Spyros Paparrizos | Wageningen University and Research Centre (original) (raw)

Papers by Spyros Paparrizos

The current study describes a technique for downscaling climatological data in areas with limited... more The current study describes a technique for downscaling climatological data in areas with limited or no grid data. In cases where grid data are unavailable and the researcher is called to operate on a regional or in the mesoscale and produce detailed and not coarse results, this technique can be a helping hand. It constitutes a combination of statistical downscaling through multi-linear regression techniques and dynamical downscaling by employing Geographical Information Systems, and it can be used in order to spatially interpolate with high resolution various climatological variables. The application of the described technique was applied on 3 agricultural areas that present different climate conditions and are characterised by complex topography. The results indicated that the current technique delivered very sufficient results as the adjusted coefficient (R 2) appears with high values in almost every case. Areas characterized by Mediterranean type of climate with hot summers (Csa) showed the strongest presumption against null hypothesis; while areas characterized by a combination of different Mediterranean climate types (Csa and Csb) used the most coefficients in the multi-linear procedure and produced relatively good results. Areas facing continental climate conditions delivered satisfactorily results, although most of the examined coefficients are presented with medium presumption against null hypothesis. Concluding, the described technique can be used for every type of climate in almost every terrain for the accurate representation of various climatological variables in the mesoscale.

Estimation of drought in a certain temporal and spatial scale is crucial in climate change studie... more Estimation of drought in a certain temporal and spatial scale is crucial in climate change studies. The current study targets on three agricultural areas widespread in Greece, Ardas River Basin in Northeastern Greece, Sperchios River Basin in Central Greece, and Geropotamos River Basin in Crete Island in South Greece that are characterized by diverse climates as they are located in various regions. The objective is to assess the spatiotemporal variation of drought conditions prevailing in these areas. The Standardized Precipitation Index (SPI) was used to identify and assess the present and future drought conditions. Future simulated data were derived from a number of Regional Climatic Models (RCMs) from the ENSEMBLES European Project. The analysis was performed for the future periods of 2021–2050 and 2071–2100, implementing A1B and B1 scenarios. The spatial analysis of the drought conditions was performed using a combined downscaling technique and the Ordinary Kriging. The Mann-Kendall test was implemented for trend investigation. During both periods and scenarios, drought conditions will tend to be more severe in the upcoming years. The decrease of the SPI values in the Sperchios River Basin is expected to be the strongest, as it is the only study area that will show a negative balance (in SPI values), regarding the drought conditions. For the Ardas and the Geropotamos River Basins, a great increase of the drought conditions will occur during the 2021–2050 period, while for 2071–2100 period, the decrease will continue but it will be tempered. Nevertheless, the situation in all study areas according to the SPI classification is characterized as “Near-normal”, in terms of drought conditions.

The determination of heat requirements in the first developing phases of plants has been express... more The determination of heat requirements in the first developing phases of plants has been expressed as Growing Degree Days (GDD). The current study focuses on three selected study areas in Greece that are characterised by different climatic conditions due to their location and aims to assess the future variation and spatial distribution of Growing Degree Days (GDD) and how these can affect the main cultivations in the study areas. Future temperature data were obtained and analyzed by the ENSEMBLES project. The analysis was performed for the future periods 2021-2050 & 2071-2100 with the A1B and B1 scenarios. Spatial distribution was performed using a combination of dynamical and statistical downscaling technique through ArcGIS 10.2.1.
The results indicated that for all the future periods and scenarios, the GDD are expected to increase. Furthermore, the increase in the Sperchios River basin will be the highest, followed by the Ardas and the Geropotamos River basins. Moreover, the cultivation period will be shifted from April-October to April-September which will have social, economical and environmental benefits. Additionally, the spatial distribution indicated that in the upcoming years the existing cultivations can find favourable conditions and can be expanded in mountainous areas as well. On the other hand, due to the rough topography that exists in the study areas, the wide expansion of the existing cultivations into higher altitudes is unaffordable. Nevertheless, new, more profitable cultivations can be introduced which can find propitious conditions in terms of GDD.

