Topographic Constraints Research Articles

Spatial distribution and structural analysis of the Neogene Siroua volcanic field (Moroccan Atlas Mountains)

Monogenetic volcanic fields develop worldwide in different geodynamic settings, and understanding their evolution may provide crustal, thermal, and topographical constraints. We focus on the small monogenetic Siroua volcanic field that has formed since the late Miocene along the tectonic lineament separating the High Atlas and the Anti-Atlas Mountains of Morocco, though the evolution of which is still unclear. We investigate the formation and evolution of the Siroua monogenetic field using geostatistical methods that allow us to classify the spatial distribution of vents in their geological contexts. In addition, we use aeromagnetism to obtain information about the tectonic structures underlying the field. Each method is evaluated separately, and then combined to discuss the relationship between the volcanism and the tectonic framework at regional and local scales. Our findings indicate that although vents are broadly randomly distributed, some correlation between volcanic alignments and the structural framework is locally observed. These findings corroborate existing knowledge about the influence of pre-existing structures on the propagation of magmas and on the spatial distribution of volcanic vents within monogenetic volcanic fields.

A Multi‐Decade Tracer Study of the Circulation and Spreading Rates of Atlantic Water in the Arctic Ocean

AbstractIn this contribution, we present tritium‐3He (3H‐3He) apparent ages and hydrographic data from 21 expeditions spanning 27 years of Arctic Ocean section work (1987–2013) to estimate flow paths and spreading velocities of the Atlantic Waters (AW) circulation on a pan‐Arctic scale. Tracer data not only corroborate the well‐organized cyclonic flow along the continental slope but also introduce a temporal dimension to these observations. Additionally, they provide insights into other circulation branches of the Atlantic layer, which are hypothesized to be influenced by deep submarine ridges. Tracer measurements indicate that mean spreading rates vary across different branches of the circulation pattern. Along the boundary current, spreading velocities range from approximately 0.7 to 1.5 cm s−1, with no significant difference observed between the waters of the two vertically stacked Atlantic branches. Within the limits of our method, tracer data support the hypothesis originally proposed by Rudels et al. (1994), https://doi.org/10.1029/gm085p0033—of stable pathways in the Atlantic Layer, influenced by topographic constraints.

Smart feasibility optimization of hybrid renewable water supply systems by digital twin technologies: A multicriteria approach applied to isolated cities

This research presents a multicriteria approach for the best hybrid water supply solution of a multipurpose Pumped-Storage Hydropower (PSH) system, using the Generalized Reduced Gradient (GRG) method in Solver, with the optimization process considering key factors, such as Net Present Value (NPV), the number of energy conversion devices, renewable energy production, source availability, reservoir capacities, topographic constraints, and energy tariffs. The methodology combines a literature review, methodological development, and machine learning applications for hybrid water-energy systems. Results indicate that solar-only solutions are insufficient in high hydropower potential scenarios while integrating wind turbines significantly enhances energy production and profitability by generating surplus energy for grid sales. The timing of energy sales and the incorporation of battery storage also impact NPV, which can exceed 180 million euros. Wind energy contributes to continuous profitability and optimized system performance, particularly in isolated regions. The PSH system can manage 130,000 cubic meters of water daily, storing 25 MWh of energy, and reducing CO2 emissions by over 18,000 tonnes per year. These findings highlight the importance of renewables, such as wind energy, and effective operational management. It enhances the economic viability and environmental sustainability of hybrid water-energy systems.

Supporting driver performance in closely spaced tunnel-interchange structure: Traffic control devices and effects on driving behavior

