bluuebunny/crossref_metadata_2025 huggingface dataset:
Classification of hydro-meteorological conditions and multiple artificial neural networks for streamflow forecasting
Authors: Toth E.
Published: April 2010

Abstract. This paper presents the application of a modular approach for real-time streamflow forecasting, that uses different system-theoretic rainfall-runoff models according to the situation characterising the forecast instant. For each forecast instant, a specific model is applied, parameterised on the basis of the data of the similar hydrological and meteorological conditions observed in the past. In particular, the hydro-meteorological conditions are here classified with a clustering technique based on Self-Organising Maps (SOM) and, in correspondence of each specific case, different feed-forward artificial neural networks issue the streamflow forecasts one to six hours ahead, for a mid-sized case study watershed. The SOM method allows a consistent identification of the different parts of the hydrograph, corresponding to current and future hydrological conditions, on the basis of the only information available in the forecast instant. The results show that an adequate distinction of the hydro-meteorological conditions characterising the basin, hence including additional knowledge on the forthcoming dominant hydrological processes, may considerably improve the rainfall-runoff modelling performance.
Monitoring temporary ponds dynamics in arid areas with remote sensing and spatial modelling
Authors: Soti V. , Puech C. , Lo Seen D. , Bertran A. , Vignolles C. , Mondet B. , Dessay N. , Tran A.
Published: April 2010

Abstract. A hydrologic pond model was developed that simulates daily spatial and temporal variations (area, volume and height) of temporary ponds around Barkedji, a village located in the Ferlo Region in Senegal. The model was tested with rainfall input data from a meteorological station and from Tropical Rainfall Measuring Mission (TRMM) satellites. During calibration phase, we used climatic, hydrologic and topographic field data of Barkedji pond collected daily during the 2002 rainy season. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Digital Elevation Model (DEM) and a QuickBird satellite image acquired in August 2005 (2.5 m pixel size) were used to apply the hydrologic model to all ponds (98 ponds) of the study area. With input rainfall data from the meteorological station, simulated water heights values for years 2001 and 2002 were significantly correlated with observed water heights for Furdu, Mous 2 and Mous 3 ponds, respectively with 0.81, 0.67 and 0.88 Nash coefficients. With rainfall data from TRMM satellite as model input, correlations were lower, particularly for year 2001. For year 2002, the results were acceptable with 0.61, 0.65 and 0.57 Nash coefficients for Barkedji, Furdu and Mous 3 ponds, respectively. To assess the accuracy of our model for simulating water areas, we used a pond map derived from Quickbird imagery (August 2007). The validation showed that modelled water areas were significantly correlated with observed pond surfaces (r2=0.90). Overall, our results demonstrate the possibility of using a simple hydrologic model with remote sensing data (Quickbird, ASTER DEM, TRMM) to assess pond water heights and water areas of a homogeneous arid area.
Landuse effects on runoff generating processes in tussock grassland indicated by mean transit time estimation using tritium
Authors: Stewart M. K. , Fahey B. D.
Published: April 2010

Abstract. The east Otago uplands of New Zealand's South Island have long been studied because of the environmental consequences of converting native tussock grasslands to other land covers, notably forestry and pasture for stock grazing. Early studies showed that afforestation substantially reduced annual water yield, stream peak flows, and 7-day low flows, mainly as a consequence of increased interception. Tritium measurements have indicated that surprisingly old water is present in catchments GH1 and GH2, and the small headwater wetland and catchment (GH5). The old water contributes strongly to baseflow (and therefore also to quickflow). The data have been simulated assuming the presence of two types of water in the baseflow, young water from shallow aquifers connecting hillside regolith with the stream, and old water from deep bedrock aquifers, respectively. The mean transit time of the young water is of the order of months, while that of the old water is 25–26 years as revealed by the presence of tritium originating from the bomb-peak in NZ rainfall in late 1960s and early 1970s. Such a long transit time indicates slow release from groundwater reservoirs within the bedrock, which constitute by far the larger of the water stores. Comparison of the results from catchments GH1 (tussock) and GH2 (pine forest) suggests that about equal quantities of water (85 mm annually) are contributed from the deep aquifers in the two catchments, although runoff from the shallow aquifers has been strongly reduced by afforestation in GH2.
Evaluation of PERSIANN database in the framework of SMOS Calibration/Validation activities over Valencia Anchor Station
Authors: Juglea S. , Kerr Y. , Mialon A. , Lopez-Baeza E. , Braithwaite D. , Hsu K.
Published: April 2010