Assessment of aridity conditions prevailing in a certain area is essential for the research on cl... more Assessment of aridity conditions prevailing in a certain area is essential for the research on climate and climate change. Greece is characterized by a variety of climatic conditions such as drought conditions or flooding phenomena. The current study focuses on three selected areas within Greece that present different climatic characteristics due to their location and aims to analyze and compare the aridity conditions prevailing in these areas. Aridity conditions were estimated using the Aridity Index (AI). Mann-Kendall test was applied to investigate possible trends. Spatial distribution of aridity conditions was performed using multi-linear regression techniques and Kriging method within ArcGIS 10.2.1. The results indicated that the study areas face humid conditions, mostly due to the existence of high altitudes. Furthermore, the various climatic conditions are responsible for differentiations in seasonal analysis regarding the aridity conditions. The study areas related to the Mediterranean climate resulted more heterogeneous conditions compared with areas affected by the continental climate. Nevertheless, the created aridity spatial maps of trend analysis presented with differentiations, especially in the mountainous areas were an extreme downward trend is appeared. For the southern investigated area in Crete Island characterized purely by Mediterranean climate, the results were more moderate in terms of aridity conditions.

Potential evapotranspiration (PET) is one of the most critical parameters in the research on agro... more Potential evapotranspiration (PET) is one of the most critical parameters in the research on agro-ecological systems. The computational methods for the estimation of PET vary in data demands from very simple (empirically based), requiring only information based on air temperatures, to complex ones (more physically based) that require data on radiation, relative humidity, wind speed, etc. The current research is focused on three study areas in Greece that face different climatic conditions due to their location. Twelve PET formulae were used, analyzed and inter-compared in terms of their sensitivity regarding their input coefficients for the Ardas River basin in northeastern Greece, Sperchios River basin in Central Greece and Geropotamos River basin in South Greece. The aim was to compare all the methods and conclude to which empirical PET method(s) better represent the PET results in each area and thus should be adopted and used each time and which factors influence the results in each case. The results indicated that for the areas that face Mediterranean climatic conditions, the most appropriate method for the estimation of PET was the temperature-based, Hamon's second version (PET Ham2). Furthermore, the PET Ham2 was able to estimate PET almost similarly to the average results of the 12 equations. For the Ardas River basin, the results indicated that both PET Ham2 and PET Ham1 can be used to estimate PET satisfactorily. Moreover, the temperature-based equations have proven to produce better results, followed by the radiation-based equations. Finally, PET ASCE , which is the most commonly used PET equation, can also be applied occasionally in order to provide satisfactory results.

Assessment of future precipitation variations prevailing in an area is essential for the research... more Assessment of future precipitation variations prevailing in an area is essential for the research regarding climate and climate change. The current paper focuses on 3 selected areas in Greece that present different climatic characteristics due to their location and aims to assess and compare the future variation of annual and seasonal precipitation. Future precipitation data from the ENSEMBLES anthropogenic climate-change (ACC) global simulations and the Climate Local Model (CLM) were obtained and analyzed. The climate simulations were performed for the future periods 2021-2050 and 2071-2100 under the A1B and B1 scenarios. Mann-Kendall test was applied to investigate possible trends. Spatial distribution of precipitation was performed using a combination of dynamic and statistical downscaling technique and Kriging method within ArcGIS 10.2.1.
The results indicated that for both scenarios, reference periods and study areas, precipitation is expected to be critically decreased. Additionally, Mann-Kendall test application showed a strong downward trend for every study area. Furthermore, the decrease in precipitation for the Ardas River basin characterised by the continental climate will be tempered, while in the Sperchios River basin it will be smoother due to the influence of some minor climatic variations in the basins' springs in the highlands where milder conditions occur. Precipitation decrease in the Geropotamos River basin which is characterized by Mediterranean climate will be more vigorous. B1 scenario is appeared more optimistic for the Ardas and Sperchios River basins, while in the Geropotamos River basin, both applied scenarios brought similar results, in terms of future precipitation response.

