Demetris Koutsoyiannis

Demetris Koutsoyiannis
National Technical University of Athens | NTUA · School of Civil Engineering

Civil Engineer, Doctor in Engineering

About

934
Publications
324,730
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15,253
Citations
Introduction
Demetris Koutsoyiannis is professor of Hydrology and Analysis of Hydrosystems in the National Technical University of Athens. He has served as Dean of the School of Civil Engineering, Head of the Department of Water Resources and Environmental Engineering, and Head of the Laboratory of Hydrology and Water Resources Development. He was Editor of Hydrological Sciences Journal for 12 years (2006-18), and member of the editorial boards of Hydrology and Earth System Sciences, Journal of Hydrology and Water Resources Research. He has been awarded the International Hydrology Prize– Dooge medal (2014) by International Association of Hydrological Sciences (IAHS), UNESCO and World Meteorological Organization (WMO), and the Henry Darcy Medal (2009) by European Geosciences Union (EGU).
Additional affiliations
November 2019 - December 2019
University of Bologna
Position
  • Professor
September 2019 - September 2019
Sapienza University of Rome
Position
  • Professor
November 2008 - present
National Technical University of Athens
Position
  • Professor of Hydrology and Analysis of Hydrosystems
Education
January 1983 - September 1988
National Technical University of Athens
Field of study
  • Hydrological Stochastics
October 1973 - July 1978
National Technical University of Athens
Field of study
  • Civil Engineering

Publications

Publications (934)
Article
Full-text available
According to the traditional notion of randomness and uncertainty, natural phenomena are separated into two mutually exclusive components, random (or stochastic) and deterministic. Within this dichotomous logic, the deterministic part supposedly represents cause-effect relationships and, thus, is physics and science (the "good"), whereas randomness...
Article
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Some known results from statistical thermophysics as well as from hydrology are revisited from a different perspective trying: (a) to unify the notion of entropy in thermodynamic and statistical/stochastic approaches of complex hydrological systems and (b) to show the power of entropy and the principle of maximum entropy in inference, both deductiv...
Article
Full-text available
Since “panta rhei” was pronounced by Heraclitus, hydrology and the objects it studies, such as rivers and lakes, have offered grounds to observe and understand change and flux. Change occurs on all time scales, from minute to geological, but our limited senses and life span, as well as the short time window of instrumental observations, restrict ou...
Article
Full-text available
The old principle of parsimonious modelling of natural processes has regained its importance in the last few years. The inevitability of uncertainty and risk, and the value of stochastic modelling in dealing with them, are also again appreciated, after a period of growing hopes for radical reduction of uncertainty. Yet in stochastic modelling of na...
Article
Full-text available
As a result of technological advances in monitoring atmosphere, hydrosphere, cryosphere and biosphere, as well as in data management and processing, several databases have become freely available. These can be exploited in revisiting the global hydrological cycle with the aim, on the one hand, to better quantify it and, on the other hand, to test t...
Article
Full-text available
Streamflow measurements provide valuable hydrological information but, at the same time, are difficult to obtain. For this reason, discharge records of regular intervals are usually obtained indirectly by a stage-discharge rating curve, which establishes a relation between measured water levels to volumetric rate of flow. Rating curves are difficul...
Poster
Full-text available
In this work we apply two different rainfall regionalization techniques over Thessaly region (Greece), an area of about 13,700 km2 with different topographic and climatological characteristics, to estimate design rainfall in ungauged sites. The first methodology is the Patched Kriging technique (Libertino et al., 2018), a year-by-year application o...
Article
Full-text available
Hydroclimatic processes such as precipitation, temperature, wind speed and dew point are usually considered to be independent of each other. In this study, the cross−correlations between key hydrological−cycle processes are examined, initially by conducting statistical tests, then adding the impact of long−range dependence, which is shown to govern...
Article
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The formation of societies is based on the dynamics of spatial clustering, which optimizes economies of scale in the management of the water–energy–food (WEF) nexus. Energy and food are determinant measures of prosperity. Using the WEF nexus as an indicator, we evaluate the social impacts of the current (2022) conflict and in particular the economi...
