Dear Colleagues,

Phenomena or processes observed within the hydrological cycle span across a hierarchy of spatio-temporal scales and show inherently multi-physics characteristics and complexity. Their phenomenology challenges our ability and competency in analysing, modelling, predicting and forecasting their behaviour in various engineering applications.

Due to their inherent multi-dimensionality across different spatial and temporal scales, phenomena associated with physical systems of the hydrological cycle are endowed with multiple degrees of freedom. In that context, the conventional description, through systems of balance equations compiled with constitutive relations, does not suffice to solve problems in predicting the evolution of such phenomena or processes. Balances can only restrict unrealistic solutions. Entropy principles, e.g., extremization or variational principles, Bayesian inference methodological approaches, consideration of the different scales of entropy (thermal, configurational), etc., provide a useful tool for tapping into the structure (geometry) of the ensemble of physically admissible solutions and in managing the associated high degree of complexity that leads to high uncertainty and variability—an inherent characteristic of hydrologic systems. One challenge is to cope with redundant or non-essential multi-dimensionality without preventing model correctness and trueness (make it simple but not too simple).

This Special Issue aims to compile current research efforts implementing entropy and/or information theory concepts and tools in addressing open, persistent or new problems in water engineering, associated with phenomena and processes within the hydrological cycle (such as wind speed, air pressure, humidity, temperature, evaporation, precipitation, surface water, groundwater, soil moisture, streamflow) and/or within the related fields, including geosciences, energy harvesting from renewable resources (wind, sun, water, flora), energy management /energy security, sustainability, etc.

Indicative applications, associated with sustainability, water security and energy transition, are: operation of urban networks, resilience of water infrastructure systems, irrigation, soil remediation, aquifer replenishment, water–energy nexus, pumped storage techniques, optimized use of water and renewable resources in combined cycles of energy harvesting and buffering (such as wind farms, hydro energy cycles, green hydrogen), etc.; the list is not exhaustive.

The ambition of this Special Issue is to provide an e-podium for researchers to present their recent work in applications of entropy to the modelling and simulation of the complex phenomena associated with the hydrological cycle. We are particularly interested in soliciting manuscripts presenting new attempts to integrate and exploit the various entropy formulations, in addressing environmental and water engineering problems associated with the hydrological cycle and even beyond, in the broader field of geosciences.

Dr. Panayiotis Dimitriadis
Prof. Dr. Marios Valavanides
Prof. Dr. Demetris Koutsoyiannis
Guest Editors

Manuscript Submission Information

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• Entropy
• water engineering
• hydrologic cycle
• water resources
• renewables
• energy security
• sustainability