Atmospheric water parameters measured by a ground-based microwave radiometer and compared with the WRF model

The microwave radiometer TROWARA measures integrated water vapour (IWV) and integrated cloud liquid water (ILW) at Bern since 1994 with a time resolution of 7 s. In this study, we compare TROWARA measurements with a simulation of summer 2012 in Switzerland performed with the Weather Research and Forecasting (WRF) model. It is found that the WRF model agrees very well with TROWARA’s IWV variations with a mean bias of only 0.7 mm. The ILW distribution of the WRF model, although similar in shape to TROWARA’s distribution, overestimates the fraction of clear sky periods (83% compared to 60%).

Zeeman effect in atmospheric O₂ measured by ground-based microwave radiometry

In this work we study the Zeeman effect on stratospheric O₂ using ground-based microwave radiometer measurements. The interaction of the Earth magnetic field with the oxygen dipole leads to a splitting of O₂ energy states, which polarizes the emission spectra. A special campaign was carried out in order to measure this effect in the oxygen emission line centered at 53.07 GHz. Both a fixed and a rotating mirror were incorporated into the TEMPERA (TEMPERature RAdiometer) in order to be able to measure under different observational angles. This new configuration allowed us to change the angle between the observational path and the Earth magnetic field direction. Moreover, a high-resolution spectrometer (1 kHz) was used in order to measure for the first time the polarization state of the radiation due to the Zeeman effect in the main isotopologue of oxygen from ground-based microwave measurements. The measured spectra showed a clear polarized signature when the observational angles were changed, evidencing the Zeeman effect in the oxygen molecule. In addition, simulations carried out with the Atmospheric Radiative Transfer Simulator (ARTS) allowed us to verify the microwave measurements showing a very good agreement between model and measurements. The results suggest some interesting new aspects for research of the upper atmosphere.

Mineral composition, major element oxides and trace element concentration of sediments from ODP Leg 180 sites

Middle Miocene to Holocene fine-grained argillaceous sediments (clays, claystones/muds, and mudstones), which volumetrically dominated the sediment recovery in the Woodlark Basin during Leg 180, were chemically analyzed for major elements, trace elements, and some rare earth elements by X-ray fluorescence. Selected samples also underwent X-ray diffraction (XRD) analysis for mineral determination. The results shed light on sediment provenance when combined with shipboard sediment descriptions, smear slide study, and XRD. The oldest sediments recovered (Site 1108) of middle-late Miocene age include volcanogenic muds with distinctive high MgO and K2O, indicative of a relatively basic calc-alkaline source related to an inferred Miocene forearc succession. The forearc basement, composed of diabase and basalt, was locally exposed (Site 1109) and eroded in the late Miocene (<5.4-9.93 Ma), giving rise to fluvial conglomerates (Sites 1109, 1115, and 1118). Chemically distinctive fine-grained claystones and siltstones (with relatively high Ti, low K) are compatible with derivation from tropically weathered basic igneous rocks, correlated with the Paleogene Papuan ophiolite. Overlying latest Miocene-Pleistocene fine-grained sediments throughout the Woodlark Basin were partly derived from calc-alkaline volcanic sources. However, relatively high abundances of Al2O3 and related element oxides (K2O and Na2O) and trace elements (e.g., Rb and Y) reflect an additional terrigenous input throughout the basin, correlated with pelitic metamorphic rocks exposed on Papua New Guinea and adjacent areas. In addition, sporadic high abundances of Cr and Ni, some other trace metals, and related minerals (talc, crysotile, and chlorite) reflect input from an ophiolitic terrain dominated by ultramafic rocks, correlated with the Paleogene Papuan ophiolite. The source areas possibly included serpentinized ultramafic ophiolitic rocks exposed in the Papua New Guinea interior highlands. Chemical evidence further indicates that fine-grained terrigenous sediment reached the Woodlark Basin throughout its entire late Miocene-Holocene history. Distinctive high-K volcanogenic muds rich in tephra and volcanic ash layers that appear at <2.3 Ma (Sites 1109 and 1115) are indicative of high-K calc-alkaline volcanic centers, possibly located in the Dawson Strait, Moresby Strait, or Dobu Seamount area. Chemical diagenesis of fine-grained sediments within the Woodlark Basin is reflected in clay neomorphism and localized formation of minerals including dolomite, ankerite, and zeolite but has had little effect on the bulk chemical composition of most samples.

Small-scale variation of vegetation in a mixed forest understorey is partly controlled by the effect of overstory composition on litter accumulation

We investigated how richness and composition of vascular plant species in the understory of a mixed hardwood forest stand varied with respect to the abundance and composition of the overstory. The stand is in central Spain and represents the southernmost range of distribution of several tree and herbaceous species in Europe. Understory species were identified in 46 quadrats (0.25 m2) where variables litter depth and light availability were measured. In addition, we estimated tree density, basal area, and percent basal area by tree species within 6-m-radius areas around each plot. Species richness and composition were studied using path analysis and scale-dependent geostatistical methods, respectively. We found that the relative abundance of certain trees species in the overstory was more important than total overstory abundance in explaining understory species richness. Richness decreased as soil litter depth increased, and soil litter increased as the relative proportion of Fagus sylvatica in the overstory increased, which accounted for a negative, indirect effect of Fagus sylvatica on richness. Regarding understory species composition, we found that some species distributed preferentially below certain tree species. For example, Melica uniflora was most frequent below Fagus sylvatica and Quercus petraea while the increasing proportion of Q. pyrenaica in the overstory favored the presence of Cruciata glabra, Arenaria montana, Prunus avium, Conopodium bourgaei, Holcus mollis, Stellaria media and Galium aparine in the understory. Overall, these results emphasize the importance of individual tree species in controlling the assemblage and richness of understory species in mixed stands. We conclude that soil litter accumulation is one way through which overstory composition shapes the understory community.

