Shoreline Change Analysis at Chilika Lagoon Coast,India Using Digital Shoreline Analysis System

Shoreline is the dynamic interfaces of both terrestrial and marine environment, which constantly affected by natural coastal processes includes wave, tide, littoral drift and cyclonic storms as well as coastal development. Wave induced littoral drift and fluvial discharge causing the gradual inlet migration and has the concurrent impact on shoreline of Chilika lagoon. This study is to determine the long-term shoreline changes along the coast of Chilika lagoon. Historical satellite images were used to analyse the shoreline erosion and accretion based on statistical approach. The satellite data from 1975 to 2015 were processed by using ERDAS Imagine and the shorelines are extracted. The shoreline oscillation was analysed at an interval of 100 m along the coast of Chilika lagoon using DSAS software. Most commonly used statistical methods such as end point rate and linear regression rate are used. The shoreline change analysis for entire coast of the lagoon since 40 years (1975–2015) indicates that 62% is of accretion, 25% is under stable coast and erosion is 13%. The result reveals that the lagoon coast shows high accretion of 9.12 m/year at updrift side of the lagoon inlet whereas the downdrift side shows high erosion of ??10.73 m/year due to the wave induced northeasterly longshore sediment transport round the year and riverine discharge. This study would provide the potential erosion and accretion area at Chilika lagoon coast and would help in adaptive shoreline management plan.     

Shoreline Change Analysis along the Coast of South Gujarat,India, Using Digital Shoreline Analysis System

Shoreline changes along the south Gujarat coast has been analyzed by using USGS Digital Shoreline Analysis System (DSAS) version 4.3. Multi-temporal satellite images pertaining to 1972, 1990, 2001 and 2011 were used to extract the shoreline. The High water line (HTL) is considered as shoreline and visual interpretation of satellite imageries has been carried out to demarcate the HTL based on various geomorphology and land use & land cover features. The present study used the Linear Regression Method (LRR) to calculate shoreline change rate. Based on the rate of shoreline changes, the coastal stretches of study area has been classified in to high erosion, low erosion, stable, low accretion and high accretion coast. The study found that about 69.31 % of the South Gujarat coast is eroding, about 18.40 % of coast is stable and remaining 12.28 % of the coast is accreting in nature. Field investigation was carried out which confirmed the coastal erosion/accretion derived from the analysis. The high erosion area are mostly found along the Umergaon (near Fansa, Maroli, Nargol, Varili river mouth, Umergaon light house) and Pardi (Kolak, Udwara)Taluka in Valsad district. Stable coastal length of the study area is 21.59 km and mostly found in Nani Dandi and near Onjal. High accretion (3.70 %) was only found near Hajira and low accretion (8.58 %) are distributed the study area. The main causes of coastal erosion of the study area were the strong tidal currents accompanied by wave action and reduced the sediment load of the river.     

基于GIS技术的莱州湾东岸河流分形研究

应用地理信息系统(GIS)技术提取了莱州湾东岸河流信息,在此基础上运用计盒方法对莱州湾东岸的黄水河和王河水系进行了分形分析,获得了两水系的主河道河长分维数和河网分维数,并以此探讨了分维数与流域地貌和地质构造之间的相互关系。分形分析为研究区流域地貌学与水文学研究提供了一种新的研究途经。     

A shoreline change analysis along the coast between Kanyakumari and Tuticorin,India, using digital shoreline analysis system

The shoreline is one of the rapidly changing landforms in coastal areas.They are the key element in coastal GIS and provide the most information on coastal land form dynamics.Therefore,accurate detection and frequent monitoring of shorelines is very essential to understand the coastal processes and dynamics of various coastal features.The present study is to investigate the shoreline changes along the coast between Kanyakumari and Tuticorin of south India(where hydrodynamic and morphologic changes occur continuously after the December 2004 tsunami)by using Digital Shoreline Analysis System(DSAS),an extension of ArcGIS.Multidate IRS and Landsat Satellite data(1999,2001,2003,2005,2007,and 2009)are used to extract the shorelines.The data is processed by using the ERDAS IMAGINE 9.1 software and analyzed by ArcGIS 9.2 workstation.The rates of shoreline changes are estimated by three statistical methods,namely,End Point Rate(EPR),Linear Regression Rate(LRR),and Least Me-dian of Squares(LMS)by using DSAS.The study reveals that most of the study area has undergoing erosion.Both natural and an-thropogenic processes along the coast modify the shoreline configuration and control the erosion and accretion of the coastal zones.The coastal zones along the estuary have experienced accretion due to the littoral processes.The zones with headlands have more eroded than other zones along the study area.The study also shows that the coastal zones where sand is mined have relatively more rate of erosion than that of the other zones.Improper and unsustainable sand mining may also lead to severe erosion problem along this area.The shoreline change rates are altered by various geological processes along the coast.Thus,the present study implies that proper beach filling and nourishment projects should be made in the study area to save from hazards.It also indicates the advantage and suitability of DSAS to assess the shoreline changes compared with the traditional manual shoreline change analysis and prom-ising its applications for coastal zone management in other regions.     

