Home About us Contact
|
Home About us Contact | ||
|
|
||
Storms
Kinds of Storms Terms modified by Storms Selected AbstractsTHE SIXTIES: THE CALM AGAINST THE STORM, OR, LEVELS OF CONCERNEDUCATIONAL THEORY, Issue 3 2000Maxine Greene First page of article [source] THE STORM OF NOVEMBER 1826 IN THE CANARY ISLANDS: POSSIBLY A TROPICAL CYCLONE?GEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 3 2010JOSÉ BETHENCOURT-GONZÁLEZ ABSTRACT. This work analyses a storm that occurred in the Canary Islands early in November 1826. Through a study based on historical climate data, some of the adverse effects of the storm are described and some of the possible causes are discussed. The main goal of this work is to establish an approximate reconstruction of this historical event which will allow us to compare it to a recent meteorological event that had a great impact on the archipelago: "Tropical Storm Delta", in November 2005. Studying and reviewing the origin of the 1826 storm verifies the hypothesis that extremely violent perturbations have not only occurred in the Canaries on other occasions, but that these past events were also more intense and had more serious consequences than Delta. Therefore, the idea that other tropical perturbations have occurred in the region of the Canary Islands before Delta is presented. [source] Evaluating STORM skills training for managing people at risk of suicideJOURNAL OF ADVANCED NURSING, Issue 6 2006Linda Gask MSc PhD FRCPsych Aim., This paper reports a study evaluating the Skills Training On Risk Management (STORM) training initiative in three mental health services in the North-West of England, UK. Background., Training for health workers has been widely advocated as a key route to suicide prevention. However, reports of evaluations are scarce in the literature. In previous research, we have demonstrated that the STORM intervention results in acquisition of new skills and can be disseminated in a community setting. Method., The training was delivered during a 6-month period in 2002 by three mental health nurses who were seconded part-time to the project. The quantitative evaluation, which assessed change in attitudes, confidence, acquisition of skills and satisfaction, used a pretest/post-test design, with participants acting as their own controls. Qualitative interviews were conducted with a purposive sample of 16 participants to explore the impact on clinical practice, and with the three trainers at the end of the study. Findings., Data from 458 staff members were collected during a 6-month period. Positive changes in attitudes and confidence were shown, but previous evidence of skill acquisition was not replicated. Qualitative interviews revealed important insights into changes in clinical practice, particularly for less experienced or unqualified nursing staff, but also concerns about the lack of an educational culture to foster and support such interventions in practice within the organizations. Conclusion., STORM training for the assessment and management of suicide risk is both feasible and acceptable in mental health trusts. However, we remain uncertain of its longer-term impact, given the lack of engagement of senior staff in the enterprise and the absence of linked supervision and support from the organizational management to reinforce skill acquisition and development. We consider that regular supervision that links STORM training to actual clinical experience would be the ideal. [source] STORM DISCHARGE, LOADS, AND AVERAGE CONCENTRATIONS IN NORTHWEST OHIO RIVERS, 1975,1995,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2001R. Peter Richards ABSTRACT: A computerized technique was developed to identify storm runoff episodes and calculate storm discharges, storm loads, and storm average concentrations for each event in datasets with up to 10,000 records. This technique was applied to four watersheds within the Lake Erie drainage basin and identified between 160 and 250 runoff events in each. Storm event loads and storm event mean concentrations were calculated for each runoff event for suspended solids, total phosphorus, soluble reactive phosphorus, nitrate, and total Kjeldahl nitrogen. The basic characteristics of the resulting data are described, as are systematic differences as a function of watershed size, seasonal differences, and trends over time. Many of the results of this study reflect the importance of nonpoint processes and improvements in agricultural best management practices in these watersheds. [source] STORM: software for testing hypotheses of relatedness and mating patternsMOLECULAR ECOLOGY RESOURCES, Issue 6 2008TIMOTHY R. FRASIER Abstract Storm is a software package that allows users to test a variety of hypotheses regarding patterns of relatedness and patterns of mate choice and/or mate compatibility within a population. These functions are based on four main calculations that can be conducted either independently or in the hypothesis-testing framework: internal relatedness; homozygosity by loci; pairwise