Abstract. Soil moisture is a key parameter for land surface water resource and climate change monitoring. ESA's Soil Moisture and Ocean Salinity (SMOS) mission will deliver, as one of its main goals, global fields of surface soil moisture with an accuracy better than 0.04 m3 m−3. SMOS relies on an L-band (1.4 GHz) interferometric radiometer. Within the context of the preparation for this mission over land, the Valencia Anchor Station (VAS) experimental site, in Spain, was selected to be one of the main test sites in Europe for the SMOS Calibration/Validation (Cal/Val) activities. This study presents preliminary analysis of PERSIANN in the framework of SMOS Cal/Val activities at the Valencia Anchor Station. The PERSIANN database is an automated system for Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks. The real interest of using the PERSIANN database into the hydrologic applications is mainly with the goal of having access to the spatial and temporal distribution of precipitation over a significant area (typically here an area equivalent to a SMOS pixel). The goal of this study is to quantify the gain of using PERSIANN instead of distributing sparse rain gauge measurements. The interest of using satellite rainfall estimates as well as the influence that the precipitation events can induce on the modelling of the water content in the soil was depicted by a comparison between different soil moisture products. Having an accurate estimation of the amount and temporal/spatial distribution of precipitation is a critical issue so as to have a faithful representation of the soil moisture distribution.
Hydrological response unit-based blowing snow modelling over an alpine ridge
Authors: MacDonald M. K. , Pomeroy J. W. , Pietroniro A.
Published: April 2010

Abstract. Snow redistribution by wind and the resulting accumulation regimes were simulated for two winters over an alpine ridge transect located in the Canada Rocky Mountains. Simulations were performed using physically based blowing snow and snowmelt models. A hydrological response unit (HRU)-based spatial discretization was used rather than a more computationally expensive fully-distributed one. The HRUs were set up to follow an aerodynamic sequence, whereby eroded snow was transported from windswept, upwind HRUs to drift accumulating, downwind HRUs. HRUs were selected by examining snow accumulation patterns from manual snow depth measurements. Simulations were performed using two sets of wind speed forcing: (1) station observed wind speed, and (2) modelled wind speed from a widely applied empirical, terrain-based windflow model. Best results were obtained when using the site meteorological station wind speed data. The windflow model performed poorly when comparing the magnitude of modelled and observed wind speeds, though over-winter snow accumulation results obtained when using the modelled wind speeds were reasonable. However, there was a notable discrepancy (17%) between blowing snow sublimation quantities estimated when using the modelled and observed wind speeds. As a result, the end-of-winter snow accumulation was considerably underestimated (32%) when using the modelled wind speeds. That snow redistribution by wind can be adequately simulated in computationally efficient HRUs over this alpine ridge has important implications for representing snow transport in large-scale hydrology models and land surface schemes. Snow redistribution by wind was shown to significantly impact snow accumulation regimes in mountainous environments as snow accumulation was reduced to less than one-third of snowfall on windswept landscapes and nearly doubled in certain lee slope and treeline areas. Blowing snow sublimation losses were shown to be significant (approximately one-quarter of snowfall or greater).
Hydrograph separation and scale dependency of natural tracers in a semi-arid catchment
Authors: Bohté R. , Mul M. L. , Bogaard T. A. , Savenije H. H. G. , Uhlenbrook S. , Kessler T. C.
Published: April 2010

Abstract. A solid understanding of the hydrological processes in a catchment is important in order to guarantee appropriate management of the available surface and groundwater resources, both in terms of quality and quantity. In order to achieve this, insights in the behaviour of the water fluxes and the interaction between groundwater and surface water is of utmost importance. This paper discusses the applicability and constraints of using hydrochemical and isotope tracers in identifying the runoff contributing sources at different scales in a semi-arid catchment in Tanzania. The hydrograph separation techniques shows that at the smallest scale (0.3 km2), for all types of tracers, the pre-event contribution is between 74–82%. At the larger scale (26 km2), two sub-catchments contribute to the flow at the weir site in Bangalala. Using the hydrochemical tracers the calculated contributions for the sub-catchments are in agreement with the catchment size and rainfall contributions over these two catchments. This showed that at the weir site 20% of the total flow comes from event water (of which 2% from Vudee sub-catchment and 18% from Ndolwa sub-catchment). The large difference is mainly due to preceding wetness conditions. However, with the isotope tracers no unambiguous results could be obtained. Two end members have been investigated to account for the ambiguous nature of the isotopic concentrations. The rainfall analysis shows that during the season the isotopical concentration changes, with a clear distinction between the two seasons. In addition, within one event the isotopic concentrations vary substantially within the area. The spring analysis also shows substantial temporal and spatial variation. The research therefore shows that the assumption of stable isotopic end-members was not met in our study. At the smaller scale the spatial variability could be neglected and the hydrograph separation technique could be applied, although for each event, end member concentrations needed to be collected to account for the temporal variability.
Performance analysis of the proposed Reservoir Project in the State of West Bengal
Authors: Roy D. , Banerjee D.
Published: April 2010

