SSC Analysis of South Maharashtra Coast: A Case Study from Vengurla Coastal Region (original) (raw)
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Journal of the Indian Society of Remote Sensing, 2006
Indian Remote Sensing Satellite (IRS) -P4 Ocean Colour Monitor (OCM) data were used to estimate Suspended Sediment Concentration (SSC) in the coastal waters offChennai and to study the distribution along the coast. Surface water samples were collected during May and October 2000 synchronized with satellite overpass, and quantitative estimates of Suspended Sediment Concentration (SSC) were done. OCM -Data Analysis System (DAS) software developed by the Space Applications Centre, Ahmedabad was used for OCM data processing and analysis. The field data and OCM derived SSC showed a correlation of r = 0.85 and r = 0.95 for the months of May and October respectively.
Computers & Geosciences, 2016
This study presents an easy, modular, user-friendly, and flexible software package for processing of Landsat 7 ETM and Landsat 8 OLI-TIRS data for estimating suspended particulate matter concentrations in the coastal waters. This package includes 1) algorithm developed using freely downloadable SCILAB package, 2) ERDAS Models for iterative processing of Landsat images and 3) ArcMAP tool for plotting and map making. Utilizing SCILAB package, a module is written for geometric corrections, radiometric corrections and obtaining normalized water-leaving reflectance by incorporating Landsat 8 OLI-TIRS and Landsat 7 ETM+ data. Using ERDAS models, a sequence of modules are developed for iterative processing of Landsat images and estimating suspended particulate matter concentrations. Processed images are used for preparing suspended sediment concentration maps. The applicability of this software package is demonstrated by estimating and plotting seasonal suspended sediment concentration maps off the Bengal delta. The software is flexible enough to accommodate other remotely sensed data like Ocean Color monitor (OCM) data, Indian Remote Sensing data (IRS), MODIS data etc. by replacing a few parameters in the algorithm, for estimating suspended sediment concentration in coastal waters.
Journal of Marine Systems, 2002
Remote sensing technique was applied to estimate suspended sediment concentration (SSC) and to understand transportation, distribution and deposition of suspended sediment in the estuary and throughout the coastal sea, off the Ganges-Brahmaputra River mouth. During low river discharge period, zone of turbidity maximum is inferred in the estuary near the shore. SSC map shows that maximum SSC reaches 1050 mg/l in this period. Magnitude of SSC is mainly owing to resuspension of the bottom surface sediments induced by tidal currents flowing over shallow water depths. The influence of depth on resuspension is farther revealed from the distribution and magnitude of SSC along the head of Swatch of No Ground (SNG) submarine canyon. During high river discharge period, huge river outflow pushed the salt wedge and flashes away the suspended sediments in the coastal sea off the river mouth. Zone of turbidity maximum is inferred in the coastal water approximately within 5-10 m depth of water, where the maximum SSC reaches 1700 mg/l. In this period, huge fluvial input of the suspended sediments including the resuspended bottom sediments and the particles remaining in suspension for longer period of time since their initial entry control mainly the magnitude of SSC. In the estuary near the shore, seasonal variation in the magnitude of SSC is not evident. In the coastal sea (> 5 m water depth), seasonal influence in the magnitude of SSC could be concluded from the discrepancy between SSC values of two different seasons. Transportation and deposition of suspended sediments also experiences seasonal variations. At present, suspended sediments are being accumulated on the shallow shelf (between 5 and 10 m water depth) in low discharge period and on the mid-shelf (between 10 and 75 m water depth) during high discharge period. An empirical (exponential) relationship was found between gradual settle down of suspended sediments in the coastal sea and its lateral distance from the turbidity maximum.
Journal of Sedimentary Environments, 2021
Grain-size distribution of beach sediments is one of the important proxies indicating aspects of sediment transport patterns and environmental characteristics. The seasonal sediment sample has been collected for 3 years at 26 stations along the tropical beaches of the eastern Arabian Sea. Sediment characteristics, sources, physical conditions, and transport patterns are derived. The sediments are medium-to-coarse in size and moderately-to-poorly sorted during the southwest monsoon attributable to high wave energy and strong winnowing action. During pre-and post-monsoon season, the sediments are medium to fine and are very well-to-moderately sorted which signifies low-to-moderate energy condition. The linear discriminate function indicates that the sediments are mainly deposited in the beach or the shallow marine environment under the influence of turbidity current. Beach or tractive current energy conditions and rolling, bottom suspension and rolling including graded suspension and no rolling mechanics of transportation are inferred from CM diagrams. The sediment transport patterns reveal that the direction in most of the stations is toward the south. The present study concludes that sediment textural parameters, mechanism of transport and deposition, and their trend are dependent on the prevailing monsoonal energies in the tropical beaches of the eastern Arabian Sea.
International Journal of Environmental Research, 2013
This study presents an empirical relationship of suspended sediment concentrations (SSCs) in the coastal waters, which is derived from the conventional methods, to radiometer remote sensing reflectance values (Rrs) and satellite data in coastal waters of Kerala. An algorithm is then developed to utilize both in situ SSCs measured from conventional methods and Rrs values. This algorithm is validated with the SSCs retrieved from Oceansat-2 Ocean Colour Monitor (OCM) data. A significant coefficient of determination (R2=0.62) is observed between the SSCs measured in situ and satellite derived SSCs. Reflectance values from more than two spectral wavelength bands are also employed to test the accuracy of results. Satellite derived SSCs range from 1- 40 mg/L in the coastal waters off Cochin, southwest India. The regional algorithm developed for the study area gives better results than Tassan’s algorithm, and this algorithm can be used in estimation of SSC for coastal waters of western India.
