scholarly journals Characterizing the Relationship between the Sediment Grain Size and the Shoreline Variability Defined from Sentinel-2 Derived Shorelines

2021 ◽  
Vol 13 (14) ◽  
pp. 2829
Author(s):  
Carlos Cabezas-Rabadán ◽  
Josep E. Pardo-Pascual ◽  
Jesus Palomar-Vázquez
Keyword(s):  
Grain Size ◽  
Remote Sensing Data ◽  
Western Mediterranean ◽  
Fundamental Parameter ◽  
Numerical Function ◽  
Sediment Grain Size ◽  
Sediment Size ◽  
Definition Of ◽  
The Relationship ◽  
Sentinel 2

Sediment grain size is a fundamental parameter conditioning beach-face morphology and shoreline changes. From remote sensing data, an efficient definition of the shoreline position as the water–land interface may allow studying the geomorphological characteristics of the beaches. In this work, shoreline variability is defined by extracting a set of Satellite Derived Shorelines (SDS) covering about three and a half years. SDS are defined from Sentinel 2 imagery with high accuracy (about 3 m RMSE) using SHOREX. The variability is related to a large dataset of grain-size samples from the micro-tidal beaches at the Gulf of Valencia (Western Mediterranean). Both parameters present an inverse and non-linear relationship probably controlled by the beach-face slope. High shoreline variability appears associated with fine sands, followed by a rapid decrease (shifting point about medium/coarse sand) and subsequent small depletions as grain sizes increases. The relationship between both parameters is accurately described by a numerical function (R2 about 0.70) when considering samples at 137 open beaches. The definition of the variability is addressed employing different proxies, coastal segment lengths, and quantity of SDS under diverse oceanographic conditions, allowing to examine the effect they have on the relation with the sediment size. The relationship explored in this work improves the understanding of the mutual connection between sediment size, beach-face slope, and shoreline variability, and it may set up the basis for a rough estimation of sediment grain size from satellite optical imagery.

scholarly journals Estimation of Boreal Forest Growing Stock Volume in Russia from Sentinel-2 MSI and Land Cover Classification

2021 ◽  
Vol 13 (21) ◽  
pp. 4483
Author(s):  
W. Gareth Rees ◽  
Jack Tomaney ◽  
Olga Tutubalina ◽  
Vasily Zharko ◽  
Sergey Bartalev
Keyword(s):  
Remote Sensing ◽  
Land Cover ◽  
Boreal Forest ◽  
Remote Sensing Data ◽  
Land Cover Classification ◽  
Fundamental Parameter ◽  
Sensing Data ◽  
Growing Stock ◽  
Stock Volume ◽  
Sentinel 2

Growing stock volume (GSV) is a fundamental parameter of forests, closely related to the above-ground biomass and hence to carbon storage. Estimation of GSV at regional to global scales depends on the use of satellite remote sensing data, although accuracies are generally lower over the sparse boreal forest. This is especially true of boreal forest in Russia, for which knowledge of GSV is currently poor despite its global importance. Here we develop a new empirical method in which the primary remote sensing data source is a single summer Sentinel-2 MSI image, augmented by land-cover classification based on the same MSI image trained using MODIS-derived data. In our work the method is calibrated and validated using an extensive set of field measurements from two contrasting regions of the Russian arctic. Results show that GSV can be estimated with an RMS uncertainty of approximately 35–55%, comparable to other spaceborne estimates of low-GSV forest areas, with 70% spatial correspondence between our GSV maps and existing products derived from MODIS data. Our empirical approach requires somewhat laborious data collection when used for upscaling from field data, but could also be used to downscale global data.

scholarly journals Universal relation with regime transition for sediment transport in fine-grained rivers

2019 ◽  
Vol 117 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Hongbo Ma ◽  
Jeffrey A. Nittrouer ◽  
Baosheng Wu ◽  
Michael P. Lamb ◽  
Yuanfeng Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Sediment Load ◽  
Yellow River ◽  
Fine Sand ◽  
Sediment Flux ◽  
Universal Relation ◽  
Sediment Grain Size ◽  
Fine Grained ◽  
Predictive Algorithm ◽  
Sediment Size

Fine-grained sediment (grain size under 2,000 μm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 μm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode between mixed suspended bed load transport and suspension-dominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities.

