scholarly journals Spatial Patterns and Characteristics of Flood Seasonality in Europe

2017 ◽  
Author(s):  
Julia Hall ◽  
Günter Blöschl
Keyword(s):  
Cluster Analysis ◽  
Geographical Location ◽  
Bimodal Distribution ◽  
Water Levels ◽  
Mountainous Areas ◽  
Continental Scale ◽  
High Flood ◽  
National Boundaries ◽  
Autumn And Winter ◽  
Flood Characteristics

Abstract. In Europe, floods are typically analysed within national boundaries and it is not well understood how the characteristics of local floods fit into a continental perspective. To gain a better understanding at the continental-scale, this study analyses seasonal flood characteristics across Europe for the period of 1960–2010. The timing within the year of annual maximum discharges or water levels of 4105 stations from a European flood database is analysed. A cluster analysis is performed to identify regions with different flood seasons. The clusters are determined using the monthly relative frequencies of the annual maxima, and are further analysed to determine the temporal flood characteristics of each region and the European-wide patterns of bimodal and unimodal flood seasonality distributions. Below 60° latitude, the mean timing of floods of individual stations transitions from winter floods in the West to spring floods in the East. Summer floods occurring in mountainous areas interrupt this West to East transition. Above 60° latitude, spring floods are dominant, except for coastal areas in which autumn and winter floods are observed. The temporal concentration of flood occurrences around a specific time of the year is highest in North-Eastern Europe, with most of the floods being concentrated within 1–2 months. The cluster analysis suggests that six regions with geographically distinct flood seasonality distributions exist. Most of the stations (~ 73 %) with more than 30 years of data exhibit a unimodal flood seasonality distribution (one or more consecutive months with high flood occurrence). Few stations (~ 3 %), mainly located on the foothills of mountainous areas, have a clear bimodal distribution. Overall, the geographical location of a station in Europe can give an indication of its flood characteristics throughout the year and is more relevant than catchment area and outlet elevation for the observed flood seasonality.

scholarly journals Spatial patterns and characteristics of flood seasonality in Europe

2018 ◽  
Vol 22 (7) ◽  
pp. 3883-3901 ◽  
Author(s):  
Julia Hall ◽  
Günter Blöschl
Keyword(s):  
Cluster Analysis ◽  
Eastern Europe ◽  
Geographical Location ◽  
Water Levels ◽  
Mountainous Areas ◽  
Continental Scale ◽  
North Eastern ◽  
Seasonal Flood ◽  
The Mean ◽  
Flood Characteristics

Abstract. In Europe, floods are typically analysed within national boundaries and it is therefore not well understood how the characteristics of local floods fit into a continental perspective. To gain a better understanding at continental scale, this study analyses seasonal flood characteristics across Europe for the period 1960–2010. From a European flood database, the timing within the year of annual maximum discharges or water levels of 4105 stations is analysed. A cluster analysis is performed to identify large-scale regions with distinct flood seasons based on the monthly relative frequencies of the annual maxima. The clusters are further analysed to determine the temporal flood characteristics within each region and the Europe-wide patterns of bimodal and unimodal flood seasonality distributions. The mean annual timing of floods observed at individual stations across Europe is spatially well defined. Below 60∘ latitude, the mean timing transitions from winter floods in the west to spring floods in the east. Summer floods occurring in mountainous areas interrupt this west-to-east transition. Above 60∘ latitude, spring floods are dominant, except for coastal areas in which autumn and winter floods tend to occur. The temporal concentration of flood occurrences around the annual mean timing is highest in north-eastern Europe, with most of the floods being concentrated within 1–2 months. The cluster analysis results in six spatially consistent regions with distinct flood seasonality characteristics. The regions with winter floods in western, central, and southern Europe are assigned to Cluster 1 (∼ 36 % of the stations) and Cluster 4 (∼ 10 %) with the mean flood timing within the cluster in late January and early December respectively. In eastern Europe (Cluster 3, ∼ 24 %), the cluster average flood occurs around the end of March. The mean flood timing in northern (Cluster 5, ∼ 8 %) and north-eastern Europe (Cluster 6, ∼ 5 %) is approximately in mid-May and mid-April respectively. About 15 % of the stations (Cluster 2) are located in mountainous areas, with a mean flood timing around the end of June. Most of the stations (∼ 73 %) with more than 30 years of data exhibit a unimodal flood seasonality distribution (one or more consecutive months with high flood occurrence). Only a few stations (∼ 3 %), mainly located on the foothills of mountainous areas, have a clear bimodal flood seasonality distribution. This study suggests that, as a result of the consistent Europe-wide pattern of flood timing obtained, the geographical location of a station in Europe can give an indication of its seasonal flood characteristics and that geographical location seems to be more relevant than catchment area or catchment outlet elevation in shaping flood seasonality.

