What is the role of the model in socio-hydrology? Discussion of “Prediction in a socio-hydrological world”*

Srinivasan et al. provide an interesting overview of the challenges for long-term socio-hydrological predictions. Although agreeing with most of the statements made, we argue for the need to take socio-hydrological analysis a step further and add some fundamental considerations, especially concerning the crucial importance of many (conscious and unconscious) assumptions made upfront of the modelling exercise. Eventual assumptions of technological determinism need correction: Models are not “value-free”, but uncertain, subjective and a product of the society in which they were shaped. It is important to acknowledge this uncertainty and bias when making decisions based on socio-hydrological models, considering also that these models are “social and political actors” in and by themselves. Furthermore, socio-hydrological models require a transdisciplinary approach, since physical water availability is only one of the boundary conditions for society. Last but not least, interaction with stakeholders remains important to enable understanding of what the variable of interest is.     

Selecting a method for interpreting GPS measurements of geodynamic movements of a point of the Earth’s surface in the high-frequency range

Different variants for interpreting the data of vertical and horizontal channels of GPS measurements are examined during experimental works. The movements of an observation point are imitated experimentally in the vertical and horizontal directions at a geophysical observatory. The experiments are carried out on a pedestal with original benchmarks in both directions. The movements are imitated in the high-frequency range with different time values of movement from one point to another, which did not exceed 1 h. The errors in imaging movements of measurement points according to the results of interpreting the readings of GPS receivers are shown in relation to the benchmark movements of measurement points in the vertical and horizontal directions. These data are processed in the differential mode using the precise point positioning (PPP) method. The experimental results confirm that there is no potential of imaging vertical movements of the Earth’s surface caused by tidal observations according to GPS receiver data.     

Scenarios of the spread of a waste heat discharge in a river — Vistula River case study

The problem of two-dimensional mathematical modelling of heated cooling water discharges into running waters is considered in the paper. Two models — one for the evaluation of 2D turbulent velocity field and the other, developed by authors of the study, for 2D heat transport in open-channels — were used in the calculations. Relevant scenarios of the spread of heated water discharged from a designed gas-stem power plant to be constructed at the Vistula River were presented. Environmentally most friendly variant of the discharge of the thermal pollution was selected from among four various variants.     

Event in the case of a single reservoir: the Ghèzala dam in Northern Tunisia

The paper focuses on the development of reservoir operating rules for dry and rainfall events, and their implementation in the case of the Ghézala dam located in northern Tunisia (characterized by Mediterranean climate). Rainfall events are defined in terms of depth and duration that are correlated to each other. A depth analysis per event is performed, conditioned on the event duration. The gamma distribution provides a good fit to depth per event, especially for events lasting at least 6 days. The event duration fits a geometric distribution, whereas the dry events during the rainy season fit a negative binomial distribution. The climatic cycle length is fitted to a gamma distribution. On this basis, many 50-year synthetic event series were generated. Every synthetic streamflow sequence obtained from synthetic rainfall sequences as well as the one derived from the historic rainfall events time series were optimized and optimal decisions were formulated. These decisions were assessed by means of multiple regression analysis to estimate the relation between the optimal decision to every stage (dry or rainfall event) and other system variables. Optimal rules, which have a linear form, were derived by predetermined useful storage interval and depend on storage, inflows and downstream demand at dry or rainfall event t. The range of t is 1–13 days (rainfall event) and 1–57 days (dry event). The rules were satisfactory for every predetermined useful storage interval. The simulated dam performance generated by the operation rules was compared with the deterministic optimum operation and the historical operation. Also included is the comparison of the implicit stochastic optimization-based operation policy per event during the water years 1985–2002.

Development of FLEMOcs – a new model for the estimation of flood losses in the commercial sector

Abstract

The estimation of flood damage is an important component for risk-oriented flood design, risk mapping, financial appraisals and comparative risk analyses. However, research on flood-loss modelling, especially in the commercial sector, has not gained much attention so far. Therefore, extensive data about flood losses were collected for affected companies via telephone surveys after the floods of 2002, 2005 and 2006 in Germany. Potential loss determining factors were analysed. The new Flood Loss Estimation MOdel for the commercial sector (FLEMOcs) was developed on the basis of 642 loss cases. Losses are estimated depending on water depth, sector and company size as well as precaution and contamination. The model can be applied to the micro-scale, i.e. to single production sites as well as to the meso-scale, i.e. land-use units, thus enabling its countrywide application.

Citation Kreibich, H., Seifert, I., Merz, B. & Thieken, A. H. (2010) Development of FLEMOcs – a new model for the estimation of flood losses in the commercial sector. Hydrol. Sci. J. 55(8), 1302–1314.     

The impact of the planetary β-effect on the vertical structure of a coherent vortex in the South China Sea

Ocean Dynamics - Vertical axes of mesoscale eddies with the coherent structure were observed to tilt southwestward significantly from the sea surface to bottom in the South China Sea. The dynamic...     

