Low-intensity Events Research Articles

Factors affecting mobility/export of particle-bound stable elements after erosive rainfalls in agroforestry Mediterranean catchments of Aragón (Spain)

The composition of sediment fluxes caused by erosion can vary greatly both spatially and temporally, causing different impacts on water bodies. The erosion process is mainly driven by soil and rainfall characteristics as well as land use. The aim of this research is to evaluate the combined effect of these factors in a mountain agroforestry system, analysing the relationship of the sediment composition generated after flooding events with soil and rainfall characteristics and the impact of land use. The analyses were based on data recorded in three catchments with Mediterranean climate. The sediments were collected after 21 seasonal campaigns and their characteristics were assessed taking into account rainfall characteristics and the main land uses in each catchment. The results confirm the differences in soil particle mobilization after high and low intensity events and the higher impact of croplands compared to other dominant land uses. The amount of sediments trapped in the catchment with the largest area of cropland almost doubled sediment collected in the other catchments. Clay and soil organic carbon in the sediments were lower than in the original sources, likely due to the lower content in the soils more susceptible to erosion and the washing out of the finer material by runoff under high amount/intensity precipitation. Differences were observed between catchments and between rainfall events in the export of stable elements, with a general sediment enrichment in Al, Be, B, Cu, Mn, S, Sr and Zn, reaching the highest values for Be, Sr and Zn. The elemental enrichment differed according to rainfall characteristics thus Cu, Zn or Mn were higher after low intensity events, while other elements like Be were enriched after high intensity events. These variable patterns evidence the complex interplay of involved factors and the key role of elemental bounds to particle sizes and organic matter.

Prediction of movement in handball with the use of inertial measurement units and machine learning

ABSTRACT Inertial Measurement Units (IMU) and machine learning are strong tools in quantifying physical demands in sports, such as handball. However, the detection of both locomotion and throw events simultaneously has not been a topic for much investigation. Wherefore, the aim of this study was to publicise a method for training an extreme gradient boosting model capable of identifying low intensity, dynamic, running and throw events. Twelve adults with varying experience in handball wore an IMU on the back while being video recorded during a handball match. The video recordings were used for annotating the four events. Due to the small sample size, a leave-one-subject-out (LOSO) approach was conducted for the modelling and feature selection. The model had issues identifying dynamic movements (F1-score = 0.66 ± 0.07), whereas throw (F1-score = 0.95 ± 0.05), low intensity (F1-score = 0.93 ± 0.02) and running (F1-score = 0.86 ± 0.05) were easier to identify. Features such as IQR and first zero crossing for most of the kinematic characteristics were among the most important features for the model. Therefore, it is recommended for future research to look into these two features, while also using a LOSO approach to decrease likelihood of artificially high model performance.

Climate change information over Fenno-Scandinavia produced with a convection-permitting climate model

This paper presents results from high-resolution climate change simulations that permit convection and resolve mesoscale orography at 3-km grid spacing over Fenno-Scandinavia using the HARMONIE-Climate (HCLIM) model. Two global climate models (GCMs) have been dynamically down-scaled for the RCP4.5 and RCP8.5 emission scenarios and for both near and far future periods in the 21st century. The warmer and moister climate conditions simulated in the GCMs lead to changes in precipitation characteristics. Higher precipitation amounts are simulated in fall, winter and spring, while in summer, precipitation increases in northern Fenno-Scandinavia and decreases in the southern parts of the domain. Both daily and sub-daily intense precipitation over Fenno-Scandinavia become more frequent at the expense of low-intensity events, with most pronounced shifts in summer. In the Scandinavian mountains, pronounced changes occur in the snow climate with a shift in precipitation falling as snow to rain, reduced snow cover and less days with a significant snow depth. HCLIM at 3-km grid spacing exhibits systematically different change responses in several aspects, e.g. a smaller shift from snow to rain in the western part of the Scandinavian mountains and a more consistent decrease in the urban heat island effect by the end of the 21st century. Most importantly, the high-resolution HCLIM shows a significantly stronger increase in summer hourly precipitation extremes compared to HCLIM at the intermediate 12-km grid spacing. In addition, an analysis of the statistical significance of precipitation changes indicates that simulated time periods of at least a couple of decades is recommended to achieve statistically robust results, a matter of important concern when running such high-resolution climate model experiments. The results presented here emphasizes the importance of using “convection-permitting” models to produce reliable climate change information over the Fenno-Scandinavian region.