ELECTRONICS INFORMATICS - KEY INDUSTRY OF THAI NGUYEN PROVINCE

2018 ◽  
Vol 63 (7) ◽  
pp. 162-168
Author(s):  
Long Nghiem Van
Keyword(s):  
Positive Solutions ◽  
Development Policy ◽  
Geographical Location ◽  
Socioeconomic Conditions ◽  
Mountainous Areas ◽  
Strong Growth ◽  
The Future ◽  
Key Industry

Thai Nguyen is a major economic, political, cultural and social center of the Northern Midland and Mountainous Areas. Geographical location, natural and socioeconomic conditions of the province are very favorable for the development of the industry, in recent years, along with positive changes in the development policy, attracting capital The electronics-informatics industry has seen a very strong growth, and is now the most important industry in the province. In the future, in order to further promote the development of this industry, improve the quality and efficiency of production, we need to synchronously implement positive solutions to meet the requirements of development.

scholarly journals Toward continental hydrologic–hydrodynamic modeling in South America

2018 ◽  
Vol 22 (9) ◽  
pp. 4815-4842 ◽  
Author(s):  
Vinícius A. Siqueira ◽  
Rodrigo C. D. Paiva ◽  
Ayan S. Fleischmann ◽  
Fernando M. Fan ◽  
Anderson L. Ruhoff ◽  
...  
Keyword(s):  
South America ◽  
Land Surface ◽  
River Discharge ◽  
Hydrological Modeling ◽  
Water Levels ◽  
Scale Model ◽  
Global Models ◽  
Discharge Data ◽  
Continental Scale ◽  
Terrestrial Water

Abstract. Providing reliable estimates of streamflow and hydrological fluxes is a major challenge for water resources management over national and transnational basins in South America. Global hydrological models and land surface models are a possible solution to simulate the terrestrial water cycle at the continental scale, but issues about parameterization and limitations in representing lowland river systems can place constraints on these models to meet local needs. In an attempt to overcome such limitations, we extended a regional, fully coupled hydrologic–hydrodynamic model (MGB; Modelo hidrológico de Grandes Bacias) to the continental domain of South America and assessed its performance using daily river discharge, water levels from independent sources (in situ, satellite altimetry), estimates of terrestrial water storage (TWS) and evapotranspiration (ET) from remote sensing and other available global datasets. In addition, river discharge was compared with outputs from global models acquired through the eartH2Observe project (HTESSEL/CaMa-Flood, LISFLOOD and WaterGAP3), providing the first cross-scale assessment (regional/continental  ×  global models) that makes use of spatially distributed, daily discharge data. A satisfactory representation of discharge and water levels was obtained (Nash–Sutcliffe efficiency, NSE > 0.6 in 55 % of the cases) and the continental model was able to capture patterns of seasonality and magnitude of TWS and ET, especially over the largest basins of South America. After the comparison with global models, we found that it is possible to obtain considerable improvement on daily river discharge, even by using current global forcing data, just by combining parameterization and better routing physics based on regional experience. Issues about the potential sources of errors related to both global- and continental-scale modeling are discussed, as well as future directions for improving large-scale model applications in this continent. We hope that our study provides important insights to reduce the gap between global and regional hydrological modeling communities.

