Steady states of elastically-coupled extensible double-beam systems

Given $\beta\in\mathbb{R}$ and $\varrho,k>0$, we analyze an abstract version of the nonlinear stationary model in dimensionless form $$\begin{cases} u"" - \Big(\beta+ \varrho\int_0^1 |u'(s)|^2\,{\rm d} s\Big)u" +k(u-v) = 0 v"" - \Big(\beta+ \varrho\int_0^1 |v'(s)|^2\,{\rm d} s\Big)v" -k(u-v) = 0 \end{cases}$$ describing the equilibria of an elastically-coupled extensible double-beam system subject to evenly compressive axial loads. Necessary and sufficient conditions in order to have nontrivial solutions are established, and their explicit closed-form expressions are found. In particular, the solutions are shown to exhibit at most three nonvanishing Fourier modes. In spite of the symmetry of the system, nonsymmetric solutions appear, as well as solutions for which the elastic energy fails to be evenly distributed. Such a feature turns out to be of some relevance in the analysis of the longterm dynamics, for it may lead up to nonsymmetric energy exchanges between the two beams, mimicking the transition from vertical to torsional oscillations

A Simple Equation for Regional Climate Change and Associated Uncertainty

Abstract Simple equations are developed to express regional climate changes for the twenty-first century and associated uncertainty in terms of the global temperature change (GTC) without a dependence on the underlying emission pathways. The equations are applied to regional temperature and precipitation changes over different regions of the world, and relevant parameters are calculated using the latest multimodel ensemble of global climate change simulations. Examples are also shown of how to use the equations to develop probability density functions (PDFs) of regional climate change based on PDFs of GTC. The main advantage of these equations is that they can be used to estimate regional changes from GTC obtained either from simple and intermediate complexity models or from target CO2 stabilization concentrations

The North Atlantic Oscillation signal in a regional climate simulation for the European region

The North Atlantic Oscillation (NAO) is a dominant pattern of large-scale variability in the Northern Hemisphere, with important regional effects on the winter climate of Europe. Nested regional climate models (RCMs) can be useful tools for studying the regional signal of the NAO. Therefore, it is important to assess whether they can reproduce the observed NAO signal over Europe when driven by lateral boundary conditions from global climate models. In this paper we investigate the NAO-related winter variability over Europe in a RCM simulation driven by large-scale fields from an atmospheric global model simulation forced with historic sea surface temperature and sea ice distribution for the period 1961–1990. We show that (1) the NAO-related winter variability signal over the European region shows substantial topographically induced fine-scale features, both for temperature and precipitation, and (2) the model is capable of reproducing many aspects of this fine-scale regional signal and, in particular, the topographically forced regional response of precipitation to NAO-type circulations. We conclude that nested regional climate models can be used to study the fine-scale regional signature of the NAO under different climatic conditions

Regional earth system modeling: review and future directions

AbstractThe authors review recent advances in the development of coupled Regional Earth System Models (RESMs), a field that is still in its early stages. To date, coupled regional atmosphere-ocean-sea ice, atmosphere-aerosol and atmosphere-biosphere models have been developed, but they have been applied only to limited regional settings. Much more work is thus needed to assess their transferability to a wide range of settings. Future challenges in regional climate modeling are identified, including the development of fully coupled RESMs encompassing not only atmosphere, ocean, cryosphere, biosphere, chemosphere, but also the human component in a fully interactive way

Threatening levels of cumulative stress due to hydroclimatic extremes in the 21st century

Summary Wet and dry hydroclimatic extremes can pose severe stress to human societies under global warming. A new metric of cumulative stress due to hydroclimatic extremes is introduced, expressed in "equivalent reference stress years (ERSY)" i.e. the mean annual stress (e.g. potential for damage) in present climate conditions. 21st century climate projections show that, under the high-end RCP8.5 greenhouse gas scenario, by 2100, increases in wet and dry extremes add ~155 ERSY over global land areas (~125 for wet and ~30 for dry extremes), with wet hotspots over Asia, Eastern Africa and the Americas, and dry hotspots throughout Central and South America, Europe, West Africa and coastal Australia. Consideration of population exposure yields potential stress hotspots exceeding 400 added ERSY over Africa, North America, and Australia. The hydroclimatic stress is considerably reduced under the RCP2.6 scenario