Three-Dimensional Hole Size (3DHS) Approach for Water Flow Turbulence Analysis over Emerging Sand Bars: Flume-Scale Experiments

The many hydrodynamic implications associated with the geomorphological evolution of braided rivers are still not profoundly examined in both experimental and numerical analyses, due to the generation of three-dimensional turbulence structures around sediment bars. In this experimental research, the 3D velocity fields were measured through an acoustic Doppler velocimeter during flume-scale laboratory experimental runs over an emerging sand bar model, to reproduce the hydrodynamic conditions of real braided rivers, and the 3D Turbulent Kinetic Energy (TKE) components were analyzed and discussed here in detail. Given the three-dimensionality of the examined water flow in the proximity of the experimental bar, the statistical analysis of the octagonal bursting events was applied to analyze and discuss the different flume-scale 3D turbulence structures. The main novelty of this study is the proposal of the 3D Hole Size (3DHS) analysis, used for separating the extreme events observed in the experimental runs from the low-intensity events.

The influence of seed-drill choice on crop performance in a semi-arid production region of South Africa

A seed-drill should facilitate seed placement in an environment conducive to uniform seedling emergence. In semi-arid rain-fed production regions, low rainfall intensity and erratic rainfall events can result in non-uniform emergence. Evaluation of seed-drills is necessary to supply small grain producers with potential solutions to combat non-uniform seedling emergence. The aim of this study was to investigate the influence of three seed-drills on seeding depth, crop emergence, biomass production and yield over the duration of two growing seasons. Barley, canola and wheat were established with three seed-drills, each equipped with a different opener. Seed-drills contained either double disc openers, tine openers, or a combination of both tines and single discs. Crops responded variably to seeding equipment under different climatic conditions. For example, accuracy of seeding depth varied between the three seed-drills utilised. Seed-drills, together with their associated seed placement characteristics, influenced crop emergence. Biomass production was variable over the course of the growing season. Biomass production of crops established with the double disc seed-drill tended to be higher than that of crops established with tine seed-drills. Additional research about adaptations of agronomic practices and seed-drill openers may increase resilience to adverse climatic conditions in semi-arid small grain production regions. Various factors, including soil physical conditions, environmental conditions, economic feasibility and practical applications must be taken into consideration when selecting a seed-drill.

An Investigation on the Impacts of Low Probability and High Intensity Events on Wind Power Generator’s Market Participation

This paper presents an extensive decision-making model for Wind Power Generators (WPGs) for profit maximization in an electricity market environment. This model has been presented at the intraday market stage due to the fact that WPGs can react according to the latest information and also they have less forecast errors in comparison to Day-ahead (DA) market. In addition, the Intraday Demand Response Exchange (IDRX) market is modelled with the aim of covering wind generation volatility so that the WPG can participate in it as a buyer. Note that, Demand Response (DR) uncertainty is modelled through Information Gap Decision Theory (IGDT) method so that the amount of financial resistance to the possible increase of the load is considered. In this article, the profitability of WPG in the event of High-Intensity and Low-Probability (HILP) events such as the hurricane, is also examined. In fact, the effects of hurricane on failure rate, reliability and aging of wind units are investigated. The Conditional Value at Risk (CVaR) is utilized to quantify the WPG risk as well. Several numerical analysis are conducted to show evidence of the approach efficacy.