In the past decades, vulnerability assessment has emerged as an important field of research in fl... more In the past decades, vulnerability assessment has emerged as an important field of research in flood risk management, in particular with respect to climate change and necessary adaptation strategies for the society. Probably starting with Chamber’s seminal article on vulnerability, coping and policy (Chambers 1989), and further developed as the causal structure of vulnerability by Bohle (2001) and others, at least two research paradigms exist: an internal side focusing on societal resilience and coping capacities, and an external side targeted at a reduction of negative effects in terms of loss reduction (Fuchs 2009). Despite considerable research effects, however, different definitions and concepts still dominate the debate; it is surely that different scientific disciplines are working with this term: natural scientists, engineers, social scientists or economists, to name just a few.
Each discipline defines vulnerability in a way which fits to their disciplinary purposes (Fuchs et al. 2011). But why has there been so little progress in our ability to adapt to flood hazards? White et al. (2001) summarised this paradox in an article with the title “Knowing better and losing even more – the use of knowledge in hazard management”. One of the fundamental reasons for the lack of progress is the continuing separation of research on natural processes and socio-economic processes without considering interaction between these systems (Fuchs
& Keiler 2013), as well as between scientific research results and the policy implementation (Medd & Marvin 2005). Moreover, as many studies were focused on the vulnerability of least developed societies to natural hazards (O’Brien et al. 2008), there is a particular lack in studies targeted at an implementation of existing adaptation frameworks at the level of highly-developed countries (Field et al. 2012; Scolobig et al. 2012). This gap results in a challenge for attempts to develop formal models into practical application and policy implementation.
This paper examines the private adaptation capacity and willingness in two different catchments in the Mediterranean.
The catchments Evros and Rafina in Greece were affected by flood events during the past 20 years.
However, even in case of extreme events, the vulnerability of the (social) system to stress is considerably low due to social networks, economic settings as well as institutional and political factors, and consequently the speed of return to the equilibrium steady state, defined as the prevailing livelihood conditions, is fast. In other words, even if the magnitude of a hazardous event is high, the vulnerability is considerably low due to multiple compensation mechanisms installed in the Greek society, ranging from spreading risk to a larger community to governmental compensation and private donation. Therefore, ex-post recovery following an event is well-organised, and the initial systems state is re-established immediately or with only little delay. Therefore, affected citizens simply do not care much about being affected by floods, will be able to prevent those damages. There are no incentives for
the affected population to react pro-active by e.g. investing in local structural protection or any other management strategy.

Evapotranspiration is an important component of the hydrologic cycle as it can significantly affe... more Evapotranspiration is an important component of the hydrologic cycle as it can significantly affect the water
budget of the natural (i.e. approximately 62% of all precipitation falling on land is evapotranspirated). In the
current study, a sensitivity analysis of various PET formulas was performed for the Crete Island in southern
Greece in order to evaluate the influence of the various coefficients in the estimation of PET. Results indicated that
some PET formulas perform more accurate results than others. Specifically, the PET equation after Jensen-Haise
(PETJen) that is based on mean air temperature (Tmean) and solar radiation (Rs) input data and the 1st version of
Hamon (PETHam1) that uses min (Tmin), mean (Tmean), max (Tmax) air temperature data and Day Length (DL)
input data during the sensitivity analysis indicated that they can be used in order to estimate with high accuracy
the potential evapotranspiration in Crete Island.

The MIKE SHE model is able to simulate the entire stream flow which includes direct and basic fl... more The MIKE SHE model is able to simulate the
entire stream flow which includes direct and basic flow.
Many models either do not simulate or use simplistic
methods to determine the basic flow. The MIKE SHE
model takes into account many hydrological data. Since
this study was directed towards the simulation of surface
runoff and infiltration into saturated and unsaturated zone,
the MIKE SHE is an appropriate model for reliable conclusions.
In the current research, the MIKE SHE model
was used to simulate runoff in the area of Sperchios River
basin. Meteorological data from eight rainfall stations
within the Sperchios River basin were used as inputs.
Vegetation as well as geological data was used to perform
the calibration and validation of the physical processes of
the model. Additionally, ArcGIS program was used. The
results indicated that the model was able to simulate the
surface runoff satisfactorily, representing all the hydrological
data adequately. Some minor differentiations appeared
which can be eliminated with the appropriate
adjustments that can be decided by the researcher0s
experience.

