Geochemical-focusing of manganese in lake sediments — An indicator of deep-water oxygen conditions

The lateral distributions of Mn concentrations in the sediments of two Swiss lakes under varying oxygen conditions have been determined. The comparison of Mn distribution patterns with oxygen in the deep-water provides strong evidence for a geochemical-focusing effect, which is driven by the redox cycle of manganese. Conditions essential for this process to occur are anoxic sediments in contact with oxic deep-water. Average sedimentary manganese concentrations determined for different water-depth ranges are directly proportional to the area of shallower sediments. This result indicates that geochemical-focusing of manganese in lake sediments is a promising proxy indicator for the reconstruction of oxygen conditions during deposition.     

Quantification of Aquatic Nano Particles after Different Steps of Bodensee Water Purification with Laser‐induced Breakdown Detection (LIBD)

The laser‐induced breakdown detection (LIBD) is a very sensitive method for the direct detection of colloids based on the plasma generation on single particles by a focused, pulsed laser beam and the detection of the produced shock wave or plasma light emission. For the determination of colloid sizes the light emission of single plasmas is detected by a microscope CCD‐camera system. With known mean particle diameter and breakdown probability the particle concentration can be calculated. The application of the LIBD to monitor the change of colloid concentration and size during the purification steps of drinking water at the Bodensee (Lake Constance, Germany) water purification plant is shown. The breakdown probability, correlating to colloid number density, decreases with every purification step. By addition of FeCl₃ as a precipitating agent and with an additional filtration step, not only suspended matter, but also colloids are effectively removed. After this process a remaining particle concentration of 50 ng/L and a mean particle diameter of 27 nm are found.     

Transient climate response to changing carbon dioxide concentration

The time-dependent response of climate changes to changing atmospheric concentration of carbon dioxide is modeled using an energy balance atmospheric model coupled to a one-dimensional upwelling diffusion model of the deep ocean. Such a model introduces time delays so that the calculated globally-averaged temperature lags that which would be predicted by assuming radiative equilibrium. The climate model is coupled to a simple carbon cycle model and a ‘social’ model that simulates decreasing emission in response to increasing global temperatures. The thermal inertia of the system is such that temperatures continue to increase after carbon dioxide concentrations are decreasing. Consultant to BNL from New York University. Semester Student, Fall 1979, Alcorn State College. This research was performed under the auspices of the United States Department of Energy under Contract No. DE-AC02-76CH00016. By acceptance of this article, the publisher and/or recipient acknowledges the U.S. Government’s right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper.     

The puzzling structure of a sunspot

Why does a sunspot look the way it does? Steven Tobias and Nigel Weiss find answers to this question, by relating new high-resolution observations to recent theoretical studies of the spot's magnetic field.     

Nowcasting precipitation, clouds, and surface state in winter

Freezing of rainwater on a surface is often caused by nocturnal clearing after precipitation, which goes along with radiative cooling. Forecasting cloudiness, and especially the risk of clearing, on a scale of 1 to 3 h is of interest in the domains of road weather, agriculture, or water management.Cloud amount and the difference between air and surface temperature are important parameters of the radiation balance. In this contribution, we show the relationship between them, proved at several stations all over Switzerland. We found a correlation coefficient of 0.88 and improved it considering other meteorological parameters like wind speed. We conclude that temperature difference is a signature for nocturnal cloudiness.We investigated nocturnal cloudiness for a case from winter 2001/02 in northern Switzerland. An ultra-dense combination of two networks with 70 stations in total is operated, measuring air and surface temperature, wind and other parameters. With the aid of our equations, these measurements where converted into cloud maps, including also precipitation seen by radar. We identified a frontal precipitation area, postfrontal clearing, freezing, and the first clouds of a following frontal passage.All these findings will contribute to a better observation and predictability of surface state and other risks connected with radiative cooling.     

Comparison of Numerical and Physical Models for Understanding Shear Fracture Processes

An understanding of the formation of shear fractures is important in many rock engineering design problems. Laboratory experiments have been performed to determine the Mode II fracture toughness of Mizunami granite rock samples using a cylindrical `punch-through' testing device. In this paper we attempt to understand and interpret the experimental results by numerical simulation of the fundamental shear fracture initiation and coalescence processes, using a random array of displacement discontinuity crack elements. It is found that qualitative agreement between the experimental and numerical results can be established, provided that shear-like micro-scale failure processes can be accommodated by the failure initiation rules that are used in the numerical simulations. In particular, it is found that the use of an exclusively tension-driven failure initiation rule does not allow the formation of macro-shear structures. It is apparent, also, that further investigation is required to determine how consistent rules can be established to link micro-failure criteria to equivalent macro-strength and toughness properties for a macro-shear slip surface.     