Abstract. Water is an essential and integral part of livelihood but it is becoming scarce and contaminated day by day. Moreover, due to huge population growth the demand for water is rising especially in agricultural, industries and for municipal uses. So, to meet the rising water demand, reservoirs are constructed in different parts of the country to store water during monsoon and supply it throughout the year according to the demand. The reservoir is also constructed for controlling the peak of high flood which is quite common in many places. The Dwarakeswar River in the district of Bankura in the State of West Bengal has only seasonal flow of water. In order to meet the agricultural and municipal water requirement throughout the year and also for controlling the flood, it has been proposed to construct a reservoir at Suknibasa on the river near Bankura Town. The analysis of the performance of this reservoir for meeting various demands (under historical as well as projected scenario) as well as its capability for moderating flood has been reported in the present paper. The projected scenario involves the modeling of streamflow for future time frame using the Thomas-Fiering method and the flood moderation analysis involves the estimation of design flood hydrograph for the river at Suknibasa. The study reveals that the Suknibasa reservoir is capable of meeting all demands and moderating flood for which it has been proposed to be constructed.
Runoff response time of a loosely defined supraglacial microbasin
Authors: Scott Munro D.
Published: April 2010

Abstract. A micrometeorological experiment was conducted in the summer of 2008, at Peyto Glacier, during four meltwater production periods of 1, 3, 4 and 5 days duration, the last two days marked by late summer snow cover. The data include a breakdown of net radiation into its short- and long-wave components, as well as wind speed, temperature and humidity profile data for use in bulk transfer estimates of sensible heat and moisture transfer. In addition, a hydrological experiment was conducted, the data comprising sonic sounder measurements of ablation and stage level records of discharge from a supraglacial microbasin. As expected, the ratio of daily average runoff flow measurement to energy budget flow estimates is less than one on most days because of weathering crust development. Also, the conversion of stage level data into discharge from a supraglacial catchment presents challenges, notably defining the area of a loosely defined basin and specifying stage level on a downward moving surface. Nevertheless, it is clear that peak discharge lags peak meltwater energy input by periods of four to six hours. A suitably lagged flow estimate can be achieved by passing the flow through a simple storage reservoir, using delay times of 14.5, 15, 7.5 and 9 h for each respective measurement period. This suggests that a substantial part of the delay in runoff from a glacier basin is tied up in ice surface hydrological processes.
Using flushing rate to investigate spring-neap and spatial variations of gravitational circulation and tidal exchanges in an estuary
Authors: Shaha D. C. , Cho Y.-K. , Seo G.-H. , Kim C.-S. , Jung K.-T.
Published: April 2010

Abstract. Spring-neap and spatial variations of gravitational circulation and tidal exchanges in the Sumjin River Estuary (SRE) were investigated using the flushing rate method. This method was applied to multiple estuarine segments to estimate both the exchanges. The strength of gravitational circulation and tidal exchanges modulated significantly between spring and neap tides, where stratification alternated between well-mixed and highly-stratified conditions over the spring-neap cycle. Strong gravitational circulation developed during neap tide along the SRE due to the significant reduction in vertical mixing that accompanied strong stratification. The tidal exchanges dominated over gravitational circulation near the mouth during spring tide due to the larger tidal amplitude that caused well-mixed conditions and rapid exchange. In contrast, the central and inner regimes were found to be partially stratified during spring tide due to the reduction in tidal amplitude which induced gravitational circulation and weakened the tidal exchange. Only the gravitational circulation dominated at the upstream end during spring and neap tides which was governed by the river flow.
Stochastic rainfall analysis for storm tank performance evaluation
Authors: Andrés-Doménech I. , Montanari A. , Marco J. B.
Published: April 2010

Abstract. Stormwater detention tanks are widely used for mitigating impacts of combined sewer overflows (CSO) from urban catchments into receiving water bodies. The optimal size of detention tanks depends on climate and sewer system behaviours and can be estimated by using derived distribution approaches. They are based on using a stochastic model to fit the statistical pattern of observed rainfall records and a urban hydrology model to transform rainfall in sewer discharge. A key issue is the identification of the optimal structure of the stochastic rainfall model. Point processes are frequently applied where rainfall events are schematised through the occurrence of rectangular pulses, which are governed by rainfall descriptors. In the model herein used these latter descriptors are the interevent time (duration of the dry period between consecutive storms), event rainfall depth and event rainfall duration. This paper focuses on the analytical derivation of the probability distribution of the number and volume of overflows from the storm tank to the receiving water body for different and non-standard shapes of the probability distribution for above mentioned descriptors. The proposed approach is applied to 2 different sites in Spain: Valencia and Santander located on the Mediterranean and northern Atlantic coastline, respectively. For both cases, it turned out that Pareto and Gamma-2 probability distributions for rainfall depth and duration provided better fit than the exponential model, widely used in previous studies. A comparison between the two climatic zones, humid and semiarid, respectively, proves the key role played by climatic conditions for storm detention tanks sizing.
Bayesian approach for three-dimensional aquifer characterization at the hanford 300 area
Authors: Murakami H. , Chen X. , Hahn M. S. , Liu Y. , Rockhold M. L. , Vermeul V. R. , Zachara J. M. , Rubin Y.
Published: April 2010