Sediment grain size and organic carbon distribution in the Cabras lagoon (Sardinia, Western Mediterranean)

2004 ◽  
Vol 20 (sup1) ◽  
pp. 367-377 ◽  
Author(s):  
G. De Falco ◽  
P. Magni ◽  
L. M. H. Teräsvuori ◽  
G. Matteucci
Keyword(s):  
Grain Size ◽  
Organic Carbon ◽  
Western Mediterranean ◽  
Carbon Distribution ◽  
Sediment Grain Size

scholarly journals Patterns of grain-size temporal variation of sediment transported by overland flow associated with moving storms: interpreting soil flume experiments

2011 ◽  
Vol 11 (9) ◽  
pp. 2605-2615 ◽  
Author(s):  
J. L. M. P. de Lima ◽  
P. A. Dinis ◽  
C. S. Souza ◽  
M. I. P. de Lima ◽  
P. P. Cunha ◽  
...  
Keyword(s):  
Grain Size ◽  
Overland Flow ◽  
Strong Relationship ◽  
Flume Experiments ◽  
Sediment Grain Size ◽  
Sediment Yields ◽  
Sediment Size ◽  
Size Evolution ◽  
Mean Grain Size ◽  
Recession Limb

Abstract. This study describes and interprets the evolution of grain-size distribution of sediment yields generated in an experimental soil flume subjected to downstream and upstream moving rain storms. Results of laboratory experiments show that downstream moving storms cause more soil loss than do upstream moving storms. The pattern of sediment grain-size evolution in time during a runoff event exhibits a clear dependence on the direction of storm movement. A strong relationship between overland flow discharge and mean sediment size is found. Nevertheless, the mean grain-size of sediments transported during the rising limb of the hydrograph is coarser than during the recession limb of the hydrograph. This is more marked for downstream moving storms.

scholarly journals Mapping riverbed sediment size from Sentinel 2 satellite data

2021 ◽  
Author(s):  
Giulia Marchetti ◽  
Simone Bizzi ◽  
Barbara Belletti ◽  
Barbara Lastoria ◽  
Francesco Comiti ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Satellite Data ◽  
Spatial Scales ◽  
Image Texture ◽  
Mapping Procedure ◽  
Bed Sediments ◽  
Sediment Size ◽  
Sentinel 2

A comprehensive understanding of river dynamics requires quantitative knowledge of the grain size distribution of bed sediments and its variation across different temporal and spatial scales. Several techniques are already available for grain size assessment based on field and remotely sensed data. However, the existing methods are only applicable on small spatial scales and on short time scales. Thus, the operational measurement of grain size distribution of river bed sediments at the catchment scale remains an open problem. A solution could be the use of satellite images as the main imaging platform. However, this would entail retrieving information at sub-pixel scales. In this study, we propose a new approach to retrieve sub-pixel scale grain size class information from Copernicus Sentinel-2 imagery building upon a new image-based grain size mapping procedure. Three Italian gravel-bed rivers featuring different morphologies were selected for Unmanned Aerial Vehicle (UAV) acquisitions coupled to field surveys and lab analysis meant to serve as ground truth grain size data. Grain size maps on river bars were generated in each study site by exploiting image texture measurements, upscaled and co-registered with Sentinel-2 data resolution. Relationships between the grain sizes measured and the reflectance values in Sentinel-2 imagery were analyzed by using a machine learning framework. Results show statistically significant predictive models (MAE of ±8.34 mm and R2=0.92). The trained model was applied on 300 km of the Po river in Italy and allows to detect grain size longitudinal variation and to identify the gravel-sand transition occurring along this river length.Our proposed approach based on freely available satellite data calibrated by low-cost automated drone technology can provide reasonably accurate estimates of surface grain size classes, in the range of sand to gravel, for bar sediments in medium to large river channels, over lengths of hundreds of kilometers.