AFBC of coal with tyre rubber. Influence of the co-combustion variables on the mineral matter of solid by-products and on Zn lixiviation

The study focuses on the generation and distribution of mineral species in fly and bottom ashes. These were formed during a fluidised co-combustion of a fossil fuel (coal) and a non-fossil fuel (tyre rubber) in a small fluidised bed combustor (7cm x 70cm). The pilot plant had continuous fuel feed using varying ratios of coal and rubber. The study also focuses on the lixiviation behaviour of metallic elements with the assessement of zinc recovering.

Bioavailability and extraction of heavy metals from contaminated soil by Atriplex halimus

Pot experiments were performed to evaluate the phytoremediation capacity of plants of Atriplex halimus grown in contaminated mine soils and to investigate the effects of organic amendments on the metal bioavailability and uptake of these metals by plants. Soil samples collected from abandoned mine sites north of Madrid (Spain) were mixed with 0, 30 and 60 Mg ha?1 of two organic amendments, with different pH and nutrients content: pine-bark compost and horse- and sheep-manure compost. The increasing soil organic matter content and pH by the application of manure amendment reduced metal bioavailability in soil stabilising them. The proportion of Cu in the most bioavailable fractions (sum of the water-soluble, exchangeable, acid-soluble and Fe?Mn oxides fractions) decreased with the addition of 60 Mg ha?1 of manure from 62% to 52% in one of the soils studied and from 50% to 30% in the other. This amendment also reduced Zn proportion in water-soluble and exchangeable fractions from 17% to 13% in one of the soils. Manure decreased metal concentrations in shoots of A. halimus, from 97 to 35 mg kg?1 of Cu, from 211 to 98 mg kg?1 of Zn and from 1.4 to 0.6 mg kg?1 of Cd. In these treatments there was a higher plant growth due to the lower metal toxicity and the improvement of nutrients content in soil. This higher growth resulted in a higher total metal accumulation in plant biomass and therefore in a greater amount of metals removed from soil, so manure could be useful for phytoextraction purposes. This amendment increased metal accumulation in shoots from 37 to 138 mg pot?1 of Cu, from 299 to 445 mg pot?1 of Zn and from 1.8 to 3.7 mg pot?1 of Cd. Pine bark amendment did not significantly alter metal availability and its uptake by plants. Plants of A. halimus managed to reduce total Zn concentration in one of the soils from 146 to 130 mg kg?1, but its phytoextraction capacity was insufficient to remediate contaminated soils in the short-to-medium term. However, A. halimus could be, in combination with manure amendment, appropriate for the phytostabilization of metals in mine soils.

Kinetics of CO2 absorption into aqueous solutions in CO2

This research has been performed to emphasize about the problem known as ?climate changes? occurring due to the greenhouse gases emissions (Carbon dioxide (CO2), Methane (CH4),Nitrogen oxides (NOx), Ozone (O3), Chlorofluorocarbons (artificial). Specially, the project will be focused on the CO2 emissions produced mainly from the fossil fuels burning in power plants and other kind of industrial processes. To understand how important the global is warming and therefore the climate change, both the increase of emissions and the evolution of those will be studied in this project drawing conclusions about its effect. The Kyoto Protocol, the most important agreement internationally, signed by a great majority of the industrialized and developed countries, which try to limit the CO2 emissions to the atmosphere, will be cited in this project. Taking into account the effects of global warming and applying the international legislation on emissions of greenhouse gases, a number of measures will be exposed, where the CO2 capture will be studied deeply. Three different kind of CO2 capture technologies will be studied, drawing the conclusion that the post-combustion capture, in particular by amine chemical absorption, is the most efficient one.

PAH occurrence during combustion of biodiesel from various feedstocks

PAHs are pollutants of concern since they are known carcinogenic compounds. Their occurrence is mainly related to combustion or pyrolysis of organic matter such as fossil fuels. In the current scenario where biofuels are growingly important, it is also necessary to characterize PAH emissions due to their combustion. There are a number of works concerning PAH emissions from biodiesel combustion in Diesel engines, however, there are few regarding the difference between them depending on the feedstock and type of alcohol used in the transesterification. The authors have processed and characterized biodiesel from several feedstocks (Le. tallow, palm, rapeseed, soy-bean, coconut, peanut and linseed oils) to obtain FAME and FAEE and they have developed a method to measure the PAHs originated during their combustion in a bomb calorimeter. The tests have been carried out under different oxygen pressure conditions, and samples have been c1eaned from the bomb after each one of these tests. The samples have been prepared for GC-MS analysis, where PAH quantities among some other combustion products have been assessed. This work shows statistical relations obtained between the measured amounts of 18 PAHs of concern and the composition (oil and type of alcohol) used to obtain the biodiesel, and also the oxygen pressure during combustion.