1,721,266 research outputs found
ANALYSIS OF TOPOGRAPHIC AND CLIMATIC CONTROL ON RAINFALL-TRIGGERED SHALLOW LANDSLIDING USING A QUASI-DYNAMIC WETNESS INDEX
No full textA model for the prediction of both topographic and climatic control on shallow landslide initiation processes in hilly
mountainous terrain is proposed. The model develops upon a theory for coupled shallow subsurface flow and landsliding of the
soil mantle previously proposed by Montgomery and Dietrich [Water Resour. Res. 30 (1994) 1153]. The model uses a ‘quasi-
dynamic’ wetness index to predict the spatial distribution of soil saturation in response to a rainfall of specified duration. The
rainfall predicted to cause instability in each topographic element is characterised by duration and frequency of occurrence. The
incorporation of a rainfall frequency – duration relationship into assessment of landslide hazard provides a practical way to
include climate information into estimation of the relative potential for shallow landsliding. The model is applied to a mountain
experimental basin where high-resolution digital elevation data are available: the Cordon catchment (5 km
2
), in north-eastern
Italy. An inventory of landslide scars is used to document sites of instability and to provide a test of model performance by
comparing observed landslide locations with model predictions. The model reasonably reproduces the observed distribution of
landslides, although spatial variability of soil properties and hydrologic complexities not accounted for by the model complicate
prediction of where landslides occur within areas of similar topographic-climatic control. Model predictions from the quasi-
dynamic model are compared with those provided by the steady-state model [Water Resour. Res. 30 (1994) 1153]. These results
suggest that the quasi-dynamic model offers significant improvement over the steady-state model in predicting existing
landslides as represented in the considered landslide inventory. q 2002 Published by Elsevier Science B.V
Metodologia per la valutazione degli effetti idroerosivi della viabilità minore in ambiente montano
No full textProgetto INMR 2001. Rapporto Conclusiv
Intensity-duration-frequency analysis of energy supply droughts from RoR hydropower and solar PV across an Alpine transect.
No full textIntensity-duration-frequency analysis of energy supply droughts from renewable energy sources across an Alpine transect.
No full textUncertainty in Estimation of Debris-Flow Triggering Rainfall: Evaluation and Impact on Identification of Threshold Relationships
No full textOperational debris-flow warning systems are often based on the use of empirical rainfall thresholds derived from rain gauge observations. However, rain gauges are usually located away from the actual debris-flow locations thus estimation of triggering rainfall properties from rain gauges can be associated with considerable uncertainty. This work examines the uncertainty in gauge-based estimation of debris-flow triggering rainfall and evaluates its impact on the identification of rainfall thresholds used for debris-flows prediction. These issues are assessed by using high-resolution radar data to represent "actual" space-time patterns of precipitation at and around the debris-flow initiation points. Rain-gauge network sampling is simulated by randomly sampling radar-rainfall fields. Rainfall is estimated by using three rainfall interpolation methods: Nearest neighbor (NN), inverse distance weighting (IDW), and ordinary kriging (OK). Comparison of results from these three methods shows that no particular benefit in intensity-duration threshold estimation is obtained by using approaches that are more complex than the NN method. NN provides estimates with smaller bias than IDW and OK but larger estimation variance. On average, decrease in gauge density leads to increased underestimation of debris-flow rainfall and subsequently this results in large underestimation of the intensity-duration thresholds
Rainfall estimation by weather radar
No full textKnowledge of the spatial and temporal variability of rainfall over a wide range of scales is required in a variety of disciplines. Examples range from hydrology, soil erosion, and cloud and precipitation physics to the design and operation of water management, telecommunication, and atmospheric remote sensing systems. As a result of the gradual development of radar technology over the past 70 years, ground-based weather radar represents now an established tool for quantitative rainfall measurement at a space-time resolution of typically 1 km2 and 5 min, over a wide range of spatial and temporal scales. This chapter provides an outline of the principles of precipitation estimation by means of weather radar, with coverage of the main techniques for weather radar observation and of the methods used to generate rainfall products starting from weather radar observables
I cabrei dell’ordine ospitaliero: dalla documentazione alla ricerca di persistenze e trasformazioni del paesaggio rurale del versante meridionale dei Berici
No full textI cabrei figurati e descrittivi, individuati dalla ricerca d’archivio di M.G. Bulla Borga, offrono interessanti considerazioni, oltre che sulle trasformazioni del paesaggio rurale, anche sulla prassi di conservazione dei patrimoni religiosi e sulle professionalità dei mappatori
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
TOPMELT 1.0: A topography-based distribution function approach to snowmelt simulation for hydrological modelling at basin scale
Full text linkEnhanced temperature-index distributed models for snowpack simulation, incorporating air temperature and a term for clear sky potential solar radiation, are increasingly used to simulate the spatial variability of the snow water equivalent. This paper presents a new snowpack model (termed TOPMELT) which integrates an enhanced temperature-index model into the ICHYMOD semidistributed basin-scale hydrological model by exploiting a statistical representation of the distribution of clear sky potential solar radiation. This is obtained by discretizing the full spatial distribution of clear sky potential solar radiation into a number of radiation classes. The computation required to generate a spatially distributed water equivalent reduces to a single calculation for each radiation class. This turns into a potentially significant advantage when parameter sensitivity and uncertainty estimation procedures are carried out. The radiation index may be also averaged in time over given time periods. Thus, the model resembles a classical temperatureindex model when only one radiation class for each elevation band and a temporal aggregation of 1 year is used, whereas it approximates a fully distributed model by increasing the number of the radiation classes and decreasing the temporal aggregation. TOPMELT is integrated within the semidistributed ICHYMOD model and is applied at an hourly time step over the Aurino Basin (also known as the Ahr River) at San Giorgio (San Giorgio Aurino), a 614 km2 catchment in the Upper Adige River basin (eastern Alps, Italy) to examine the sensitivity of the snowpack and runoff model results to the spatial and temporal aggregation of the radiation fluxes. It is shown that the spatial simulation of the snow water equivalent is strongly affected by the aggregation scales. However, limited degradation of the snow simulations is achieved when using 10 radiation classes and 4 weeks as spatial and temporal aggregation scales respectively. Results highlight that the effects of space-time aggregation of the solar radiation patterns on the runoff response are scale dependent. They are minimal at the scale of the whole Aurino Basin, while considerable impact is seen at a basin scale of 5 km
- …