The role of Spatial Data Infrastructures (SDIs) plays a very important part in improving electron... more The role of Spatial Data Infrastructures (SDIs) plays a very important part in improving
electronic governance in Greece. Following the INSPIRE Directive, the European Parliament
and Council for the creation of infrastructure for geospatial data in the European community
began making slow but steady progress in 2007 in Greece towards creating geoportals that
will meet the needs of those interested in acquiring geospatial information and data.
In the current paper, a reference to geoportals providing the necessary geodata is provided
concerning the completion of hydrological projects in Greece. A brief description of the
framework conditions in Europe on this subject and an assessment of Greek geoportals are
presented following scrutiny and the use of available geospatial data. Additionally, some
suggestions are given for future improvements aimed at further development. In short, the
current work reveals the need for collaboration between the existing geoportal providers in
the creation of a common bank consisting of geospatial data and geo-information, where all
the necessary geo-spatial data can be uploaded, verified and made available to potential
users.

Στόχος του παρόντος βιβλίου είναι να επικεντρωθεί στις πληροφορίες του νερού που προέρχονται από ... more Στόχος του παρόντος βιβλίου είναι να επικεντρωθεί στις πληροφορίες του νερού που προέρχονται από τις παρατηρήσεις της γης και τα λογισμικά, τα συστήματα και τις τεχνολογίες για τη βελτίωση της μοντελοποίησης των πληροφοριών για τους υδατικούς πόρους, την ανάλυση, την οπτικοποίηση και την κοινή χρήση τους.

Απευθύνεται κυρίως στους προπτυχιακούς και μεταπτυχιακούς φοιτητές που διδάσκονται το μάθημα της υδρογεωπληροφορικής καθώς και σε επιστήμονες που αναζητούν στοχευόμενες λύσεις στα προβλήματα της υδρολογίας, της υδραυλικής και περιβαλλοντικής μηχανικής για την αειφορική διαχείριση των υδάτων με τη χρήση μοντέλων προσομοίωσης και πληροφορικής.

Οι αναγνώστες θα εξοικειωθούν με τα μοντέλα που εφαρμόζονται σε συστήματα με βάση το νερό, θα αναπτύξουν βασικές δεξιότητες και ικανότητες στην διαχείριση των υδάτων χρησιμοποιώντας τα σημαντικότερα υδρολογικά μοντέλα αξιοποιώντας τα γεωγραφικά συστήματα πληροφοριών καθώς και διάφορα συστήματα πληροφόρησης και στήριξης αποφάσεων.

Η Υδρογεωπληροφορική προέρχεται από τη σύζευξη των 3 λέξεων: της υδρολογίας, της γης και της πληροφορικής και εύκολα καταλαβαίνει κανείς ότι αφορά ένα έντονα διεπιστημονικό πεδίο, το οποίο συνδέει το νερό και τα περιβαλλοντικά προβλήματα με διάφορες υπολογιστικές μεθόδους μοντελοποίησης και τις ραγδαία αναπτυσσόμενες τεχνολογίες της χωρικής πληροφορίας, των συστημάτων στήριξης αποφάσεων και της επικοινωνίας.

Το βιβλίο αυτό περιλαμβάνει 12 Κεφάλαια. Η ιδιαιτερότητά του είναι ότι σε κάθε κεφάλαιο πέρα από το θεωρητικό κομμάτι περιλαμβάνει αναλυτικά παραδείγματα για κάθε εφαρμογή που αποτελούν ένα πλήρη οδηγό για όποιον τα εφαρμόσει.

Το 1ο κεφάλαιο περιλαμβάνει μια εισαγωγή στην ορολογία και τους στόχους που πραγματεύεται το συγκεκριμένο βιβλίο καθώς και τους τρόπους και τα μέσα που θα χρησιμοποιηθούν προς την κατεύθυνσης της επίτευξης των συγκεκριμένων στόχων.

Το 2ο κεφάλαιο αναφέρεται στα δεδομένα (προέλευση και δομή) που χρησιμοποιούνται ως δεδομένα εισόδου (input data) προκειμένου να επιτευχθούν οι διάφορες υδρολογικές λειτουργίες.