Shoreline oscillation of Dhanushkodi,Rameswaram, India

Rameswaram Island located on the southeast coast of India bounded by Gulf of Mannar (GoM) on the south and Palk Bay (PB) on the north, respectively, is unique in nature. The southeastern part of Rameswaram Island known as Dhanushkodi foreland is a long sand spit of about 20?km length. Shoreline erosion/accretion rates are computed based on End-Point Rate, Linear Regression Rate and Net Shoreline Change from Indian Remote sensing Satellite, Linear Imaging Self scanning Sensor III images from 1998 to 2012. Along the PB coast of Dhanushkodi foreland, eroding shorelines are dominant except Arichamunai, whereas it is reversing along GoM. Inter-annual shoreline change revealed that changing trend and stability of Island are affirmed with statistical approaches. An equilibrium shoreline trend is noticed on both the sides of Dhanushkodi foreland. Annual shoreline change rate indicates erosion and accretion in northern and southern coastline of Dhanushkodi foreland varies, respectively.     

渤海湾西岸近百年来海岸线变迁遥感分析

渤海湾是中国典型的淤泥质海岸带,应用不同时期的历史资料、地形图、航空照片及多时相的MSS、TM、ETM遥感数据,经计算机处理,进行信息增强及信息复合,提取了百年来海岸线变化信息,划分为侵蚀、淤积和稳定不同类型岸段,表明渤海湾西岸泥质海岸带近百年来已发生了"缓变型地质环境变化"中的"相对快速的变化"。     

官厅水库的遥感动态变化探测及边岸稳定性判别

利用TM卫星多时相数据，采用变化探测技术研究了官厅水库1988—2001年时间段库区边岸的动态变化。对库区淤积、边岸侵蚀等问题进行了探讨；结合水位差数据，提出边岸坡度和边岸稳定性的遥感时空分析方法和判据；分析了上述问题对官厅水库水资源利用的影响。边岸稳定性判别方法可应用于湖泊、海洋的滩涂地区。     

官厅水库的遥感动态变化探测及边岸稳定性判别

利用TM卫星多时相数据，采用变化探测技术研究了官厅水库1988—2001年时间段库区边岸的动态变化。对库区淤积、边岸侵蚀等问题进行了探讨；结合水位差数据，提出边岸坡度和边岸稳定性的遥感时空分析方法和判据；分析了上述问题对官厅水库水资源利用的影响。边岸稳定性判别方法可应用于湖泊、海洋的滩涂地区。     

基于遥感技术的海岸带土地利用、覆被信息提取方法研究

本文以地处莱州湾东海岸的莱州市为研究区域,以TM影像为主要信息源,在分析各类地物分类效果的基础上,结合区域特点和地物光谱特征,综合利用两期典型季相的遥感图像,并针对每一种土地利用类型确定最佳信息提取影像,提出了基于光谱、地形等多种知识的分层信息提取方法.结果表明该方法分层目标明确,分类精度和计算效率都有明显提高,且在数...     

