Annual Transport Research Articles

Examining contaminant transport hotspots and their predictability across contrasted watersheds.

Hydrobiogeochemical processes governing water quantity and quality are highly variable in space and time. Focusing on thirty river locations in Québec, Canada, three water quality hotness indices were used to classify watersheds as contaminant transport hotspots. Concentration and load data for suspended solids (SS), total nitrogen (TN), and total phosphorous (TP) were used to identify transport hotspots, and results were compared across hotness indices with different data requirements. The role of hydroclimatic and physiographic characteristics on the occurrence and temporal persistence of transport hotspots was examined. Results show that the identification of transport hotspots was dependent on both the type of data and the hotness index used. Relationships between temporal and spatial predictors, however, were generally consistent. Annual transport hotspot occurrence was found to be related to temporal characteristics such as the number of dry days, potential evapotranspiration, and snow water equivalent, while hotspot temporal persistence was correlated to landcover characteristics. Stark differences in the identification of SS, TN, and TP transport hotspots were attributed to differences in mobilization processes and provided insights into dominant water and nutrient flowpaths in the studied watersheds. This study highlighted the importance of comparing contaminant dynamics across watersheds even when high-frequency water quality data or discharge data are not available. Characterizing hotspot occurrence and persistence, among hotness indices and water quality parameters, could be useful for watershed managers when identifying problematic watersheds, exploring legacy effects, and establishing a prioritization framework for areas that would benefit from enhanced routine monitoring or targeted mitigation strategies.

The first spatio-temporal study of the microplastics and meso–macroplastics transport in the Romanian Danube

BackgroundTransport, accumulation, and degradation of microplastics (MiPs) in the aquatic environment represent a significant concern to the researchers and policy-makers, due to the detrimental impact on biota and human health through food ingestion. Although consistent investigations and research data are available worldwide, comparing the results is still challenging due to the need for more regulations regarding the sampling methods, analysis, and results reporting. The European regulatory efforts include studies on the MiPs transport in the western basin of the Danube River developed with active nets-based multipoint sampling methods from suspended sediments and proposed for standardization. In this context, the present study aimed to address for the first time the transport of MiPs in the Romanian sector of the Danube, starting after entering the country (Moldova Veche) and before the formation of the Danube Delta (Isaccea).ResultsThe multipoint nets sampling procedure facilitated the collection of suspended sediments in the water columns as deep as 0.0–0.6 and 3.0–3.6 m depths and near riverbed sediments (autumn 2022 sampling) during an extensive spatio-temporal study from spring 2022 until spring 2023. The estimate of the maximum annual transport of 46–51 and 93–100 t·y−1 for MiPs and total (micro–meso–macroplastics) MPs at Moldova Veche was based on 135 collected and processed samples using 2021 water flow data. Polyethylene (58–69%) and polypropylene (21–33%) were the main polymer components in the separated fragments, foils, microfibers, and different colors spheroids of MiPs ( < 5 mm), and the foils and fibers of meso–macroplastics (5–100 mm). Advanced investigations highlighted various microstructural degradations of the plastic fragments at the micro- and nanoscale and attached minerals (clays) and heavy metals.ConclusionThis paper presents the first comprehensive data set for microplastic annual transport in the "Low Danube", filling the need for a complete transport assessment in one of the most significant European rivers. 4–5 times lower values were measured before the entrance to the Danube Delta than those from Moldova Veche. The investigations should continue, including flooding events, and the sampling points should be expanded to deeper water column layers during all the campaigns for further validation.Graphical

Spatiotemporal variation, composition, and implications for transport flux of nitrogen in Leizhou Peninsula coastal water, China