Objectives With the rapid development of expressways in the mountainous regions of southwestern China, closely spaced tunnel-interchange structures have inevitably emerged due to topographical constraints and environmental limitations. Given the unfavorable road geometry and rapid cross-section transitions, drivers face significant safety concerns. This study aims to investigate drivers’ safety performance at closely spaced tunnel-interchange sections and determine how safety risks can be mitigated through improved traffic control devices design. Methods Thirty-nine participants conducted an experimental study in a fixed-base simulator. The test scenario was modeled on the Xingyan Freeway-S3801 and accurately reproduced in the simulator. For each safety performance metric, the driving simulator experiments yielded a dataset with 780 observations. To address the idiosyncratic variation due to individual driver differences, a series of linear mixed effects models (LMM) were developed to analyze drivers’ behavior responses. Results In closely spaced tunnel-interchange sections, a general impairment of both longitudinal and lateral performance was observed. This study identified potential critical impact variables in traffic control device systems. According to the LMM results: (a) Removing the 0.5 km interchange ramp exit advance guide sign located in the tunnel exit area reduces dangerous behavior in the corresponding impact area. (b) Replacing the 0.5 km interchange ramp exit advance guide sign with arrow pavement markers as an information source supports improved driver performance, promoting driver safety. (c) Adding tunnel exit distance signs within tunnels is recommended to enhance situation awareness for drivers. Conclusions This study addresses the scientific issues related to traffic control devices setup for closely spaced tunnel-interchange sections, focusing on identifying potential critical impact variables. The findings provide guidance on the design of traffic control devices for such sections and support revisions to national engineering standards.

Calculation method of temporary cable force in incremental launching construction of large span steel box girder without auxiliary pier

The Fenshui River Bridge is a steel–concrete composite girder bridge with a main span of 90 m. Due to the topographical constraints, the steel box girder was constructed without the use of auxiliary piers, employing incremental launching techniques. This article focuses on the construction technology used for the steel box girder of the Fenshui River Bridge. Firstly, using the influence matrix method, the cable force is determined based on the maximum cantilever state of the structure, with the vertical deformation of the front end of the guide beam and the horizontal deformation of the top of the tower as the control objectives. The unstressed cable length is then calculated based on the mechanical relationship between cable deformation and cable force. A calculation method for adaptive cable force is proposed, which is based on the variation of the stress-free cable length within the adaptive structural system. Next, the finite element analysis method was employed to determine the optimal layout position for the tower. The results indicate that during the incremental launching construction of the steel box girder, the calculated cable forces using the method proposed in this paper are in close agreement with the measured cable forces. At the maximum cantilever state of the structure, the calculated and measured values of the cable force resulted in a percentage difference of 3.96%. The calculated values of deformation and stress in key sections showed a percentage difference of 6.4% for deformation and 6.6% for stress. To maximize the effectiveness of the tower and cable, the tower should be positioned above the bridge pier when the guide beam crosses the maximum span. The findings of this paper can serve as a reference for the construction of similar types of bridges.

Blue rings in Bristlecone pine as a high resolution indicator of past cooling events

This study develops the use of ‘blue rings’ (BR), reflecting incomplete cell wall lignification, as a sensitive thermal indicator in bristlecone pine (Pinus longaeva D.K. Bailey). Using double-stained anatomical thin-sections, we explore the climatic and topographical constraints governing BR formation by developing a time-series from 83 cores and comparing BR occurrence with the full temporal span of available climatic data (1895–2008 CE). Lignification is temperature-dependent and continues at a cellular level post-radial growth completion. As BRs reflect incomplete lignification, they can serve as a higher resolution and more sensitive proxy for past cooling than previously established tree-growth indicators. Results indicate that blue ring formation is primarily induced by low September temperatures and responds more sensitively to cooling than the well-established frost-ring record. Additionally, the occurrence and intensity of blue rings decreases gradually below the upper tree line. Bristlecone pine BRs are demonstrated to have significant capacity to enhance the reconstruction of past cooling events in North America connected with both localized and hemispheric scale forcing over multi-millennial timescales. Given its unmatched longevity, the species offers an unparalleled potential for Holocene length climate reconstruction. Findings also highlight the potential for blue rings to provide a more nuanced understanding of past temperature fluctuations across multi-millennial timescales.