Abstract. This study presents a stochastic, three-dimensional characterization of a heterogeneous hydraulic conductivity field within DOE's Hanford 300 Area site, Washington, by assimilating large-scale, constant-rate injection test data with small-scale, three-dimensional electromagnetic borehole flowmeter (EBF) measurement data. We first inverted the injection test data to estimate the transmissivity field, using zeroth-order temporal moments of pressure buildup curves. We applied a newly developed Bayesian geostatistical inversion framework, the method of anchored distributions (MAD), to obtain a joint posterior distribution of geostatistical parameters and local log-transmissivities at multiple locations. The unique aspects of MAD that make it suitable for this purpose are its ability to integrate multi-scale, multi-type data within a Bayesian framework and to compute a nonparametric posterior distribution. After we combined the distribution of transmissivities with depth-discrete relative-conductivity profile from the EBF data, we inferred the three-dimensional geostatistical parameters of the log-conductivity field, using the Bayesian model-based geostatistics. Such consistent use of the Bayesian approach throughout the procedure enabled us to systematically incorporate data uncertainty into the final posterior distribution. The method was tested in a synthetic study and validated using the actual data that was not part of the estimation. Results showed broader and skewed posterior distributions of geostatistical parameters except for the mean, which suggests the importance of inferring the entire distribution to quantify the parameter uncertainty.
Possibilistic uncertainty analysis of a conceptual model of snowmelt runoff
Authors: Jacquin A. P.
Published: April 2010

Abstract. This study presents the analysis of predictive uncertainty of a conceptual type snowmelt runoff model. The method applied uses possibilistic rather than probabilistic calculus for the evaluation of predictive uncertainty. Possibility theory is an information theory meant to model uncertainties caused by imprecise or incomplete knowledge about a real system rather than by randomness. A snow dominated catchment in the Chilean Andes is used as case study. Predictive uncertainty arising from parameter uncertainties of the watershed model is assessed. Model performance is evaluated according to several criteria, in order to define the possibility distribution of the model representations. The likelihood of the simulated glacier mass balance and snow cover are used for further assessing model credibility. Possibility distributions of the discharge estimates and prediction uncertainty bounds are subsequently derived. The results of the study indicate that the use of additional information allows a reduction of predictive uncertainty. In particular, the assessment of the simulated glacier mass balance and snow cover helps to reduce the width of the uncertainty bounds without a significant increment in the number of unbounded observations.
Topographic effects on solar radiation distribution in mountainous watersheds and their influence on reference evapotranspiration estimates at watershed scale
Authors: Aguilar C. , Herrero J. , Polo M. J.
Published: April 2010

Abstract. Distributed energy and water balance models require time-series surfaces of the climatological variables involved in hydrological processes. Among them, solar radiation plays an important role, especially in arid environments, as it is a key variable to the circulation of water in the atmosphere. The lack of reliable data for the assessment of solar radiation has led to the use of models. Most of the hydrological GIS-based models apply simple interpolation techniques to data measured at sparse meteorological stations disregarding topographic effects. Here, a topographic solar radiation algorithm is included for the generation of detailed time-series solar radiation surfaces using limited data and relatively simple methods, in order to quantify the effects of topography on the water losses through evapotranspiration estimates in a mountainous watershed in southern Spain. First, the comparison between the topographically corrected interpolated values of daily solar radiation and those obtained by a direct spatial interpolation technique (Inverse Distance Weighed, IDW) is provided. The results show the major role of topography in local values and differences of up to +60% and −90% in the estimated daily values. Besides, the results are compared to experimental data proving the usefulness of the model for the estimation of spatially distributed radiation values in complex terrain, with a good adjustment for daily values and the best fits under cloudless skies at hourly time steps. Finally, evapotranspiration fields estimated through the ASCE-Penman-Monteith equation using both corrected and non-corrected radiation values address the hydrologic importance of using topographically corrected solar radiation fields as inputs to the equation over uniform values with mean differences in the watershed of 62 mm/year and 142 mm/year of standard deviation. High speed computations in a 1300 km2 watershed in the south of Spain with up to a one-hour time scale in 30×30 m2 cells can be easily carried out on a desktop PC.
A global and high-resolution assessment of the green, blue and grey water footprint of wheat
Authors: Mekonnen M. M. , Hoekstra A. Y.
Published: April 2010