Classifying Major Explosions and Paroxysms at Stromboli Volcano (Italy) from Space

Stromboli volcano has a persistent activity that is almost exclusively explosive. Predominated by low intensity events, this activity is occasionally interspersed with more powerful episodes, known as major explosions and paroxysms, which represent the main hazards for the inhabitants of the island. Here, we propose a machine learning approach to distinguish between paroxysms and major explosions by using satellite-derived measurements. We investigated the high energy explosive events occurring in the period January 2018–April 2021. Three distinguishing features are taken into account, namely (i) the temporal variations of surface temperature over the summit area, (ii) the magnitude of the explosive volcanic deposits emplaced during each explosion, and (iii) the height of the volcanic ash plume produced by the explosive events. We use optical satellite imagery to compute the land surface temperature (LST) and the ash plume height (PH). The magnitude of the explosive volcanic deposits (EVD) is estimated by using multi-temporal Synthetic Aperture Radar (SAR) intensity images. Once the input feature vectors were identified, we designed a k-means unsupervised classifier to group the explosive events at Stromboli volcano based on their similarities in two clusters: (1) paroxysms and (2) major explosions. The major explosions are identified by low/medium thermal content, i.e., LSTI around 1.4 °C, low plume height, i.e., PH around 420 m, and low production of explosive deposits, i.e., EVD around 2.5. The paroxysms are extreme events mainly characterized by medium/high thermal content, i.e., LSTI around 2.3 °C, medium/high plume height, i.e., PH around 3330 m, and high production of explosive deposits, i.e., EVD around 10.17. The centroids with coordinates (PH, EVD, LSTI) are: Cp (3330, 10.7, 2.3) for the paroxysms, and Cme (420, 2.5, 1.4) for the major explosions.

ASSESSMENT OF RESIDUAL SOIL PROPERTIES FOR SLOPE STABILITY ANALYSIS

Slope instability is a common natural geological hazard in tropical countries like Malaysia, with abundant residual soil and frequent rainfall. Over the years, these rainfalls have induced instabilities that lead to significant human and economic loss. To reduce the expected disastrous impacts due to rainfall-induced slope failure characterization of residual soil is necessary for evaluation of slope stability assessment. Therefore, this study aims to characterize the residual soil for numerical modelling of rainfall-induced slope failure and preliminary slope stability assessment so that future slope failure can be reduced. A series of experiments involving index properties tests and engineering properties tests were carried out on the residual soil samples collected from a slope located in UniversitiTeknologi Malaysia (UTM). Based on the particle size distribution and consistency the soil can be classified as high plasticity silt (MH). The maximum dry unit weight and optimum moisture content are 13.17kN/m3 and 30 %, respectively. Saturated hydraulic conductivity from the falling head test is 2.32055E-07 m/s, while the saturated gravimetric water content was 54%. The effective cohesion and angle of the internal fraction were 8 kPa and 32°, respectively. The average undrained shear strength and unconfined compressive strength were 105 kPa and 43 kPa, respectively. The result obtained in this study was utilized for the preliminary rainfall slope stability assessment in tropical residual soils by simulating rainfall of different intensities and duration on a typical slope profile using PLAXIS 2d. The results show that due to the low hydraulic conductivity and fine-grained nature of the soil, the slopes in the study area are more critical to the low intensity and long duration rainfall events (I≤4Ks). The highly intense and short-duration rainfall (I≥8Ks) has no significant effect on the safety of the soil, as most of the precipitation will contribute to runoff, and only a minor amount of water will infiltrate into the slope.

Simulating Rainfall Interception by Caatinga Vegetation Using the Gash Model Parametrized on Daily and Seasonal Bases

Rainfall partitioning by trees is an important hydrological process in the contexts of water resource management and climate change. It becomes even more complex where vegetation is sparse and in vulnerable natural systems, such as the Caatinga domain. Rainfall interception modelling allows extrapolating experimental results both in time and space, helping to better understand this hydrological process and contributing as a prediction tool for forest managers. In this work, the Gash model was applied in two ways of parameterization. One was the parameterization on a daily basis and another on a seasonal basis. They were validated, improving the description of rainfall partitioning by tree species of Caatinga dry tropical forest already reported in the scientific literature and allowing a detailed evaluation of the influence of rainfall depth and event intensity on rainfall partitioning associated with these species. Very small (0.0–5.0 mm) and low-intensity (0–2.5 mm h−1) events were significantly more frequent during the dry season. Both model approaches resulted in good predictions, with absence of constant and systematic errors during simulations. The sparse Gash model parametrized on a daily basis performed slightly better, reaching maximum cumulative mean error of 9.8%, while, for the seasonal parametrization, this value was 11.5%. Seasonal model predictions were also the most sensitive to canopy and climatic parameters.