relatedness; and a new metric called allele inheritance, which calculates the proportion of loci at which an offspring inherits a paternal allele different from that inherited from its mother. STORM allows users to test four hypotheses based on these calculations and Monte Carlo simulations: (i) are individuals within observed associations or groupings more/less related than expected; (ii) do observed offspring have more/less genetic variability (based on internal relatedness or homozygosity by loci) than expected from the gene pool; (iii) are observed mating pairs more/less related than expected if mating is random with respect to relatedness; and (iv) do observed offspring inherit paternal alleles different from those inherited from the mother more/less often than expected based on Mendelian inheritance. [source] Adrenaline Storm in the Emergency PhysicianACADEMIC EMERGENCY MEDICINE, Issue 12 2006David C. Cone MD No abstract is available for this article. [source] Health Policy Roundtable: How Are Medicaid and SCHIP Weathering the Storm?HEALTH SERVICES RESEARCH, Issue 3p1 2006Christina E. Folz First page of article [source] EGYPT: Riding the StormAFRICA RESEARCH BULLETIN: ECONOMIC, FINANCIAL AND TECHNICAL SERIES, Issue 7 2009Article first published online: 27 AUG 200 No abstract is available for this article. [source] STORM: software for testing hypotheses of relatedness and mating patternsMOLECULAR ECOLOGY RESOURCES, Issue 6 2008TIMOTHY R. FRASIER Abstract Storm is a software package that allows users to test a variety of hypotheses regarding patterns of relatedness and patterns of mate choice and/or mate compatibility within a population. These functions are based on four main calculations that can be conducted either independently or in the hypothesis-testing framework: internal relatedness; homozygosity by loci; pairwise relatedness; and a new metric called allele inheritance, which calculates the proportion of loci at which an offspring inherits a paternal allele different from that inherited from its mother. STORM allows users to test four hypotheses based on these calculations and Monte Carlo simulations: (i) are individuals within observed associations or groupings more/less related than expected; (ii) do observed offspring have more/less genetic variability (based on internal relatedness or homozygosity by loci) than expected from the gene pool; (iii) are observed mating pairs more/less related than expected if mating is random with respect to relatedness; and (iv) do observed offspring inherit paternal alleles different from those inherited from the mother more/less often than expected based on Mendelian inheritance. [source] Comparison by restriction fragment differential display RT‐PCR of gene expression pattern in bovine oocytes matured in the presence or absence of fetal calf serumMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 1 2001S. Jacek Rzucidlo Abstract A novel restriction fragment differential display (RFDD) RT‐PCR has been used to compare patterns of mRNA expression in bovine oocytes matured in vitro in the presence (10%) or absence of fetal calf serum (FCS). Total RNA extracted from matured and denuded oocytes was processed using display Profile kit (Display System Biotech). RFDD RT‐PCR products were separated on 6% polyacrylamide gel and analyzed using a Storm 860 scanner. Selected bands representing potentially differentially expressed fragments were excised from the gel and re‐amplified. Re‐amplified fragments with size matched to the original fragment were cloned into the TA vector and sequenced. Initially, 10 and 15 differentially expressed fragments were isolated from oocytes matured in the presence and absence of FCS, respectively. Eight out of 10 and 10 out of 15 fragments were re‐amplified successfully as evidenced bysize similarity to the original fragments. Finally, the size of six inserts sequenced from each group matched the size of corresponding original as well as re‐amplified fragments. Sequence comparison search revealed similarity of some isolated fragments to 18s ribosomal RNA, bovine apolipoprotein A‐I, bovine mitochondrion DNA, human CGI‐79 mRNA, human Ab1‐interactor protein, and bovine satellite DNA. The other sequenced fragments may represent novel genes. We showed that RFDD RT‐PCR can be effectively applied to contrast gene expression pattern in bovine oocytes and that presence or absence of FCS during maturation interval affects gene expression pattern in matured bovine oocytes. Mol. Reprod. Dev. 59:90–96, 2001. © 2001 Wiley‐Liss, Inc. [source] Authors of the Storm: Meteorologists and the Culture of Prediction by Gary Alan FineAMERICAN ETHNOLOGIST, Issue 3 2009CAITLIN ZALOOM No abstract is available for this article. [source] Mapping and Ablation of Trigger Premature Ventricular Contractions in a Case of Electrical Storm Associated with Ischemic CardiomyopathyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2007TARO OKADA M.D. We report a case of polymorphic ventricular tachycardia and ventricular