Implementation of a wetting-and-drying model in simulating the Kennebec–Androscoggin plume and the circulation in Casco Bay

A high-resolution coastal ocean model was developed to simulate the temporal/spatial variability of the Kennebec–Androscoggin (K–A) river plume and the circulation in Casco Bay. The model results agree favorably with the moored and shipboard observations of velocity, temperature, and salinity. The surface salinity gradient was used to distinguish the plume from the ambient coastal water. The calculated plume thickness suggests that the K–A plume is surface trapped. Its horizontal scales correlate well with Q ^0.25, where Q is the volume discharge of the rivers. Directional spreading is affected by the wind with the upwelling favorable wind transporting the plume water offshore. Both the wind and the tide also enhance mixing in the plume. The inclusion of a wetting-and-drying (WAD) scheme appears to enhance the mixing and entrainment processes near the estuary. The plume becomes thicker near the mouth of the estuary, the outflow velocity of the plume is weaker, and the radius of the river plume shrinks. The flow field in the model run with the WAD is noisier, not only in shallow areas of Casco Bay but also in the plume and even on the shelf. We speculate that the WAD processes can affect much larger areas than the intertidal zones, especially via a river plume that feeds into a coastal current.     

Cold water anomalies in the middle layer of the northern Taiwan Strait in spring—a numerical approach

Ocean Dynamics - Cold water anomalies were found in the middle layer in the northern Taiwan Strait in the spring of 2015. The cold water was located at a depth of approximately...     

Ghana’s experience in the establishment of a national data center

The government of Ghana in a bilateral agreement with the Preparatory Commission for the Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO) has established a National Data Center in Ghana with the aim of monitoring the testing of nuclear explosions. Seismic, hydroacoustic, radionuclide and infrasound methods are used for the monitoring. The data center was commissioned on 3 February, 2010 at the Ghana Atomic Energy Commission. At present Ghana does not have any operational, centralised data (seismic, hydroacoustic, radionuclide and infrasound) acquisition system with the capability of accessing data from other international stations. Hence, the need of setting up the National Data Center which would enable us constantly monitor, manage and coordinate both natural and man-made seismic activities in the country and around the globe, upload data to the International Data Center (IDC) as well as receive and use International Monitoring System (IMS) data and IDC products for treaty verification and compliance. Apart from these, the center also accesses and analyzes seismic waveforms relevant to its needs from the International Data Center; makes data available to its stakeholder institutions for earthquake disaster mitigation; reports on all aspects of disasters related to earthquake to the relevant government agencies that deal with disasters; makes recommendations to the government of Ghana on earthquake safety measures; provides information to assist government institutions to develop appropriate land and building policies. The center in collaboration with stakeholder agencies periodically organises public lectures on earthquake disaster risk mitigation.     

Role of magnetospheric convection and precipitation in the formation of the “dusk effect” during the main phase of a magnetic storm

This paper studies the role of magnetospheric factors, such as convection and energetic electron precipitation during the formation of positive disturbances in the total electron content under the conditions of the summer evening ionosphere. à numerical model of the ionosphere and plasmasphere, where time variations in the magnetospheric convection velocity and electron precipitation parameters correspond to the main phase of a magnetic storm, has been used for this purpose. It has been indicated that the total electron content sharply increases (the “dusk effect”) in the eastern and western sectors at approximately the same geomagnetic latitudes corresponding to the subauroral zone provided that a sudden storm commencement is registered in the morning hours. local time. This peak of the total electron content is formed as a result of joint reconstruction of the magnetospheric convection pattern and energetic electron precipitation during the main phase of a storm. In this case, magnetospheric convection plays the main role, raising the F2 layer by 40–80 km into the region with a lower recombination rate.     

Spatiotemporal distributions of earthquakes in the northeastern segment of the Amur plate in two phases of variations in the modulus of the Earth’s rotation rate

The modeling results are presented on the annual dynamics of seismicity in the northeastern segment of the Amur plate, which are obtained from statistical studies of the number of earthquakes with magnitudes 2 ≤ М ≤ 6 in different phases of variations in the Earth’s rotation rate. We have calculated a degree of relationship between the observed seismicity variations and phases of decrease and increase in the Earth’s rotation rate for the magnitude ranges between 2 ≤ М < 4 and 4 ≤ М < 5 using rank correlation methods. It has been established that epicenters of earthquakes with magnitudes 5 ≤ М ≤ 6 are spatially grouped into a sequence of homogeneous equally spaced, 3.5°–4°, on average, east-westerly oriented clusters.     

