Chemical Ozone Loss in the Arctic Winter 1994/95 as Determined by the Match Technique

The chemically induced ozone loss inside the Arctic vortex during the winter 1994/95 has been quantified by coordinated launches of over 1000 ozonesondes from 35 stations within the Match 94/95 campaign. Trajectory calculations, which allow diabatic heating or cooling, were used to trigger the balloon launches so that the ozone concentrations in a large number of air parcels are each measured twice a few days apart. The difference in ozone concentration is calculated for each pair and is interpreted as a change caused by chemistry. The data analysis has been carried out for January to March between 370 K and 600 K potential temperature. Ozone loss along these trajectories occurred exclusively during sunlit periods, and the periods of ozone loss coincided with, but slightly lagged, periods where stratospheric temperatures were low enough for polar stratospheric clouds to exist. Two clearly separated periods of ozone loss show up. Ozone loss rates first peaked in late January with a maximum value of 53 ppbv per day (1.6 % per day) at 475 K and faster losses higher up. Then, in mid-March ozone loss rates at 475 K reached 34 ppbv per day (1.3 % per day), faster losses were observed lower down and no ozone loss was found above 480 K during that period. The ozone loss in hypothetical air parcels with average diabetic descent rates has been integrated to give an accumulated loss through the winter. The most severe depletion of 2.0 ppmv (60 %) took place in air that was at 515 K on 1 January and at 450 K on 20 March. Vertical integration over the levels from 370 K to 600 K gives a column loss rate, which reached a maximum value of 2.7 Dobson Units per day in mid-March. The accumulated column loss between 1 January and 31 March was found to be 127 DU (36 %).     

Rock, till, and stream-sediment geochemistry in the search for porphyry-type Mo---Cu---Au deposits in the proterozoic rautio batholith, Western Finland

About 170 bedrock, 550 till, and 180 organic-rich stream-sediment samples were collected at a regional scale over the Rautio batholith, and 490 rock and 1050 till samples at a local scale from around the Susineva Mo---Cu---Au occurrence which is located in the middle of the batholith. The rock samples from the regional study and selected rock samples from the Susineva area were analyzed for 32 elements. The rest of the rock samples from Susineva and all other sample types were analyzed for Mo and Cu only.     

Geodetic determination of the surface topography of the Baltic Sea

The Baltic Sea Level Project is an international scientific observation program to unify the vertical datums of the countries of the Baltic Sea with GPS measurements. In total, 35 tide gauges on shores and islands of the Baltic were occupied with GPS in 1993. After computing a new gravimetric geoid over the Baltic Sea, it was possible to unify the datums as well as to calculate the orthometric heights and the sea surface topography values for the tide gauge stations. The results obtained are shown.     

Climate change: changing means and changing extremes

Ongoing global warming not only involves changes in temperature and the global mean; it affects more or less every part of the climate. Regional temperature changes are often greater or smaller than corresponding changes in the global mean. In some cases the direction of change may also be different. For example, temperature changes are higher over land than over the ocean. Precipitation increases in some regions but decreases in others. Changes in extreme events may differ from changes in the corresponding mean. Present scientific knowledge clearly indicates that the already observed global trend towards warmer conditions will continue and that it will be accompanied by changes in yet other aspects of climate. This paper highlights, as a brief review, aspects of our changing climate from the available scientific knowledge with a bearing on the energy sector. Its focus is on temperature and precipitation, with some consideration of wind and sea level, among others. While uncertainties remain as far as the magnitude of future global-scale changes is concerned, and even more so their many regional patterns, significant changes are foreseen in, for example, global and regional temperature and precipitation, sea level rise, and in the characteristics of various extreme events.     