Abstract. The aim of this study is to estimate the green, blue and grey water footprint of wheat in a spatially-explicit way, both from a production and consumption perspective. The assessment is global and improves upon earlier research by taking a high-resolution approach, estimating the water footprint of the crop at a 5 by 5 arc minute grid. We have used a grid-based dynamic water balance model to calculate crop water use over time, with a time step of one day. The model takes into account the daily soil water balance and climatic conditions for each grid cell. In addition, the water pollution associated with the use of nitrogen fertilizer in wheat production is estimated for each grid cell. We have used the water footprint and virtual water flow assessment framework as in the guideline of the Water Footprint Network. The global wheat production in the period 1996–2005 required about 1088 billion cubic meters of water per year. The major portion of this water (70%) comes from green water, about 19% comes from blue water, and the remaining 11% is grey water. The global average water footprint of wheat per ton of crop was 1830 m3/ton. About 18% of the water footprint related to the production of wheat is meant not for domestic consumption but for export. About 55% of the virtual water export comes from the USA, Canada and Australia alone. For the period 1996–2005, the global average water saving from international trade in wheat products was 65 Gm3/yr. A relatively large total blue water footprint as a result of wheat production is observed in the Ganges and Indus river basins, which are known for their water stress problems. The two basins alone account for about 47% of the blue water footprint related to global wheat production. About 93% of the water footprint of wheat consumption in Japan lies in other countries, particularly the USA, Australia and Canada. In Italy, with an average wheat consumption of 150 kg/yr per person, more than two times the word average, about 44% of the total water footprint related to this wheat consumption lies outside Italy. The major part of this external water footprint of Italy lies in France and the USA.
Impact of climate evolution and land use changes on water yield in the Ebro basin
Authors: López-Moreno J. I. , Vicente-Serrano S. M. , Moran-Tejeda E. , Zabalza J. , Lorenzo-Lacruz J. , García-Ruiz J. M.
Published: April 2010

Abstract. In this study the climatic and hydrological trends across 88 sub-basins of the Ebro River basin were analyzed for the period 1950–2006. A new database of climate information and river flows for the entire basin facilitated a spatially distributed assessment of climate-runoff relationships. It constitutes the first assessment of water yield evolution across the whole Ebro basin, a very representative example of large Mediterranean rivers. The results revealed a marked decrease in river discharges in most of the sub-basins. Moreover, a number of changes in the seasonality of the river regime was found, resulting from dam regulation and a decrease in snowpack in the headwaters. Significant and positive trends in temperature were observed across most of the basin, whereas most of the precipitation series showed negative coefficients, although the decrease in magnitude was low. The time evolution of the residuals from empirical models that relate climate and runoff in each sub-basin provided evidence that climate alone does not explain the observed decrease in river discharge. Thus, changes in water yield are associated with an increase in evapotranspiration rates in natural vegetation, growth of which has expanded as a consequence of land abandonment in areas where agricultural activities and livestock pressure have decreased. In the lowlands of the basin the decrease in water yield has been exacerbated by increased water consumption for domestic, industrial and agricultural uses. Climate projections for the end of the 21st century suggest a reduced capacity for runoff generation because of increasing temperature and less precipitation. Thus, the maintenance of water supply under conditions of increasing demand presents a challenging issue requiring appropriate coordination amongst politicians and managers.
A quality assessment of spatial TDR soil moisture measurements in homogenous and heterogeneous media with laboratory experiments
Authors: Graeff T. , Zehe E. , Schlaeger S. , Morgner M. , Bauer A. , Becker R. , Creutzfeldt B. , Bronstert A.
Published: April 2010

Abstract. Investigation of transient soil moisture profiles yields valuable information of near- surface processes. A recently developed reconstruction algorithm based on the telegraph equation allows the inverse estimation of soil moisture profiles along coated, three rod TDR probes. Laboratory experiments were carried out to prove the results of the inversion and to understand the influence of probe rod deformation and solid objects close to the probe in heterogonous media. Differences in rod geometry can lead to serious misinterpretations in the soil moisture profile but have small influence on the average soil moisture along the probe. Solids in the integration volume have almost no effect on average soil moisture but result in locally slightly decreased moisture values. Inverted profiles obtained in a loamy soil with a clay content of about 16% were in good agreement with independent measurements.
Introducing a rainfall compound distribution model based on weather patterns sub-sampling
Authors: Garavaglia F. , Gailhard J. , Paquet E. , Lang M. , Garçon R. , Bernardara P.
Published: April 2010

Abstract. This paper presents a new probabilistic model for daily rainfall, using sub-sampling based on meteorological circulation. We classified eight typical but contrasted synoptic situations (weather patterns) for France and surrounding areas, using a "bottom-up" approach, i.e. from the shape of the rain field to the synoptic situations described by geopotential fields. These weather patterns (WP) provide a discriminating variable that is consistent with French climatology, and allows seasonal rainfall records to be split into more homogeneous sub-samples. An exponential POT model is used to fit the distribution of each sub-sample. The distribution of the multi-exponential weather patterns (MEWP) is then defined as the composition, for a given season, of all WP sub-sample marginal distributions, weighted by the relative frequency of occurrence of each WP. The MEWP distribution appears able to fit various shapes of distributions using a simple and robust approach for asymptotic behaviour. It is a new contribution to the ongoing debate on the probabilistic tools used to study the asymptotic behaviour of extreme rainfall from observed records. The paper is illustrated throughout with the example of the Lyon (France) rainfall record for the period 1953–2005.
Assessing the application of a laser rangefinder for determining snow depth in inaccessible alpine terrain
Authors: Hood J. L. , Hayashi M.
Published: April 2010