Nitrogen, as the main bioactive element, plays an important role in biological productivity, ecosystem function, and biogeochemical processes in marine environment. In this study, seawater samples collected from China’s Leizhou Peninsula coastal water (LZPCW) during dry, normal, and wet seasons in 2018 were explored to reveal the spatiotemporal variation, composition, and transport flux of dissolved inorganic nitrogen (DIN) linked to hydrographic condition. DIN concentration and speciation showed significantly seasonal variation (P < 0.01), and the concentration of DIN species was significantly higher in dry season than other seasons. The annual mean DIN concentration was 8.01 ± 5.79 μmol L−1. In addition, the N–NO2−, N–NO3− and N–NH4+ were significantly different in the DIN bulk in different seasons. The largest fraction of DIN was N–NO3−, followed by N–NH4+, the lowest was N–NO2−, comprising up to 67.92 ± 23.20%, 23.90 ± 23.19% and 8.18 ± 8.19%, respectively. Besides, the Beibu Gulf was subjected to 7.28 × 1010 mol DIN annual flux through the Qiongzhou Strait. The annual transport fluxes of N–NO2−, N–NO3−, and N–NH4+ accounted for 6.43%, 77.20% and 16.36%, respectively. The DIN concentration and coastal water flow led to the largest DIN flux transport in dry season. This study revealed that the coastal ocean currents, river plumes and human activities jointly drove the dynamic variations of N species in LZPCW. It provides a baseline data for studying the spatiotemporal effects of hydrographic condition on nitrogen distribution and transport flux in the LZPCW, which is implications for understanding nutrients dynamics and coastal water quality management in future.

Large wood recruitment, retention and mobilization in low-order streams of the Brazilian Savanna

The delivery of wood to streams varies in space and time and may occur continuously or episodically. Once in a stream, wood may be retained or transported due to the balance between driving (water flow) and resisting forces (channel features and wood characteristics). Despite there being few studies directly measuring wood mobility, notable variations in annual transport rates and mean travelled distances have already been detected worldwide. In the tropics, due to wetter and warmer conditions and consequently higher decay rates and peak discharge, wood is believed that more readily degraded and transported downstream. However, there exists a knowledge gap regarding wood dynamics in tropical streams and even more considering tropical non-forested environments. In the present study, we aimed to document large wood (LW) recruitment, retention, and mobilization over a period of one year in eight low-order streams of the Cerrado (the South American Savanna) by tagging and tracing LW pieces. We detected high LW transport and recruitment rates in Cerrado streams, such that the total wood amounts remained constant over time. However, there were important differences between streams due to their distinct channel morphologies and the occurrence of episodic events. The LW length and diameter, original location and orientation were the most important factors in the prediction of the LW travelled distance, which ranged from zero to almost 100 m in one year. Our findings provide unprecedented information regarding wood mobility in tropical savanna streams in South America. To further advance knowledge about the dynamics of wood in Cerrado streams, future studies should characterize the great diversity of wood, especially with regard to densities that may strongly affect wood mobility. Furthermore, it is essential to perform long-term studies to document the dynamics of wood over years in these environments.

Glacial Meltwater in the Current System of Southern Greenland

AbstractThe Greenland Ice Sheet is losing mass at an accelerating pace, increasing its contribution to the freshwater input into the Nordic Seas and the subpolar North Atlantic. It has been proposed that this increased freshwater may impact the Atlantic Meridional Overturning Circulation by affecting the stratification of the convective regions of the North Atlantic and Nordic Seas. Observations of the transformation and pathways of meltwater from the Greenland Ice Sheet on the continental shelf and in the gyre interior, however, are lacking. Here, we report on noble gas derived observations of submarine meltwater distribution and transports in the East and West Greenland Current Systems of southern Greenland and around Cape Farewell. In southeast Greenland, submarine meltwater is concentrated in the East Greenland Coastal Current core with maximum concentrations of 0.8%, thus significantly diluted relative to fjord observations. It is found in water with density ranges from 1,024 to 1027.2 kg m−3 and salinity from 30.6 to 34, which extends as deep as 250 m and as far offshore as 60 km on the Greenland shelf. Submarine meltwater transport on the shelf averages 5.0 ± 1.6 mSv which, if representative of the mean annual transport, represents 60%–80% of the total solid ice discharge from East Greenland and suggests relatively little offshore export of meltwater east and upstream of Cape Farewell. The location of the meltwater transport maximum shifts toward the shelfbreak around Cape Farewell, positioning the meltwater for offshore flux in regions of known cross‐shelf exchange along the West Greenland coast.

