Evaluation of a global ensemble flood prediction system in Peru     

Konstantinos Bischiniotis  Bart van den Hurk  Ervin Zsoter  Erin Coughlan de Perez  Manolis Grillakis  Jeroen C. J. H. Aerts 《水文科学杂志》2013,58(10):1171-1189

ABSTRACT

Flood early warning systems play a more substantial role in risk mitigation than ever before. Hydrological forecasts, which are an essential part of these systems, are used to trigger action against floods around the world. This research presents an evaluation framework, where the skills of the Global Flood Awareness System (GloFAS) are assessed in Peru for the years 2009–2015. Simulated GloFAS discharges are compared against observed ones for 10 river gauges. Forecasts skills are assessed from two perspectives: (i) by calculating verification scores at every river section against simulated discharges and (ii) by comparing the flood signals against reported events. On average, river sections with higher discharges and larger upstream areas perform better. Raw forecasts provide correct flood signals for 82% of the reported floods, but exhibit low verification scores. Post-processing of raw forecasts improves most verification scores, but reduces the percentage of the correctly forecasted reported events to 65%.  相似文献   

Evaluation of low-rank coals as raw material for Fe and Ca organomineral fertilizer using a new EDXRF method   总被引：2，自引：2，他引：0  

Konstantinos Chassapis  Maria Roulia 《International Journal of Coal Geology》2008,75(3):185-188

A rapid and reliable method for analyzing Fe and Ca in low-rank Greek coals was developed. The presence of Fe and Ca is of importance regarding the potential use of these coals as raw material for organomineral fertilizers. Samples were collected from the main Greek lignite deposits and standards were prepared using Atomic Absorption Spectroscopy (AAS), which were also employed in the Energy Dispersive X-ray Fluorescence (EDXRF) method. The new method offers the advantages of being timesaving, non-destructive and can be easily incorporated in a fertilizer production line. Analysis of low-rank Greek coals demonstrated a significant Fe and Ca content ranging from 0.15 to 1.97 wt.% for Fe and from 0.04 to 2.51 wt.% for Ca. When both EDXRF and AAS techniques were applied, the Fe and Ca concentration values differed less than 5%, demonstrating that both techniques are reliable for low-rank coals in the above concentration range. These EDXRF results may be used as a preliminary test regarding the application of Greek coals in organomineral fertilizer production, given that in these coals iron and calcium are the most abundant metals.  相似文献   

A multisource approach for coastal mapping purposes: Limeni bay,Mani and surrounding area,southern Greece     

Nikolaos Sabatakakis  Konstantinos G. Nikolakopoulos  George Papatheodorou  George Kelasidis 《Earth Science Informatics》2016,9(2):183-196

A multipurpose engineering geological map of a natural heritage site including inland and offshore areas has been compiled to provide information on many aspects for land use optimization, sustainable development and environmental protection. The mapping approach was based on data provided by conventional onland field works, marine remote sensing survey and aerial photo interpretation. These data sources were integrated into a GIS platform allowing reliable mapping solutions. The geological formations encountered were grouped into individual geotechnical units according to uniformity in lithological character, while the seabed sub-bottom structure was also obtained through several seafloor thematic map compilation. Shoreline variability and evolution for a long time period (1945–2008) were also investigated and mapped. The synergistic use of the results deducted from those disciplinary surveys is finally presented in a single engineering geological map covering the onshore and offshore area.  相似文献   

Investigation of flash flood natural causes of Xirolaki Torrent,Northern Greece based on GIS modeling and geomorphological analysis     

Konstantinos Tsanakas  Kalliopi Gaki-Papanastassiou  Kleomenis Kalogeropoulos  Christos Chalkias  Petros Katsafados  Efthimios Karymbalis 《Natural Hazards》2016,80(2):1015-1030

  相似文献   

Assessing soil water content spatio-temporal variability at the hillslope scale in a headwater catchment using a multi variable interpolation model based on EMI surveys (Draix,South Alps,France)     

Florian Mallet  Simon D. Carrière  Konstantinos Chalikakis  Vincent Marc 《Environmental Earth Sciences》2018,77(13):507

To improve flood prediction in headwater catchments, hydrologists need to know initial soil moisture conditions that precede rain events. In torrential hydrology, soil moisture mapping provides a valuable tool for investigating surface runoff generation processes. In these mountainous environments, soil moisture prediction is challenging because of highly heterogeneous land cover and soil properties. This survey propose a methodology to study spatial soil moisture variations in the mountainous and torrential environment of the Draix Bléone experimental site—Laval 0.86 km². This approach associates water content measurements at the plot scale with spatialized soil bulk electrical conductivity (EC_a) measurements combined in a multivariate statistical analysis based on topographical parameters. Between the summer of 2015 and winter of 2016, four geophysical surveys were conducted under various moisture conditions and along the same pathway, using the Slingram electromagnetic induction (EMI) technique (EM31 device) in horizontal dipole to identify changes in soil properties to a depth of 3 m. These results were analyzed to determine water dynamics in this mountainous catchment. Temporal variations of EC_a vary among land cover types (forest, grassland, and black marl). A significant relationship was observed between EC_a and soil water content (SWC) measured with capacitive sensors in forest and grassland. A multiple linear regression produced using the spatial interpolation code LISDQS shows a significant correlation between EC_a and landform units depicted on a high-resolution DEM. EC_a variations decrease with distance to talwegs. Riparian zones appear as potential hydrological contributing areas with patterns varying according to moisture status. This study shows that multiple linear regression analysis and EMI make it possible to fill gaps between SWC plot measurements, over wide areas that are steep and that present numerous obstacles due to vegetation cover.  相似文献   

