61 research outputs found

    Evaluation of downscaled DEMETER multi‐model ensemble seasonal hindcasts in a northern Italy location by means of a model of wheat growth and soil water balance

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    In this paper we explore the new possibilities for early crop yield assessment at the local scale arising from the availability of dynamic crop growth models and of downscaled multi-model ensemble seasonal forecasts.We compare the use of the latter with other methods, based on crop growth models driven by observed climatic data only. The soil water balance model developed and used at ARPA Emilia-Romagna (CRITERIA) was integrated with crop growth routines from the model WOFOST 7.1. Some validation runs were first carried out and we verified with independent field data that the new integrated model satisfactorily simulated above-ground biomass and leaf area index. The model was then used to test the feasibility of using downscaled multi-model ensemble seasonal hindcasts, coming from the DEMETER European research project, in order to obtain early (i.e. 90, 60 and 30 d before harvest) yield assessments for winter wheat in northern Italy. For comparison, similar runs with climatology instead of hindcasts were also carried out. For the same purpose, we also produced six simple linear regression models of final crop yields on within season (end of March, April and May) storage organs and above-ground biomass values. Median yields obtained using downscaled DEMETER hindcasts always outperformed the simple regression models and were substantially equivalent to the climatology runs, with the exception of the June experiment, where the downscaled seasonal hindcasts were clearly better than all other methods in reproducing the winter wheat yields simulated with observed weather data. The crop growth model output dispersion was almost always significantly lower than the dispersion of the downscaled ensemble seasonal hindcast used as input for crop simulations

    Development of a European Multi-Model Ensemble System for Seasonal to Inter-Annual Prediction (DEMETER)

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    A multi-model ensemble-based system for seasonal-to-interannual prediction has been developed in a joint European project known as DEMETER (Development of a European Multimodel Ensemble Prediction System for Seasonal to Interannual Prediction). The DEMETER system comprises seven global atmosphere–ocean coupled models, each running from an ensemble of initial conditions. Comprehensive hindcast evaluation demonstrates the enhanced reliability and skill of the multimodel ensemble over a more conventional single-model ensemble approach. In addition, innovative examples of the application of seasonal ensemble forecasts in malaria and crop yield prediction are discussed. The strategy followed in DEMETER deals with important problems such as communication across disciplines, downscaling of climate simulations, and use of probabilistic forecast information in the applications sector, illustrating the economic value of seasonal-to-interannual prediction for society as a whole

    Culture and low-carbon energy transitions

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    How does culture influence low-carbon energy transitions? How can insights about cultural influences guide energy planners and policymakers trying to stimulate transitions, particularly at a time of rapid technological change? This Review examines the influence of culture on a selection of low-carbon technologies and behavioural practices that reflect different dimensions of sustainability. Based on a typology of low-carbon technology and behaviour, we explore the cultural dimensions of four specific cases: eco-driving, ridesharing, automated vehicles and whole-house retrofits. We conclude with recommendations for those seeking to analyse, understand, develop, demonstrate and deploy low-carbon innovations for sustainable energy transitions

    Witnessing the quantumness of a system by observing only its classical features

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    Quantum mechanics: witnessing quantumness by observing only classical features Witnessing quantum-like features of systems whose dynamics is not completely specified is a central problem in physics. For example, one wants to test whether a macroscopic system, such as a living system, obeys quantum theory, or whether the gravitational field displays quantum effects. Here, scientists for UK propose a thought experiment that witnesses non-classicality of a physical system by probing it with a qubit, without having to assume any specific dynamics on the physical system. This experiment does not require any quantum control of the system, involving only measuring a single classical observable on it. That non-classicality of a system can be established indirectly, by coupling it to a qubit, opens up exciting possibilities, for example that quantum gravitational effects might be witnessed in the lab

    Evolution without evolution and without ambiguities

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    In quantum theory it is possible to explain time, and dynamics, in terms of entanglement. This is the timeless approach to time, which assumes that the universe is in a stationary state, where two noninteracting subsystems, the "clock" and the "rest," are entangled. As a consequence, by choosing a suitable observable of the clock, the relative state of the rest of the universe evolves unitarily with respect to the variable labeling the clock observable's eigenstates, which is then interpreted as time. This model for an "evolution without evolution" (Page and Wootters, 1983), albeit elegant, has never been developed further, because it was criticized for generating severe ambiguities in the dynamics of the rest of the universe. In this paper we show that there are no such ambiguities; we also update the model, making it amenable to possible new applications
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