Article
Full-text available
The identification of the second-order dependence structure of streamflow has been one of the oldest challenges in hydrological sciences, dating back to the pioneering work of H.E Hurst on the Nile River. Since then, several large-scale studies have investigated the temporal structure of streamflow spanning from the hourly to the climatic scale, co...
Presentation
Full-text available
Current-day scholars have rediscovered change and given particular emphasis on climate change. However change has been well known and well studied on philosophical and scientific grounds since the era of Heraclitus and Aristotle. The omnipresence of change is confirmed by modernday geological and paleoclimatic studies. These have provided concrete...
Presentation
Full-text available
Contribution to the Scientific Conference in honour of the Professor Emeritus Gerasimos A. Athanassoulis (School of Naval Engineering of the National Technical University of Athens).
Article
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Environmental determinism is often used to explain past social collapses and to predict the future of modern human societies. We assess the availability of natural resources and the resulting carrying capacity (a basic concept of environmental determinism) through a toy model based on Hurst–Kolmogorov dynamics. We also highlight the role of social...
Article
Full-text available
Uncertainty is inherent in the modelling of any physical processes. Regarding hydrological modelling, the uncertainty has multiple sources including the measurement errors of the stresses (the model inputs), the measurement errors of the hydrological process of interest (the observations against which the model is calibrated), the model limitations...
Data
This report contains Supplementary Information, namely, mathematical derivations, justifications and illustrations, for the paper series Revisiting causality using stochastics (Koutsoyiannis et al., 2022a,b) and in particular its first part, Theory (Koutsoyiannis et al., 2022a). It comprises three sections, namely Relationship of continuous- and di...
Data
This report contains Supplementary Information, namely, mathematical derivations, justifications and illustrations, for the paper series Revisiting causality using stochastics and in particular its second part, Applications (Koutsoyiannis et al., 2022b). It comprises three sections, namely Assessment of uncertainty in the identification of the impu...
Presentation
Full-text available
Κύκνειο μάθημα στο ΕΜΠ πριν τη συνταξιοδότηση [Swan lecture at NTUA before retirement]
Article
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Bluecat is a recently proposed methodology to upgrade a deterministic model (D-model) into a stochastic one (S-model), based on the hypothesis that the information contained in a time series of observations and the concurrent predictions made by the D-model is sufficient to support this upgrade. The prominent characteristics of the methodology are...
Article
Full-text available
In a companion paper, we develop the theoretical background of a stochastic approach to causality with the objective of formulating necessary conditions that are operationally useful in identifying or falsifying causality claims. Starting from the idea of stochastic causal systems, the approach extends it to the more general concept of hen-or-egg c...
Article
Full-text available
Causality is a central concept in science, in philosophy and in life. However, reviewing various approaches to it over the entire knowledge tree, from philosophy to science and to scientific and technological applications, we locate several problems, which prevent these approaches from defining sufficient conditions for the existence of causal link...
Preprint
Full-text available
Bluecat is a recently proposed methodology to upgrade a deterministic model (D-model) into stochastic (S-model), based on the hypothesis that the information contained in a time series of observations and the concurrent predictions by the D-model is sufficient to support this upgrade. Prominent characteristics of the methodology are its simplicity...
Article
Full-text available
Ombrian curves, i.e., curves linking rainfall intensity to return period and time scale, are well-established engineering tools crucial to the design against stormwaters and floods. Though the at-site construction of such curves is considered a standard hydrological task, it is a rather challenging one when large regions are of interest. Regional m...
Article
Full-text available
The newly excavated urban water supply system of the city of ancient Piraeus provides an excellent opportunity for the study and evaluation of the issues of sustainability, adaptability, simplicity and environmental protection, which are of main concern in modern engineering design practices. Well-digging in the area of Pireaus dates back to the ci...
Preprint
Full-text available
Ombrian curves, i.e. curves linking rainfall intensity to return period and time-scale, are well-established engineering tools, crucial to the design against storm waters and floods. Whereas at-site construction of such curves is considered a standard hydrological task, it is a rather challenging one when large regions are of interest. Regional mod...