scholarly journals Variability of suspended sediment grain size distribution in winter floods

2016 ◽  
Vol 48 (2) ◽  
pp. 141-151
Author(s):  
Agnieszka Hejduk ◽  
Leszek Hejduk
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Standard Deviation ◽  
Size Distribution ◽  
Suspended Sediment ◽  
Grain Size Distribution ◽  
Sediment Grain Size ◽  
Mean Values ◽  
Average Value ◽  
Sediment Size

Abstract Variability of suspended sediment grain size distribution in winter floods. The work presents the results of research concern variability of suspended sediment grain size, transported during the winter floods in agricultural catchment, in the period of hydrological years 2012-2015. The information about grain size distribution from nine winter flood events were collected over the study period, which allowed to analyze the variability of suspended sediment particle size during the various events. Grain size of sediment was determined using a laser particle size analyzer Mastersizer Microplus from Malvern Instruments Ltd. Variability of individual particle size classes were observed in each flood. Sand fraction dominated in seven of nine measured events. There was no significant increase of suspended sediment size in relation to the maximum of discharge. It can be explain by a relatively low discharge of recorded events. The percentage of material classified as clay (<4 μm) ranged from 0.08 to 1.01%, silt-sized material (>4 and <63 μm) ranged between 9.31 and 67.17% and sand-size material (>63 μm) ranged from 32.01 to 90.61%. The relationship between the particle size and the discharge requires further studies. The diameter d10, d50 and d90 and a standard deviation were calculated for each flood. Mean values of d50 for individual flood ranged between 41.05 and 191.32 μm with average value of 99.01 μm and average standard deviation of 32.57.

Effects of aeration, sediment grain size and burial on stream litter breakdown and consumer performance: a microcosm study

2017 ◽  
Vol 68 (12) ◽  
pp. 2266 ◽  
Author(s):  
Olatz Pereda ◽  
Maite Arroita ◽  
Ibon Aristi ◽  
Lorea Flores ◽  
Aitor Larrañaga ◽  
...  
Keyword(s):  
Grain Size ◽  
Hyporheic Zone ◽  
Food Resource ◽  
Low Flow ◽  
Sediment Grain Size ◽  
Water Abstraction ◽  
Fine Sediments ◽  
Sediment Size ◽  
Microcosm Study ◽  
Laboratory Microcosm

Turbulence and aeration are reduced in many streams during low-flow periods as a consequence of drought or water abstraction, thus affecting invertebrate interactions and pivotal ecosystem processes such as the breakdown of organic matter (OM). These effects can be larger in the hyporheic zone (HZ), the ecotone connecting the surface stream and groundwater, especially when fine sediments reduce hydraulic conductivity. In addition, OM breakdown in the HZ could depend on the availability of OM in the benthic zone (BZ), because the latter would not only be a more accessible, and thus preferred, food resource, but also more easily scoured downstream. In a laboratory microcosm experiment of 28 days duration, we manipulated aeration, sediment size and location of OM (either all buried or half buried with half on the surface, simulating the HZ and BZ respectively). Six mayfly (Habroleptoides) individuals and four stonefly (Capnioneura) individuals were enclosed in each microcosm and the consumption of OM was measured. Lack of aeration reduced oxygen saturation from 94 to 66%, reducing OM consumption particularly on the surface, in contrast with our expectations. As hypothesised, the availability of surface OM significantly reduced invertebrate consumption of buried OM. Habroleptoides performed better than Capnioneura, especially in fine sediments. The results suggest that reduced turbulence can affect invertebrate trophic interactions as well as the decomposition of OM, depending on sediment grain size and the location of OM.

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