Unpacking future climate extremes and their sectoral implications in western Nepal

Existing climate projections and impact assessments in Nepal only consider a limited number of generic climate indices such as means. Few studies have explored climate extremes and their sectoral implications. This study evaluates future scenarios of extreme climate indices from the list of the Expert Team on Sector-specific Climate Indices (ET-SCI) and their sectoral implications in the Karnali Basin in western Nepal. First, future projections of 26 climate indices relevant to six climate-sensitive sectors in Karnali are made for the near (2021–2045), mid (2046–2070), and far (2071–2095) future for low- and high-emission scenarios (RCP4.5 and RCP8.5, respectively) using bias-corrected ensembles of 19 regional climate models from the COordinated Regional Downscaling EXperiment for South Asia (CORDEX-SA). Second, a qualitative analysis based on expert interviews and a literature review on the impact of the projected climate extremes on the climate-sensitive sectors is undertaken. Both the temperature and precipitation patterns are projected to deviate significantly from the historical reference already from the near future with increased occurrences of extreme events. Winter in the highlands is expected to become warmer and dryer. The hot and wet tropical summer in the lowlands will become hotter with longer warm spells and fewer cold days. Low-intensity precipitation events will decline, but the magnitude and frequency of extreme precipitation events will increase. The compounding effects of the increase in extreme temperature and precipitation events will have largely negative implications for the six climate-sensitive sectors considered here.

Social and spatial variation in heatwave-related emergency department visits in Australia

BACKGROUND AND AIM: Heatwaves are extreme weather events that cause more urgent medical care than any other hazard in Australia. Heatwave impacts vary between populations and locations and empirical evidence concerning vulnerable places and people at a local level is critical for effective policy, planning, and interventions, especially in a warming climate. This study aimed to examine heatwave-related morbidity in Australia (using emergency department (ED) presentations) at a small-area level and identify susceptibility by neighbourhood characteristics. METHODS: ED presentations data for eight Australian cities from 2013-2018 during the warm-season (October- March) were extracted from a national database. In each city, we examined the association of heatwave severity (defined using Excess Heat Factor) with ED visits at the Statistical Areas 2 geographical unit using a time-stratified case-crossover approach. Effect modification by neighbourhood characteristics were examined and city-level estimates were pooled using random-effects meta-analyses. RESULTS:A total of 23,233,374 all-cause ED presentations were included in the analysis. Pooled ED relative risk estimates indicate that ED visits increased by 2.9% (95%CI: 1.5-4.2%) and 3.4% (95%CI: 1.2-5.5%) during low-intensity and severe/extreme heatwaves, respectively. There were 67,974 excess ED presentations during heatwaves with 82% of these occurring during low-intensity events which are more frequent than severe/extreme heatwaves. The effects varied substantially by city with the highest number of excess ED presentations observed in Adelaide (28,198) and Sydney (19,899). Heat-related conditions such as dehydration and heat exhaustion/stroke were significantly greater during heatwaves and the effect increased from low-intensity to severe/extreme heatwaves. Analysis of neighbourhood characteristics on heatwave-related ED presentations revealed greater health impacts for areas with high social vulnerability e.g., household composition, language and culture, and housing quality. CONCLUSIONS:Overall, ED presentations are sensitive to heatwaves across all severity classes and the effects are stronger for individuals with certain health conditions and neighbourhood contexts. KEYWORDS: Heatwaves, integrated data, vulnerability, excess heat factor