Assessing the impact of biosecurity practices and animal welfare in small-scale mountain dairy farming

This study estimates the association between the level of biosecurity, animal welfare, milk quality, and economic performance on 2291 mountain dairy farms which largely differs in management and structure from large dairy operations in the lowlands mainly due to climatic and topographic constraints in mountain areas. The dairy industry’s increasing emphasis on biosecurity is crucial for ensuring animal health, productivity, and disease mitigation. Therefore, in the present study the biosecurity and animal welfare status of mountain dairy farms were assessed considering the official welfare protocol for dairy cows of the Italian ClassyFarm system. Our findings reveal a suboptimal adoption of biosecurity measures, attributed to structural limitations in mountain farms and farmers’ awareness gaps. Despite these challenges, the economic significance of biosecurity adoption is evident, emphasizing potential benefits for farm viability and animal health. Conversely, the study indicates a moderate to good welfare status in assessed farms, reflecting farmers’ awareness of the importance of high welfare standards for dairy cows. Improved welfare positively correlates with milk sales and productivity, highlighting the economic advantages of prioritizing animal well-being. Challenges persist, particularly regarding animal housing deficiencies and related consumer concerns about animal welfare in dairy production. Therefore, targeted interventions and educational initiatives are crucial to empower farmers and promote best practices in biosecurity and animal welfare management. However, addressing resultant production cost increases necessitates society’s willingness to pay more for animal-based food, emphasizing the importance of aligning economic incentives with sustainable farming practices.

Climate‐resilient water infrastructure in India

AbstractIndia receives an annual precipitation of about 3880 BCM and the average water availability is 1999 BCM. Out of this, utilizable water resources are 1126 BCM due to topographic constraints, distribution effects and so forth. In India, agriculture remains the principal source of livelihood for about 54.6% of the population. The overall water demand of the country in 2010 was estimated at 710 BCM, of which the water use in irrigation was about 557 BCM (78%). With limited water resources available for fulfilling the water requirement of all the sectors, it is projected that by 2050 our overall water demand (1180 BCM) would outgrow the total utilizable water resources, namely 1126 BCM. Moreover, the groundwater table in various regions of the country is seeing a decline at an alarming rate.Additionally, climate change poses significant and far‐reaching threats in all spheres of life and the economy. The erratic rainfall pattern makes a significant contribution to the frequent occurrence of floods and droughts in the country.This paper attempts to put in context the impact of climate change observed on various facets of water resources, the need to develop and invest in climate‐resilient water infrastructure, and to highlight several initiatives taken by the government of India in this direction.

Rock and ice avalanche-generated catastrophic debris flow at Chamoli, 7 February 2021: New insights from the geomorphic perspective

Within mountainous landscapes neighboring glaciers, slope instabilities and consequent catastrophic mass flows are vital processes on Earth's surface, which have been of increasing interest for decades. These events commonly exhibit large volume, high velocity, and high mobility. Recently, a catastrophic debris flow occurred in India on 7 February 2021, which unfortunately claimed 70 lives and left 134 people missing. The failed mass comprises 80 % rock debris and 20 % glacier ice. Our remote sedimentological investigation of remnant deposition shows clear evidence of wet granular flow in upper Ronti Gad valley, which doesn't support the previous interpretation of immediate melting of the failed 20 % ice mass during the falling and impacting process. We further utilized the superelevation phenomenon to back-calculate the velocity downstream of the impact zone, and estimated the peak discharge, which is verified by field-documented data. Our results revealed an initial waning trend of rock and ice mass flow. As it entered the narrow valley of the lower Ronti Gad River, the extensive material erosion resulted in three-fold flow enlargement, which gave rise to a maximal peak discharge of up to 48–54 × 104 m3/s. The transition from granular flow to debris flow occurred in the 2-km-long channel downstream of the Ronti Gad-Rishigangga confluence. The sediment deposition of 4.8 × 104 m3 and the incorporation of stream water in this zone have dominated the rheologic transition. We inferred that the intense erosion of erodible sediment due to topographic constraint plays an essential role in maintaining the mobility of the flow. Therefore, the effect of glacier ice meltwater on high mobility may be overestimated. As long as the granular flow can access the stream water in major rivers, flow transformation can easily happen because of sufficient water supply in the channel. The valley morphology in the proglacial region is commonly featured by the shift from an upstream U-shaped valley carved by glacier erosion into a downstream fluvial-erosion-dominated V-shaped valley. This geomorphic setting of glaciated tributary favors the long-distance run-out of rock and ice avalanche.