fibrillation (PVT/VF) storm associated with ischemic cardiomyopathy (ICM). The electrocardiogram (ECG) monitor revealed frequent premature ventricular contractions (PVCs) initiated PVT/VF. Electroanatomic mapping revealed the plausible origins of PVCs were located in the scar border zone at the posterior septum of the left ventricle. Purkinje-like potentials (PLPs) always preceded PVCs and a decremental property for the PLPs and infarcted myocardium junction was observed. Ablation at these sites eliminated both PVCs and PVT/VF. [source] Incrementalism before the Storm: Network Performance for the Evacuation of New OrleansPUBLIC ADMINISTRATION REVIEW, Issue 2006John J. Kiefer Hurricane Katrina revealed a lack of preparedness in disaster management networks covering the New Orleans area. This paper focuses on the operation of networks in preparing to evacuate residents in advance of a major disaster. There are two cases: the relatively successful evacuation of residents who left by private conveyance and the widely publicized failure to provide for those who could not or would not leave on their own. We trace the actions and inactions of various players to reach conclusions about the strengths and weaknesses of networks in the special circumstances of disaster preparation. [source] The sting at the end of the tail: Damaging winds associated with extratropical cyclonesTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 597 2004K. A. Browning Abstract Strong surface winds often accompany the low-level jets that occur along the cold fronts of extratropical cyclones, but there is evidence that the strongest surface winds occur in a distinctly different part of a certain class of cyclone. The most damaging extratropical cyclones go through an evolution that involves the formation of a bent-back front and cloud head separated from the main polar-front cloud band by a dry slot. When the cyclone attains its minimum central pressure, the trailing tip of the cloud head bounding the bent-back front forms a hook which goes on to encircle a seclusion of warm air. The most damaging winds occur near the tip of this hook,the sting at the end of the tail. Observations of the Great Storm of October 1987 in south-east England are re-examined in some detail to study this phenomenon. The cloud head is shown to have a banded structure consistent with the existence of multiple mesoscale slantwise circulations. Air within these circulations leaves the hooked tip of the cloud head (and enters the dry slot) much faster than the rate of travel of the cloud-head tip, implying rapid evaporation and diabatic cooling immediately upwind of the area of damaging surface winds. The circumstantial evidence from the observational study leads one to hypothesize that the mesoscale circulations and the associated evaporative heat sinks may play an active role in strengthening the damaging winds. Regardless of how important this role may be, the evolution of the cloud pattern seen in satellite imagery is a useful tool for nowcasting the occurrence and location of the worst winds. Copyright © 2004 Royal Meteorological Society [source] Antiarrhythmic Induced Electrical Storm in Brugada Syndrome: A Case ReportANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2007Sandeep Joshi M.D. Brugada syndrome (BS) may be "unmasked" by several pharmacological and/or physiological agents in an otherwise normal electrocardiogram. Once diagnosed the possibility of persistent ventricular tachycardia/fibrillation exists. Although this is treated with various antiarrhythmic agents, there remains a cohort of patients who fail to respond to conventional antiarrhythmic therapy therefore, amplifying the electrical storm. We report a case of a BS diagnosed via procainamide challenge, the resultant near fatal electrical storm aggravated by amiodarone and the eventual resolution with isoproterenol. [source] Effects of spatially structured vegetation patterns on hillslope erosion in a semiarid Mediterranean environment: a simulation studyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2005Matthias Boer Abstract A general trend of decreasing soil loss rates with increasing vegetation cover fraction is widely accepted. Field observations and experimental work, however, show that the form of the cover-erosion function can vary considerably, in particular for low cover conditions that prevail on arid and semiarid hillslopes. In this paper the structured spatial distribution of the vegetation cover and associated soil attributes is proposed as one of the possible causes of variation in cover,erosion relationships, in particular in dryland environments where patchy vegetation covers are common. A simulation approach was used to test the hypothesis that hillslope discharge and soil loss could be affected by variation in the spatial correlation structure of coupled vegetation cover and soil patterns alone. The Limburg Soil Erosion Model (LISEM) was parameterized and verified for a small catchment with discontinuous vegetation cover at