Remote Sensing of suspended sediments along the Tamil Nadu coastal waters
Journal of the Indian Society of Remote Sensing, 1996
Indian Remote Sensing satellite (IRS) IA & IB digital data in combination with field measurement were used to map distribution and concentration of suspended sediments along the Tamil Nadu coastal waters for monsoon and non-monsoon periods. Qualitative suspended sediment ...
Suspended sediment is one of significant factors related to cause of erosion and deposition in coastal zone. Hence, monitoring and understanding of the suspended sediment dynamics are vital components to handle coastal problems. Despite numerous studies worldwide, it is still a challenge to estimate suspended sediment concentration and its siltation characteristics in the continental shelf of the Bay of Bengal, Bangladesh. In this study, we addressed this challenge using in situ measurements and satellite based techniques. In understanding the spatial variation of suspended sediment concentration, its spatial distribution and siltation, three different levels of experiment were done. Firstly, the in situ data were collected from two study areas and analyzed in the laboratory. Since satellite imagery has been found to be propitious for providing information on suspended sediment concentration (SSC), secondly, we calibrated the in situ data of SSC to the contemporary Landsat 8OLI imagery spectral information and developed an algorithm based on the nearinfrared (NIR) band and in situ measurements to derive SSC spatial distribution maps over the whole northern part of the shelf zone. Thirdly, we used eco-sounding based bathymetry charts of two different years (i.e. 1982 and 2007 AD) developed by the Bangladesh Internal Water Transport Authority (BIWTA) to assess spatial variation of sediment deposition in the shelf zone and resulting bottom topography change over from 1982 to 2007 AD. Results revealed that, maximum and minimum SSC were found near the Meghna estuary (1.9gml-1) and near the head of the Swatch of no Ground (SNG) (0.22 gml-1), respectively. Maximum turbidity zone was found near the shore within the 5meter water depth contour line but may exceed during the monsoon season. During the season of low water discharge from the river network this turbidity is mainly triggered by the bottom sediment re-suspension induced by the action of tide and wave energy. The SSC maps revealed a high magnitude of SSC (≈ 2 gml-1) found in the estuary near the shore, which is not significant (<0.3 gml-1) beyond the 10 meter water depth contour line.
In the recent decades hydrologists, geologists, and stream ecologists have shown substantial interest in analyzing suspended sediments in water. Extracting information like suspended sediment concentration (SSC) in coastal waters is very important for assessment and monitoring of coastal settings and their effects on their ecology. This article demonstrates importance of Landsat 8 Operational Land Imager (OLI) for monitoring seasonal variation in SSC and movement (pre and post monsoon) along Thiruvananthapuram coast in India. The data was converted into marine reflectance after correcting due atmospheric errors. SSC was extracted using spectral analysis data analysis. Movement of SSC was monitored using wave direction and significant wave height data. The results revealed that the SSC decreased rapidly with the increase in distance from the beach and depth of the seabed. Wave with higher frequency in deeper water caused sparely circulation of sediments and their concentration at the lower depth in high bathymetry. Thus, the suspended sediments were indirectly proportional to bathymetry and distance from the shoreline and directly proportion to wave direction and littoral current at offshore. High concentration of sediments was found to be accumulated at shallow depth (< 10m), which was estimated to be 92 mg/l and decreased up to 30mg/l at a depth of 30 m. The movement of sediments was observed north-south during the pre-monsoon and reversed during post-monsoon due to reversal in wind direction. Satellite remote sensing techniques and data processing can be efficiently used for SSC monitoring and their movement in ocean. Such estimates over temporal and spatial scales can be used for coastal zone management and conservation. 1 Introduction Suspended loads are generally the portion of sediments, which contain fine sand, silt and clay etc and are carried to the ocean by the action of the fluid. These particles settle in such a way that they certainly do not touché the bed, which is maintained
SEASONAL VARIABILITY IN SEDIMENT DISTRIBUTION ALONG THE SOUTHWEST COAST OF TAMIL NADU, INDIA
Sedimentological studies have been used to decipher the provenance of the sediment samples. Granulometric analysis of sediments in the region from Kanyakumari coast, eight sandy beaches have been selected and studied for analyzing the textural parameters namely mean, sorting, skewness, and kurtosis. Abundance of medium sand and low fine sand deposits prevails in postmonsoon, summer and SW monsoon seasons, only medium sand deposits are available in NE monsoon. The presence of medium sand indicates that the deposition might have been formed under a high-energy condition and fine sands correspond to moderately low-energy conditions. The Linear Discriminant Functions of the sediment samples (Y1, Y2 and Y3) indicate beach, shallow agitated, and fully shallow marine environment in the coast and less influence of aeolian, beach process in all the seasons. Bivariate plot means vs standard deviation and sorting vs skewness show that majority of the samples fall in beach environment and few samples fall in riverine environments. CM diagram of SW coast sediments implies that overall deposition takes place by optimum grain size for the rolling process sector. The seasonal wave response associated with grain size variation clearly reflects the predominant transport rate higher in SW monsoon than the rest of the period. The post monsoon and summer season have the similar characteristics of the sediment origination. On the other side, SW monsoon and NE monsoon have akin relationship one among the others. The results show that seasonal action implies sediment dynamics except in Kanyakumari, and Kadiapattinam due to the presence of rocky cliffs, estuaries and anthropogenic activities. The present work provides an insight on the depositional feature of sediment in selected stations of the SW coast, India.