Στο 3ο κεφάλαιο περιγράφεται η αναλυτικά η διαδικασία του ελέγχου ομοιογένειας των μετεωρολογικών δεδομένων καθώς επίσης και η συμπλήρωση και επέκταση αυτών των χρονοσειρών.

Το 4ο κεφάλαιο αποτελεί ένα λεπτομερή οδηγό δημιουργίας επιφανειών με τη χρήση των γεωγραφικών συστημάτων πληροφοριών και γεωστατικών μεθόδων δημιουργίας επιφανειών.

Το 5ο κεφάλαιο αναδεικνύει την σημαντικότητα της διακριτικής ικανότητας (ανάλυσης) και γενικά της χωρικής μεταβλητότητας της κατά τη χρησιμοποίηση της σαν δεδομένο εισόδου στις διάφορες υδρολογικές διαδικασίες.

Στο 6ο κεφάλαιο γίνεται μοντελοποίηση της εξατμισοδιαπνοής με τη χρησιμοποίηση πληροφοριακών συστημάτων.

Στο 7ο κεφάλαιο γίνεται μοντελοποίηση της διήθησης σε συνδυασμό με διάφορες διαφορικές εξισώσεις.

Στο 8ο κεφάλαιο γίνεται μια αναφορά στην υδραυλική τραχύτητα και στους τρόπους υπολογισμού της.

Στο 9ο κεφάλαιο γίνεται αναφορά στη μοντελοποίηση διάφορων υδρολογικών διαδικασιών με τη χρησιμοποίηση του εργαλείου ArcHydro και του προγράμματος ArcGIS.

Στο 10ο κεφάλαιο περιλαμβάνει μια λεπτομερή αναφορά στη μη αυτόματη υδρολογική μοντελοποίηση μέσω του προγράμματος ArcGIS σε επίπεδο λεκάνης απορροής.

Το 11ο κεφάλαιο περιλαμβάνει τη μοντελοποίηση του μοναδιαίου υδρογραφήματος με το συνδυασμό της μεθόδου του Clarke και τη χρήση των Γ.Σ.Π..

Στο 12ο κεφάλαιο παρουσιάζεται το πληροφοριακό σύστημα ολοκληρωμένης μελέτης διευθέτησης λεκανών απορροής Torrential-MIK, ένα λογισμικό που αναπτύχθηκε από το Εργαστήριο Διευθέτησης Ορεινών Υδάτων και Διαχείρισης Κινδύνου του Τμήματος Δασολογίας και Διαχείρισης Περιβάλλοντος & Φυσικών Πόρων του Δημοκρίτειου Πανεπιστημίου Θράκης, ενώ τέλος παρουσιάζονται εκτενή παραδείγματα που αφορούν το συγκεκριμένο λογισμικό.

English summary

The aim of this current book is to focus on the water information derived from the observations of the earth as long as the various software, systems and technologies to improve the modeling of information on the water resources, their analysis, visualization and their shared use.

The book addresses to all the undergraduate and graduate students who are being taught the lesson of “Hydrogeoinformatics” as long as scientists who seek for targeted solutions regarding problems that refer to hydrology, hydraulics and environmental engineering for sustainable water management using modeling
and software simulations.

Potential readers will become familiar with models applicable to systems based on water, will develop key skills as long as skills in water management using the major hydrological models, utilizing geographic information systems and various information systems and decision support systems.

Hydrogeoinformatics originates from the coupling of three words: hydrology, geo (earth) and informatics and that makes it easy for someone to understand that it refers to a strongly interdisciplinary field, which links water and environmental problems with various computational modeling methods and the rapidly developing technologies of spatial information systems, decision support systems and communication systems.

This book includes 12 chapters. Its specificity is that each chapter beyond the theoretical part includes detailed examples for each application. These examples constitute a complete guide for those who will apply the given procedures.

The 1st chapter includes an introduction to the terminology and objectives dealt within this book as well as the ways and means that are used towards the achievement of the specific targets.

The 2nd chapter refers to the data (sources and structure) that are used as input data in order to achieve the various hydrological functions.