Rambla Honda, SE Spain. Using the same parameter sets LISEM was subsequently used to simulate water and sediment fluxes on 1 ha hypothetical hillslopes with simulated spatial distributions of vegetation and soil parameters. Storms of constant rainfall intensity in the range of 30,70 mm h,1 and 10,30 min duration were applied. To quantify the effect of the spatial correlation structure of the vegetation and soil patterns, predicted discharge and soil loss rates from hillslopes with spatially structured distributions of vegetation and soil parameters were compared with those from hillslopes with spatially uniform distributions. The results showed that the spatial organization of bare and vegetated surfaces alone can have a substantial impact on predicted storm discharge and erosion. In general, water and sediment yields from hillslopes with spatially structured distributions of vegetation and soil parameters were greater than from identical hillslopes with spatially uniform distributions. Within a storm the effect of spatially structured vegetation and soil patterns was observed to be highly dynamic, and to depend on rainfall intensity and slope gradient. Copyright © 2005 John Wiley & Sons, Ltd. [source] Severe Deep Moist Convective Storms: Forecasting and MitigationGEOGRAPHY COMPASS (ELECTRONIC), Issue 1 2008David L. Arnold Small-scale (2,20 km) circulations, termed ,severe deep moist convective storms', account for a disproportionate share of the world's insured weather-related losses. Spatial frequency maximums of severe convective events occur in South Africa, India, Mexico, the Caucasus, and Great Plains/Prairies region of North America, where the maximum tornado frequency occurs east of the Rocky Mountains. Interest in forecasting severe deep moist convective systems, especially those that produce tornadoes, dates to 1884 when tornado alerts were first provided in the central United States. Modern thunderstorm and tornado forecasting relies on technology and theory, but in the post-World War II era interest in forecasting has also been driven by public pressure. The forecasting process begins with a diagnostic analysis, in which the forecaster considers the potential of the atmospheric environment to produce severe convective storms (which requires knowledge of the evolving kinematic and thermodynamic fields, and the character of the land surface over which the storms will pass), and the likely character of the storms that may develop. Improvements in forecasting will likely depend on technological advancements, such as the development of phased-array radar systems and finer resolution numerical weather prediction models. Once initiated, the evolution of deep convective storms is monitored by satellite and radar. Mitigation of the hazards posed by severe deep moist convective storms is a three-step process, involving preparedness, response, and recovery. Preparedness implies that risks have been identified and organizations and individuals are familiar with a response plan. Response necessitates that potential events are identified before they occur and the developing threat is communicated to the public. Recovery is a function of the awareness of local, regional, and even national governments to the character and magnitude of potential events in specific locations, and whether or not long-term operational plans are in place at the time of disasters. [source] Storms, tea cups and the adverse effects of statinsINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 9 2009A. S. Wierzbicki No abstract is available for this article. [source] Books and Multimedia ReviewsMETEORITICS & PLANETARY SCIENCE, Issue 12 2002Article first published online: 26 JAN 2010 Book reviewed in this article: Chemical Dynamics in Extreme Environments, Volume 11 of Advanced Series in Physical Chemistry edited by Rainer A. Dressler. Storms in Space by John Freeman. Major Impacts and Plate Tectonics: A Model for the Phanerozoic Evolution of the Earth's Lithosphere by Neville J. Price. Meteorite Hunter: The Search For Siberian Meteorite Craters by Roy A. Gallant. [source] The effects of aerosols on intense convective precipitation in the northeastern United States,THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 643 2009Alexandros A. Ntelekos Abstract A fully coupled meteorology-chemistry-aerosol mesoscale model (WRF-Chem) is used to assess the effects of aerosols on intense convective precipitation over the northeastern United States. Numerical experiments are performed for three intense convective storm days and for two scenarios representing ,typical' and ,low' aerosol conditions. The results of the simulations suggest that increasing concentrations of aerosols can lead to either enhancement or suppression of precipitation. Quantification of the aerosol effect is sensitive to the metric used due to a shift of rainfall accumulation distribution when realistic aerosol concentrations are included in the simulations. Maximum rainfall accumulation amounts and areas with rainfall accumulations