Article
Full-text available
Impacts to landscapes have been identified as major drivers of social opposition against renewable energy projects. We investigate how the process of mitigating landscape impacts can be improved and accelerated, through a re-conceptualization of visibility analysis. In their conventional format, visibility analyses cannot be implemented in early pl...
Article
Full-text available
Landscape design of major civil infrastructure works has often been undermined as a policy requirement or been neglected in practice. We investigate whether this is justified by technical challenges, high costs or proven lack of utility of landscape design of infrastructure, focussing on dam-design practice. Initially, we investigate global practic...
Article
Full-text available
There is a widespread perception that every year wildfires are intensifying on a global scale, something that is often used as an indicator of the adverse impacts of global warming. However, from the analysis of wildfires that have occurred in the US, Canada, and Mediterranean countries, a trend that justifies this perception could not be identifie...
Article
Full-text available
We present a new method for simulating and predicting hydrologic variables and in particular river flows, which is rooted in the probability theory and conceived in order to provide a reliable quantification of its uncertainty for operational applications. Our approach, which we term with the acronym "Bluecat", results from a theoretical and numeri...
Presentation
Full-text available
Η παρακμή των Δυτικών κοινωνιών αντανακλάται στο έλλειμμα σκέψης, στην κυριαρχία αποχαυνωτικών στερεοτύπων «πολιτικής ορθότητας», και στην αντικατάσταση του ορθολογισμού από τον παραλογισμό. Καίριο παράδειγμα είναι η αποκαλούμενη «κλιματική κρίση», η οποία κηρύχθηκε από το Ευρωπαϊκό Κοινοβούλιο τον Νοέμβριο 2019, ενώ πρόσφατα στην Ελλάδα δημιουργήθ...
Article
Full-text available
Regional estimations of Potential Evapotranspiration (PET) are of key interest for a number of geosciences, particularly those that are water-related (hydrology, agrometeorology). Therefore , several models have been developed for the consistent quantification of different time scales (hourly, daily, monthly, annual). During the last few decades, r...
Chapter
Full-text available
Ombrian curves, i.e. mathematic relationships linking average rainfall intensity to time scale of averaging and return period, also known as IDF (intensity-duration-frequency) curves, are essential tools in hydrology and engineering. Their use is supported by long-term hydrological experience, yet related formulas remain mostly empirical and lack a...
Article
Full-text available
We present a new method for simulating and predicting hydrologic variables with uncertainty assessment and provide example applications to river flows. The method is identified with the acronym “Bluecat" and is based on the use of a deterministic model which is subsequently converted to a stochastic formulation. The latter provides an adjustment on...
Article
Full-text available
The creation of innovative tools, objects and artifacts that introduce abstract ideas in the real world is a necessary step for the evolution process and characterize the creative capacity of civilization. Sculpture is based on the available technology for its creation process and is strongly related to the level of technological sophistication of...
Chapter
Full-text available
The ARCHYTAS platform is based on using (i) reliable mechanical models and damage thresholds for assessing structural performance (ii) a network of sensors for updating the model parameters, (iii) detailed estimates of earthquake and flood hazard at the sites of interest and (iv) a state-of-art approach for multi-hazard risk assessment that can del...
Preprint
Full-text available
This is a working draft of a book in preparation. Current version 0.4 – uploaded on ResearchGate on 25 January 2022. (Earlier versions: 0.3 – uploaded on ResearchGate on 17 January 2022. 0.2 – uploaded on ResearchGate on 3 January 2022. 0.1 (initial) – uploaded on ResearchGate on 1 January 2022.) Some stuff is copied from Koutsoyiannis (2021, http...
Research
Full-text available
Here I make public my reply to the Editor for the rejection of my paper.
Presentation
Full-text available
Lecture notes – Global Classroom – Department of Bioorganic Chemistry – School of Pharmacy – Saarland University Germany – Global Classroom is supported by the DAAD (German Academic Exchange Service)
Article
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The stochastic structures of potential evaporation and evapotranspiration (PEV and PET or ETo) are analyzed using the ERA5 hourly reanalysis data and the Penman–Monteith model applied to the well-known CIMIS network. The latter includes high-quality ground meteorological samples with long lengths and simultaneous measurements of monthly incoming sh...