A comprehensive five-year evaluation of IMERG Late Run precipitation estimates over the Netherlands

AbstractApplications like drought monitoring and forecasting can profit from the global and near real-time availability of satellite-based precipitation estimates once their related uncertainties and challenges are identified and treated. To this end, this study evaluates the IMERG V06B Late Run precipitation product from the Global Precipitation Measurement mission (GPM), a multi-satellite product that combines space-based radar, passive microwave (PMW), and infrared (IR) data into gridded precipitation estimates. The evaluation is performed on the spatiotemporal resolution of IMERG (0.1° × 0.1°, 30 min) over the Netherlands over a five-year period. A gauge-adjusted radar precipitation product from the Royal Netherlands Meteorological Institute (KNMI) is used as reference, against which IMERG shows a large positive bias. To find the origin of this systematic overestimation, the data is divided into seasons, rainfall intensity ranges, echo top height (ETH) ranges, and categories based on the relative contributions of IR, morphing, and PMW data to the IMERG estimates. Furthermore, the specific radiometer is identified for each PMW-based estimate. IMERG’s detection performance improves with higher ETH and rainfall intensity, but the associated error and relative bias increase as well. Severe overestimation occurs during low-intensity rainfall events and is especially linked to PMW observations. All individual PMW instruments show the same pattern: overestimation of low-intensity events and underestimation of high-intensity events. IMERG misses a large fraction of shallow rainfall events, which is amplified when IR data is included. Space-based retrieval of shallow and low-intensity precipitation events should improve before IMERG can be implemented over the middle and high-latitudes.

Impacts of permeable interlocking concrete pavement on the runoff hydrograph: Volume reduction, peak flow mitigation, and extension of lag times

AbstractPermeable pavements are implemented to provide at‐source treatment of urban stormwater runoff while supporting vehicular and pedestrian use. Studies on these systems have mainly focused on those treating only direct rainfall and installed atop well‐drained soils which typically provide substantial hydrologic mitigation through exfiltration that may not be representative of more hydrologically taxing conditions. A single lane parking area retrofitted with permeable interlocking concrete pavement in Vermilion, OH, USA was monitored over a 15‐month period to quantify its hydrologic performance under such conditions. The 470 m2 permeable pavement was underlain by silt loam soils and a shallow bedrock layer and treated run‐on from the adjacent 324 m2 asphalt drive lane. Observed data were compared to a calibrated SWMM model developed to simulate the pre‐retrofit conditions of the site (i.e., a completely impervious parking lot). Cumulative runoff volumes were reduced by 43% across all events in the monitoring period compared to a fully impervious parking lot. While median peak flows were reduced by 75%, substantial mitigation was limited to smaller, lower intensity events with longer antecedent dry periods (i.e., non‐flood producing events). The permeable pavement significantly delayed the occurrence of peak flows from the site following peak rainfall intensity by a median 29 min. Results from this study demonstrate that permeable pavements which receive run‐on from adjacent imperious cover and are installed atop poorly drained soils can significantly reduce runoff volumes and peak flow rates and delay the occurrence of peak discharge. The modelling approach implemented can provide a better estimation of diffuse inflows to green infrastructure stormwater controls and aid in refining design features which enhance the hydrologic performance in systems underlain by poorly drained soils.

Shake‐table tests of innovative drift sensitive nonstructural elements in a low‐damage structural system