Evaluation of the Capacity of Comprehensive Earthquake Prevention System in a Region and Its Countermeasures

A model for evaluating the capacity of the comprehensive prevention system in a region in terms of economic losses is established in this paper by using fuzzy mathematics.The authors have explored the weak links of the system mentioned above and suggested an effective procedure of increasing the capacity of earthquake resistance and disaster prevention in a region.Through taking suitable means of decision making,the mathematical model presented in this paper can be used for reference during establishing the comprehensive prevention system in a region to reduce the earthquake disasters.     

Long-range dependence in the time series of Taiţa River discharges

ABSTRACT

The aim of this article is to offer an insight into the hydrology of southeast Romanian catchments, which have not been studied systematically. The complex behaviour of the Tai?a, one of the most important rivers situated in the northern part of Dobrogea, is demonstrated. Long-range dependence (LRD) in the time series of its streamflow, including the presence of trends, is supported by an estimated Hurst exponent of approximately 0.8, as well as statistical tests.

Editor D. Koutsoyiannis; GUEST editor S. Weijs     

Chloropigments a in the Gulf of Gdańsk (Baltic Sea) as markers of the state of this environment

The Gulf of Gdańsk receives the waters of the Wis?a (Vistula), the largest Polish river and the second largest river flowing into the Baltic Sea. Chloropigments a (chlorophyll a and its derivatives) were determined in water and sediments from the Gulf. Samples were collected during cruises of R.V. 'Oceania' at 19 stations located at different water depths and distances from the shore, in May (2003) and October (2004), i.e., at the beginning and at the end of the growing season, respectively. Seawater was also sampled on the beach at Sopot in June, July and August 2004, i.e., during the height of the growing season. All water samples were collected with a bathometer and passed through Whatman GF/F filters. Recent sediments (0-10 cm) were collected with a core sampler and divided into sub-samples (0-1, 1-5 and 5-10 cm). The pigments were determined using HPLC-DAD. The results were first correlated with a set of parameters measured in situ during sample collection (salinity, temperature, oxygen content of seawater) and determined in the same material (organic carbon content, granulometry), then worked up statistically. Although this investigation shows that particular chloropigments a in recent sediments are indicative of the prevailing environmental conditions in the study area and the trends in their variations, they should be treated as a relative and not an absolute measure, since this is the first such study based on a large and coherent set containing both chloropigment a and environmental data. In addition, a chlorophyll a budget is estimated for the Gulf of Gdańsk on the basis of the literature and the authors' own data. Only c. 10% of the chlorophyll a produced annually in the Gulf of Gdańsk is transferred to sediments in the form of chloropigments a; 2.8% is in the form of undecomposed chlorophyll a and 7.2% in the form of chlorophyll a derivatives. About 90% of chlorophyll a is decomposed to colourless products.     

Geometry and dynamics of the freshwater—seawater interface in a coastal aquifer in southeastern Spain

Abstract

The contact between freshwater and seawater in coastal aquifers is studied using a relatively simple model for homogeneous aquifers. However, for real aquifers it is not so simple. The desalination plant built to supply water to the city of Almería is situated over the aquifer in the southern part of the River Andarax Delta. Its design capacity is 1100 L s^?1, and it is supplied from boreholes pumping water from beneath the freshwater—seawater contact in this aquifer. Well logs kept over a period of two years have allowed us to accurately define the interface geometry of the freshwater—seawater contact. Lithological data collected from 31 boreholes have also indicated the existence of strata with low hydraulic conductivity, within others of high conductivity. During a simultaneous pumping test of six wells with 690 L s^?1 total discharge, electrical conductivity measurements showed the influx of seawater 6–10 m below sea level and a drawdown of the interface in the piezometers closest to the pumping wells.     

Variations in the area of the global field of noctilucent clouds of the northern hemisphere in 2007–2012 seasons

Using daily distributions of noctilucent cloud fields obtained for 2007–2012 by the AIM satellite, we analyzed temporal changes in the area of the global field of mesospheric noctilucent clouds. These clouds have been shown to be characterized by some common features that can be approximated mathematically by simple functions reflecting the seasonal course of the temperature and humidity regime of the high-latitude mesosphere, allowing a clear physical interpretation. We discuss the specific features of changes in the cloud field area for individual seasons.     

Forcing mechanism of the Pleistocene east Asian monsoon variations in a phase perspective

The variations of the Earth’s geometry (ETP) pre-dominate climate changes such as monsoon on the Earth[1], serving as its external forcing. The loess/ paleosol sequence in Central China provides a good record of terrestrial deposition to study the evolution of the east Asian monsoon[2―4]. However, the deep sea deposition, due to its high resolution dating and abun-dant climate proxies, should be able to provide more climatic information in the geological time, such as the forcing mechanis…     

Hydrological Processes in a Lagoon–Channel Estuary in the Warm Season: Case Study of the Mouth of the Bol’shaya R., Western Kamchatka

Water Resources - The results of long-term field studies are used to consider in detail the issues of hydrological regime formation in a lagoon–channel estuary of the Bol’shaya R. in...