Comprehensive life cycle cost analysis of ammonia-based hydrogen transportation scenarios for offshore wind energy utilization

As the importance of achieving carbon neutrality continues to grow, green hydrogen energy has emerged as a promising solution as a clean and sustainable energy source. One of the environmentally friendly methods of producing hydrogen is through offshore wind energy, which generates no pollutants during the process. While there have been economic analyses conducted on this production process, the subsequent life cycle study of hydrogen transport scenarios is often overlooked. To bridge this gap, this study focuses on conducting a comprehensive life cycle cost analysis of two hydrogen transport scenarios that utilize ammonia as the carrier. The analysis encompasses various aspects, including life cycle cost analysis, net present value, and the calculation of the levelized cost of hydrogen. Comprehensive sensitivity analysis is performed, considering indicators such as boil-off gas leakage rate and annual transportation mass. Furthermore, this study analyzes the operational risk rate and payback period of the two transportation scenarios. The findings reveal that for transportation distances within 100 km, the life cycle construction cost for the pipeline transport scenario amounts to 761 M$, whereas for ship transportation, it is 201 M$. The annual transport mass for the pipeline is estimated to be 12,000 metric tons, while for the ship, it is 8600 metric tons. The levelized cost of hydrogen is calculated to be 14.62 $/kg for pipeline transportation and 15.54 $/kg for ship transportation. Notably, the annual transport mass emerges as a significant factor impacting the levelized cost of hydrogen in both scenarios. Furthermore, by achieving an annual transport mass of 18,000 metric tons, the levelized cost of hydrogen can be reduced to 10.42 $/kg when the transportation distance extends to 450 km. This highlights the importance of considering the annual transport mass to optimize the cost-efficiency of hydrogen transportation.

Do urban rivers in the amazon coast trap macroplastic?

Amazon Rivers are important sources of macroplastic that enter the oceans. The estimated macroplastic transport is still inaccurate as hydrodynamics are not considered and data are not collected in situ. The present study shows the first quantification of floating macroplastics at different temporal scales, and an annual transport estimate through urban rivers in the Amazon: the Acará and Guamá Rivers, which discharge into the Guajará Bay. We conducted visual observations of macroplastics (>2.5 cm) in different river discharges and tidal stages, and we measured current intensity and direction in the three rivers. We quantified 3481 floating macroplastics, which varied according to tidal cycle and seasonality. Although connected to and affected by the same tidal regime, the urban estuarine system had an import rate of 12 ton.y−1 through the Guamá River and an export rate of 21.7 ton.y−1 of macroplastics through the Guajará Bay, affected by local hydrodynamics.

A simple method for annual sediment transport estimation at ungauged cross-sections and its application to assess sustainable sand mining from river margins in Uruguay

Estimation of sediment transport rate in rivers is a complex task that requires a large amount of information, resulting in the need for a considerable budget to address related problems. In this work, a methodology is proposed for mean annual sediment transport estimations at ungauged reaches, based on a simplified calculation of the channel-forming discharge. It consists of (1) determination of the channel-forming discharge from a simulated monthly flow series and a sediment rating curve; (2) calculation of the sediment transport rate corresponding to the channel-forming discharge through the sediment rating curve, and (3) determination of the mean annual transport under the assumption that the channel-forming discharge flows constantly for a year. The method was tested in the Santa Lucía basin, Uruguay. It was validated for the case study by applying it to a gauged cross-section and then used in other ungauged reaches of the basin to assess the sustainability of sediment mining from river margins. Results show that the proposed method tends to overestimate the annual transport. Nevertheless, it is a useful practical tool to set a limit to the annual sediment volume extracted by sand mining at river margins, and to estimate the order of magnitude of annual sediment transport in data-scarce rivers.

