A reach‐scale biogeochemical model for temporary rivers     

Ourania Tzoraki  Nikolaos P. Nikolaidis  Anna Rosa Trancoso  Frank Braunschweig  Ramiro Neves 《水文研究》2009,23(2):272-283

The RS‐tempQ Model ( r each– s cale t emporary flow biogeochemical model) is a conceptual model that can describe the hydrologic, sediment transport and biogeochemical processes of temporary rivers at the reach scale. The model takes into account the expansion–contraction of the inundated area of the river. It simulates the sediment transport and the nutrient fluxes that are transferred to the coastal area due to the first flash flood and during extreme rain events. The RS‐tempQ Model simulates the in‐stream processes during the wet and dry cycles as the river corridor expands and contracts. The model was used to assess and quantify the hydrologic and geochemical processes occurring in a temporary river reach (Krathis River) in Greece. Since the conventional gauging techniques cannot measure the flow in rivers that are split into small braided streams, discharge measurements could not be obtained in order to calibrate and verify the model. Other field measurements such as infiltration losses and sediment accumulation were used for model calibration. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Bather density as a predominant factor for health effects related to recreational bathing: results from the Greek bathers cohort study     

Papastergiou P  Mouchtouri VA  Rachiotis G  Pinaka O  Katsiaflaka A  Hadjichristodoulou C 《Marine pollution bulletin》2011,62(3):590-595

Our aim was to examine the health effects on bathers from exposure to recreational seawater on three beaches with different microbiology quality and bather density through a cohort study. An initial questionnaire and a 10 day follow up were used. Univariate and backward logistic regression analyses were used to asses the risk of developing symptoms or diseases among the bathers. In total, 3805 bathers were included in the study and 149 samples were collected from the three beaches. Despite all the beaches being characterized of high quality the levels of bacterial indicators differed among them. Health effects among bathers were not associated with bacterial indicators. A statistically significant increased risk for symptoms related to respiratory illness, gastroenteritis, medical consultation and use of medication was observed among bathers at the higher bather density beaches. Beach bather numbers should always be taken into account when considering a risk assessment approach.  相似文献   

Introduction to “Geographic information science: a multi-disciplinary and multi-paradigmatic discipline”     

Ourania Kounadi 《制图学和地理信息科学》2014,41(3):193-195

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Environmental study for pollution in the area of Megalopolis power plant (Peloponnesos,Greece)   总被引：1，自引：0，他引：1  

Apostolos Sarris  Eleni Kokinou  Eleni Aidona  Nikolaos Kallithrakas-Kontos  Pavlos Koulouridakis  Georgia Kakoulaki  Kassiani Droulia  Ourania Damianovits 《Environmental Geology》2009,58(8):1769-1783

The main purpose of the present study is to investigate the suitability of magnetic properties in correlation to geochemical measurements as a pollution-monitoring tool and study the metal transmission factors in an area around a major local source, namely a lignite-burning power plant. Surface soil samples were collected in the wide area of the power plant of Megalopolis (Peloponnesos, Greece). The magnetic susceptibility and other magnetic properties of the surface soils were originally measured and mapped. Loci of high values of magnetic susceptibility within the study area gave rise to further analyze the soil samples for metal concentrations. GIS techniques were used for mapping all the chemical constituent concentrations and the magnetic measurements on the various topographic and geological features of the area. Maps were created through interpolation algorithms indicating the spatial distribution of the above measurements. Spatial tools and statistical analysis through the calculation of Pearson’s coefficients proved the correlation between magnetic properties, metal concentrations and the terrain attributes (especially the geological structure and the wind currents) of the region.  相似文献   

Population at risk: using areal interpolation and Twitter messages to create population models for burglaries and robberies     

Ourania Kounadi  Alina Ristea  Michael Leitner  Chad Langford 《制图学和地理信息科学》2018,45(3):205-220

Population at risk of crime varies due to the characteristics of a population as well as the crime generator and attractor places where crime is located. This establishes different crime opportunities for different crimes. However, there are very few efforts of modeling structures that derive spatiotemporal population models to allow accurate assessment of population exposure to crime. This study develops population models to depict the spatial distribution of people who have a heightened crime risk for burglaries and robberies. The data used in the study include: Census data as source data for the existing population, Twitter geo-located data, and locations of schools as ancillary data to redistribute the source data more accurately in the space, and finally gridded population and crime data to evaluate the derived population models. To create the models, a density-weighted areal interpolation technique was used that disaggregates the source data in smaller spatial units considering the spatial distribution of the ancillary data. The models were evaluated with validation data that assess the interpolation error and spatial statistics that examine their relationship with the crime types. Our approach derived population models of a finer resolution that can assist in more precise spatial crime analyses and also provide accurate information about crime rates to the public.  相似文献   

Simulating streamflow variability and aquatic states in temporary streams using a coupled groundwater-surface water model     

E.P. Querner  J. Froebrich  F. Gallart  M.M. Cazemier  O. Tzoraki 《水文科学杂志》2013,58(1):146-161

Abstract

In order to apply the EU Water Framework Directive for temporary streams, it is important to quantify the space–time development of different aquatic states. We report on research on the development of aquatic states for temporary streams in the Evrotas basin, Greece. The SIMGRO regional hydrological model was used in a GIS framework to generate flow time series for the Evrotas River and all major tributaries. Five flow phases were distinguished: flood conditions, riffles, connected pools, isolated pools and dry bed conditions. Thresholds based on local hydraulic characteristics were identified per stream reach and flow phase, enabling the frequency of flow phases per month and the average frequencies for all streams to be derived. Three historical scenarios within the 20th century, marking periods of major changes in water management, were investigated. Additionally, a climate scenario for the 2050s was analysed. Simulations revealed that low flows are now much lower, mainly because more groundwater is abstracted for irrigation. The consequence is that stretches of the river fall dry during several months, causing the ecological status to deteriorate.