Abstract. Snow is a major contributor to stream flow in alpine watersheds and quantifying snow depth and distribution is important for hydrological research. However, direct measurement of snow in rugged alpine terrain is often impossible due to avalanche and rock fall hazard. A laser rangefinder was used to determine the depth of snow in inaccessible areas. Laser rangefinders use ground based light detection and ranging technology but are more cost effective than airborne surveys or terrestrial laser scanning systems and are highly portable. Data was collected within the Opabin watershed in the Canadian Rockies. Surveys were conducted on one accessible slope for validation purposes and two inaccessible talus slopes. Laser distance data was used to generate surface models of slopes when snow covered and snow-free and snow depth distribution was quantified by differencing the two surfaces. The results were compared with manually probed snow depths on the accessible slope. The accuracy of the laser rangefinder method as compared to probed depths was 0.21 m or 12% of average snow depth. Results from the two inaccessible talus slopes showed regions near the top of the slopes with 6–9 m of snow accumulation. These deep snow accumulation zones result from re-distribution of snow by avalanches and are hydrologically significant as they persist until late summer.
Spectral approach to seawater intrusion in heterogeneous coastal aquifers
Authors: Chang C.-M. , Yeh H.-D.
Published: April 2010

Abstract. This work presents a two-dimensional horizontal plane model of seawater intrusion into a heterogeneous coastal unconfined aquifer under the spatially random recharge condition from a stochastic point of view. The stochastic response of the coastal unconfined aquifer is attributed to uncertainties related to the heterogeneity of aquifer properties and spatial variability of the recharge. Based on the sharp-interface assumption, analytical expressions for the variances of the seawater-freshwater interface elevation and specific discharge in the longitudinal and transverse directions are developed using the perturbation approximation and spectral Fourier-Stieltjes nonstationary representations. We focus on the study of the impact of the heterogeneity of aquifer properties and recharge on these results.
Robust extraction of thalwegs network from DTM: application on badlands
Authors: Thommeret N. , Bailly J. S. , Puech C.
Published: April 2010

Abstract. This paper presents methods to extract badlands thalwegs network from regular grid DTM by combining terrain morphology indices to a drainage algorithm. The computation of a continuous vector network will permit the study of the badlands spatial patterns. These methods aim at delineating a thalweg only where the DTM denotes a significant curvature with respect to DTM accuracy. It relies on three major steps. Firstly, discontinuous concave areas are detected from the DTM using morphological criteria; the plan curvature and the convergence index. Secondly, the concave areas are connected using a drainage algorithm which provides continuous and tree-structured thick scheme. We assume that these areas present physical significance and correspond to a gully floor area. Finally, the thick path is reduced to its main curve and vectorised to obtain a thalwegs network. The methods are applied on both virtual and actual cases DTM. The actual case is a LiDAR DTM of Draix Badlands (French Alps). The obtained networks are quantitatively compared both to the one obtained with usual drainage area criteria and to a reference network. The networks comparison shows the great potential of the convergence index based method for thalwegs network extraction.
Study of electromagnetic emissions associated with seismic activity in Kamchatka region
Authors: Gladychev V. , Baransky L. , Schekotov A. , Fedorov E. , Pokhotelov O. , Andreevsky S. , Rozhnoi A. , Khabazin Y. , Belyaev G. , Gorbatikov A. , Gordeev E. , Chebrov V. , Sinitsin V. , Lutikov A. , Yunga S. , Kosarev G. , Surkov V. , Molchanov O. , Hayakawa M. , Uyeda S. , Nagao T. , Hattori K. , Noda Y.
Published: April 2010

Abstract. A review of data processing of electromagnetic emission observation collected at the Complex Geophysical Observatory Karimshino (Kamchatka peninsula) during the first 5 months (July–November, 2000) of its operation is given. The main goal of this study addresses the detection of the phenomena associated with Kamchatka seismic activity. The following observations have been conducted at CGO: variations of ULF/ELF magnetic field, geoelectric potentials (telluric currents), and VLF signals from navigation radio transmitters. The methods of data processing of these observations are discussed. The examples of the first experimental results are presented.
Radon measurements along active faults in the Langadas Basin, northern Greece
Authors: Papastefanou C. , Manolopoulou M. , Stoulos S. , Ioannidou A. , Gerasopoulos E.
Published: April 2010

Abstract. A network of three radon stations has been established in the Langadas Basin, northern Greece for radon monitoring by various techniques in earthquake prediction studies. Specially made devices with plastic tubes including Alpha Tracketch Detectors (ATD) were installed for registering alpha particles from radon and radon decay products exhaled from the ground, every 2 weeks, by using LR-115, type II, non-strippable Kodak films, starting from December 1996. Simultaneous measurements started using Lucas cells alpha spectrometer for instantaneous radon measurements in soil gas, before and after setting ATDs at the radon stations. Continuous monitoring of radon gas exhaling from the ground started from the middle of August 1999 by using silicon diode detectors, which simultaneously register meteorological parameters, such as rainfall, temperature and barometric pressure. The obtained data were studied together with the data of seismic events, such as the magnitude, ML, of earthquakes that occurred at the Langadas Basin during the period of measurements, as registered by the Laboratory of Geophysics, Aristotle University of Thessaloniki, in order to find out any association between them.
Nonlinear mechanism of tsunami wave generation by atmospheric disturbances
Authors: Pelinovsky E. , Talipova T. , Kurkin A. , Kharif C.
Published: April 2010

