Simultaneous measurements of Martian plasma boundaries by Rosetta and Mars Express

We present the first two-spacecraft near-simultaneous observations of the Martian bow shock (BS), magnetic pileup boundary (MPB) and photo-electron boundary (PEB) obtained by the plasma instruments onboard Rosetta and Mars Express during the Rosetta Mars flyby on February 25, 2007. Our observations are compared with shape models for the BS and MPB derived from previous statistical studies. The MPB is found at its expected position but the BS for this event is found significantly closer to the planet than expected for the rather slow and moderately dense solar wind. Cross-calibration of the density measurements on the two spacecraft gives a density profile through the magnetosheath, indicating an increasing solar wind flux during the Rosetta passage which is consistent with the multiple BS crossings at the Rosetta exit.     

Comparison of preparatory signal analysis techniques for consideration in the (post-)Kyoto policy process

Our study is a preparatory exercise. We focus on the analysis of uncertainty in greenhouse gas emission inventories. Inventory uncertainty is monitored, but not regulated, under the Kyoto Protocol to the United Nations Framework Convention on Climate Change. Under the Convention, countries publish annual or periodic national inventories of greenhouse gas emissions and removals. Policymakers use these inventories to develop strategies and policies for emission reductions and to track the progress of these policies. However, greenhouse gas inventories contain uncertainty for a variety of reasons, and these uncertainties have important scientific and policy implications. For most countries, the emission changes agreed under the Protocol are of the same order of magnitude as the uncertainty that underlies their combined (carbon dioxide equivalent) emissions estimates. Here we apply and compare six available techniques to analyze the uncertainty in the emission changes that countries agreed to realize by the end of the Protocol’s first commitment period 2008–2012. Any such technique, if implemented, could “make or break” claims of compliance, especially in cases where countries claim fulfillment of their commitments to reduce or limit emissions. The techniques all perform differently and can thus have a different impact on the design and execution of emission control policies. A thorough comparison of the techniques has not yet been made but is needed when expanding the discussion on how to go about dealing with uncertainty under the Kyoto Protocol and its successor.     

Ion escape from Mars as a function of solar wind conditions: A statistical study

The influence of solar EUV and solar wind conditions on ion escape at Mars is investigated using ion data from the Aspera-3 instrument on Mars Express, combined with solar wind proxy data obtained from the Mars Global Surveyor (MGS) spacecraft. A solar EUV flux proxy based on data from the Earth position, scaled and shifted in time for Mars, is used to study relatively long time scale changes related to solar EUV variability. Data from May 2004 until November 2005 has been used. A clear dependence on the strength of the subsolar magnetic field as inferred from MGS measurements is seen in the ion data. The region of significant heavy ion flows is compressed and the heavy ion flux density is higher for high subsolar magnetic field strength. Because of the difference in outflow area, the difference in estimated total outflow is somewhat less than the difference in average flux density. We confirm previous findings that escaping planetary ions are mainly seen in the hemisphere into which the solar wind electric field is pointed. The effect is more pronounced for the high subsolar magnetic field case.The average ion motion has a consistent bias towards the direction of the solar wind electric field, but the main motion is in the antisunward direction. The antisunward flow velocity increases with tailward distance, reaching above at 2 to 3 martian radii downtail from Mars for O⁺ ions. Different ion species reach approximately the same bulk flow energy. We did not find any clear correlation between the solar EUV flux and the ion escape distribution or rate, probably because the variation of the solar EUV flux over our study interval was too small. The results indicate that the solar wind and its magnetic field directly interacts with the ionosphere of Mars, removing more ions for high subsolar magnetic field strength. The interaction region and the tail heavy ion flow region are not perfectly shielded from the solar wind electric field, which accelerates particles over relatively large tail distances.     

Relationships between drainage area characteristics and lake water quality

The aim of this work is to quantify some of the complex relationships between drainage area characteristics (such as bedrocks and quaternary deposits) and lake water quality (pH, alkalinity, conductivity, and hardness). Seventysix drainage lakes, mainly oligotrophic, are described with respect to drainage area characteristics, morphometry, and water chemistry. The DAZ (drainage area zonation) method has been used to describe the drainage areas. The method utilizes a weighting system to reduce the impact of land types with increasing distance from the lake. The most significant parameter governing the water chemistry parameters seems to be the percentage of open land (cultivated land and/or meadows) in the drainage areas. High percentage leads to high pH, alkalinity, conductivity, and hardness. The correlations concerning alkalinity and pH are improved using the DAZ method. No significant relationships between bedrock geology of the drainage areas and lake water chemistry have been recorded.     

Reduction of horizontal wind speed in a boundary layer with obstacles

The reduction of horizontal wind speed at hub height in an infinite cluster of wind turbines is computed from a balance between a loss of horizontal momentum due to the drag and replenishment from above by turbulent fluxes. This reduction is derived without assumptions concerning the vertical wind profile above or below hub height, only some basic assumptions on turbulent exchange have been made. Two applications of the result are presented, one considering wind turbines and one pressure drag on orographic obstacles in the atmospheric boundary layer. Both applications are basically governed by the same kind of momentum balance.     

Situational and cognitive obstacles to political consensus on climatic change

The discussion draws on results from the project entitledCultural and Techno-Ecological Constraints and Opportunities for Natural Resources Management, financed by the Swedish Council for Planning and Coordination of Research.