Chapter 3 describes in detail the process of homogeneity test for the meteorological data as well as the filling and the extension of the data series.

Chapter 4 constitutes a detailed guide to create surfaces with the use of geographical information systems and surfaces generation geostationary methods.

The 5th chapter highlights the importance of the resolution and generally the spatial variability while using it as input to the various hydrological processes.

Chapter 6 analyses the modeling of the evapotranspiration using information systems, chapter 7 describes the modeling of filtration in combination with various differential equations, while chapter 8 shortly describes the method for calculation of the hydraulic roughness.

Chapter 9 refers to various hydrological modeling procedures performed by using the ArcHydro tool, an extension from ArcGIS program, while chapter 10 includes a detailed guide in manual hydrological modeling through the ArcGIS program in a basin scale.

Chapter 11 includes the modeling of the unit hydrograph combining the method of Clarke and the use of geographical information systems.

Chapter 12 presents the integrated information system for the management of waterbasins, Torrential-MIK, software that was developed from the laboratory of mountainous watersheds and risk management, department of Forestry and management of the environment and the natural resources, Democritus University of Thrace, while in the second part of this chapter detailed examples that refer to the software are presented.

A method for supporting an operational regional risk and vulnerability analysis for hydrological ... more A method for supporting an operational regional risk and vulnerability analysis for hydrological hazards is sug-gested and applied in the Island of Cyprus. The method aggregates the output of a hydrological flow model forced by observed temperatures and precipitations, with observed discharge data. A scheme supported by observed dis-charge is applied for model calibration. A comparison of different calibration schemes indicated that the same model parameters can be used for the entire country. In addition, it was demonstrated that, for operational pur-poses, it is sufficient to rely on a few stations. Model parameters were adjusted to account for land use and thus for vulnerability of elements at risk by comparing observed and simulated flow patterns, using all components of the hydrological model. The results can be used for regional risk and vulnerability analysis in order to increase the resilience of the affected population. Fotios Maris (1) , Kyriaki Kitikidou (1) , Spyridon Paparrizos (2) , Konstantinos Karagiorgos (3) , Simeon Potouridis (1) , Sven Fuchs (3) Abstract A method for supporting an operational regional risk and vulnerability analysis for hydrological hazards is suggested and applied in the Island of Cyprus. The method aggregates the output of a hydrological flow model forced by observed temperatures and precipitations, with observed discharge data. A scheme supported by observed discharge is applied for model calibration. A comparison of different calibration schemes indicated that the same model parameters can be used for the entire country. In addition, it was demonstrated that, for operational purposes, it is sufficient to rely on a few stations. Model parameters were adjusted to account for land use and thus for vulnerability of elements at risk by comparing observed and simulated flow patterns, using all components of the hydrological model. The results can be used for regional risk and vulnerability analysis in order to increase the resilience of the affected population.

There is no golden rule concerning the optimal equations to estimate reference potential evapotra... more There is no golden rule concerning the optimal equations to estimate reference potential evapotranspiration (PETref) under various climates because even in the same climatic type, different studies have produced mixed results in relation to the performance of the empirical PETref equations. Knowledge of reference potential evapotranspiration (PETref) conditions is important for a number of vegetation and hydrological related applications. Direct estimations of PETref are difficult and require sophisticated instrumentation and methods. The equations of estimating potential evapotranspiration require several meteorological variables (e.g. solar radiation, wind speed), which most of the times are rarely available in daily values for the Greek meteorological stations. In the current research there is an attempt to estimate the potential evapotranspiration with EmPEst software which includes 13 different approaches, using daily and monthly data of the meteorological station of Lamia which is located within Sperchios river valley in central Greece. Finally, by the use of the statistical indicators that occur as an output from the software, there is a comparison and analysis of the exported results. The differentiations of the results showed which PET methods and series data (daily - monthly) were more suitable for the estimation of PET in the area of research.

