Volatile Organic Compounds in the Po Basin. Part A: Anthropogenic VOCs

Measurements of volatile organic compounds (VOCs) were performed in the Po Basin, northern Italy in early summer 1998 within the PIPAPO project as well as in summer 2002 and autumn 2003 within the FORMAT project. During the three campaigns, trace gases and meteorological parameters were measured at a semi-rural station, around 35 km north of the city center of Milan. Low toluene and benzene concentrations and lower toluene to benzene ratios on weekends, on Sundays, and in August enabled the identification of a ‘weekend’ and a ‘vacation’ effect when anthropogenic emissions were lower due to less traffic and reduced industrial activities, respectively. Recurrent nighttime cyclohexane peaks suggested a periodical short-term release of cyclohexane close to the semi-rural sampling site. A multivariate receptor model analysis resulted in the distinction of different characteristic concentration profiles attributed to natural gas, biogenic impact, vehicle exhaust, industrial activities, and a single cyclohexane source.     

The pattern speed of the spiral galaxy NGC 1253

We present Very Large Array H  i observations of the gas-rich, interacting spiral galaxies, NGC 1253/1253A (Arp 279). The larger of the two galaxies, NGC 1253, has a very pronounced H  i ring and well-defined spiral structure. The velocity structure of the H  i data shows a sudden change at the position of the spiral arms; we identify this change as evidence of a strong spiral shock and hence proceed to estimate the pattern speed, Ω_p, of the spiral arms in NGC 1253. Assuming that the pattern speed is constant across the disc our derived value places the outer Lindblad resonance (OLR) at the position of the observed H  i ring. As an accumulation of gas is expected at the OLR when this falls within the disc of a galaxy this agreement provides independent support for the derived value of Ω_p.     

Generation of fluorine-bearing fluids in hydrothermal experiments

Fluorine-bearing fluids can be generated by breakdown of PdF₂ in hydrothermal experiments. This promising technique allows addition of a fixed amount of F without affecting the composition of the rest of the system. The method is simpler, more flexible and potentially yields better results than most other techniques of F addition. Melting and crystallization experiments using natural starting materials are particularly well suited to application of this method.     

Constraints on melting and magma production in the crust

Major intrusions of granitic rocks are found in several tectonic settings and, in all cases, crustal melts may contribute to the volumes of granitic magma. High-grade metamorphism and partial melting of the crust take place predominantly under fluid-absent conditions. We present a model for calculating the amounts of melt that may be formed by fluid-absent breakdown of micas and amphiboles in common crustal rock types (pelitic, quartzofeldspathic, intermediate and mafic). Melt proportions depend mainly on the kind of source rock, the pressure at which melting takes place, the temperature and the hydrous mineral (H₂O) content of the source. As a consequence of the pressure dependence of water solubility in silicate melts, any given source rock will produce more melt, by a given fluid-absent reaction, at lower pressure. At a given pressure, higher-temperature reactions can produce more melt from a given source rock. Based on a survey of the compositions of common rock types, we show that the amounts of melt can vary from < 10to> 50vol.%. Thus, crustal rocks vary widely in their “fertility” as magma sources, depending on the types and amounts of hydrous phases they contain. In general, muscovite breakdown in pelites will yield only small quantities of melt and lead to migmatite formation. Biotite breakdown in pelites occurs at higher temperature and, because most high-grade pelites (below granulite grade) are biotite-rich, can yield up to about 50 vol.% of granitoid melt. Rocks of intermediate composition and hornblende-rich mafic rocks are potentially highly fertile magma sources also, provided that the high temperatures necessary for biotite and hornblende breakdown are realized. Pyroxene-rich mafic rocks and quartzofeldspathic rocks are much less potentially fertile. Data suggest that mechanisms exist for the efficient segregation of melt and restite in systems with < 30and probably< 20vol.% melt. The pressure-temperature history of a region can greatly influence crustal source fertility through its control over the occurrence of subsolidus dehydration and melting equilibria.     

Regional dynamical downscaling with CCLM over East Asia

Inspired by the framework of the Coordinated Regional Climate Downscaling Experiment (CORDEX), the hindcast (1971–2000) and projection (2021–2050) simulations based on a resolution of $0.44^\circ$ over the East Asia domain are performed with the regional climate model COSMO-CLM (CCLM). The simulations are driven by ERA-40 reanalysis data and output of the global climate model ECHAM5. This is the first time that the CCLM is adapted and evaluated for the East Asia Monsoon region; the setup is considered a starting point for further improvements in this region by the CCLM community. The evaluation results show that the CCLM is able to reasonably capture the climate features in this region, especially the monsoon dynamics on small scales. However, total precipitation in the northern part of the domain, over the Tibetan Plateau, and over east Indonesia has a pronounced wet bias. The projected climate change under the A1B scenario indicates an overall annual surface temperature increase of 1–2 K, but no significant precipitation changes.     

On correcting precipitation as simulated by the regional climate model COSMO-CLM with daily rain gauge observations

Precipitation amounts simulated by the regional climate model COSMO-CLM are compared with observations from rain gauges at German precipitation stations for the period 1960–2000. The model overestimates precipitation by about 26 %. This bias is accompanied with a shift of the frequency distribution of rain intensities. The model overestimation varies regionally. A correction function is derived which adjusts rain intensities at every model grid point to the observations.     

Thermo-optical parameter acquisition and characterization of geologic properties: a 400-m deep BHE in a karstic alpine marble aquifer

To dimension a geothermal array, it is necessary to explore the geophysical and geologic qualities of the subsoil. At the following example the project engineering of a prospective geothermal array is shown from the investigation up to the execution planning. For the geothermic investigation a 400 m (1312 ft.) deep drilling was established and equipped with 50 mm (1.97 in.) duplex BHE. With the mounting of the BHE a fiberglass hybrid cable was inserted as a loop parallel to the shanks of the BHE. By means of optical frequency domain reflectometry (OFDR) an enhanced geothermal response test has been executed. Due the high local resolution of the resulting profile of conductivities the geological profile can be differentiated in areas with mainly conductive and areas of convective influenced heat transfer. By knowledge of these both parts and its parameters the incident of groundwater flow on the BHE can be calculated (Peclet number analysis/ Darcy velocity). With the help of the ascertained geophysical and hydraulic rock parameters solid rock, cleavages and karst cavity could be identified. Also the undisturbed ground temperature, the effective thermal conductivity and areas with different geothermal gradients and the groundwater velocity in cleaved and caveated rocks could be determined.