Abstract. The problem of tsunami wave generation by variable meteo-conditions is discussed. The simplified linear and nonlinear shallow water models are derived, and their analytical solutions for a basin of constant depth are discussed. The shallow-water model describes well the properties of the generated tsunami waves for all regimes, except the resonance case. The nonlinear-dispersive model based on the forced Korteweg-de Vries equation is developed to describe the resonant mechanism of the tsunami wave generation by the atmospheric disturbances moving with near-critical speed (long wave speed). Some analytical solutions of the nonlinear dispersive model are obtained. They illustrate the different regimes of soliton generation and the focusing of frequency modulated wave packets.
A precursory ULF signature for the Chi-Chi earthquake in Taiwan
Authors: Akinaga Y. , Hayakawa M. , Liu J. Y. , Yumoto K. , Hattori K.
Published: April 2010

Abstract. ULF emission data at Lunping (epicentral distance, 120 km) have been analysed for the Chi-Chi earthquake (with magnitude 7.6 and depth of 11 km) in Taiwan which occurred on 21 September 1999. Simple intensity analyses have not yielded any significant results but we have found, based on the analysis of polarization (the ratio of vertical magnetic field component Z to the horizontal component G), that the polarization (Z/G) showed a significant enhancement for two months before the earthquake. This kind of temporal evolution of polarization seems to be very similar to previous results, so that it is highly likely that this phenomenon may be associated with the Chi-Chi earthquake. Also, the comparison of the results of polarization analyses, by changing the signal threshold, has given us an approximate intensity of the seismogenic emission of the order of the monthly mean value.
Electromagnetic-wave radiation due to diastrophism of magma dike growth in Izu-Miyake volcanic eruptions in Japan in 2000
Authors: Hata M. , Takumi I. , Yasukawa H.
Published: April 2010

Abstract. A large 10 cm per day diastrophism of the crust was experienced between Kozu and Niijima Islands during the Izu-Miyake volcanic eruptions in Japan on 3–4 August 2000. The diastrophism was detected through GPS observation. The seismometer also complied a swarm of earth-quakes at this time. Our electromagnetic wave data, observed at 223 Hz at the Omaezaki site, about 110 km and 150 km northwest of the Kozu and Miyake Islands, respectively, detected a clear, anomalous magnetic flux radiation that corresponded well with the seismographic and GPS data. Similar radiation was received for about one week preceding the big volcanic eruption that occurred on 18 August 2000. These observations indicate that the electromagnetic wave monitoring system has the potential to monitor and/or warn of volcanic activity, and the facts disclose one of the mysterious radiation mechanisms of electromagnetic waves emitted from the Earth.
A simple qualitative approach for mapping regional landslide susceptibility in the Faroe Islands
Authors: Dahl M.-P. J. , Mortensen L. E. , Veihe A. , Jensen N. H.
Published: April 2010

Abstract. The Faroe Islands in the North Atlantic Ocean are highly susceptible to landslides. Following recent landslide incidents, Jarðfeingi (Faroese Earth and Energy Directorate) has pointed out, that the risk of human lives or of property being lost or affected by landslides may be increasing. This paper aims at presenting and testing a simple qualitative approach for mapping regional landslide susceptibility in the Faroe Islands, using few key parameters. The susceptibility model holds information about both landslide initiation areas and runout zones. Landslide initiation areas are determined from slope angle thresholds (25°–40°) and soil cover data, while runout zones are delineated using the angle of reach approach taking into account the presence/absence of geological benches in the runout path, which has not been considered in earlier studies. Data input is obtained from a landslide database containing 67 debris flows throughout the Faroe Islands. Angle of reach values differ significantly with the presence/absence of geological benches in the runout path. Two values of angle of reach, 21.5° and 27.6°, are used for calculating runout zones. The landslide susceptibility model is tested in a study area at the town of Klaksvík in the northern part of the Faroe Islands. A map validation comparing predicted susceptibility zones with a validation-dataset of 87 actual landslides in the study area reveal that 69% and 92%, respectively, of actual landslide initiation areas and runout zones are correctly predicted. Moreover 87% of the actual landslides are included in the overall predicted landslide susceptibility areas.
Multimodel SuperEnsemble technique for quantitative precipitation forecasts in Piemonte region
Authors: Cane D. , Milelli M.
Published: April 2010