Research
Full-text available
In our new paper published in journal Entropy in October 2021, we provide insights on the concept of entropy and its relevance to societal and economic issues, with emphasis on wealth. We claim that the concept is widely misunderstood and misused, for example, to support ideologies related to ecological economics and negative Malthusian perspective...
Conference Paper
Full-text available
The seed motivation behind this paper is the realization that time is not given its due as a concept in Civil Engineering. The corresponding education need is expressed with the question "what educational material can stress the importance of time and how can it be produced?". The approach chosen to answer the first part of the question was to juxt...
Article
Full-text available
While entropy was introduced in the second half of the 19th century in the international vocabulary as a scientific term, in the 20th century it became common in colloquial use. Popular imagination has loaded “entropy” with almost every negative quality in the universe, in life and in society, with a dominant meaning of disorder and disorganization...
Presentation
Full-text available
This in an invited talk for the Webinar of the journal Water, entitled “Water Climate Change and Water Resources: Evidence, Impacts, Adaptation (https://water-3.sciforum.net/)”. Its title is “The perpetual change in climate and the technology-augmented human ability of adaptation”. Its subtitle is “Μωραίνει Κύριος ὃν βούλεται ἀπολέσαι (Whom God wis...
Article
Full-text available
The large-scale surface-water monitoring infrastructure for Greece Open Hydrosystem Information Network (Openhi.net) is presented in this paper. Openhi.net provides free access to water data, incorporating existing networks that manage their own databases. In its pilot phase, Openhi.net operates three telemetric networks for monitoring the quantity...
Article
Full-text available
The stochastic analysis in the scale domain (instead of the traditional lag or frequency domains) is introduced as a robust means to identify, model and simulate the Hurst–Kolmogorov (HK) dynamics, ranging from small (fractal) to large scales exhibiting the clustering behavior (else known as the Hurst phenomenon or long-range dependence). The HK cl...
Data
Version 1 of our paper “Entropy and Wealth” received three anonymous reviews and an additional assessment by an anonymous Academic Editor. Based on them, the paper thankfully received a decision for publication in the journal Entropy after major revisions. As seen below, where all review material is reproduced, the opinions about the paper cover th...
Preprint
Full-text available
We present a new method for simulating and predicting hydrologic variables with uncertainty assessment and provide example applications to river flows. The method is identified with the acronym "Bluecat" and is based on the use of a deterministic model which is subsequently converted to a stochastic formulation. The latter provides an adjustment on...
Article
Full-text available
We outline and test a new methodology for genuine simulation of stochastic processes with any dependence structure and any marginal distribution. We reproduce time dependence with a generalized, time symmetric or asymmetric, moving-average scheme. This implements linear filtering of non-Gaussian white noise, with the weights of the filter determine...
Preprint
Full-text available
While entropy was introduced in the second half of the 19th century in the international vocabulary as a scientific term, in the 20th century it became common in colloquial use. Popular imagination has loaded “entropy” with almost every negative quality in the universe, in life and in society, with a dominant meaning of disorder and disorganization...
Article
Full-text available
Water, energy, land, and food are vital elements with multiple interactions. In this context, the concept of a water-energy-food (WEF) nexus was manifested as a natural resource management approach, aiming at promoting sustainable development at the international, national, or local level and eliminating the negative effects that result from the us...
Article
Full-text available
Near-surface air temperature is one of the most widely studied hydroclimatic variables, as both its regular and extremal behaviors are of paramount importance to human life. Following the global warming observed in the past decades and the advent of the anthropogenic climate change debate, interest in temperature’s variability and extremes has been...
Chapter
Humanity has been modifying the natural water cycle by building large-scale water infrastructure for millennia. For most of that time, the principles of hydraulics and control theory were only imperfectly known. Moreover, the feedback from the artificial system to the natural system was not taken into account, either because it was too small to not...
Presentation
Full-text available
In the frame of the 2021 World Environmental & Water Resources Congress, Virtual Online, organized by the American Society of Civil Engineers, the Session 5-4 was a Panel Session entitled "Advancing New Methods for the Treatment of Climate Change and Extreme Events". The following scientists constituted the panel, while the audience made comments a...
