Anticlockwise Pattern Research Articles

Examining the Relationship between Rainfall, Runoff, and Turbidity during the Rainy Season in Western Japan

Given the changing climate, understanding the recent variability in large-scale rainfall patterns is a crucial task in order to better understand the underlying hydrological processes that occur within a watershed. This study aims to investigate how rainfall events in western Japan have changed due to climate change and how these changes have affected runoff–turbidity dynamics during the rainy season. To address the research objectives, we analyzed two decades of precipitation records in the Gōno River watershed and examined the associated runoff–turbidity dynamics during floods using turbidity–discharge (T-Q) loops, quantified using an enhanced hysteresis index. Our findings revealed a kind of intense rainfall event occurring every 3 to 4 years. Additionally, spatial pentad analysis showed varying intensities of accumulated precipitation, indicating that extreme rainfall is not confined to a specific spatial zone. Regarding turbidity–discharge behavior, we found that clockwise hysteresis patterns were caused by sediment sources from near-channel areas, while anticlockwise patterns were caused by soil erosion from nearby areas. Another notable finding was that turbidity peaks during floods may represent the earlier (or later) arrival of turbid water from distant upstream sources due to intense precipitation. One of the key challenges in quantifying hysteresis patterns is that there is no agreed-upon definition for how to determine the start and end of a flood event. This can lead to bias in the quantification of these patterns.

Numerical simulation of thermal hydraulics of supercritical pressure water with 2×2 rod assembly wrapped differently with a wire

Through the use of CFD, a thermal-hydraulic analysis was carried out on a set of 4 rod assemblies. The common wire-wrapped spacers on the fuel assemblies are wound in the same direction for all rods. Because of this design, it is anticipated that there would be an adverse flow in all of the sub-channels. In the course of this analysis, this flow was demonstrated to be real. In order to achieve desirable flow characteristics for coolant mixing, a novel configuration for wire-wrapped spacers is proposed here. This pattern designates a group of 4 rods, the rods have the wrapping system of clockwise and anticlockwise pattern. It was determined that this pattern had an exceptional mixing effect as well as a uniform flow. This pattern has a maximum temperature area that is approximately 8.5 °C lower than that of the conventional wire-wrapped fuel bundle arrangement. When compared to the regular pattern, the pressure drop caused by the new arrangement was approximately 1.9% less severe. The redesigned layout of the rod assembly improves heat transfer while also reducing the amount of pressure loss that occurs.

Extreme storm events shift DOC export from transport-limited to source-limited in a typical flash flood catchment

Dissolved organic carbon (DOC) export regimes are co-determined by DOC source supply and hydrological transport. Field studies have indicated that catchment DOC export is a single regime (source- or transport-limited, or chemostatic). If a shift between DOC export regimes exists, as has been rarely reported before based on low-frequency observation, then conceptual paradigms regarding lateral carbon export need to be revised. DOC dynamics of a flash flood catchment were investigated in this study with high-frequency observations during flood seasons. A three-phase DOC concentration and discharge relationship (n = 713) was observed, i.e., slow increase, rapid increase, and flat phases that occurred during the inter-storm, moderate storm, and extreme storm periods, respectively. Further hysteresis analysis showed that the anticlockwise pattern observed during moderate storms shifted to a clockwise pattern during extreme storms. These transitions suggest that extreme storm events shifted DOC export from transport-limited to source-limited. Failure to consider such a shift can cause significant overestimation of DOC yield in flash flood catchments where DOC yield is largely driven by storms.