Gravimetry-based terrigenous freshwater extension in the southwestern South China Sea and its response to monsoon under ENSO

Terrigenous discharge represents a mass movement from land to oceanic environment. While previous studies characterized terrigenous freshwater via oceanographic (physical and biochemical) data, the persistent fresh water in the far-field ocean via satellite-gravimetric observation has been rarely explored. This paper aims to characterize the spatiotemporal extension of Mekong freshwater and the interchangeable role of runoff and climatic factors in the southwestern South China Sea. Employing wavelet coherence analysis between the in situ runoff and oceanic freshwater variations inferred from satellite gravimetry, the coherence and transport duration were obtained at annual, intra- and inter-annual time scales during 2003–2015. Despite weak relationship at 6-month and 24-month scales in regions away from the estuary, the two time series remained significantly correlated at the 12-month scale with a highly positive coherence over 0.97. Spatial pattern of the annual transport duration further indicated that freshwater firstly flowed alongshore before turning eastward offshore, qualitatively consistent with the northeastward western boundary current and an anticyclonic eddy during the summertime generated from the ocean circulation model. Using partial wavelet coherence, the time-variable relationship at all these three scales was found closely related to the Indian Monsoon and Western North Pacific Monsoon. A series of alternating ENSO events during 2007–2011 were responsible for the inter-annual variations, contributing <5 % to the seasonal freshwater extension. Compared with the averaged transport duration of the isotope method (i.e., 21.5 days) and the geostrophic current computation (i.e., 38.8 days) in the summer of 2007, our method yielded a comparable transport duration of 23.9 days with smaller uncertainties. The wind-driven Ekman transport, however, was primarily responsible for the anticyclonic movement of freshwater transport in the southwestern South China Sea during late summer.

Sediment concentrations and transport in icebergs, Scoresby Sound, East Greenland

AbstractGlaciers erode their beds and the adjacent landscape by abrasion and plucking and entraining sediment on their way downwards driven by gravity. Ice becomes a sediment transport agent. To determine glacial transport of sediment, measurements of both the ice flux and its concentration of sediment are needed. Once glaciers reach the ocean, ice and its entrained sediment is released into the ocean by calving. Further transport takes place by icebergs. Quantification of IRD (ice‐rafted debris) fluxes, which upon ultimate deposition on the ocean floor is an important climate indicator, becomes even more complicated as icebergs topple and differentially melt while being in transport. While the volume of tidewater glacier ice released by recent calving is quite well constrained by satellite measurements, there is a lack of measurements of the concentration of sediment within the moving ice. Here, we describe a method to collect samples of ice from icebergs systematically for the first time in Greenland together with a strategy to obtain representative samples. Our method is tested in Scoresby Sound, East Greenland in order to describe the transport of sediment into the fjord system related to calving from known glacial source areas. Our data clearly demonstrate that biased and sparse sampling potentially produces unrealistic values of sediment concentrations. Seventy‐two samples from 24 icebergs had an average concentration of sediment of 35.5 g/L of ice with a standard deviation of 97%, between the 24 individual icebergs. The origin of the sediment is related to specific source areas. Based on the samples, we present an estimate of the annual transport of sediment out of Scoresby Sound related to calving ~100 (0.3–200) million t year−1. Finally, we discuss the uncertainties of our estimate.

ЛОГІСТИЧНІ МОДЕЛІ ОЦІНЮВАННЯ ЕФЕКТИВНОСТІ ТОВАРОРУХУ

The article deals with an important applied problem of logistics management - evaluating the efficiency of goods movement. Given the importance of the problem of managing material flows at enterprises and constant changes in the conditions of the organization of supply chains, this topic is very relevant. In the conditions of the restructuring of many logistics supply chains, it is necessary to apply the following models for evaluating the movement of goods, which will take into account the most important criteria. In particular, a significant impact on the reconstruction of logistics chains and patterns of goods movement was made as a result of military operations in part of the territory of our country. Thus, the question arises of evaluating the effectiveness of new schemes of goods movement, taking into account new criteria. With this in mind, we included annual operating costs, annual transport costs, total capital investments, and the payback period of the project as part of the proposed distribution system selection model. The proposed model makes it possible to compare two distribution systems and choose the best one. The next task in the field of goods movement was the task of determining the coordinates of the distribution center, taking into account such parameters as the distance to the consumer and the traffic of distribution centers. The model for determining the coordinates of the distribution center proposed in the article makes it possible to take into account the changing factors of the external environment as much as possible and to choose the location of the distribution center that saves on transport costs, since the minimum distance and number of deliveries are ensured. The article also presented a graphic justification of the location of the distribution center.In order to maintain the appropriate level of quality of the logistics system of Ukrainian enterprises, the model for determining the level of logistics service was substantiated in the article. To assess the level of logistics service, we compared the time for logistics services that are actually provided by the firm with the time that would have to be spent on providing the entire set of possible services. All considered logistical tasks provide an opportunity to make effective management decisions regarding the organization of material flows at the enterprise.