Sustainable groundwater resources exploration and management in a complex geological setting as part of a humanitarian project (Mahafaly Plateau,Madagascar)     

Simon Damien Carrière  Konstantinos Chalikakis  Chloé Ollivier  Tom Heath  Marie Mangin  Jean Kempf  Jacques Bablon Randriatsitohaina  Marina Gillon  Théodore Razakamanana  Jean Lapègue 《Environmental Earth Sciences》2018,77(21):734

Southwestern Madagascar is a semi-arid region and a hot-spot of global change. On the Mahafaly plateau, people live with quasi-permanent water stress and groundwater, the only available resource, is difficult to exploit due to a complex hydrogeological environment. A methodology (suitable for humanitarian projects; <?40 k€) was developed in four phases to assess the sustainable exploitation of the water resource: (A) regional scale exploration, (B) village scale exploration, (C) drilling campaign, and (D) hydro-climatic monitoring. This integrated hydrogeophysical approach involves geophysical measurements (262 TEM-fast soundings, 2588 Slingram measurements, 35 electrical soundings), hydrochemical analyses (112 samples), and a piezometric survey (127 measurements). Two groundwater resources were identified, one deep (below 150 m) and one shallow (<?20 m). Hydrochemical results highlighted the vulnerability of both resources: anthropic contamination for the shallower and seawater intrusion for the deeper. Therefore, subsequent geophysical surveys supported the siting of six boreholes and three wells in the shallow aquifer. This methodological approach was successful in this complex geological setting and requires testing at other sites in and outside Madagascar. The study demonstrates that geophysical results should be used in addition to drilling campaigns and to help monitor the water resource. In fact, to prevent over-exploitation, piezometric and meteorological sensors were installed to monitor the water resource. This unique hydro-climatic observatory may help (1) non-governmental organization and local institutions prevent future water shortages and (2) scientists to understand better how global change will affect this region of the world.  相似文献   

Hazard zonation mapping of earthquake-induced secondary effects using spatial multi-criteria analysis     

Karpouza  Maria  Chousianitis  Konstantinos  Bathrellos  George D.  Skilodimou  Hariklia D.  Kaviris  George  Antonarakou  Assimina 《Natural Hazards》2021,109(1):637-669

Natural Hazards - The present study aims to suggest an approach that allows the simultaneous hazard zonation mapping of earthquake-induced secondary effects. The modeling process of the applied...  相似文献   

On the theory of the type III burst exciter     

Robert A. Smith  Melvyn L. Goldstein  Konstantinos Papadopoulos 《Solar physics》1976,46(2):515-527

In situ satellite observations of type III burst exciters at 1 AU show that the beam does not evolve into a plateau in velocity space, contrary to the prediction quasilinear theory. The observations can be explained by a theory that includes mode coupling effects due to excitation of the parametric oscillating two-stream instability and its saturation by anomalous resistivity. The time evolution of the beam velocity distribution is included in the analysis.NAS/NRC Postdoctoral Resident Research Associate.  相似文献   

Size selectivity of diamond and square mesh codends for four commercial Mediterranean fish species   总被引：2，自引：2，他引：2  

Petrakis  George; Stergiou  Konstantinos I. 《ICES Journal of Marine Science》1997,54(1):13-23

  相似文献   

Possible implications of climatic variability on the presence of capelin (Mallotus villosus) off the Norwegian coast     

Konstantinos I. Stergiou 《Climatic change》1991,19(4):369-391

The distribution of capelin in the southern Barents Sea shifts in the east-west direction in response to warming or cooling trends. The capelin arrives at the spawning grounds earlier and spawning takes place in deeper water in cold years as compared to warm years. Although the ultimate regulators of capelin distribution/abundance in the Barents Sea may involve complex interactions/responses between capelin and abiotic and biotic variables, water temperature was found to be a successful predictor and proximate regulator of capelin distribution/ abundance in that area.It has been maintained that capelin did not visit the Norwegian coastal waters during the turn of the 18th century and in 1830–1840. Yet, meteorological, oceanographic and ecological data hitherto presented provide cumulative evidence that capelin migrated to the Norwegian spawning grounds during both periods. Nevertheless, capelin arrived early in the year and remained and spawned further offshore in deeper waters. Since capelin in earlier fisheries were fished by means of land-fixed nets, the size of the catch depended on access by the capelin to the immediate coastal fishing areas. Thus, capelin were not accessible to Norwegian fishermen.  相似文献