The polar magnetic fields of July and August 1968

Observations of the polar magnetic fields were made during the period July 3–August 23, 1968, with the Mt. Wilson magnetograph. The scanning aperture was 5 × 5. The magnetic field was found to be ofS polarity near the heliographic north pole and ofN polarity near the south pole. At lower latitudes the polarity was the opposite. The polarity reversal occurred at a latitude of about +70° in the north and -55° in the south hemisphere. This coincides with the position of the polar prominence zones at that time. The observations indicate that the average field strength at the south pole was well above 5 G.Synoptic charts of the magnetic fields have been plotted in a polar coordinate system for two consecutive solar rotations.     

A Mössbauer investigation of natural troilite from the Agpalilik meteorite

Troilite close to FeS, with 0.17 weight percent Cr as main impurity, was obtained from the Agpalilik meteorite. Powder Mössbauer spectroscopy was made in the temperature range 77–645 K. The full Hamiltonian was applied in the fittings. Assuming the asymmetry parameter η to be constant on passing from the high-temperature NiAs-type structure to the medium-temperature MnP-type structure yields a quadrupole splitting (dq=0.5e² qQ(1+(η²)/3)^1/2) value of ?0.25(2) mm/s for these phases. In low-temperature troilite |dq|=0.85 mm/s at room temperature. The combinations of (η, θ, φ) in troilite giving identical spectra range from (0, 49°, -) to (1, 45°, 50°) for negative V _zz or from (0.3, 57°, 78°) to (1, 58°, 54°) for positive V _zz . Assuming a negative V _zz and B‖c gives a θ value in agreement with the shortest Fe-S join being the V _zz orientation. The magnetic spin flip of 90° is proposed to occur in the MnP-phase only. The MnP phase-troilite transition occurs at lower temperatures and is more sluggish than in pure FeS.     

The impact of compensatory measures on public support for carbon taxation: an experimental study in Sweden

This study aims at better understanding how, and to what extent, perceptions of a policy instrument’s distributional effects impact on policy support, focusing on the case of CO₂ taxes on petrol in Sweden. Through a large-scale (N?=?5000) randomized survey experiment with a 2?×?3 factorial design, the extent to which perceptions of fairness determine attitudes to a suggested increase of the Swedish CO₂ tax is explored. Furthermore, the study considers whether these effects change with the level of the suggested tax increase, as well as whether negative sentiments can be alleviated by combining it with a compensatory measure in the shape of a simultaneous income tax cut financed by the revenues from the tax increase. The results show that a higher tax increase is both viewed as more unfair and enjoys weaker support. Furthermore, compensatory measures can be a powerful policy design tool to increase perceptions of the policy as fair, but the effect of compensation on policy support is conditioned by the individual’s left–right ideological position. Whereas people self-identifying to the right react favourably to compensatory measures, people self-identifying to the left become less supportive of a tax increase when combined with a simultaneous cut in income taxes.

Key policy insights

• Perceptions of fairness are highly important for explaining public support for climate policy tools, specifically CO₂ taxes.

• Compensatory measures can be a powerful policy design tool to increase perceptions of the policy as less unfair.

• However, the effect of compensatory measures on policy support is conditioned by ideological position, and only successful among people to the ideological right.

• In contexts dominated by right-wing ideals, a combination of a tax and a compensatory scheme may be a successful route forward towards increased climate policy support.

• In left-oriented contexts the results imply that a CO₂ tax without compensation seems more likely to increase support.

     

Mesosphere summer echoes,temperature, and meridional wind variations at mid- and polar latitudes

VHF Radar echoes in the summer mesosphere at mid- and polar latitudes ([P]MSE—[polar] mesosphere summer echoes) are connected with very cold temperatures where ice particles can exist. Temperature variations can cause conditions for the generation and evaporation of ice particles and affect the [P]MSE occurrence. The impact of temperature and meridional wind oscillations on [P]MSE is described. Generally at mid-latitudes, strong mesosphere summer echoes are strongly affected by meridional wind variations if the mean temperature is near the frost point of water vapor. In contrast, at polar latitudes there is mostly no significant impact of the meridional wind on radar echoes. A mean temperature well below the frost point and a weaker meridional temperature gradient than at mid-latitudes are reasons for this reduced influence. Due to higher temperatures in 2002, long period temperature and meridional wind variations impact the PMSE more than during the other years.     