Abstract. The Multimodel SuperEnsemble technique is a powerful post-processing method for the estimation of weather forecast parameters reducing direct model output errors. It has been applied to real time NWP, TRMM-SSM/I based multi-analysis, Seasonal Climate Forecasts and Hurricane Forecasts. The novelty of this approach lies in the methodology, which differs from ensemble analysis techniques used elsewhere. Several model outputs are put together with adequate weights to obtain a combined estimation of meteorological parameters. Weights are calculated by least-square minimization of the difference between the model and the observed field during a so-called training period. Although it can be applied successfully on the continuous parameters like temperature, humidity, wind speed and mean sea level pressure, the Multimodel SuperEnsemble gives good results also when applied on the precipitation, a parameter quite difficult to handle with standard post-processing methods. Here we present our methodology for the Multimodel precipitation forecasts, involving a new accurate statistical method for bias correction and a wide spectrum of results over Piemonte very dense non-GTS weather station network.
A multi-level strategy for anticipating future glacier lake formation and associated hazard potentials
Authors: Frey H. , Haeberli W. , Linsbauer A. , Huggel C. , Paul F.
Published: April 2010

Abstract. In the course of glacier retreat, new glacier lakes can develop. As such lakes can be a source of natural hazards, strategies for predicting future glacier lake formation are important for an early planning of safety measures. In this article, a multi-level strategy for the identification of overdeepened parts of the glacier beds and, hence, sites with potential future lake formation, is presented. At the first two of the four levels of this strategy, glacier bed overdeepenings are estimated qualitatively and over large regions based on a digital elevation model (DEM) and digital glacier outlines. On level 3, more detailed and laborious models are applied for modeling the glacier bed topography over smaller regions; and on level 4, special situations must be investigated in-situ with detailed measurements such as geophysical soundings. The approaches of the strategy are validated using historical data from Trift Glacier, where a lake formed over the past decade. Scenarios of future glacier lakes are shown for the two test regions Aletsch and Bernina in the Swiss Alps. In the Bernina region, potential future lake outbursts are modeled, using a GIS-based hydrological flow routing model. As shown by a corresponding test, the ASTER GDEM and the SRTM DEM are both suitable to be used within the proposed strategy. Application of this strategy in other mountain regions of the world is therefore possible as well.
Possible soil thermal response to seismic activities in Alborz region (Iran)
Authors: Rezapour N. , Fattahi M. , Bidokhti A. A.
Published: April 2010

Abstract. In this investigation, relations between the ground's thermal properties and 70 earthquakes with a magnitude >4 Richter in the Alborz region during a period of 12 years (1992 to 2004) were studied. Typical changes of ground temperature, 0.4 °C; thermal diffusivity, 0.028 m2 s−1×10−6 and ground heat flux take place a few hours prior to the earthquakes. The values of thermal diffusivity depend on the ground moisture content, which may change during seismic activities. The analysis of ground heat flux from the epicentre and it's surrounding regions show some anomalous behavior before the earthquakes but with different signs in the areas close to the sea and far away from the sea. The changes of the ground's thermal properties prior to the earthquakes in the Alborz region are attributed to the increase in seismic activities in the epicentre and it's surrounding regions. The anomalous behavior in the ground thermal properties shows great potential in providing early warning of imminent earthquake.
The 24 July 2008 outburst flood at the western Zyndan glacier lake and recent regional changes in glacier lakes of the Teskey Ala-Too range, Tien Shan, Kyrgyzstan
Authors: Narama C. , Duishonakunov M. , Kääb A. , Daiyrov M. , Abdrakhmatov K.
Published: April 2010

Abstract. On 24 July 2008, a glacier lake outburst flood (GLOF) occurred at the western (w-) Zyndan glacier lake in the Tong District of Ysyk-Köl Oblast, Kyrgyzstan. The flood killed three people and numerous livestock, destroyed infrastructure, and devastated potato and barley crops as well as pastures. Tuurasuu village and a downstream reservoir on the Zyndan river escaped heavy damage because the main flood was diverted toward the Tong river. RTK-GPS and satellite data (Landsat 7 ETM+, ALOS/PRISM, and ALOS/AVNIR-2) reveal that the flood reduced the lake area from 0.0422 km2 to 0.0083 km2, discharging 437 000 m3 of water. This glacier lake was not present in a Landsat 7 ETM+ image taken on 26 April 2008. It formed rapidly over just two and half months from early May to the late July, when large amounts of snow and glacier melt water became trapped in a basin in the glacier terminus area, blocked by temporary closure of the drainage channel through the terminal moraine that included much dead-ice. In the same mountain region, most other glacier-lake expansions were not particularly large during the period from 1999–2008. Although events like the w-Zyndan glacier lake outburst occur infrequently in the high Central Asian mountains, such fast developing, short-lived lakes are particularly dangerous and not easy to monitor using satellite data. Appropriate measures to protect against such lake outburst hazards in this region include educating residents on glacier hazards and monitoring techniques, providing frequently updated maps of glacier lakes, and planning and monitoring land-use, including house locations.