Rainfall and runoff characteristics in a karstic basin of China

2018 ◽  
Vol 10 (1) ◽  
pp. 117-129
Author(s):  
Chongxun Mo ◽  
Guiyan Mo ◽  
Junkai Qin ◽  
Ming Zhou ◽  
Qing Yang ◽  
...  
Keyword(s):  
Seasonal Pattern ◽  
Kendall Test ◽  
Water Levels ◽  
Low Flow ◽  
Vegetation Coverage ◽  
Annual Streamflow ◽  
Average Annual Change ◽  
Formation Conditions ◽  
Autumn And Winter ◽  
Opposite Tendency

Abstract This paper examines the rainfall and runoff characteristics in a karstic basin of China. The results indicated that the inner-annual distributions of rainfall and runoff were uneven and slightly different, as the concentration period of rainfall (from April to October) was earlier; there was a delay of about a month before the runoff (from May to September), and the concentrated volume accounted for 87% of annual precipitation or annual streamflow. Interannually, rainfall changed more significantly than runoff, the wet years lasted longer than the dry years (rainfall), while the high and low flow years were equal for runoff. In addition, judging from the value of the Mann-Kendall test, the average annual change of rainfall (−2.36) was more significant than that of runoff (−2.05), and the seasonal pattern of runoff maintained an opposite tendency in autumn and winter before 1990. The changes in runoff were mainly associated with rainfall and the formation conditions in the karstic area, and the reservoir in this basin should be operated with different flood limiting water levels, and the vegetation coverage should be improved.

Crowdfunding Platforms Dynamics

2021 ◽  
pp. 109-133
Author(s):  
Amaya Erro-Garcés ◽  
Begoña Urien
Keyword(s):  
Cluster Analysis ◽  
Significant Role ◽  
The Other ◽  
Geographic Proximity ◽  
Other Hand ◽  
National Boundaries ◽  
Practical Implications

This chapter compares two national crowdfunding markets based on their platforms and regulatory legislation on crowdfunding. Spain and France were selected though a cluster analysis since both differ on those characteristics. Mean comparison tests were carried out to estimate differences. Data were based on a survey specifically designed and conducted for this research. While crowdfunding is an internet-powered activity with global accessibility, national boundaries and geographic proximity play a significant role in shaping the performance of crowdfunding platforms. Regarding practical implications, as each country developed its specific legislation, it is concluded that this legislation may boost or hinder the growth of crowdfunding. On the other hand, the different way platforms managed their business does not affect their outcomes in terms of number of projects and funds raised. As a result, although platforms are indispensable as an intermediate agent between funders and investors, they determine neither the number of projects hosted nor the funds raised.

scholarly journals Delimitation of flood areas based on a calibrated a DEM and geoprocessing: case study on the Uruguay River, Itaqui, southern Brazil

2019 ◽  
Vol 19 (1) ◽  
pp. 237-250 ◽  
Author(s):  
Paulo Victor N. Araújo ◽  
Venerando E. Amaro ◽  
Robert M. Silva ◽  
Alexandre B. Lopes
Keyword(s):  
Statistical Analysis ◽  
Flood Hazard ◽  
Satellite Image ◽  
Water Levels ◽  
Calibration Model ◽  
Southern Brazil ◽  
Temporal Series ◽  
Vertical Accuracy ◽  
High Flood ◽  
Uruguay River

Abstract. Flooding is a natural disaster which affects thousands of riverside, coastal, and urban communities causing severe damage. River flood mapping is the process of determining inundation extents and depth by comparing historical river water levels with ground surface elevation references. This paper aims to map flood hazard areas under the influence of the Uruguay River, Itaqui (southern Brazil), using a calibration digital elevation model (DEM), historic river level data and geoprocessing techniques. The temporal series of maximum annual level records of the Uruguay River, for the years 1942 to 2017, were linked to the Brazilian Geodetic System using geometric leveling and submitted for descriptive statistical analysis and probability. The DEM was calibrated with ground control points (GCPs) of high vertical accuracy based on post-processed high-precision Global Navigation Satellite System surveys. Using the temporal series statistical analysis results, the spatialization of flood hazard classes on the calibrated DEM was assessed and validated. Finally, the modeling of the simulated flood level was visually compared against the flood area on the satellite image, which were both registered on the same date. The free DEM calibration model indicated high correspondence with GCPs (R2=0.81; p<0.001). The calibrated DEM showed a 68.15 % improvement in vertical accuracy (RMSE = 1.00 m). Five classes of flood hazards were determined: extremely high flood hazard, high flood hazard, moderate flood hazard, low flood hazard, and non-floodable. The flood episodes, with a return time of 100 years, were modeled with a 57.24 m altimetric level. Altimetric levels above 51.66 m have a high potential of causing damage, mainly affecting properties and public facilities in the city's northern and western peripheries. Assessment of the areas that can potentially be flooded can help to reduce the negative impact of flood events by supporting the process of land use planning in areas exposed to flood hazard.