Effect of sequentially altering topographical constraints on migration and local ordering of epithelial cells

Effect of sequentially altering topographical constraints on migration and local ordering of epithelial cells

Topography and Time Shape Mire Morphometry and Large‐Scale Mire Distribution Patterns in the Northern Boreal Landscape

AbstractPeatlands are major terrestrial soil carbon stores, and open mires in boreal landscapes hold a considerable fraction of the global peat carbon. Despite decades of study, large‐scale spatiotemporal analyses of mire arrangement have been scarce, which has limited our ability to scale‐up mire properties, such as carbon accumulation to the landscape level. Here, we use a land‐uplift mire chronosequence in northern Sweden spanning 9,000 years to quantify controls on mire distribution patterns. Our objectives include assessing changes in the spatial arrangement of mires with land surface age, and understanding modifications by upland hydrotopography. Characterizing over 3,000 mires along a 30 km transect, we found that the time since land emergence from the sea was the dominant control over mire coverage, especially for the establishment of large mire complexes. Mires at the youngest end of the chronosequence were small with heterogenous morphometry (shape, slope, and catchment‐to‐mire areal ratios), while mires on the oldest surfaces were variable in size, but included larger mires with more complex shapes and smaller catchment‐to‐mire ratios. In general, complex topography fragmented mires by constraining the lateral expansion, resulting in a greater number of mires, but reduced total mire area regardless of landscape age. Mires in this study area occurred on slopes up to 4%, indicating a hydrological boundary to peatland expansion under local climatic conditions. The consistency in mire responses to spatiotemporal controls illustrates how temporal limitation in peat initiation and accumulation, and topographic constraints to mire expansion together have shaped present day mire distribution patterns.

Development of pedotransfer functions for predicting saturated hydraulic conductivity in a Himalayan catchment: Sikkim, India

AbstractSaturated hydraulic conductivity (Ks) plays a vital role in irrigation and drainage system design. Generally, Ks is estimated in the laboratory; however, it is expensive and tedious, especially in the Himalayan ranges where soil sampling is challenging due to topographical constraints. Therefore, in this study, pedotransfer functions were generated using multiple linear regression (MLR) models for the predictability of Ks in a Himalayan catchment in India. Fifty soil samples were collected and divided into two groups at a 70:30 ratio. Different soil attributes derived from 70% of samples were used for MLR generation, and attributes of the remaining 30% of samples were used for model validation. Six different MLR models constituting different independent soil attributes were generated and compared statistically. The results indicate that the MLR model comprising soil texture, bulk density, particle density, soil moisture content (MC), organic carbon content and porosity results in the highest adjusted coefficient of determination (R2; 0.93 and 0.89 during model generation and validation, respectively). Additionally, it was found that the weight basis MC ranged from 14% to 29% with a median value of 24%. These results demonstrate that simple MLR models can be used as an alternative to laborious experimental setups for Ks estimation. These findings can be used as guidelines for proper irrigation planning and design in mountainous catchments.

Genetic Differentiation of the Bloodsucking Midge Forcipomyia taiwana (Diptera: Ceratopogonidae): Implication of the Geographic Isolation by the Central Mountain Ranges in Taiwan.

Forcipomyia (Lasiohelea) taiwana, a small bloodsucking midge, thrives in moderately moist habitats and is commonly found in grassy and bushy areas at an elevation below 250 m. This species exhibits a diurnal biting pattern and shows a marked preference for human blood. Although not known to transmit arthropod-borne diseases, the bites of F. taiwana can induce severe allergic reactions in some individuals. As a significant nuisance in Taiwan, affecting both daily life and the tourism industry, comprehensive studies on its population genetics across different geographical regions remain scarce. The central mountain ranges in Taiwan, comprising more than two hundred peaks above 3000 m in elevation, extend from the north to the south of the island, creating distinct eastern and western geographical divisions. This study utilizes microsatellite markers to explore the genetic differentiation of F. taiwana populations located in the eastern and western regions of the mountain ranges. Our findings reveal substantial genetic differentiation among populations inhabiting Taiwan's western region compared to those in the eastern region. This indicates that the topographical barriers presented by the mountain ranges significantly restrict gene flow, particularly given the species' limited active flight ability and habitat preferences. Although passive dispersal mechanisms, like wind or human activity, could contribute, this study concludes that the gene flow of F. taiwana between the western and eastern regions is primarily influenced by topographical constraints.