In flux: Annual transport and deposition of suspended heavy metals and trace elements in the urbanised, tropical Red River Delta, Vietnam

Due to the depositional environment, river deltas are said to act as filters and sinks for pollutants. However, many deltas are also densely populated and rapidly urbanizing, creating new and increased sources of pollutants. These sources pose the risk of tipping these environments from pollution sinks to sources, to the world's oceans. We provide detailed seasonal and annual assessments of metal contaminants in riverine suspended particulate matter (SPM) across the densely populated Red River Delta (RRD), Vietnam. The global contributions of elements from the RRD are all <0.2% with many elemental fluxes <0.01%, suggesting the RRD is not a major source of elemental pollution to the ocean. However, ‘hotspots’ of metal pollution due to human activity and the impacts of tropical storm Son Tinh (July 2018) exceed both national level regulations and international measures of toxicity (e.g. enrichment factors). There is widespread ‘extreme pollution’ of Cd (enrichment factor >40) and concentrations of As higher than national regulation limits (>17 mg/Kg) at all sites other than one upstream, agricultural-dominated tributary in the dry season. These ‘hotspots’ are characterised by high inputs of organic matter (e.g. manure fertiliser and urban wastewater), which influences elemental mobility in the particulate and dissolved phases, and are potentially significant sources of pollution downstream. In addition, in the marine and fresh water mixing zone, salinity effects metal complexation with organic matter increasing metals in the particulate phase. Our calculations indicate that the delta is currently acting as a pollutant sink (as determined by high levels of pollutant deposition ∼50%). However, increased in-washing of pollutants and future projected increases in monsoon intensity, saline intrusion, and human activity could shift the delta to become a source of toxic metals. We show the importance of monitoring environmental parameters (primarily dissolved organic matter and salinity) in the RRD to assess the risk of transport and accumulation of toxic metals in the delta sediments, which can lead to net-increases in anthropogenic pollution in the coastal zone and the incorporation of toxic elements in the food chain.

Aerosol atmospheric rivers: climatology, event characteristics, and detection algorithm sensitivities

Abstract. Leveraging the concept of atmospheric rivers (ARs), a detection technique based on a widely utilized global algorithm to detect ARs (Guan and Waliser, 2019, 2015; Guan et al., 2018) was recently developed to detect aerosol atmospheric rivers (AARs) using the Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) reanalysis (Chakraborty et al., 2021a). The current study further characterizes and quantifies various details of AARs that were not provided in that study, such as the AARs' seasonality, event characteristics, vertical profiles of aerosol mass mixing ratio and wind speed, and the fraction of total annual aerosol transport conducted by AARs. Analysis is also performed to quantify the sensitivity of AAR detection to the criteria and thresholds used by the algorithm. AARs occur more frequently over, and typically extend from, regions with higher aerosol emission. For a number of planetary-scale pathways that exhibit large climatological aerosol transport, AARs contribute up to a maximum of 80 % to the total annual transport, depending on the species of aerosols. Dust (DU) AARs are more frequent in boreal spring, sea salt AARs are often more frequent during the boreal winter (summer) in the Northern (Southern) Hemisphere, carbonaceous (CA) AARs are more frequent during dry seasons, and often originate from the global rainforests and industrial areas, and sulfate AARs are present in the Northern Hemisphere during all seasons. For most aerosol types, the mass mixing ratio within AARs is highest near the surface. However, DU and CA AARs over or near the African continent exhibit peaks in their aerosol mixing ratio profiles around 700 hPa. AAR event characteristics are mostly independent of species with the mean length, width, and length / width ratio around 4000 km, 600 km, and 7–8, respectively.

