158 research outputs found
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The European Climate Research Alliance (ECRA): collaboration from bottom-up
The European Climate Research Alliance (ECRA) is an association of leading European research institutions in the field of climate research (http://www.ecra-climate.eu/, last access: 6 December 2018). ECRA is a bottom-up initiative and helps to facilitate the development of climate change research, combining the capacities of national research institutions, and inducing closer ties between existing national research initiatives, projects and infrastructures. ECRA works as an open platform to bring together climate researchers, providing excellent scientific expertise for policy makers and of societal relevance. The ECRA Board consists of representatives of ECRA partners and decides on governance, scientific priorities, and organisational matters.
Currently organized into four Collaborative Programmes, climate scientists share their knowledge, experience and expertise to identify the most important research requirements for the future, thus developing a foresight approach. The CPs cover the topics: (1) Arctic variability and change, (2) Sea level changes and coastal impacts, (3) Changes in the hydrological cycle and (4) High impact events. The CP activities are planned in workshops and participation is open to all interested scientists from the relevant research fields. In particular, young researchers are actively encouraged to join the network. Each CP develops its joint research priorities for shaping European research into the future. Because scientific themes are interconnected, the four Collaborative Programmes interact with each other, e.g. through the organization of common workshops or joint applications. In addition, the Collaborative Programme leads attend the Board meetings.
The different formats of ECRA meetings range from scientific workshops to briefing events and side events at conferences to involve different groups of interests. This facilitates the interaction of scientists, various stakeholder groups and politicians. A biennial open ECRA General Assembly that is organised in Brussels represents an umbrella event and acts as a platform for discussion and contact with stakeholders. This event is an excellent opportunity to jointly discuss research priorities of high societal relevance
Brewing of filter coffee
We report progress on mathematical modelling of coffee grounds in a drip filter coffee machine. The report focuses on the evolution of the shape of the bed of coffee grounds during extraction with some work also carried out on the chemistry of extraction. This work was sponsored by Philips who are interested in understanding an observed correlation between the final shape of the coffee grounds and the quality of the coffee. We used experimental data gathered by Philips and ourselves to identify regimes in the coffee brewing process and relevant regions of parameter space. Our work makes it clear that a number of separate processes define the shape of the coffee bed depending on the values of the parameters involved e.g. the size of the grains and the speed of fluid flow during extraction. We began work on constructing mathematical models of the redistribution of the coffee grounds specialised to each region and on a model of extraction. A variety of analytic and numerical tools were used. Furthermore our research has progressed far enough to allow us to begin to exploit connections between this problem and other areas of science, in particular the areas of sedimentology and geomorphology, where the processes we have observed in coffee brewing have been studied
Nova light curves from the Solar Mass Ejection Imager (SMEI) - II. The extended catalogue
We present the results from observing nine Galactic novae in eruption with the Solar Mass Ejection Imager (SMEI) between 2004 and 2009. While many of these novae reached peak magnitudes that were either at or approaching the detection limits of SMEI, we were still able to produce light curves that in many cases contained more data at and around the initial rise, peak, and decline than those found in other variable star catalogs. For each nova, we obtained a peak time, maximum magnitude, and for several an estimate of the decline time (t2). Interestingly, although of lower quality than those found in Hounsell et al. (2010a), two of the light curves may indicate the presence of a pre-maximum halt. In addition the high cadence of the SMEI instrument has allowed the detection of low amplitude variations in at least one of the nova light curves
emerging perspectives for flood risk assessment and management
Flood estimation and flood management have traditionally been the domain of
hydrologists, water resources engineers and statisticians, and disciplinary
approaches abound. Dominant views have been shaped; one example is the
catchment perspective: floods are formed and influenced by the interaction of
local, catchment-specific characteristics, such as meteorology, topography and
geology. These traditional views have been beneficial, but they have a narrow
framing. In this paper we contrast traditional views with broader perspectives
