88 research outputs found
A stochastic model for the hourly solar radiation process for application in renewable resources management
Since the beginning of the 21st century, the scientific
community has made huge leaps to exploit renewable energy sources, with solar
radiation being one of the most important. However, the variability of solar
radiation has a significant impact on solar energy conversion systems, such
as in photovoltaic systems, characterized by a fast and non-linear response
to incident solar radiation. The performance prediction of these systems is
typically based on hourly or daily data because those are usually available
at these time scales. The aim of this work is to investigate the stochastic
nature and time evolution of the solar radiation process for daily and hourly
scale, with the ultimate goal of creating a new cyclostationary stochastic
model capable of reproducing the dependence structure and the marginal
distribution of hourly solar radiation via the clearness index KT.</p
HESS Opinions: "Climate, hydrology, energy, water: recognizing uncertainty and seeking sustainability"
Since 1990 extensive funds have been spent on
research in climate change. Although Earth Sciences, including
climatology and hydrology, have benefited significantly,
progress has proved incommensurate with the effort
and funds, perhaps because these disciplines were perceived
as “tools” subservient to the needs of the climate change enterprise
rather than autonomous sciences. At the same time,
research was misleadingly focused more on the “symptom”,
i.e. the emission of greenhouse gases, than on the “illness”,
i.e. the unsustainability of fossil fuel-based energy production.
Unless energy saving and use of renewable resources
become the norm, there is a real risk of severe socioeconomic
crisis in the not-too-distant future. A framework for drastic
paradigm change is needed, in which water plays a central
role, due to its unique link to all forms of renewable energy,
from production (hydro and wave power) to storage (for
time-varying wind and solar sources), to biofuel production
(irrigation). The extended role of water should be considered
in parallel to its other uses, domestic, agricultural and
industrial. Hydrology, the science of water on Earth, must
move towards this new paradigm by radically rethinking its
fundamentals, which are unjustifiably trapped in the 19thcentury
myths of deterministic theories and the zeal to eliminate
uncertainty. Guidance is offered by modern statistical
and quantum physics, which reveal the intrinsic character of
uncertainty/entropy in nature, thus advancing towards a new
understanding and modelling of physical processes, which is
central to the effective use of renewable energy and water
resources
Calculation of potential solar radiation from geomorphologic information for snow melting estimation
Some results on rainfall modelling - Univariate versus multivariate stochastic modelling of rainfall
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