Understanding and attributing the Euro‐Russian summer blocking signatures

In this work, we focus on summer blocking events over the Euro-Russian region related with heat waves. An analysis of the main characteristics of summer Euro-Russian blocking events in global Reanalysis as well as in the 20th century CLIVAR atmospheric simulations is carried out to assess whether anthropogenic forcing might have affected the blocking events occurrence and the associated heat waves strength in recent decades. Over the Euro-Russian region, blocking episodes, associated to warm events over Northern and Central Europe, become significantly longer in the second half of the century when the anthropogenic forcing is included in the simulations. © 2014 Royal Meteorological Society

High-Efficiency Digital Readout Systems for Fast Pixel-based Vertex Detectors

Particle physics is one of the science branches which heavily relies on most advanced technologies due to the increasing complexity of the problems it has to face. In future colliders, luminosities and beam energies are scaling upwards. These are necessary conditions for the discovery of new physics which both result in a larger amount of data that need to be brought out of the detector. That’s why one of the crucial points for new experiments is the evolution of data acquisition systems. Data acquisition systems employed in particle physics experiments followed the global technology trend and moved towards digital electronics and transmission lines, in this chapter we will describe how the effort of our work has been applied in this direction trying to extend digital processing on the very front-end of the detector. We will show how digital elaboration on the very front-end can help coping with new stringent requirements

Comparison of convective parameterizations in RegCM4 experiments over China with CLM as the land surface model

AbstractIn the latest version of the International Centre for Theoretical Physics' regional climate model, RegCM4, CLM was introduced as a new land surface scheme. The performance over China of RegCM4-CLM with different convection schemes is analyzed in this study, based on a series of short-term experiments. The model is driven by ERA-Interim data at a grid spacing of 25 km. The convection schemes employed are: Emanuel; Grell; Emanuel over land and Grell over ocean; Grell over land and Emanuel over ocean; and Tiedtke. The simulated mean surface air temperature and precipitation in December–February–January and June–July–August are compared against observation. In general, better performance of Emanuel is found both for temperature and precipitation, and in both seasons. Thus, the model physics of CLM and Emanuel for the land surface processes and convection, respectively, are recommended for further application of RegCM4 over the China region. The deficiencies that remain in the model are also outlined a..

Connection between Spring Conditions and Peak Summer Monsoon Rainfall in South America: Role of Soil Moisture, Surface Temperature, and Topography in Eastern Brazil

A link between peak summer monsoon rainfall in central-east Brazil, composing part of the South American monsoon core region, and antecedent conditions in spring is disclosed. Rainfall in this region during part of spring holds a significant inverse correlation with rainfall in peak summer, especially during ENSO years. A surface–atmosphere feedback hypothesis is proposed to explain this relationship: low spring precipitation leads to low spring soil moisture and high late spring surface temperature; this induces a topographically enhanced low-level anomalous convergence and cyclonic circulation over southeast Brazil that enhances the moisture flux from northern and central South America into central-east Brazil, setting up favorable conditions for excess rainfall. Antecedent wet conditions in spring lead to opposite anomalies. The main links in this hypothesis are confirmed through correlation analysis of observed data: spring precipitation is negatively correlated to late spring surface temperature in central-east Brazil, and surface temperature in southeast Brazil is positively correlated with peak summer monsoon precipitation in central-east Brazil. The intermediary links of the surface–atmosphere feedback are tested in sensitivity experiments with the regional climate model version 3 (RegCM3). These experiments confirm that the proposed links are possible: the reduced soil moisture in central-east Brazil is shown to increase the surface temperature and produce a cyclonic anomaly over southeast Brazil, as well as increased precipitation in central-east Brazil. A crucial role of the mountains of southeast Brazil in anchoring the patterns of intraseasonal variability, and sustaining the “dipolelike” precipitation mode observed over South America, is suggested. The low predictability of monsoon rainfall anomalies in central-east Brazil during the austral summer might be partially ascribed to the fact that the models do not well reproduce the topographical features and the land–atmosphere interactions that are important for the variability in that region