exceeding specified thresholds provide robust metrics of the aerosol effect on convective precipitation. Storms developing over areas with medium to low aerosol concentrations showed a suppression effect on rainfall independent of the meteorological environment. Storms developing in areas of relatively high particulate concentrations showed enhancement of rainfall when there were simultaneous high values of convective available potential energy, relative humidity and wind shear. In these cases, elevated aerosol concentrations resulted in stronger updraughts and downdraughts and more coherent organization of convection. For the extreme case, maximum rainfall accumulation differences exceeded 40 mm. The modelling results suggest that areas of the northeastern US urban corridor that are close to or downwind of intense sources of aerosols, could be more favourable for rainfall enhancement due to aerosols for the aerosol concentrations typical of this area. Copyright © 2009 Royal Meteorological Society [source] A Bayesian approach to inverse modelling of stratigraphy, part 1: methodBASIN RESEARCH, Issue 1 2009Karl Charvin ABSTRACT The inference of ancient environmental conditions from their preserved response in the sedimentary record still remains an outstanding issue in stratigraphy. Since the 1970s, conceptual stratigraphic models (e.g. sequence stratigraphy) based on the underlying assumption that accommodation space is the critical control on stratigraphic architecture have been widely used. Although these methods considered more recently other possible parameters such as sediment supply and transport efficiency, they still lack in taking into account the full range of possible parameters, processes, and their complex interactions that control stratigraphic architecture. In this contribution, we present a new quantitative method for the inference of key environmental parameters (specifically sediment supply and relative sea level) that control stratigraphy. The approach combines a fully non-linear inversion scheme with a ,process,response' forward model of stratigraphy. We formulate the inverse problem using a Bayesian framework in order to sample the full range of possible solutions and explicitly build in prior geological knowledge. Our methodology combines Reversible Jump Markov chain Monte Carlo and Simulated Tempering algorithms which are able to deal with variable-dimensional inverse problems and multi-modal posterior probability distributions, respectively. The inverse scheme has been linked to a forward stratigraphic model, BARSIM (developed by Joep Storms, University of Delft), which simulates shallow-marine wave/storm-dominated systems over geological timescales. This link requires the construction of a likelihood function to quantify the agreement between simulated and observed data of different types (e.g. sediment age and thickness, grain size distributions). The technique has been tested and validated with synthetic data, in which all the parameters are specified to produce a ,perfect' simulation, although we add noise to these synthetic data for subsequent testing of the inverse modelling approach. These tests addressed convergence and computational-overhead issues, and highlight the robustness of the inverse scheme, which is able to assess the full range of uncertainties on the inferred environmental parameters and facies distributions. [source] Three-Dimensional Optimization of Urban Drainage SystemsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2000A. Freire Diogo A global mathematical model for simultaneously obtaining the optimal layout and design of urban drainage systems for foul sewage and stormwater is presented. The model can handle every kind of network, including parallel storm and foul sewers. It selects the optimal location for pumping systems and outfalls or wastewater treatment plants (defining the natural and artificial drainage basins), and it allows the presence of special structures and existing subsystems for optimal remodeling or expansion. It is possible to identify two basic optimization levels: in the first level, the generation and transformation of general layouts (consisting of forests of trees) until a convergence criterion is reached, and in the second level, the design and evaluation of each forest. The global strategy adopted combines and develops a sequence of optimal design and plan layout subproblems. Dynamic programming is used as a very powerful technique, alongside simulated annealing and genetic algorithms, in this discrete combinatorial optimization problem of huge dimension. [source] Shelter from the storm?CONSERVATION LETTERS, Issue 1 2010misuse of coastal vegetation bioshields for managing natural disasters Abstract Vegetated coastal ecosystems provide goods and services to billions of people. In the aftermath of a series of recent natural disasters, including the Indian Ocean Tsunami, Hurricane Katrina and Cyclone Nargis, coastal vegetation has been widely promoted for the purpose of reducing the