Masses were discussed, along with meteorological data. The results showed that the average number concentration was 12,540 cm− 3 at Nanjing and only 2791 cm− 3 at Mt. Huang. The aerosol number concentration in Nanjing was 3–7 times higher than that in Mt. Huang; the large discrepancy was in the range of 10–100 nm. Different types of Air Masses had different effects on number concentration distribution. The number concentration of aerosols was higher in marine Air Masses, continental Air Masses and continental–marine mixed Air Masses at 10–50 nm, 100–500 nm and 50–200 nm, respectively. Under the four types of Air Masses, the aerosol size spectra had bimodal distributions in Nanjing and unimodal distributions in Mt. Huang (except under continental Air Masses: HT1). The effects of the diverse Air Masses on aerosol size segments of the concentration peak in Mt. Huang were stronger than those in Nanjing. The local Air Masses were dominant at these two sites and accounted for 44% of the total Air Masses. However, the aerosol number concentration was the lowest in Mt. Huang and the highest in Nanjing when local Air Masses were present. The number concentrations for foreign Air Masses increased at Mt. Huang and decreased at Nanjing. Different types of Air Masses had greater effects on the aerosol spectrum distribution at Mt. Huang than at Nanjing. During the NPF events, the particle growth rates at Mt. Huang (6.5–9.0 nm h− 1) were faster than those at Nanjing (4.8–5.6 nm h− 1). The relative humidity at Mt. Huang (36–65%) was higher than that at Nanjing (30–47%), but the wind speed trend was the opposite. The Air Masses during the NPF events were clean, i.e., they were mainly from over the ocean or districts with low ultrafine particle concentrations.
Y. Viisanen - One of the best experts on this subject based on the ideXlab platform.
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Aerosol characteristics of Air Masses in northern Europe: Influences of location, transport, sinks, and sources
Journal of Geophysical Research, 2005Co-Authors: Peter Tunved, Markku Kulmala, E.d. Nilsson, H.-c. Hansson, Johan Ström, Pasi Aalto, Y. ViisanenAbstract:Synoptic-scale Air Masses at different stations were classified following a definition based on Berliner Wetterkarte. This Air mass classification has been related to 1 year of aerosol number siz ...
Casimiro Pio - One of the best experts on this subject based on the ideXlab platform.
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sulphur and nitrogen compounds in variable marine continental Air Masses at the southwest european coast
Atmospheric Environment, 1996Co-Authors: Casimiro Pio, Mário Cerqueira, Luís M. Castro, Maria L. SalgueiroAbstract:Measurements of atmospheric sulphur and nitrogen species were made on the west coast of Portugal, within the framework of BMCAPE project. Four research intensive campaigns took place between November 1993 and August 1994 and revealed pronounced seasonal cycles for DMS and MSA. Surprisingly high levels of DMS were detected during autumn (mean concentration: 776ngSm−3), possibly as a consequence of a later algae bloom or local marsh emissions. COS displayed a slight seasonal variation with mean concentrations ranging from 741 ng S m−3 in autumn up to 903 ng S m−3 in summer. On the basis of backward Air mass trajectories and local meteorological data, samples were assigned into different classes of Air Masses. The lowest concentrations of SO2, nssSO42−, NH3, NH4+, HNO3, N03− and NO2 were found in Air Masses transported over the Atlantic Ocean and were about 3–10 times lower than those recorded in Air Masses from continental origin. Nevertheless, for many of the species, the mean concentrations in maritime Air were still significantly higher than those previously recorded in remote marine sites, presumably owing to long-range transport of pollutants or contamination induced by mesoscale wind circulation.
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Sulphur and nitrogen compounds in variable marine/continental Air Masses at the southwest European coast
Atmospheric Environment, 1996Co-Authors: Casimiro Pio, Mário Cerqueira, Luís M. Castro, Maria L. SalgueiroAbstract:Measurements of atmospheric sulphur and nitrogen species were made on the west coast of Portugal, within the framework of BMCAPE project. Four research intensive campaigns took place between November 1993 and August 1994 and revealed pronounced seasonal cycles for DMS and MSA. Surprisingly high levels of DMS were detected during autumn (mean concentration: 776ngSm−3), possibly as a consequence of a later algae bloom or local marsh emissions. COS displayed a slight seasonal variation with mean concentrations ranging from 741 ng S m−3 in autumn up to 903 ng S m−3 in summer. On the basis of backward Air mass trajectories and local meteorological data, samples were assigned into different classes of Air Masses. The lowest concentrations of SO2, nssSO42−, NH3, NH4+, HNO3, N03− and NO2 were found in Air Masses transported over the Atlantic Ocean and were about 3–10 times lower than those recorded in Air Masses from continental origin. Nevertheless, for many of the species, the mean concentrations in maritime Air were still significantly higher than those previously recorded in remote marine sites, presumably owing to long-range transport of pollutants or contamination induced by mesoscale wind circulation.