Impact of the construction of cascade reservoirs on suspended sediment peak transport variation during flood events in the Three Gorges Reservoir

Peak sediment transport during flood events is very important to the sustainability of the Three Gorges Reservoir (TGR), and thus, in-depth research on peak sediment transport must be performed for the refined regulation of this reservoir. The variation in peak sediment transport and its corresponding causes following the completion of the cascade reservoirs in the lower Jinsha River in the TGR are still unclear. In this study, based on daily discharge and suspended sediment concentration time series, hysteresis patterns and peak sediment transport times were used to determine the peak sediment transport variations. The temporal peak sediment transport variations and their origins were revealed based on wave theory and a one-dimensional hydraulic model. The results show that peak sediment hysteresis has become more obvious recently, and the greatest influencing factor is the construction of cascade reservoirs. Rising water levels in the TGR contributed to slowing SSC, doubling the proportion of anti-clockwise patterns, and increasing the peak sediment transport time by approximately 31% after 2003. The cascade reservoirs in the lower Jinsha River reduced the peak discharge by approximately 15%, which had a relatively large influence on the SSC peak, increasing the SSC peak transport time by approximately 22% and increasing the proportion of the anti-clockwise pattern at the inflow reach. These results can provide references for reservoir regulation during flood events; more significant sediment hysteresis means the regulation timing should be changed. The lag between the peak sediment and peak discharge is affected by the flow process and water level and can be used to help develop a reservoir regulation model.

Changes in brachiopod body size prior to the Early Toarcian (Jurassic) Mass Extinction

Herein we analyze the shell length as estimation of the body size of several brachiopod assemblages recorded into the extinction interval prior to the Early Toarcian Mass Extinction. They were collected from representative localities around the Iberian Massif (Spain and Portugal) presenting different paleoenvironmental conditions. The analysis performed has revealed two different trends of spatial and temporal changes in body size. (1) Mean size decreases in the assemblages following an anticlockwise pattern from Iberian to Lusitanian basins, in relation to the progressive environmental stress caused by shifts on terrigenous input and in depth. This diminution results from changes in the relative abundance of bigger or smaller species in each area rather than from miniaturization of the taxa. (2) Some new evolved or more resilient species show increasing sizes over time along the extinction interval. This increase affects both big spiriferinides in the Iberian Basin and small rhynchonellides and koninckinides in the Lusitanian Basin, and runs in parallel to the drop in diversity and the progressive warming of the sea water in this interval in all the localities. This increase in body size has been related to the changes in diversity that could have favored the access to resources for resilient or new evolved species. The observed patterns are comparable with those detected in the end-Permian Crisis, and might indicate a generalizable response to similar biotic crises.

Colour asymmetry between galaxies with clockwise and counterclockwise handedness

Recent studies have shown that SDSS galaxies with clockwise patterns are photometrically different from galaxies with anti-clockwise patterns. The purpose of this study is to identify possible differences between the colour of galaxies with clockwise handedness and the colour of galaxies with anti-clockwise handedness. A dataset of 162,514 SDSS galaxies was separated into clockwise and counterclockwise galaxies, and the colours of spiral galaxies with clockwise handedness were compared to the colour of spiral galaxies with anti-clockwise handedness. The results show that the i-r colour in clockwise galaxies in SDSS is significantly higher compared to anti-clockwise SDSS galaxies. The colour difference is strongest between the right ascension of 30$^o$ and 60$^o$, while the RA range of 180$^o$ to 210$^o$ shows a much smaller difference.

Sap flow characteristics and their response to environmental variables in a desert riparian forest along lower Heihe River Basin, Northwest China.

Hysteresis, related to tree sap flow and associated environmental variables, plays a critical ecological role in the comprehensive understanding of forest water use dynamics. Nevertheless, only limited researches related to this unique ecological phenomenon have been conducted to date in desert riparian forests under extreme arid regions. Populus euphratica Oliv sap flow velocity (VS) was measured during the 2012 growing season using the heat ratio method, at the same time as environmental variables, such as photosynthetically active radiation (PAR), vapor pressure deficit (VPD), and leaf water potential. We found clockwise patterns of hysteresis between VS and VPD but anticlockwise patterns between VS and PAR. Pronounced hysteretic VS lag time, a function of PAR and VPD, was approximately 1.0~1.5 and -0.5h, respectively. Hysteresis was primarily caused by the biophysical declining in canopy conductance. Sigmoid response of VS to synthetic meteorological variables was enhanced by approximately 56% after hysteresis calibration to sunny days. Consequently, hysteresis can be seen as a protection mechanism for plants to avoid the overlapping of peak VS and environmental variables. Furthermore, the consistent presence of hysteresis suggested that estimating of plant water use in large temporal and spatial models may require certain provisions to different VS responses to variables between morning and afternoon and between seasons.