Field Investigation on the Coastal Erosion and Progradation Evolution of the Binzhou Shelly Chenier in China: Comparisons between Normal and Typhoon Hydrodynamics

The shelly chenier is a dike-like accumulation formed by waves, currents, and other hydrodynamic forces pushing the shells and their debris in the intertidal zone to the high tide line. It is a special type of coastal dike. The shelly chenier located in Wangzi Island of northern Shandong Province is the last well-preserved chenier of the Bohai Bay with natural attributes exposed on the surface. It has unique and irreplaceable attributes among the shell beaches of China. Based on remote sensing interpretation, field investigation, and GPS-RTK (Real-Time Kinematic) measurement, this paper investigates the coastal erosion and progradation evolution of the Binzhou Shelly Chenier in China usingcomparisons between normal and typhoon hydrodynamics. The results show that: (1) There are two kinds of shelly chenier in the study area, the first is “the tidal channel shelly chenier” which is significantly affected by the tidal current, and the second is “the open shelly chenier”, which is significantly affected by direct scouring and silting of waves. The open shelly chenier is continuously eroding under the normal hydrodynamics and the shell beach is supplied by a large number of shells and their debris under the typhoon hydrodynamics, while the tidal channel shelly chenier is gradually developed due to the action of alongshore currents and in–out flows. (2) The energy of waves and currents under normal hydrodynamics is insufficient to transport the shells and their debris in the intertidal zone to the shell-beach. On the contrary, the continuous action of waves makes the shells and their debris on the open-shell beach finer and transports the shells and their debris to the sea causing erosion and retreat of the shelly chenier. (3) The action of typhoons and other strong winds and waves results in the original accumulation on the open shell-beach being further transported to the land and provides a large amount of shells and debris from the intertidal zone to the shelly chenier. Based on GPS-RTK monitoring data from 2020–2021, it was found that the transport volume of shells and debris caused by a typhoon storm surge is equivalent to the annual transport volume under normal ocean dynamics.

The role of current transport expenditure in mitigating the risk of modal shift during Covid-19 – Lessons from Polish cities

This article shows that current expenditure allocated by local authorities for the routine maintenance of public transport (i.e., providing passengers with clean and frequent services) is crucial to effectively limit the modal shift from public transit to private cars during the Covid-19 pandemic. In our analysis, we define public transport as the bus, tram, metro and trolley operations which are ordered and funded by 11 local authorities in Poland; we also assume that the modal shift is reflected in the growth of traffic congestion. Taking into account these assumptions and considering the long-term financial data from 2010 to 2020, we then conduct hierarchical linear regression and state that cities with a higher share of current expenses in cities’ total annual transport expenditure have registered during the pandemic a lower number of weeks with congestion level exceeding the pre-pandemic level. We argue that this is due to the allocation of current expenditure to cleaning services and the transport service supply, which could have a significant impact on perceptions of crowding and safety on public transport. Both issues belong to the essential determinants of the quality of public transport services and could play a key role in mitigating the modal shift by reducing the fear of catching Covid-19. In contrast to this finding, we also show that investment expenditure (allocated to improvements of transport infrastructure) does not have a similar impact on the congestion during the pandemic. In this context, we emphasise that cutting spending on cleaning services and the transport supply service as a response to the reduced number of passengers would be more devastating for public transport than postponing new infrastructure investments. Based on the results achieved in the analysis, we provide recommendations for local authorities that can help implement new funding models and reframe local transport policy, namely: (1) close the funding gap resulting from lower revenues to local budgets, (2) provide resources for maintaining the infrastructure investments and adapting them to a “new normality”, (3) maintain the attractiveness of public transport post-Covid.

