10 research outputs found
Long chain n-3 polyunsaturated fatty acids and vascular function in patients with chronic kidney disease and healthy subjects: a cross-sectional and comparative study
Heterothermy, and the Energetic Consequences of Huddling in Small Migrating Passerine Birds
Evaluation of the GEM-AQ model in the context of the AQMEII Phase 1 project
In the scope of the AQMEII Phase 1 project the GEM-AQ model was run over Europe for the year
2006. The modelling domain was defined using a global variable resolution grid with a rotated
equator and uniform resolution of 0.2° × 0.2° over the European
continent. Spatial distribution and temporal variability of the GEM-AQ model results were analysed
for surface ozone and PM<sub>10</sub> concentrations. Model results were compared with measurements
available in the ENSEMBLE database. Statistical measures were used to evaluate performance of the
GEM-AQ model. The mean bias error, the mean absolute gross error and the Pearson correlation
coefficient were calculated for the maximum 8 h running average ozone concentrations and daily
mean PM<sub>10</sub> concentrations. The GEM-AQ model performance was characterized for station
types, European climatic regions and seasons. The best performance for ozone was obtained at
suburban stations, and the worst performance was obtained for rural stations where the model tends
to underestimate. The best results for PM<sub>10</sub> were calculated for urban stations, while
over most of Europe concentrations at rural sites were too high. Discrepancies between modelled
and observed concentrations were discussed in the context of emission data uncertainty as well as
the impact of large-scale dynamics and circulation of air masses. Presented analyses suggest that
interpretation of modelling results is enhanced when regional climate characteristics are taken
into consideration
2014 iAREA campaign on aerosol in Spitsbergen Part 1: Study of physical and chemical properties
This paper presents the results of measurements of aerosol physical and chemical properties during
iAREA2014 campaign that took place on Svalbard between 15th of Mar and 4th of May 2014. With
respect to field area, the experiment consisted of two sites: NyeÅlesund (78�550N, 11�560E) and Longyearbyen
(78�130N, 15�330E) with further integration of Aerosol Robotic Network (AERONET) station in
Hornsund (77�000N, 15�330E). The subject of this study is to investigate the inesitu, passive and active
remote sensing observations as well as numerical simulations to describe the temporal variability of
aerosol singleescattering properties during spring season on Spitsbergen. The retrieval of the data indicates
several event days with enhanced singleescattering properties due to the existence of sulphate
and additional seaesalt load in the atmosphere which is possibly caused by relatively high wind speed.
Optical results were confirmed by numerical simulations made by the GEMeAQ model and by chemical
observations that indicated up to 45% contribution of the seaesalt to a PM10 total aerosol mass concentration.
An agreement between the in-situ optical and microphysical properties was found, namely:
the positive correlation between aerosol scattering coefficient measured by the nephelometer and
effective radius obtained from laser aerosol spectrometer as well as negative correlation between aerosol
scattering coefficient and the Ångstrom exponent indicated that slightly larger particles dominated
during special events. The inesitu surface observations do not show any significant enhancement of the
absorption coefficient as well as the black carbon concentration which might occur during spring. All of
extensive singleescattering properties indicate a diurnal cycle in Longyearbyen, where 21:00e5:00 data
stays at the background level, however increasing during the day by the factor of 3e4. It is considered to
be highly connected with local emissions originating in combustion, traffic and harbour activities. On the
other hand, no daily fluctuations in NyeÅlesund are observed. Mean values in NyeÅlesund are equal to
8.2, 0.8 Mm�1 and 103 ng/m3 for scattering, absorption coefficients and black carbon concentration; however in Longyearbyen (only data from 21:00e05:00 UTC) they reach 7.9, 0.6 Mm�1 as well as 83 ng/
m3 respectively. Overall, the spring 2014 was considerably clean and seaesalt was the major aerosol
componen