impact of large storm surges and tsunami. In this paper, we review the use of coastal vegetation as a "bioshield" against these extreme events. Our objective is to alter bioshield policy and reduce the long-term negative consequences for biodiversity and human capital. We begin with an overview of the scientific literature, in particular focusing on studies published since the Indian Ocean Tsunami in 2004 and discuss the science of wave attenuation by vegetation. We then explore case studies from the Indian subcontinent and evaluate the detrimental impacts bioshield plantations can have upon native ecosystems, drawing a distinction between coastal restoration and the introduction of exotic species in inappropriate locations. Finally, we place bioshield policies into a political context, and outline a new direction for coastal vegetation policy and research. [source] Gauging the societal impacts of natural disasters using a capability approachDISASTERS, Issue 3 2010Paolo Gardoni There is a widely acknowledged need for a single composite index that provides a comprehensive picture of the societal impact of disasters. A composite index combines and logically organizes important information policy-makers need to allocate resources for the recovery from natural disasters; it can also inform hazard mitigation strategies. This paper develops a Disaster Impact Index (DII) to gauge the societal impact of disasters on the basis of the changes in individuals' capabilities. The DII can be interpreted as the disaster impact per capita. Capabilities are dimensions of individual well-being and refer to the genuine opportunities individuals have to achieve valuable states and activities (such as being adequately nourished or being mobile). After discussing the steps required to construct the DII, this article computes and compares the DIIs for two earthquakes of similar magnitude in two societies at different levels of development and of two disasters (earthquake and wind storm) in the same society. [source] Forest blowdown impacts of Hurricane Rita on fluvial systemsEARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2009Jonathan D. Phillips Abstract Hurricane Rita, a category three hurricane which struck the US Gulf Coast near the Louisiana/Texas border in 2005, did not cause extensive river flooding. However, the storm did result in extensive forest damage and tree blowdown. High-resolution post-storm aerial photography allowed an inventory of river bank trees blown into the channel along the lower Neches and Sabine Rivers of southeast Texas and southwest Louisiana. Blowdowns directly into the channel averaged 9·3 per kilometer in the lower Neches and 13·4 in the lower Sabine River, but individual reaches 10 to 20 km in length had rates of 20 to 44 blowdowns per kilometer. Though large woody debris (LWD) from Hurricane Rita was widely perceived to reduce the capacity of channels to convey flow, no strong evidence exists of increased flooding or significant reductions in channel conveyance capacity due to LWD from the storm. The Rita blowdown inventory also allowed an assessment of whether similar blowdown events could account for major logjams and rafts on Red, Atchafalaya, and Colorado Rivers on the Gulf Coast, which blocked navigation from tens to hundreds of kilometers in the 1800s. Results from Hurricane Rita suggest that blowdown into channels alone , not withstanding blowdown elsewhere in the river valleys or along tributaries which could deliver LWD to the river , is sufficient to completely block channels, thus providing a plausible mechanism for initiating such (pre)historic log rafts. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of spatially structured vegetation patterns on hillslope erosion in a semiarid Mediterranean environment: a simulation studyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2005Matthias Boer Abstract A general trend of decreasing soil loss rates with increasing vegetation cover fraction is widely accepted. Field observations and experimental work, however, show that the form of the cover-erosion function can vary considerably, in particular for low cover conditions that prevail on arid and semiarid hillslopes. In this paper the structured spatial distribution of the vegetation cover and associated soil attributes is proposed as one of the possible causes of variation in cover,erosion relationships, in particular in dryland environments where patchy vegetation covers are common. A simulation approach was used to test the hypothesis that hillslope discharge and soil loss could be affected by variation in the spatial correlation structure of coupled vegetation cover and soil patterns alone. The Limburg Soil Erosion Model (LISEM) was parameterized and verified for a small catchment with discontinuous vegetation cover at Rambla Honda, SE Spain. Using the same parameter sets LISEM was subsequently used to simulate water and sediment fluxes on 1 ha hypothetical hillslopes with simulated spatial distributions of vegetation and soil