Earthquakes in Switzerland and surrounding regions during 2015 and 2016

This report summarizes the seismicity in Switzerland and surrounding regions in the years 2015 and 2016. In 2015, the Swiss Seismological Service detected and located 735 earthquakes in the region under consideration. With a total of 20 earthquakes of magnitude M_L ≥ 2.5, the seismic activity of potentially felt events in 2015 was close to the average of 23 earthquakes over the previous 40 years. Seismic activity was above average in 2016 with 872 located earthquakes of which 31 events had M_L ≥ 2.5. The strongest event in the analyzed period was the M_L 4.1 Salgesch earthquake, which occurred northeast of Sierre (VS) in October 2016. The event was felt in large parts of Switzerland and had a maximum intensity of V. Derived focal mechanisms and relative hypocenter relocations of aftershocks image a SSE dipping reverse fault, which likely also hosted an M_L 3.9 earthquake in 2003. Another remarkable earthquake sequence in the Valais occurred close to Sion with four felt events (M_L 2.7–3.2) in 2015/16. We associate this sequence with a system of WNW-ESE striking fault segments north of the Rhône valley. Similarities with a sequence in 2011, which was located about 10 km to the NE, suggest the existence of an en-echelon system of basement faults accommodating dextral slip along the Rhône-Simplon line in this area. Another exceptional earthquake sequence occurred close to Singen (Germany) in November 2016. Relocated hypocenters and focal mechanisms image a SW dipping transtensional fault segment, which is likely associated with a branch of the Hegau-Bodensee Graben. On the western boundary of this graben, micro-earthquakes close to Schlattingen (TG) in 2015/16 are possibly related to a NE dipping branch of the Neuhausen Fault. Other cases of earthquakes felt by the public during 2015/16 include earthquakes in the region of Biel, Vallorcine, Solothurn, and Savognin.     

Measuring whether municipal climate networks make a difference: the case of utility-scale solar PV investment in large global cities

With cities being responsible for up to 70% of energy-related carbon emissions, municipal governments worldwide are becoming increasingly aware of their responsibility to act. Many large cities have committed to mitigation by becoming member of a municipal climate network, such as the C40 or the Compact of Mayors. However, there is no consistent assessment of whether membership of such networks translates into measurable outcomes. To fill this gap, we propose the use of novel outcome variables, combining financial data with geospatial information. As a starting point, this paper compares utility-scale investment in photovoltaics (PV) within the administrative boundaries of large global cities, combining the Bloomberg New Energy Finance database with information from Google Maps. We analyse 512 global cities with a population of above 1 million, and consider the impact of 5 networks and 2 reporting platforms. The results suggest that membership of the C40 network has a positive effect on utility-scale solar PV investment, while no such evidence is found for any of the other networks or reporting platforms under study. Based on our findings, we recommend that municipal climate networks increase their efforts to trigger city regulation that is conducive to solar PV investment. More generally, measuring early indicators, such as low-carbon investment, can help municipal climate networks in their role as ‘commitment brokers’ for climate action on the ever-more important city level.

Key policy insights

• Cities have considerable policy space to foster utility-scale solar PV investment within their administrative boundaries.

• While some large global cities exhibited significant growth in utility-scale solar PV, many others with good solar potential did not have a single project by the end of 2016.

• Outside of China (where city boundaries often include rural areas), Tokyo tops the list with utility-scale solar PV projects by far, followed by San Diego and Rome.

• Membership of the C40 network appears to make a positive difference to PV investment, unlike other networks or reporting platforms.

• Outcome measures like low-carbon investment can be used more generally to assess the climate action performance of cities.

     

Policy goals,partisanship and paradigmatic change in energy policy – analyzing parliamentary discourse in Germany over 30 years

The successful implementation of the Paris Agreement requires substantial energy policy change on the national level. In national energy policy-making, climate change mitigation goals have to be balanced with arguments on other national energy policy goals, namely limiting cost and increasing energy security. Thus far, very little is known about the relative importance of these goals and how they are related to political partisanship. In order to address this gap, we focus on parliamentary discourse around low-carbon energy futures in Germany over the past three decades and analyze the relative importance of, and partisanship around, energy policy goals. We find that the political discourse revolves around four, rather than three, goals as conventionally assumed; improving the competitiveness of the national energy technology industry is not only an additional energy policy goal, it is also highly important in the political discourse. In general, the relative importance of these goals is rather stable over time and partisanship around them is limited. Yet, a sub-analysis of the discourse on renewable energy technologies reveals a high level of partisanship, albeit decreasing over time. Particularly, the energy industry goal’s importance increases while its partisanship vanishes. We discuss how these findings can inform future energy policy research and provide a potential inroad for more ambitious national energy policies.

Key policy insights

• In addition to the three classic goals of energy policy (limiting cost, securing access and reducing the environmental burden) we identify a fourth policy goal: strengthening the national energy technology industry

• Conformity between the three classical energy and the industrial policy goals is a key driver explaining policy change

• For renewable energy technologies, partisanship around this fourth goal is lower than around other goals and decreases over time as innovation allows these technologies to increasingly correspond to policy-makers’ high-level goals

• Extant research underestimates the importance of industry policy goals, but overestimates environmental co-benefits of low-carbon energy options

• Paradigmatic policy change in Germany did not depend on top-down shifts in high-level policy goals but was driven by lower-level technology-specific goals