AbstractPost‐earthquake damage reports have continuously highlighted the significant vulnerability of nonstructural elements to seismic events. Nonstructural damage has severe impact in the building recovery, increasing the socioeconomic losses even for low intensity events. In the last few years, research efforts have focused on the development of innovative nonstructural solutions, to be combined with damage‐resistant structural skeletons in order to obtain an overall high‐performance building. As part of a European Union (EU)‐funded project, the effectiveness of such integrated skeleton&envelope low‐damage system in reducing the earthquake related losses was investigated. Tridimensional shake table tests on a 1:2 scaled timber‐concrete low‐damage structural skeleton, “dressed” by different innovative nonstructural elements (glass/concrete facades, gypsum/masonry partitions), were performed at the National Laboratory for Civil Engineering (LNEC) in Lisbon, Portugal. The shake table tests were carried out at increasing seismic intensities to investigate the structural and nonstructural performance up to a higher‐than Collapse Prevention Limit State according to the Italian Code (975 years return period). This paper focuses on the dynamic behavior of nonstructural elements with detailed discussion on construction detailing, seismic demand and performance of the innovative solutions. The high performance of nonstructural elements proved the potential of the details introduced in the partitions/facades. Minimal or no damage was observed up to the end of the overall testing sequence, which reached moderate‐to‐high interstory drift ratios (more than 1.00%) ‐ typically expected to cause severe damage to traditional nonstructural partitions/infills/facades.

Failure Analysis of Unconfined Brick Masonry with Experimental Verification

The survival of low rise unconfined masonry structure against earthquakes is very rare even due to low or moderate intensity events. To understand the failure mechanism and cracking pattern of unconfined masonry, a scaled specimen of four unconfined brick was analyzed using finite element software in conjunction with experimental verification. This study started by developing 3D finite element model of unconfined masonry subjected to in-plane loading. Bricks and joints were modeled discretely in the model, allowing for nonlinear deformation characteristics of the both materials. This model exhibits the local effect and is capable of displaying the behavior of masonry walls in which high local stresses and stress gradients are presented in the color contour diagram. The overall result of stress is presented using the von Mises (distortion energy method). The analysis of the model concluded that the unconfined brick masonry specimen structure generally fails along the brick joints, although in-plane shear stresses can cause cracks through the brick in the translation to tensile stress zone.

Earthquake-induced energy response of reinforced concrete dual-system tall buildings

The distribution of earthquake-induced energy in a 42-storey reinforced concrete dual-system building at three ground shaking intensities was investigated. The earthquake-induced energy response of the building was obtained in terms of elastic energy (kinetic energy and strain energy) and inelastic energy (hysteretic energy and structural damping energy) components for each structural member. Hysteretic energy is an indicator of inelastic deformations (i.e. potential damage) and is considered particularly important as it leads to high irrecoverable energy demands in a building and identifies critical members that require higher energy absorption capacity. The ratio of hysteretic energy to input energy was assessed among different structural members as well as along the building height. The results showed that the hysteretic energy constituted less than 10% of the total input energy and was mostly dissipated in the frame members for low-intensity events, whereas 75% of the input energy was dissipated in the hysteretic mechanism, prominently by the beams. In terms of hysteretic energy demands, the critical floor levels were found to be the 12th and 26th floors. The findings of this research will help engineers obtain a reasonable estimate of the expected hysteretic energy demand once the input energy is known.

Workload Differences Between Training Drills and Competition in Elite Netball.

To examinepotential differences in internal and external workload variables between playing positions and between training drills and games within an elite netball team during training and competition. Nine elitefemale netballers were monitored during 15 games and all training sessions over 28 weeks. Workload variables assessed were relative PlayerLoad (PL per minute), accelerations, decelerations, jumps, changes of direction, high-intensity events, medium-intensity events, low-intensity events, PL in a forward direction, PL in a sideways direction, PL in a vertical direction, and summated heart-rate zones using heart-rate monitors and inertial measurement units. Conditioning and match play during training were the only drills that matched or exceeded game workloads. Workloads during small-sided games were lower than game workloads for all variables. In games, goalkeeper, goal attack, and goal shooter had a greater frequency of jumps compared with other positions. Midcourt positions had a greater frequency of low-intensity events in a game. Workloads during small-sided games were lower than game workloads across all external and internal variables; therefore, netball staff should modify these small-sided games if they wish them to develop game-based qualities. Specific game workload variables indicate that there are differences within some positional groups; coaches need to be aware that positional groupings may fail to account for differences in workload between individual playing positions.