Effects of ozone depletion and increased ultraviolet-B radiation on northern vegetation

The stratospheric ozone layer has been depleted at high and mid-latitudes as a consequence of man's pollution of the atmosphere, and this results in increasing ultraviolet-B radiation at ground level. We investigate the effects of further radiation increases on plants and ecosystems by irradiating natural sub-Arctic and Arctic vegetation with artificial UV-B radiation in field experiments extending over several years. Our experimental sites are located at Abisko, in northern Sweden (68°N), and Adventdalen, on the island of Spitsbergen (78°N). Additional UV-B induced interspecific differences in plant response in terms of reduced (or, in one case, increased) growth, changed morphology and changed pigment content. In some cases effects seem to be accumulated from one year to another. Plant litter decomposition is retarded. We are also studying how UV-B enhancement may affect the interaction between species. In some experiments we combine UV-B enhancement with changes in other factors: carbon dioxide concentration, water availability, and temperature. In some cases the effect of radiation enhancement is modified, or even reversed, by such changes. Over a four year period we did not find any significant radiation induced change in species composition, but based on the effects on individual plant species, such changes can be expected to take place over a longer time.     

A closure study of sub-micrometer aerosol particle hygroscopic behaviour

The hygroscopic properties of sub-micrometer aerosol particles were studied in connection with a ground-based cloud experiment at Great Dun Fell, in northern England in 1995. Hygroscopic diameter growth factors were measured with a Tandem Differential Mobility Analyser (TDMA) for dry particle diameters between 35 and 265 nm at one of the sites upwind of the orographic cloud. An external mixture consisting of three groups of particles, each with different hygroscopic properties, was observed. These particle groups were denoted less-hygroscopic, more-hygroscopic and sea spray particles and had average diameter growth factors of 1.11–1.15, 1.38–1.69 and 2.08–2.21 respectively when taken from a dry state to a relative humidity of 90%. Average growth factors increased with dry particle size. A bimodal hygroscopic behaviour was observed for 74–87% of the cases depending on particle size. Parallel measurements of dry sub-micrometer particle number size distributions were performed with a Differential Mobility Particle Sizer (DMPS). The inorganic ion aerosol composition was determined by means of ion chromatography analysis of samples collected with Berner-type low pressure cascade impactors at ambient conditions. The number of ions collected on each impactor stage was predicted from the size distribution and hygroscopic growth data by means of a model of hygroscopic behaviour assuming that only the inorganic substances interacted with the ambient water vapour. The predicted ion number concentration was compared with the actual number of all positive and negative ions collected on the various impactor stages. For the impactor stage which collected particles with aerodynamic diameters between 0.17–0.53 μm at ambient relative humidity, and for which all pertinent data was available for the hygroscopic closure study, the predicted ion concentrations agreed with the measured values within the combined measurement and model uncertainties for all cases but one. For this impactor sampling occasion, the predicted ion concentration was significantly higher than the measured. The air mass in which this sample was taken had undergone extensive photochemical activity which had probably produced hygroscopically active material other than inorganic ions, such as organic oxygenated substances.     

Mesan, an operational mesoscale analysis system

A system for mesoscale analyses of selected variables has been developed. The analysed parameters are of general interest in operational weather forecasting, but normally not available from NWP systems, or available, but with a significantly lower quality than achieved by the mesoscale analysis system. A supplementary objective is to produce initial information to be used for now-casting techniques. Examples of parameters are precipitation, temperature, humidity, visibility, wind and clouds. The basis of the analysis system is the optimal interpolation technique (OI). The use of observations from automatic stations, radars and satellites have been investigated. The investigation indicates that a dense network of ordinary precipitation gauge measurements can produce more accurate analyses than more elaborate systems like radar that suffers from anomalous echoes and other errors.