that are emerging from an improved understanding of the climatic context of
floods. We come to the following conclusions: (1) extending the traditional
system boundaries (local catchment, recent decades, hydrological/hydraulic
processes) opens up exciting possibilities for better understanding and
improved tools for flood risk assessment and management. (2) Statistical
approaches in flood estimation need to be complemented by the search for the
causal mechanisms and dominant processes in the atmosphere, catchment and
river system that leave their fingerprints on flood characteristics. (3)
Natural climate variability leads to time-varying flood characteristics, and
this variation may be partially quantifiable and predictable, with the
perspective of dynamic, climate-informed flood risk management. (4) Efforts
are needed to fully account for factors that contribute to changes in all
three risk components (hazard, exposure, vulnerability) and to better
understand the interactions between society and floods. (5) Given the global
scale and societal importance, we call for the organization of an
international multidisciplinary collaboration and data-sharing initiative to
further understand the links between climate and flooding and to advance flood
research
Floods and climate: emerging perspectives for flood risk assessment and management
Flood estimation and flood management have traditionally been the domain of
hydrologists, water resources engineers and statisticians, and disciplinary
approaches abound. Dominant views have been shaped; one example is the
catchment perspective: floods are formed and influenced by the interaction
of local, catchment-specific characteristics, such as meteorology,
topography and geology. These traditional views have been beneficial, but
they have a narrow framing. In this paper we contrast traditional views with
broader perspectives that are emerging from an improved understanding of the
climatic context of floods. We come to the following conclusions: (1) extending the traditional
system boundaries (local catchment, recent decades, hydrological/hydraulic
processes) opens up exciting possibilities for better understanding and
improved tools for flood risk assessment and management. (2) Statistical
approaches in flood estimation need to be complemented by the search for the
causal mechanisms and dominant processes in the atmosphere, catchment and
river system that leave their fingerprints on flood characteristics.
(3) Natural climate variability leads to time-varying flood characteristics, and
this variation may be partially quantifiable and predictable, with the
perspective of dynamic, climate-informed flood risk management.
(4) Efforts are needed to fully account for factors that contribute to changes
in all three risk components (hazard, exposure, vulnerability) and to
better understand the interactions between society and floods. (5) Given the
global scale and societal importance, we call for the organization of an
international multidisciplinary collaboration and data-sharing initiative to
further understand the links between climate and flooding and to advance
flood research
Swift X-Ray Observations of Classical Novae. II. The Super Soft Source sample
The Swift GRB satellite is an excellent facility for studying novae. Its
rapid response time and sensitive X-ray detector provides an unparalleled
opportunity to investigate the previously poorly sampled evolution of novae in
the X-ray regime. This paper presents Swift observations of 52
Galactic/Magellanic Cloud novae. We included the XRT (0.3-10 keV) X-ray
instrument count rates and the UVOT (1700-8000 Angstroms) filter photometry.
Also included in the analysis are the publicly available pointed observations
of 10 additional novae the X-ray archives. This is the largest X-ray sample of
Galactic/Magellanic Cloud novae yet assembled and consists of 26 novae with
super soft X-ray emission, 19 from Swift observations. The data set shows that
the faster novae have an early hard X-ray phase that is usually missing in
slower novae. The Super Soft X-ray phase occurs earlier and does not last as
long in fast novae compared to slower novae. All the Swift novae with
sufficient observations show that novae are highly variable with rapid
variability and different periodicities. In the majority of cases, nuclear
burning ceases less than 3 years after the outburst begins. Previous
relationships, such as the nuclear burning duration vs. t_2 or the expansion
velocity of the eject and nuclear burning duration vs. the orbital period, are
shown to be poorly correlated with the full sample indicating that additional
factors beyond the white dwarf mass and binary separation play important roles
in the evolution of a nova outburst. Finally, we confirm two optical phenomena
that are correlated with strong, soft X-ray emission which can be used to
further increase the efficiency of X-ray campaigns.Comment: Accepted to ApJ Supplements. Full data for Table 2 and Figure 17
available in the electronic edition. New version of the previously posted
paper since the earlier version was all set in landscape mod
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