parameters. Storms of constant rainfall intensity in the range of 30,70 mm h,1 and 10,30 min duration were applied. To quantify the effect of the spatial correlation structure of the vegetation and soil patterns, predicted discharge and soil loss rates from hillslopes with spatially structured distributions of vegetation and soil parameters were compared with those from hillslopes with spatially uniform distributions. The results showed that the spatial organization of bare and vegetated surfaces alone can have a substantial impact on predicted storm discharge and erosion. In general, water and sediment yields from hillslopes with spatially structured distributions of vegetation and soil parameters were greater than from identical hillslopes with spatially uniform distributions. Within a storm the effect of spatially structured vegetation and soil patterns was observed to be highly dynamic, and to depend on rainfall intensity and slope gradient. Copyright © 2005 John Wiley & Sons, Ltd. [source] Landslide inventories and their statistical propertiesEARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2004Bruce D. Malamud Abstract Landslides are generally associated with a trigger, such as an earthquake, a rapid snowmelt or a large storm. The landslide event can include a single landslide or many thousands. The frequency,area (or volume) distribution of a landslide event quanti,es the number of landslides that occur at different sizes. We examine three well-documented landslide events, from Italy, Guatemala and the USA, each with a different triggering mechanism, and ,nd that the landslide areas for all three are well approximated by the same three-parameter inverse-gamma distribution. For small landslide areas this distribution has an exponential ,roll-over' and for medium and large landslide areas decays as a power-law with exponent -2·40. One implication of this landslide distribution is that the mean area of landslides in the distribution is independent of the size of the event. We also introduce a landslide-event magnitude scale mL = log(NLT), with NLT the total number of landslides associated with a trigger. If a landslide-event inventory is incomplete (i.e. smaller landslides are not included), the partial inventory can be compared with our landslide probability distribution, and the corresponding landslide-event magnitude inferred. This technique can be applied to inventories of historical landslides, inferring the total number of landslides that occurred over geologic time, and how many of these have been erased by erosion, vegetation, and human activity. We have also considered three rockfall-dominated inventories, and ,nd that the frequency,size distributions differ substantially from those associated with other landslide types. We suggest that our proposed frequency,size distribution for landslides (excluding rockfalls) will be useful in quantifying the severity of landslide events and the contribution of landslides to erosion. Copyright © 2004 John Wiley & Sons, Ltd. [source] Testing a model for predicting the timing and location of shallow landslide initiation in soil-mantled landscapesEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2003M. Casadei Abstract The growing availability of digital topographic data and the increased reliability of precipitation forecasts invite modelling efforts to predict the timing and location of shallow landslides in hilly and mountainous areas in order to reduce risk to an ever-expanding human population. Here, we exploit a rare data set to develop and test such a model. In a 1·7 km2 catchment a near-annual aerial photographic coverage records just three single storm events over a 45 year period that produced multiple landslides. Such data enable us to test model performance by running the entire rainfall time series and determine whether just those three storms are correctly detected. To do this, we link a dynamic and spatially distributed shallow subsurface runoff model (similar to TOPMODEL) to an in,nite slope model to predict the spatial distribution of shallow landsliding. The spatial distribution of soil depth, a strong control on local landsliding, is predicted from a process-based model. Because of its common availability, daily rainfall data were used to drive the model. Topographic data were derived from digitized 1 : 24 000 US Geological Survey contour maps. Analysis of the landslides shows that 97 occurred in 1955, 37 in 1982 and ,ve in 1998, although the heaviest rainfall was in 1982. Furthermore, intensity,duration analysis of available daily and hourly rainfall from the closest raingauges does not discriminate those three storms from others that did not generate failures. We explore the question of whether a mechanistic modelling approach is better able to identify landslide-producing storms. Landslide and soil production parameters were ,xed from studies elsewhere. Four hydrologic parameters characterizing the saturated hydraulic conductivity of the soil and underlying bedrock and its decline with