Preprint
Full-text available
We outline and test a new methodology for genuine simulation of stochastic processes with any dependence and any marginal distribution. We reproduce time dependence with a generalized, time symmetric or asymmetric, moving-average scheme. This implements linear filtering of non-Gaussian white noise, with the weights of the filter determined by analy...
Article
Full-text available
Whilst hydrology is a Greek term, it was not in use in the Classical literature, but much later, during the Renaissance, in its Latin form, hydrologia. On the other hand, Greek natural philosophers (or, in modern vocabulary, scientists) created robust knowledge in related scientific areas, to which they gave names such as meteorology, climate and h...
Data
This supplement provides material supporting the analyses and conclusions of the main paper and comprises four sections: S1. On the human teeth problem and the debate of Russell and Aristotle S2. Modern imaginative explanations of the Nile floods S3. The appearance of the term hydrology S4. Original texts of the quotations translated in the artic...
Article
Lacking coastal and offshore wind speed time series of sufficient length, reanalysis data and wind speed models serve as the primary sources of valuable information for wind power management. In this study, long-length observational records and modelled data from Uncertainties in Ensembles of Regional Re-Analyses system are collected, analyzed and...
Presentation
Full-text available
Changes in the land cover occur all the time at the surface of the Earth both naturally and anthropogenically. In the last decades, certain types of land cover change, including urbanization, have been correlated to local temperature increase, but the general dynamics of this relationship are still not well understood. This work examines whether la...
Conference Paper
Full-text available
Since the pre-industrial era at the end of the 18th century, the atmospheric carbon dioxide concentration (CO2) has increased by 47.46% from the level of 280 ppmv (parts per million volume) to 412.89 ppmv (Mauna Loa – NOAA Station, November 2020). These increased concentrations caused by natural & anthropogenic activities, interact with the aquatic...
Presentation
Full-text available
Curves of rainfall intensity at various scales and for various return periods, else known as ombrian (or IDF) curves, are central design tools in hydrology and engineering. Construction of such curves often relies heavily on empirical or semi-empirical approaches, which hinder their applicability over large scales, and preclude simulation. Recent w...
Conference Paper
Full-text available
The storage-reliability-yield (SRY) relationship is a well-established tool for preliminary design of reservoirs fulfilling consumptive water uses, yet rarely employed within hydropower planning studies. Here, we discuss the theoretical basis for representing the trade-offs between reservoir size and expected revenues from hydropower production, un...
Presentation
Full-text available
Probabilistic hydrological modelling methodologies often comprise two-stage post-processing schemes, thereby allowing the exploitation of the information provided by conceptual or physically-based rainfall-runoff models. They might also require issuing an ensemble of rainfall-runoff model simulations by using the rainfall-runoff model with differen...
Presentation
Full-text available
In the last few years, the island of Crete (Greece - Eastern Mediterranean) has been affected by extreme events. In recent decades, hydrometeorological processes in the island of Crete are monitored by an extensive network of meteorological stations. Here we stochastically analyze the spatial stochastic structure of precipitation in the island by e...
Book
Full-text available
Much is said and written about hydroclimatic hazards: storms, floods, droughts. Such hazards have existed and will always exist, while the usual scaremongering on them is of little help to avoid them. Instead, what is needed is a cool look at risk, based on measurement data, using scientific methodology, and ultimately employing technology in the s...
Article
Full-text available
Since prehistoric times, water conflicts have occurred as a result of a wide range of tensions and/or violence, which have rarely taken the form of traditional warfare waged over water resources alone. Instead, water has historically been a (re)source of tension and a factor in conflicts that start for other reasons. In some cases, water was used d...
Article
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We investigate the impact of time's arrow on the hourly streamflow process. Although time asymmetry, i.e., temporal irreversibility, has been previously implemented in stochastics, it has only recently attracted attention in the hydrological literature. Relevant studies have shown that the time asymmetry of the streamflow process is manifested at s...
Method
Full-text available
All required equations for quantifying the presence of water vapour in the atmosphere are gathered in one page. They are physically consistent and accurate, and mathematically easy to use for meteorological and hydrological applications. Physical and mathematical details are given in two Appendices.