Large-Scale Block Bundle Adjustment of LROC NAC Images for Lunar South Pole Mapping Based on Topographic Constraint

Large-Scale Block Bundle Adjustment of LROC NAC Images for Lunar South Pole Mapping Based on Topographic Constraint

Borehole TV Imaging Technology for Horizontal Directional Drilling Based on an Optimization Algorithm for Structural Planes

The horizontal directional drilling technology combined with the borehole TV imaging technology can be used to obtain most of the geological information in conventional adit exploration. This combination has little impact on the environment and is free from topographic constraints, thus contributing to green exploration. However, conventional algorithms for structural planes fail to accurately extract information on the attitudes of incomplete structural planes in boreholes of any azimuth. Moreover, existing borehole TV devices are mostly cable-based and, thus, difficult to put in place in horizontal drilling. They are prone to get stuck in the collapse section of boreholes, thus damaging the devices. Given these challenges, this study develops an optimization algorithm for structural planes: (1) first, information on multiple points in the 2D unfolded view is fitted using a sinusoidal function curve, three arbitrary points are constructed using the fitted curve, and the normal vector of the plane determined by the three points is calculated; (2) the normal vector in the geodetic coordinate system is obtained after two rotations of the spatial coordinate system based on the theory of transformation of Cartesian coordinate system; (3) finally, the dip angle and dip direction of a structural plane are calculated using the normal vector in the geodetic coordinate system. By making the best use of the information on multiple points in the 2D unfolded view, the optimization algorithm can overcome the defect that is difficult for conventional two-point methods to locate the highest and lowest points of discontinuous structural planes. Therefore, the optimization algorithm applies to calculating the attitudes of structural planes in boreholes of any azimuth. Based on this optimization algorithm, this study successfully develops a cable-free, storage-based TV device for boreholes of any azimuth. This device was employed for laboratory experiments on 20 complete structural planes and 32 incomplete structural planes. As indicated by the experiment results, the optimization algorithm proposed in this study is applicable to many types of structural planes, with a dip direction error of less than 10° and a dip angle error of less than 5°, thus meeting the production requirements.

A Mapping Methodology Adapted to all Polar and Subpolar Oceans with a Stretching/Shrinking Constraint

Abstract Polar and subpolar oceans play a particularly important role in the global climate and its temporal changes, yet these regions are less well sampled than the rest of the global ocean. To better understand the physical or biogeochemical properties and their variabilities in these regions, accurate data mapping is crucial. In this paper, we introduce a mapping methodology that includes a water column shrinking and stretching constraint (SSC) based on the principle of conservation of potential vorticity. To demonstrate the mapping scheme efficiency, we map the ocean temperature in the southern Sea of Okhotsk, where the bottom topography comprises a broad and shallow shelf, a sharp continental slope, and a deep oceanic basin. Such topographic features are typical of polar and subpolar marginal seas. Results reveal that the SSC integrated (SSCI) mapping strongly reduces the mapping error in the broad and shallow shelf compared with a recently introduced topographic constraint integrated (TCI) mapping procedure. We also tested our mapping scheme in the Southern Ocean, which has a comparatively slanted shelf, a wider and gentler slope, and a deep and broad oceanic basin. We found that the SSCI and TCI methods are practically equivalent there. The SSCI mapping is thus an effective method to map the ocean’s properties in various topographic environments and should be adequate in all polar and subpolar regions. Importantly, we introduced a standardized procedure for determining the decorrelation length scales—a necessary step prior to implementing any mapping scheme—in any topographic conditions.

