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Haltern 70 amphora sherds from Castro do Vieito and from kilns in the Roman provinces Baetica and Lusitania were studied by Mössbauer spectroscopy, EDX and XRD. An amphora whose handle was carefully studied must have been fired reducingly at a temperature of or above about 900°C and cooled in oxidizing conditions in the end. Oxidation and hematite formation went hand in hand, and the amount of hematite formed depended sensitively of the speed of penetration of the oxygen and the cooling rate in the interior of the ceramic body. [ABSTRACT FROM AUTHOR]

The article discusses the measurement of the scattering and absorption of aerosol coefficient from 2006 to 2008 in the grounds of Évora in Portugal. The study shows that both are low in magnitude and relatively closer to the rural sites and background sites compared to urban city. In urban sites, the absorption coefficient presents annual cycle such as colder period, warmer period, and traffic and may vary from different aerosol types and regions.

Abstract: Herbarium specimens of Quercus robur L. from 25 localities on the Iberian Peninsula covering the time period from 1901 to 2003 were studied to develop a suitable stomatal index (SI)-atmospheric CO2 inference model that met the specific demands of the abundant fossil material from this geographical region. Significant SI changes were observed under the atmospheric CO2 increase since the onset of industrialization, resembling a sigmoidal response. The highly comparable SI response rates of Iberian and Northwest European data sets confirmed that Q. robur has reached its response limit at 330 ppmv, and adaptation of Quercus to changing CO2 concentration is in principle the same. A 3.5% SI difference between both data sets is likely to be a result of the differences in irradiation level at the high and low latitudes. An adjusted SI-CO2 calibration data set for the Northern Iberian Peninsula is provided for the CO2 range from 295 ppmv to 330 ppmv, where the best statistical fit for the CO2 inference model is achieved when data are restricted to an altitudinal range of 0–1000 m a.s.l. Geographical extension of the model is attained by the incorporation of the month irradiance average (W/m2) as an independent factor. Additional pore length increase was observed over the same CO2 range. Usage of the Stomata-Pore Coefficient (proportion of pore length over the Stomatal length) was introduced in order to give a better description of the response of stomatal dimensions to the rising atmospheric CO2 concentrations. [Copyright &y& Elsevier]

Abstract: This study presents a characterization of aerosols columnar properties measured at three different AERONET sites in the western part of the Iberian Peninsula, namely Évora and Cabo da Roca, in Portugal, and Cáceres, in Spain, during the period from 2005 to 2010. AERONET level 2.0 products have been analyzed. The comparison of these three stations has great interest because it has not been conducted yet and it allows to characterize the aerosols of a wide region in western Iberian Peninsula by a long-term analysis of their aerosol properties. In addition, it allows analyzing the possible differences in these properties between the three sites located at different distances from the coast. The results show differences between the aerosol optical depth at 440 and 1020 nm at the three stations, being the mean values in Cabo da Roca at 1020 and 440 nm (0.08 and 0.16) slightly higher than in the other two stations (Évora: 0.06 and 0.15; Cáceres: 0.05 and 0.14). Greater differences among the three stations are found for the Ångström exponent values. Thus, Cáceres shows the highest mean value (1.33), followed by Évora (1.14) and, finally, by Cabo da Roca (1.00) which exhibits the smallest median α values due to the presence of coarse sea salt particles and high atmospheric humidity. These values are consistent with the values of volume size distribution, exhibiting a greater value of large particles at Cabo da Roca. The mean values of the single scattering albedo (ω) have been also analyzed, obtaining higher results as the coast is approached: Cabo da Roca: ω (440) = 0.95; ω (1020) = 0.96, Évora: ω (440) = 0.93; ω (1020) = 0.95 and Cáceres: ω (440) = 0.88; ω (1020) = 0.83. The differences between the three stations are explained in terms of the distance to the coast and to the occasional arrival of diverse air masses transporting different aerosol types to each station. One classification method proposed for the study region has been applied to multi-year measurements performed at the three sites and verified by means of daily 120-h back-trajectory analyses of air masses. The most frequent situations observed at all sites include the clean, maritime and continental situations, which account for about 80% or more. The remaining percentage is accounted by the more episodic situations of desert dust (10–14%) and forest fires emissions (3–5%). The probability density plots calculated for the different classified aerosol situations show significant differences consistent with the different paths of the air masses corresponding to each aerosol situation. [Copyright &y& Elsevier]

Vertically resolved optical and microphysical properties of biomass burning aerosols, measured in 2011 with a multiwavelength Raman lidar, are presented. The transportation time, within 1-2 days (or less), pointed towards the presence of relatively fresh smoke particles over the site. Some strong layers aloft were observed with particle backscatter and extinction coefficients (at 355 nm) greater than 5 Mm(-1)sr(-1) and close to 300 Mm(-1), respectively. The particle intensive optical properties showed features different from the ones reported for aged smoke, but rather consistent with fresh smoke. The Ångström exponents were generally high, mainly above 1.4, indicating a dominating accumulation mode. Weak depolarization values, as shown by the small depolarization ratio of 5% or lower, were measured. Furthermore, the lidar ratio presented no clear wavelength dependency. The inversion of the lidar signals provided a set of microphysical properties including particle effective radius below 0.2 μm, which is less than values previously observed for aged smoke particles. Real and imaginary parts of refractive index of about 1.5-1.6 and 0.02i, respectively, were derived. The single scattering albedo was in the range between 0.85 and 0.93; these last two quantities indicate the nonnegligible absorbing characteristics of the observed particles.