New insights into the Asian dust cycle derived from CALIPSO lidar measurements

A full understanding of the Asian dust cycle can help with evaluation of the profound impact of mineral dust on human health, the ecosystem, the terrestrial and oceanic biogeochemical cycles, and the weather and climate. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP)-based 3-D dust detection and routine sampling capability, with the accurate dust mass extinction efficiency from Dust Constraints from joint Observational-Modelling-experimental analysis (DustCOMM) dataset, has made it possible to estimate the climatology of Asian dust mass loading (DML) and its transport flux. This study draws on this to provide new insights into the Asian dust cycle, especially the variability of its mass-weighted dust transport central axis (TCA), the contribution of different desert sources to its downstream effects, and the resulting dust budgets in terrestrial and oceanic regions. Dust aerosols emitted from the East Asian and Central Asian deserts together form a heavy dust transport belt stretching from the Taklimakan Desert (TD) and Gobi Desert (GD) to the Pacific Ocean. South Asian dust from the Thar Desert (ThD) can also affect southern China by crossing the Hengduan Mountains and the Yunnan-Guizhou Plateau. The dust TCA is controlled by the terrain of northwest inland China, but shifts in remote regions in the range of 35-50°N due to the western Pacific subtropical high and Aleutian low, and it trend towards a zonal straight line as the altitude increases. The dust transport contribution of the East Asian deserts to the mainland of China and adjacent sea is about 7 times than that of South Asia, with the annual transport fluxes being 214.28 and 30.43 Tg, respectively. The GD dominates the contribution of Asian deserts to the downstream effects and accounts for about 60% of the dust. This can be attributed to its maximum transport flux being near the surface, while the dust transport of the TD and ThD is above 3 km because of the blocking effect of the surrounding terrain. The deposition of Asian dust in the adjacent seas decreases significantly along the dust TCA, with the annual deposition rates being about 40.12, 20.41, and 4.01 g m-2 in the Yellow Sea, Japan Sea and the Northwest Pacific Ocean, respectively. These new findings and quantification of the Asian dust cycle will help with validation of the simulations provided by global and regional climate models and enable further evaluation of the impact of Asian dust on various related Earth systems.

Relationship between transport infrastructure expenditures and costs and transport indicators - an overview of European and Ukrainian situation

Quality of transport infrastructure determines the quality of the provision of services for the transportation of goods and passengers. The infrastructure sector is a guarantee of efficiency, mobility and uninterrupted economic activity. However, the high quality of the transport infrastructure implies significant and long-term investments. According to a McKinsey research report, to support sustainable economic growth in the world in line with forecasts for 2030, it is necessary to cover the need for additional investment of $ 3.3 trillion annually, equivalent to 3.8% of world GDP. The purpose of this work is to analyze the existing European approach to assessing transport infrastructure expenditures and costs, their impact on transport performance at the country level, as well as trends in Ukrainian policy regarding the support and development of road infrastructure. Transport infrastructure costs include the investment in new infrastructure, the cost of upgrading the existing infrastructure, the cost of maintaining the infrastructure, and the operating costs to enable the use of the transport infrastructure. Directive 2011/76 / EU prescribes that the weighted average infrastructure charges should be linked to construction costs, as well as the costs of operation, maintenance and development of the corresponding infrastructure network. The official Eurostat data of investment and O&amp;M costs of transport infrastructure based on the citizenship principle was taken for this study, namely: - the number of ton-kilometers traveled per year; - the volume of investments in road infrastructure per year; - the amount of funds for the maintenance of road infrastructure per year. The indicators were taken for countries of the EU for which statistics were available for 2016 and 2019. According to the study, the effect of investments in transport infrastructure is strongly manifested both in the same year and affects subsequent years in terms of the volume of annual transport work. That is, an increase in investment in road infrastructure clearly has a positive effect on the volume of transport work performed. On the other hand, the volume of investments in the EU infrastructure brings a much greater positive effect than funds for road maintenance. Thus, the experience of developed countries shows a positive relationship between investment in the maintenance and construction of transport infrastructure and economic performance of the state. Part of the research was devoted to the study of the impact of investments in road infrastructure of Ukraine on the example of the global Ukrainian infrastructure project "Big Construction". It is projected that in 2024, thanks to road works under the Big Construction, Ukraine's GDP will be 4.4% higher than GDP in 2020. But, as the research shows, good transport infrastructure is a necessary, but not a sufficient condition for growth. "Big Construction" project in Ukraine does not show any positive effect on the volume of performed internal transport work now. The reasons may lie both in more long-term effect from improving the infrastructure, and in the facts of corruption and theft of funds allocated for the project.