Estimation of flow in river basins is frequently required in hydrological practice and is of gre... more Estimation of flow in river basins is frequently required in hydrological practice and is of great economic significance. This study uses streamflow and catchment characteristics data, including land use information, from three catchments in Sperchios river basin (Central Greece) and applies the quantile regression modeling. From 100% of the observations, a 20% was selected randomly and used for
independent testing of the quantile regression. The test observations and the observations used for the model development were found to have similar characteristics. It has been found that the quantile regression method in general provides accurate flow estimates; however, the users of these techniques should have in mind that there is a chance of large errors in particular conditions and provision
should be made accordingly.

Η διάβρωση του εδάφους θεωρείται μια από τις μεγαλύτερες απειλές για τα ευρωπαϊκά εδάφη, ιδιαίτερ... more Η διάβρωση του εδάφους θεωρείται μια από τις μεγαλύτερες απειλές για τα ευρωπαϊκά εδάφη, ιδιαίτερα στις μεσογειακές περιοχές. Τα μοντέλα διάβρωσης του εδάφους διαδραματίζουν σημαντικό ρόλο, τόσο στην αντιμετώπιση των συγκεκριμένων αναγκών των στόχων προστασίας του εδάφους, όσο και στην προώθηση της επιστημονικής κατανόησης των διαδικασιών διάβρωσης του εδάφους. Τα μοντέλα χρησιμοποιούνται κάθε φορά που το κόστος ή ο χρόνος που χρειάζεται για την πραγματοποίηση των μετρήσεων της διάβρωσης του εδάφους είναι απαγορευτικός. Τα θέματα που σχετίζονται με την επιλογή του σωστού μοντέλου σχετίζονται με τις επιθυμητές πληροφορίες και τα διαθέσιμα δεδομένα.

The main basin of river Tsai, river Vathi and river Lykorema presented with severe and complex te... more The main basin of river Tsai, river Vathi and river Lykorema presented with
severe and complex terrain, dense river network, which in combination with
the intense geological and fire that broke out in 2007, encourage erosion,
deposition and transport of sediment. The present research examined the
maximum rates of flow and mass transfer of river basin Loutros
Alexandroupolis and the wider region.
The subject is approached by the application of three empirical methods
within a GIS environment. The first method is the Universal Soil Loss Equation
(USLE), the second is the method of Gavrilovic, as it was modified by Zemljic
(1971) and the third is Kronfeller-Kraus method.

The MIKE SHE model is able to simulate the entire stream flow which includes direct and basic flo... more The MIKE SHE model is able to simulate the entire stream flow which includes
direct and basic flow. Many models either do not simulate, or use simplistic
methods to determine the basic flow. The MIKE SHE model takes into account
many hydrological data. Since this study was directed towards the simulation
of surface runoff and infiltration into saturated and unsaturated zone, the
MIKE SHE is an appropriate model for reliable conclusions. In this research,
the MIKE SHE model was used to simulate runoff in the area of river basin
Sperchios. The rainfall data from meteorological stations covering the whole
river basin Sperchios were selected and used. The use of daily data entry
stations, combined with geological and soil data, primarily from the literature,
and these parameters, data and vegetation leaf area, were an important
foundation for proper calibration and simulation of all physical processes.
Overall, the model was able to simulate the surface runoff sufficiently
satisfactory, representing all the hydrological data adequately

River “Sperchios”, starts from Timfristos mountain of the county of Evritania, and with overall d... more River “Sperchios”, starts from Timfristos mountain of the county of Evritania, and with overall direction
to the east, enters in Fthiotida, crosses the homonymous valley (Valley of Sperchios) and decants to
Maliakos Gulf. It is powered by a multitude of torrents in severe torrential action. The total area of its
watershed is 1727,763 km2. This research aims at the assessment of the soil loss, on the hilly and semi
mountainous watersheds caused by the torrential action, and the sediment yield transported on the plain
areas.
The subject is approached by the application of three empirical methods within a GIS environment. The
first method is the Universal Soil Loss Equation (USLE), the second is the method of Gavrilovic, as it
was modified by Zemljic (1971) and the third is Kronfeller-Kraus method.

Στο 6ο κεφάλαιο γίνεται μοντελοποίηση της εξατμισοδιαπνοής με τη χρησιμοποίηση πληροφοριακών συστημάτων.