Expressive fluxes over Amazon floodplain revealed by 2D hydrodynamic modelling

Water fluxes in the Amazon River floodplain affect hydrodynamic and ecological processes from local to global scales, but they remain poorly understood due to difficult accessibility and limited data. We characterized the hydrodynamics of eight floodplain units of the central Amazon River (40000 km2) using the 2D hydraulic model HEC-RAS. High resolution modelling (∼400 m) improved the representation of river and floodplain discharge, water surface elevation (77 cm accuracy) and flood extent (∼80% - high water period, ∼52% - low water period) compared to past modelling studies. Our results show that floodplain flows during floods are very intense with upstream inflow and downstream outflow of the floodplain units. These gross flows are much larger than the net flows, with values of up to 20% of the Amazon River discharge and residence time around 6 days during floods (several months during low water period). Water extent did not show strong interannual variability during floods as the volume stored in the floodplain did, possibly due to topographic constraints. Significant hysteresis in flood extent and volume, and active and storage zones on the floodplain highlight the complexity of floodplain hydrodynamics. Extreme floods strongly impacted the onset and duration of the flood by up to one month and, consequently on duration of high water renewal period with the river. Our characterization is important to assess the effects of extreme floods on riverine communities, understand nutrient and sediment variations in the floodplain, and characterize the export of water, sediment, and carbon flux to the ocean from the world's largest hydrological system.

How does agricultural production outsourcing services affect chemical fertilizer use under topographic constraints: a farm-level analysis of China.

Agricultural production outsourcing services (APOS) are an important means to promote green and low-carbon development of agriculture in China. Topography is the key factor limiting the development of APOS. There is little research on the influence relationship between APOS and farmers' chemical fertilizer use from the perspective of topography. Based on the theory of economies of scale, this study empirically evaluated the effect of APOS on chemical fertilizer use and their differences from the perspective of nutrient elements under different topographic conditions by using micro survey data for farmers in China and econometric methods. The results show that APOS can reduce farmers' chemical fertilizer use, and this effect is more obvious for farmers with large farmland sizes and high education levels. Farmland topography directly affects the fertilizer reduction effect of APOS in China. Compared with plain areas, hilly and mountainous areas weaken this effect. To enhance the fertilizer reduction effect of APOS, China should fully consider farmland topography when promoting APOS development. In plain areas, farmland scale management should be further encourage to better utilize APOS as a means of reducing chemical fertilizer use. In hilly and mountainous areas, high-standard farmland construction and small agricultural machinery use can alleviate the constraints of topographical on the scale expansion of APOS. It is necessary to fully consider the differences in farmers' resource endowments and their awareness of purchasing agricultural services in promoting APOS development, especially in regard to the farmers with small farmland sizes and low education levels.

Topographic constraints on visual development

Topographic constraints on visual development

Autonomous generation of alluvial fans in landscape evolution models

AbstractWe develop a robust and simple rule‐based algorithm to autonomously simulate alluvial fan deposition and evolution under continuously developing landscape conditions without prescribing deposition locations or imposing topographic constraints. Augmented with this algorithm, landscape evolution models are capable of dynamically detecting locations of potential fan deposition by statistical measures of surface topography and fluvial dynamics, then depositing fan sediments where and when the developed conditions require. To assess the method's efficacy in depositing sediment at a mountain‐valley transition zone characterized by a transport surface that permits unobstructed exit of sediment and water, a hypothetical scenario is created that involves a frontal, normal fault. It is followed by a series of sensitivity analyses to ascertain the influence of parameters affecting fan deposition and secondary processes. Uplift (u) and precipitation significantly impact fan morphological characteristics, which are within the range of real‐world fans. Higher rates of each cause the notable expansion of the fan area except in cases of exceptionally high precipitation rates. Fan area has a power‐law relationship with most of the tested parameters, , where is erodibility (lithology), and are fluvial parameters, and is catchment area ( ~0.9). This study is the first showcasing fan power‐law relationships using numerical modelling. While fan area increases with precipitation, there exists a threshold beyond which fan area diminishes, and the formation of fans ceases altogether. The algorithm provides a basis for improving mechanistic understanding of fans by offering a robust platform for testing process dominance and scaling. The results demonstrate its applicability for landscape evolution simulation over a long time and broad spatial scales. We also investigate the hydrological significance of including autonomously generated alluvial fans in coupled landscape evolution—hydrology models that focus on groundwater as well as surface water hydrology.