Methodology for interspecific assessment of the economic efficiency of the use of aircraft

The article discusses the problem of correct accounting of capital investments (one-time costs) in the current annual costs (the cost of an annual transport operation), which are borne by the operator through the existing financial instruments in the interspecific assessment of the economic efficiency of the use of aircraft. The article defines the structure of capital investments, and also proposes ways to determine the required volume of capital investments for the compared aircraft. Further, having chosen a suitable financial instrument that converts one-time costs (capital investments) into current annual payments, these payments are taken into account in the structure of the cost of an annual transport operation.

Modelling of annual sand transports at the Dutch lower shoreface

Dutch coastal policy aims for a safe, economically strong and attractive coast. This is achieved by maintaining the part of the coast that support these functions; the coastal foundation. The coastal foundation is maintained by means of sand nourishments. Up to now, it has been assumed that net transports across the coastal foundation’s offshore boundary at the 20 m depth contour are negligibly small. In the framework of the Coastal Genesis 2.0 program we investigated sand transports across this boundary and across other depth contours at the lower shoreface.This paper presents a computationally efficient approach to compute the annual sand transport rates at the Dutch lower shoreface. It is based on the 3D Dutch Continental Shelf Model with Flexible Mesh (3D DCSM-FM), a wave transformation tool and a 1DV sand transport module. We validate the hydrodynamic input against field measurements and present flow, wave and sand transport computations for the years 2013–2017.Our computations show that the net annual sand transport rates along the Dutch coast are determined by peak tidal velocities (and asymmetry thereof), density driven residual flows, wind driven residual flows and waves.The annual mean alongshore transports vary along the continuous 20 m depth contour. The computed total cross-shore transports are onshore directed over the continuous 20 m, 18 m and 16 m depth contours and increase with decreasing water depth.The effect of density difference and wind on the 3D structure of the flow and on the sand transports cannot be neglected along the Dutch lower shoreface. Our computations show that excluding the effect of density results in a significant decrease of the onshore directed transports. Also switching off wind largely counteracts this effect.The net cross-shore transport is determined by a delicate balance between gross onshore and offshore transports, where wave conditions are important. We show an example for Scheveningen where the net cross-shore transport is onshore directed when including all wave conditions but would be offshore directed when excluding waves higher than 3.5 m. In contrast, at Callantsoog the highest waves contribute more to the offshore directed transports. These results suggest that storm conditions play an important role in the magnitude and direction of the net annual transport rates at the lower shoreface.

Glacial landscape configuration influences channel response to flooding

AbstractThe influence of glaciation‐induced watershed configuration on channel response to flooding remains a topic of comparatively little research despite the prevalence of paraglacial landscapes. This study examines the response of Guichon Creek, a 1,200 km2 catchment in the southern interior of British Columbia, to major flood events during consecutive freshets with return periods of 20–40 years. The glacial history of the Guichon Creek landscape has influenced the spatial pattern of sediment availability to the channel, with erosion of thick glaciofluvial deposits located adjacent to the mainstem channel leading to extensive destabilization of downstream reaches. Over the two flood events, Guichon Creek widened by a factor of eight, but only downstream of sediment sources. Where sediment was not available to enter the channel, major changes in width were not observed. At least 163,000 ± 83,000 m3 and 73,890 ± 11,752 m3 of sediment entered the stream channel during the 2017 and 2018 freshets, respectively, representing an input more than 200 times the mean annual transport capacity. Between 40% and 60% of this sediment was of a sufficient caliber to be transported as bedload. While aggradation and degradation exceeding several meters in depth was observed at some sites, net increase in storage was small, indicating substantial sediment export. Specific patterns of channel change downstream of sediment input sites correspond to gradients in stream power. We present a conceptual model contrasting profile form, sediment availability, and transport capacity between a previously glaciated and a non‐glaciated basin of similar size and relief. These findings illustrate the broad implications of glacial landscape history on channel response to flooding, and have direct implications for river management, particularly as it pertains to channel stability and aquatic habitat.