Residual currents and bedform migration in a natural tidal inlet (Knudedyb, Danish Wadden Sea)

The morphology and hydrodynamics of the natural tidal inlet Knudedyb in the Danish Wadden Sea were investigated by the analysis of high resolution bathymetric data and hydrodynamic numerical modeling. In contrast to the expected anticlockwise pattern similar to the other inlets in the Wadden Sea, a clockwise tidal residual current was found, which drives the sediment transport and results from the presence of a confluent meander bend. The channel is draped by bedforms of several hierarchical scales (on average, approximately 155m long and 2.3m high), with average sizes decreasing from south to north and seaward (i.e., westward). Primary bedforms in the area are mostly asymmetric ebb-directed and migrate in the ebb direction in the order of 3myr−1. Bedform sections at the northern channel flank show more symmetrical profiles; crests migrate flood-ward, leading to crestal flexing in the central channel. Lateral recirculation cells develop during ebb tide on both sides of the channel seaward of a bend, before the tidal reversal occurs in the rest of the model domain. As a result of the longer flood phase, a main clockwise residual eddy exists in the middle reach of the channel. Bedform migration patterns and hydrodynamic simulations reveal that the pronounced tidal asymmetry in the channel is enhanced by the effects of the channel morphology on the confined flow (at low tide).

Temporal variation of suspended sediment transport in the Koga catchment, North Western Ethiopia and environmental implications

AbstractEvent sediment transport and yield were studied for 45 events in the upstream part of the 260 km2 agricultural Koga catchment that drains to an irrigation reservoir. Discharge and turbidity data were collected over a period of more than a year, accompanied by grab sampling. Turbidity was very well correlated with the sediment concentrations from the samples (r = 0.99), which allowed us to estimate the temporal patterns of sediment concentrations within events. The hysteresis patterns between discharge and sediment concentrations were analysed to provide insight into the different sediment sources. Anticlockwise patterns are the dominant hysteresis patterns in the area, suggesting smaller contributions of suspended sediment from the river channels than from the hillslopes and agricultural areas. Complicated types of hysteresis patterns were mostly observed for long events with multiple peaks. For a given discharge, sediment yields in August and September, when the catchment was almost completely covered with vegetation, were much smaller than during the rest of the rainy season. The hysteresis patterns and timing suggest that the sediment availability from the agricultural areas and hillslopes affects sediment yields more strongly than does peak discharge. Two distinct types of sediment rating curves were observed for the season when the agricultural land was covered with vegetation and when it was not, indicating the dominating contribution of land use/cover to sediment yields in the catchment. The rate of suspended sediment transport in the area was estimated as 25.6 t year−1 ha−1. Copyright © 2013 John Wiley & Sons, Ltd.

Application of Satellite Remote Sensing for Investigation of Suspended Sediment Dispersion Pattern in the Near Shore Region: A Case Study from the Central West Coast of India

NAYAK, S.R.; HEGDE, V.S.; SHALINI, R.; RAJAWAT, A.S.; ALI, M.; VENKATESHWARLU, B., and RAMANA, I.V., 2012. Application of satellite remote sensing for investigation of suspended sediment dispersion pattern in the near shore region: A case study from the Central West Coast of India.Indian Remote Sensing -P4 (IRS P4) Ocean Color Monitor (OCM) data is used to understand seasonal variations in suspended sediment (SS) dispersal pattern in the near-shore waters of the Central West Coast of India. Four distinct patterns of sediment dispersion are observed. (1) During monsoon, plume-like sediment dispersion seaward is observed especially in the mouths of rivers. (2) As the monsoon progresses, there is northerly transport of sediments with anticlockwise pattern within the plumes. (3) During NE monsoon, sediment concentration is less and its transport is southward. (4) During premonsoon, SS concentration is high in the near-shore water and transport is landward. Sequential OCM data analyses indicated the influence of tidal currents, especially during premonsoon in the vicinity of the river mouths on sediments dispersion. During rising tide, sediments move into the estuary, and during falling tide they flow seaward resulting in erosion and formation of shoals. Sediment-dispersal patterns largely follow wind and wave patterns, a characteristic feature of the mesotidal coast. Presence of a number of mudflats within the estuary along with the siltation in the channels suggests that a net landward transport of sediments occur in the region.