Origin of ultra-nickeliferous olivine in the Kevitsa Ni–Cu–PGE-mineralized intrusion, northern Finland

The 2,058 ± 4 Ma mafic–ultramafic Kevitsa intrusion is located in the Central Lapland greenstone belt, northern Finland. It is hosted by a Paleoproterozoic volcano–sedimentary sequence that contains komatiitic volcanic rocks and sulfide- and graphite-rich black schists. Economic Ni–Cu–(PGE) sulfide mineralization occurs in the middle part of the ultramafic lower unit of the intrusion. Two main types of ore are distinguished, “normal” and “Ni–PGE” ores. The normal ore is characterized by ~2 to 6 vol% disseminated sulfides and average Ni and Cu grades of 0.3 and 0.42 wt %, respectively (Ni/Cu < 1). The Ni–PGE ore has broadly similar sulfide contents, but a higher Ni grade and lower Cu grade. As a result, the Ni/Cu ratio reaches 15, much higher than in the normal ore. The Ni–PGE ores occur as irregular, discontinuous, lense-like bodies in the ultramafic rocks. Notably, the olivines in the Ni–PGE ore contain extremely high Ni contents of up to 14,000 ppm, which is significantly higher than the Ni content of olivine in other mafic–ultramafic igneous rocks globally (up to ~5,000 ppm) and in harmony with the associated Ni-rich sulfide assemblage containing pentlandite, millerite and pyrite. Microprobe mapping of olivine from the Ni–PGE ore suggests relatively low and homogeneous S contents and homogeneous distribution of Ni, Mg, Fe, which is inconsistent with the presence of sulfide inclusions in the olivine grains, or diffusion of Ni from interstitial sulfides into the olivine grains. We therefore conclude that Ni substitutes for Mg in the olivine lattice. The clinopyroxenes from the Ni–PGE ore also have unusually high Ni concentrations reaching 1,500 ppm and show a positive correlation with the nickel content of the associated olivine. The Ni_cpx/Ni_olivine is ~0.1 to 0.2 corresponding to high T partitioning of Ni between clinopyroxene and olivine. K _D of 20 can account for the partitioning of nickel between olivine and the sulfide phase, consistent with magmatic equilibration. These data suggest that the olivine, clinopyroxene, and sulfides all crystallized from a basaltic magma with an unexceptionally high Ni content ranging from 300 to 1,100 ppm. The Ni–PGE ores are spatially associated with ultramafic xenoliths. Olivine in these ultramafic xenoliths have relatively high Fo contents (up to 90 mol %) and high Ni contents (up to 5,200 ppm) suggesting that the xenoliths formed from a komatiitic parental magma. It is proposed that assimilation by the Kevitsa magma of massive or semi-massive sulfides associated with komatiitic rocks elevated the Ni content of the magma and resulted in the formation of Ni–PGE ores and related extremely Ni-rich olivines.     

Optimization of photovoltaic solar power plant locations in northern Chile

The optimization of photovoltaic solar power plants location in Atacama Desert, Chile, is presented in this study. The study considers three objectives: (1) Find sites with the highest solar energy potential, (2) determine sites with the least impact on the environment, and (3) locate the areas which produce small social impact. To solve this task, multi-criteria decision analyses (MCDAs) such as analytical hierarchy process and ordered weighted averaging were applied in a GIS environment. In addition, survey results of social impacts were analyzed and included into the decision-making process, including landscape values. The most suitable sites for solar energy projects were found near roads and power lines throughout the study area. Large suitable areas were found also from central valley from Arica and Parinacota to the north edge of Atacama region. In Atacama region, most suitable sites were found in the Andes. On the contrary, Andes were also found to have high environmental values and scenically valuable landscapes. Moderate and low suitability were found on the coast, especially in Atacama region. Factors such as slope and distance to power lines and roads influenced largely the sensitivity analysis. Area of high suitability increased by 15% when distance to roads was excluded and 18% when distance to power lines or slope was removed. MCDA-GIS method was found to be useful and applicable to the optimization of solar power plant locations in northern Chile.     

Some air electricity phenomena caused by waterfalls: Correlative study of the spectra

According to our previous measurements, waterfalls permanently modify air ion spectra. In this paper we performed a correlative study of these results and proposed some pathways which can produce the observed waterfall ions. The small ion composition near waterfalls should be different from that further away due to gaseous OH⁻ core (water shell) clusters. We assumed that the combination of factors (autoionization, fluctuating charge rearrangement, surface protrusions, collisions, Coulomb explosion) serves as the main source of observed intermediate ions, and an extra source for large ions. Evaporation of droplets produces nearly equal numbers of positive and negative intermediate and large ions. Waterfall-produced intermediate ions can attach to the waterfall-produced larger particles, which creates an additional link between the waterfall intermediate and large ions.