Στο 7ο κεφάλαιο γίνεται μοντελοποίηση της διήθησης σε συνδυασμό με διάφορες διαφορικές εξισώσεις.

Στο 8ο κεφάλαιο γίνεται μια αναφορά στην υδραυλική τραχύτητα και στους τρόπους υπολογισμού της.

English summary

The 1st chapter includes an introduction to the terminology and objectives dealt within this book as well as the ways and means that are used towards the achievement of the specific targets.

The 2nd chapter refers to the data (sources and structure) that are used as input data in order to achieve the various hydrological functions.

Chapter 3 describes in detail the process of homogeneity test for the meteorological data as well as the filling and the extension of the data series.

Chapter 4 constitutes a detailed guide to create surfaces with the use of geographical information systems and surfaces generation geostationary methods.

The 5th chapter highlights the importance of the resolution and generally the spatial variability while using it as input to the various hydrological processes.

Chapter 11 includes the modeling of the unit hydrograph combining the method of Clarke and the use of geographical information systems.

Assessment of future precipitation and Growing Degree Days variations prevailing in an area is es... more Assessment of future precipitation and Growing Degree Days variations prevailing in an area is essential for the research regarding climate and climate change.
The current study focuses on Evros Region in north-eastern Greece that is characterized by intense agricultural activity and aims to assess the future response and spatial distribution of precipitation and Growing Degree Days (GDD) and how these can affect the main cultivations in the study area.
Future precipitation and temperature data from the ENSEMBLES European project were obtained and analysed. The climate simulations were performed for the future periods of 2021-2050 and 2071-2100 under the A1B and B1 scenarios.
Data extraction was conducted using the Mathworks version 2014a. Spatial distribution of precipitation and GDD was performed using a combination of dynamic and statistical downscaling techniques and Kriging method within ArcGIS 10.2.1.
Results regarding the future responses of precipitation indicated that for both scenarios and future periods, precipitation is expected to be critically decreased. Reductions will start from 30% according to the B1 scenario for the 2021-2050 period, and they will reach up to 50% according to A1B scenario for the 2071-2100 period. On the other hand, GDD are expected to be increased. Specifically, during the simulation period of 2021-2050 the GDD are expected to be increased by 10% according to B1 scenario, while by the end of the century they will reach up to 23% under the A1B scenario. In the upcoming decades, the existing cultivations can find favourable conditions and can be expanded into higher altitudes. Nevertheless, reductions in precipitation amount can act as an inhibitor towards the expansion and thus the economic development of the agricultural section in Evros Region.

Assessment of future precipitation and Growing Degree Days variations prevailing in an area is es... more Assessment of future precipitation and Growing Degree Days variations prevailing in
an area is essential for the research regarding climate and climate change.
The current study focuses on Evros Region in north-eastern Greece that is
characterized by intense agricultural activity and aims to assess the future response
and spatial distribution of precipitation and Growing Degree Days (GDD) and how
these can affect the main cultivations in the study area.
Future precipitation and temperature data from the ENSEMBLES European project
were obtained and analysed. The climate simulations were performed for the future
periods of 2021-2050 and 2071-2100 under the A1B and B1 scenarios.
Data extraction was conducted using the Mathworks version 2014a. Spatial
distribution of precipitation and GDD was performed using a combination of
dynamic and statistical downscaling techniques and Kriging method within ArcGIS
10.2.1.
Results regarding the future responses of precipitation indicated that for both
scenarios and future periods, precipitation is expected to be critically decreased.
Reductions will start from 30% according to the B1 scenario for the 2021-2050
period, and they will reach up to 50% according to A1B scenario for the 2071-2100
period. On the other hand, GDD are expected to be increased. Specifically, during
the simulation period of 2021-2050 the GDD are expected to be increased by 10%
according to B1 scenario, while by the end of the century they will reach up to 23%
under the A1B scenario.
In the upcoming decades, the existing cultivations can find favourable conditions and
can be expanded into higher altitudes. Nevertheless, reductions in precipitation
amount can act as an inhibitor towards the expansion and thus the economic
development of the agricultural section in Evros Region.

Ph.D. Thesis - Paparrizos Spyridon