Hydrological behavior of a semi-dry forest in Northern Mexico: Factors controlling surface runoff

The understanding of the hydrological processes in transitional zones between semi-arid and temperate ecosystems is essential since these areas are particularly sensitive to changes in precipitation and land cover. The objectives were to (1) determine the most critical factors in the generation of surface runoff during one rainy season; and (2) analyze the effect of different rainfall variables and soil moisture on the amount of surface runoff. The study area is in a semi-dry forest in the state of Chihuahua, Mexico. Vegetation, soil, and precipitation variables were monitored on three micro-catchments (0.19–0.27 ha) in 2018. Maximum 30-min rainfall intensity, rainfall depth, and soil moisture were the main variables controlling surface runoff. Rainfall intensity was better related to the amount of surface runoff, with an increase in runoff when rainfall intensities were greater than 25 mm h−1. The highest runoff coefficients (10%) occurred only when rainfall intensity exceeded 30 mm h−1. Similarly, surface runoff was only activated when rainfall depth exceeded 20 mm, or when the maximum volumetric water content by rainfall event exceeded 30%. Only 10% of storms exceeded these thresholds, indicating the difficulty of runoff generation in transitional zones. The interception (36%; s.d. = 30.7%), and the drastic decrease in soil moisture after each storm, suggest that more than 90% of the rainfall was lost by evapotranspiration. Our findings suggest that the groundwater recharge in a given year in these transitional zones is highly related to the number of low intensity and long duration rainfall events.

Relationships Between External- and Internal-Workload Variables in an Elite Female Netball Team and Between Playing Positions.

To examine relationships between external- and internal-workload variables in an elite female netball team, with consideration of positional differences. Nine elite female netball athletes had their weekly workloads monitored across their preseason and competition phases of a season. Internal workload was determined using summated heart-rate (HR) zones and session ratings of perceived exertion (sRPE), whereas external workload was determined using inertial movement units and included absolute PlayerLoad (PL), relative PL (PL per minute), accelerations (ACCEL), decelerations (DECEL), jumps, changes of direction (COD), high-intensity events, medium-intensity events, low-intensity events, PL in the forward direction, PL in the sideways direction, and PL in the vertical direction. Relationships between external- and internal-workload variables in the team and relative to playing position were examined. Across the team, the strongest external workloads that correlated with summated HR zones were PL (r = .65), COD (r = .64), ACCEL (r = .61), and DECEL (r = .61). The strongest external workloads that correlated with sRPE were COD (r = .79), followed by jumps (r = .76), ACCEL (r = .75), and DECEL (r = .75). For all positions, except-goal shooter, the strongest correlation was between PL and sRPE (r = .88-.94). In the goal-shooter position, the strongest correlation was between summated HR zones and DECEL (r = .89). The inertial movement unit-derived external-workload variables are strongly related to common internal-workload variables. In particular, COD and sRPE appear to provide a good monitoring combination of external and internal training loads for elite netball players.

Investigation of Coherent Flow Turbulence in the Proximity of Mid-Channel Bar

The turbulent flow characteristics in the vicinity of mid-channel bar are studied in this paper. The velocity is measured with the help of the acoustic Doppler velocimetry (ADV). Fractal modelling is done for analysing the fractal nature of bursting events. The conditional Reynolds stress structure was analysed by using the quadrant technique. Decomposition of Reynolds stress help in studying the distribution of stress among the four quadrants. The hole-size concept is utilized for segregating the extreme bursting events from the low intensity events. Variation of quadrants stresses with the hole-size is analysed. The result of hole-size study indicates that the extreme turbulent burst is produced by the mid channel bar. The new parameter inclination ratio is evolved in this research to reflect streambed elevation changes. The results indicate that the high-level turbulence is generated at region near upstream end of mid-channel bar. The presence of mid-channel bar causes the critical changes to the turbulent structure of flow, where high Reynolds stresses are generated at region near upstream region of mid-channel bar. Third order moments are computed for vertical lines in the proximity of mid-channel bar. High value of third order moments for bar condition indicate that the intense turbulent mixing and momentum exchange take place.