depth were ,rst calibrated on the 1955 landslide record. Success was characterized as the most number of actual landslides predicted with the least amount of total area predicted to be unstable. Because landslide area was consistently overpredicted, a threshold catchment area of predicted slope instability was used to de,ne whether a rainstorm was a signi,cant landslide producer. Many combinations of the four hydrological parameters performed equally well for the 1955 event, but only one combination successfully identi,ed the 1982 storm as the only landslide-producing storm during the period 1980,86. Application of this parameter combination to the entire 45 year record successfully identi,ed the three events, but also predicted that two other landslide-producing events should have occurred. This performance is signi,cantly better than the empirical intensity,duration threshold approach, but requires considerable calibration effort. Overprediction of instability, both for storms that produced landslides and for non-producing storms, appears to arise from at least four causes: (1) coarse rainfall data time scale and inability to document short rainfall bursts and predict pressure wave response; (2) absence of local rainfall data; (3) legacy effect of previous landslides; and (4) inaccurate topographic and soil property data. Greater resolution of spatial and rainfall data, as well as topographic data, coupled with systematic documentation of landslides to create time series to test models, should lead to signi,cant improvements in shallow landslides forecasting. Copyright © 2003 John Wiley & Sons, Ltd. [source] Extreme events controlling erosion and sediment transport in a semi-arid sub-andean valleyEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2002R. Coppus Abstract The importance of extreme events in controlling erosion and sediment transport in semi-arid areas has long been appreciated but in practice being by definition rare and episodic they are difficult to study. When they are observed this is frequently in catchments for which little data are available. Another difficulty is that even when catchments are being monitored the instruments that record discharge, sediment load and hillslope sediment fluxes perform inaccurately or unpredictably during extreme weather conditions. This paper describes slope and channel processes that were actually observed by the authors during a (at least) 1 : 30 year 30 minute event with a rainfall intensity of 240 mm h,1 in a second-order tributary of the Rio Camacho near Tarija in southern Bolivia. During the event, it could be observed how different tributary streams and slope sections contributed sediments and flow to the main channel. Evidence for these contributions did not survive the event, which has implications for both modelling and monitoring. Before the onset of the event open erosion plots were functioning on the slopes where rainfall and runoff were being measured. Rainfall experiments were used to obtain infiltration rates. The storm began with a moderate intensity of about 5 cm per hour but increased after 5 minutes to 30 cm per hour and continued for 30 minutes. At this time, the rainfall intensity greatly exceeded the infiltration capacity and water started draining the steep slopes. The ephemeral channel rapidly filled up with runoff. Erosion by hailstones was considerable. Provisionally, the discharge during peak runoff was estimated at 43·7 m3 s,1 (Manning equation). On the basis of sediment loads carried by previous storms, (average concentration of 21 g l,1) the total suspended load discharge during the storm would have been 15 ton ha,1. Within the ephemeral channel, 10 to 50 cm thick layers of coarse sediments were deposited. The collectors of the open erosion plots could not handle the large amounts of runoff and sediment and were completely filled to overflowing. Comparing these data with soil losses during less intense storms it can be concluded that extreme events largely contribute to erosion and sediment transport and that the majority of the rainstorms play only a minor role. The results also show how limited the values of rainfall experiments are in understanding geomorphic events. This makes modelling of erosion and soil losses a difficult and hazardous task. Copyright © 2002 John Wiley & Sons, Ltd. [source] Not just gastroenteritis: Thyroid storm unmaskedEMERGENCY MEDICINE AUSTRALASIA, Issue 3 2004Rabind Antony Charles Abstract Establishing the diagnosis of thyroid storm is difficult in the ED, especially where there is no antecedent history of thyroid disease or clinical clues like goitre, exophthalmos or altered mentation, yet early recognition and treatment are essential in reducing mortality and morbidity from this endocrine emergency. We present a case where suspected infective gastroenteritis in a newly diagnosed diabetic masked the major symptomatology of thyroid storm, and review the diagnosis and management of thyrotoxic crisis. [source] | |||||||||||||||||||||||||||||||||||||||||||