Study of lightning current by remanent magnetization

A study of remanent magnetization is made at the areas of lightning strikes. In the case of triggered lightning (Okushishiku, Hokuriku district), the magnetic direction of the specimens shows a clockwise rotation pattern around the point of lightning strike. At an archaeological site in Miyagi Prefecture, an anticlockwise pattern of the magnetic direction was detected. These results indicate that a stable remanent magnetization is acquired by the strong magnetic field induced surrounding the lightning current, both in negative and positive lightning flashes. Also, a detailed analysis of magnetization clarifies the electric current flow underground caused by the lightning. The study of remanent magnetization will become a useful method to elucidate the path of the lightning current. © 1998 Scripta Technica, Electr Eng Jpn, 123(4): 41–47, 1998

Architectural and Mechanical Properties of the Black Coral Skeleton (Coelenterata: Antipatharia): A Comparison of Two Species.

Black coral skeletons are laminated composites, composed primarily of chitin fibrils and non-fibrillar protein. This paper examines mechanical properties of the composite and the architecture of the chitin component. Two species are shown to differ significantly in their tensile strength and fibril structure. The skeleton of Antipathes salix, a Caribbean species of commercial value, is stiffer, harder, darker, more dense, and more hydrophobic than Antipathes fiordensis from New Zealand. The chitin fibrils constitute a greater proportion of the skeleton in A. salix, where they are helically wound in an anticlockwise pattern within layer. Adjacent layers of skeleton are arranged with relatively small layer-to-layer fibril biases. There is no evidence of "helicoidal" structure in this skeleton. The fibrils in A. fiordensis are also wound anticlockwise within layer, but with rather large fibril biases between layers, giving the appearance of a meshwork. Large-scale helicoidal patterns with apparent rotations of 180{deg} characterize this material. Skeletal architecture is compared with the cuticle of insects and other arthropods. The skeletons of both species exhibit spines characteristic of the Antipatharia. We suggest that these have a significant reinforcing effect on the strength of the skeleton, contributing to an overdesign for the habitat in which these organisms presently occur.

Cardiac valve bioprosthesis frames and donor aortic valve commissural spacing

Intercommissural distances in 300 porcine and 200 human aortic valves were expressed as percentages of the smallest dimension. The right coronary cusp was generally the largest but whereas in porcine valves the noncoronary cusp was generally the smallest, in human valves this status was shared about equally between the noncoronary and left coronary cusps. The dominant pattern was with all three dimensions unequal (difference > 5%). Seventy-seven percent of the porcine valves and 84% of the human valves were in this category. The asymmetry existed in both clockwise and anticlockwise directions. Accurate concordance between the valve commissures and supporting frame struts is essential in the fabrication of bioprosthetic cardiac valves and the optimum utilisation of donor aortic valves would result from using frames in which the strut angles were 110°, 120°, 130° for porcine valves and 111°, 120°, 129° for human valves, in both clockwise and anticlockwise patterns.

The influence of trade winds, local air-masses and topographic obstacles on the aeolian movement of sand particles and the origin and distribution of dunes and ergs in the Sahara and Australia

The Saharan ergs consist of a wide range of aeolian land forms, while in Australia, sand-ridges are the main form. The ergs are situated along major sandflows of continental extent along which sand is transported. These are oriented approximately from NE to SW in the Sahara. In Australia they form an anticlockwise pattern open to the west. The spatial and temporal factors that govern the origin of sand-ridges are reviewed.