scholarly journals Hydrometeorological drivers of flood characteristics in the Brahmaputra river basin in Bangladesh

2021 ◽  
Author(s):  
Sazzad Hossain ◽  
Hannah L. Cloke ◽  
Andrea Ficchì ◽  
Andrew G. Turner ◽  
Elisabeth M. Stephens
Keyword(s):  
Water Level ◽  
Morphological Changes ◽  
High Water ◽  
Water Levels ◽  
Future Climate Change ◽  
South Asian Summer Monsoon ◽  
Large Variability ◽  
Long Duration ◽  
The Impact ◽  
Flood Characteristics

Abstract. While flooding is an annual occurrence in the Brahmaputra basin during the South Asian summer monsoon, there is large variability in the flood characteristics that drive risk: flood duration, rate of water level rise and peak water level. The aim of this study is to understand the key hydrometeorological drivers influencing these flood characteristics. We analyse hydrometeorological time series of the last 33 years to understand flood dynamics focusing on three extraordinary floods in 1998 (long duration), 2017 (rapid rise) and 2019 (high water level). We find that long duration floods in the basin have been driven by basin-wide seasonal rainfall extremes associated with the development phase of strong La Niña events, whereas floods with a rapid rate of rise have been driven by more localized rainfall falling in a hydrological ‘sweet spot’ that leads to a concurrent contribution from the tributaries into the main stem of the river. We find that recent record high water levels are not coincident with extreme river flows, hinting that sedimentation and morphological changes are also important drivers of flood risk that should be further investigated. Understanding these drivers is essential for flood forecasting and early warning and also to study the impact of future climate change on flood.

scholarly journals Investigating the interaction of waves and river discharge during compound flooding at Breede Estuary, South Africa

2021 ◽  
Author(s):  
Sunna Kupfer ◽  
Sara Santamaria-Aguilar ◽  
Lara van Niekerk ◽  
Melanie Lück-Vogel ◽  
Athanasios Vafeidis
Keyword(s):  
South Africa ◽  
South African ◽  
Hydrodynamic Model ◽  
River Discharge ◽  
Water Levels ◽  
Flood Events ◽  
Flood Magnitude ◽  
Compound Events ◽  
Flood Characteristics ◽  
Water Depths

Abstract. Recent studies have drawn special attention to the significant dependencies between flood drivers and the occurrence of compound flood events in coastal areas. This study investigates compound flooding from tides, river discharge (Q) and specifically waves using a hydrodynamic model at Breede Estuary, South Africa. We quantify vertical and horizontal differences in flood characteristics caused by driver interaction, and assess the contribution of waves. Therefore, we compare flood characteristics resulting from compound flood scenarios to those in which single drivers are omitted. We find that flood characteristics are more sensitive to Q than to waves, particularly when the latter only coincide with high spring tides. When interacting with Q, however, the contribution of waves is high, causing 10–12 % larger flood extents and 45–85 cm higher water depths, as waves caused backwater effects and raised water levels inside the lower reaches of the estuary. With higher wave intensity, the first flooding began up to 12 hours earlier. Our findings provide insights on compound flooding in terms of flood magnitude and timing at a South African estuary and demonstrate the need to account for the effects of compound events, including waves, in future flood impact assessments of open South African estuaries.

scholarly journals Understanding Hydrologic Variability across Europe through Catchment Classification

2016 ◽  
Author(s):  
Anna Kuentz ◽  
Berit Arheimer ◽  
Yeshewatesfa Hundecha ◽  
Thorsten Wagener
Keyword(s):  
Spatial Patterns ◽  
Geographical Location ◽  
Dynamic Modelling ◽  
Regression Tree ◽  
Classification And Regression Tree ◽  
Low Flow ◽  
Average Percentage ◽  
Continental Scale ◽  
Hydrologic Variability ◽  
Predictions In Ungauged Basins

Abstract. This study contributes to better understanding the physical controls on spatial patterns of pan-European flow signatures – taking advantage of large open datasets for catchment classification and comparative hydrology. We explored similarities in 16 flow signatures and 35 catchment descriptors across entire Europe. A database of catchment descriptors and selected flow signatures was compiled for 35 215 catchments and 1366 river gauges across Europe. Correlation analyses and stepwise regressions were used to identify the best explanatory variables for each signature resulting in a total of 480 regression models to predict signatures for similar catchments. Catchments were clustered and analyzed for similarities in flow signature values, physiography and for the combination of the two. From the statistical analysis, we found: (i) about 400 statistically significant correlations between flow signatures and physiography; (ii) a 15 to 33 % (depending on the classification used) improvement in regression model skills using catchment classification vs. the full domain; and (iii) 12 out of 16 flow signatures to be mainly controlled by climatic characteristics, while topography was the main control for flashiness of flow and low flow magnitude, and geology for the flashiness of flow. Classifying catchments based on flow signatures or on physiographic characteristics led to very different spatial patterns, but a classification and regression tree (CART) allowed us to predict flow signatures-based classes according to catchment physiographic characteristics with an average percentage of 60 % of correctly classified catchments in each class. As a result, we show that Europe can be divided into ten classes with both similar flow signatures and physiography. We noted the importance of separating energy-limited catchments from moisture-limited catchment to understand catchment behavior. For improved understanding, we interpreted characteristics in hydrographs, flow signatures, physiography and geographical location to define dominant flow-generating processes. We found that rainfall response, snow-melt, evapotranspiration, damping, storage capacity, and human alterations could explain the hydrologic variability across Europe. Finally, we discuss the relevance of these empirical results for predictions in ungauged basins across Europe and for dynamic modelling at the continental scale.

scholarly journals The Role of Absolute Pitch Memory in the Oral Transmission of Folksongs

2015 ◽  
Vol 10 (3) ◽  
pp. 161 ◽  
Author(s):  
Merwin Olthof ◽  
Berit Janssen ◽  
Henkjan Honing
Keyword(s):  
Geographical Location ◽  
Empirical Support ◽  
Absolute Pitch ◽  
Bimodal Distribution ◽  
Oral Traditions ◽  
Contextual Cues ◽  
Oral Transmission ◽  
Family Analysis ◽  
Audio Recordings

Absolute Pitch (AP) is the ability to identify or produce isolated tones in the absence of contextual cues or reference pitches. While AP is thought to differ from other human abilities in its bimodal distribution (Takeuchi &amp; Hulse, 1993) &ndash; either you have it or you do not &ndash; recent evidence suggests that memory for absolute pitch in a melody is actually widespread (Schellenberg &amp; Trehub, 2003). In the current project the Dutch collection of historic audio recordings, <em>Onder de Groene Linde </em>(Grijp, 2008), is used as a source to explore the potential role of AP in the memory of songs transmitted in oral traditions. Since the melodies in this database are grouped by <em>tune family</em> and are available as sound files, they can serve as empirical support for the Absolute Pitch Memory (APM) hypothesis predicting that these tunes are memorized and transmitted over time and geographical location based on their absolute pitch height. To this end, a between- and a within-tune family analysis was performed. In the between tune family analysis, two tune families showed significant inter-recording tonic pitch consistency. The within tune family analysis further substantialized that effect, while controlling for possible factors of variance, such as gender, geographical origin, and lyrics. Together, the results are taken as empirical support that APM plays a significant role in the oral transmission of folksongs.

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