Remote Sensing Data Reveals Eco-Environmental Changes in Urban Areas of Klang Valley, Malaysia: Contribution from Object Based Analysis

Understanding the growth and changes in urban environments are the most dynamic system on the earth’s surface is critical for urban planning and sustainable management. This study attempts to present a space-borne satellite-based approach to demonstrate the urban change and its relation with land surface temperature (LST) variation in urban areas of Klang valley, Malaysia. For this purpose an object-based nearest neighbour classifier (S-NN) approach was first applied on SPOT 5 data acquired on 2003 and 2010 and subsequently five land cover categories were extracted. The overall accuracies of the classified maps of 2003 and 2010 were 90.5 % and 91 % respectively. The classified maps were then used as inputs to perform the post classification change detection. The results revealed that the post-classification object-based change detection analysis performed reasonably well with an overall accuracy of 87.5 %, with Kappa statistic of 0.81 %. The changes represented that the urban expanded by 10 % over the period, whereas the urban expansion had caused reduction in soil (1.4 %) and vegetation (11.4 %), and growth in oil palm (2 %), and water (0.7 %). Additionally decision tree method was used to derive the surface heat fluxes from thermal infrared Landsat TM and ETM+bands. Subsequently, a comparison was made with classified result from SPOT 5 images. Results showed high correlation between urban growth and LST.     

An Extended Approach of Particle Swarm Optimization for Shoreline Extraction from RASAT Imagery

This study presents an extended shoreline detection approach from pansharpened images of Turkish RASAT satellite which covers red, green and blue bands of the optical spectrum with 15 m ground resolution and panchromatic band with 7.5 m spatial resolution. The Lake Ercek of Turkey has been selected as the study area, which is a tectonic lake and home to a variety of water birds. The satellite images of the lake taken in 2013 and 2014 were considered for analysis. The proposed shoreline extraction system consists of a sequence of image processing steps in which simple linear clustering (SLIC) and particle swarm optimization (PSO) are the main components. SLIC was used to create superpixels that form basis for object-based image analysis while PSO was employed for classifying objects into corresponding classes. The resulting images still contained unwanted artefacts; therefore, a post-processing step was performed to improve the accuracy of segmentation by applying thresholding, morphological processing, and manual editing for noise removal. The proposed framework was applied on two temporal RASAT images to test the variations of defined parameter settings. The success of the proposed system was to obtain shorelines with satisfying accuracy without using NIR band. Finally, the extracted shorelines were vectorised and compared with manually digitized shorelines from pansharpened satellite images for accuracy assessment.     

黄河口—莱州湾地区海岸线的变迁及陆地面积增长

本文针对黄河口——莱州湾地区海岸线的变迁及陆地面积的增长,利用MSS陆地卫星图像和1∶5万地形图,对东经117°45′～119°45′、北纬37°00′～38°30′的地区进行了动态变化研究。计算出平均每年陆地增长的速度。     

Seasonal warm-water refuge and sanctuary usage by the Florida manatee (Trichechus manatus latirostris) in Kings Bay,Citrus County,Florida

The largest Florida manatee (Trichechus manatus latirostris) aggregation at a natural warm-water site occurs in Kings Bay, Crystal River, FL. In accordance with the Manatee Recovery Plan, manatee protection areas within Kings Bay have been created by the United States Fish and Wildlife Service (USFWS) and the State of Florida including a year-round refuge designation and seven Federal manatee sanctuaries during the winter manatee season (15 November–31 March). Over the last 30 years, an increase in manatee counts has been observed in Kings Bay which has prompted the need to review existing manatee protection measures. Aerial survey data collected between 1983 and 2012 were used to examine the seasonal change in manatee distribution within Kings Bay to assess the effectiveness of current sanctuary sizes and locations. Regression analysis suggested a significant change in manatee abundance among the winter seasons (p < 0.05). The average winter manatee counts increased by 4.81 animals per year over the 30-year period. Spatially explicit maps using geographic information system (GIS) analysis revealed a strong correlation between high manatee density and artesian springs in Kings Bay during the winter seasons. Highest abundances were identified at three locations: King Spring, Three Sisters Springs, and Magnolia Springs, which coincide with preexisting sanctuary designations. Additional coverage is advocated to support the overflow of manatees outside of sanctuary boundaries. As density patterns were not uniform across summer periods, a consideration of additional boat speed regulations is recommended.     

Quantifying urban land cover change between 2001 and 2006 in the Gulf of Mexico region

We estimated urbanization rates (2001–2006) in the Gulf of Mexico region using the National Land Cover Database (NLCD) 2001 and 2006 impervious surface products. An improved method was used to update the NLCD impervious surface product in 2006 and associated land cover transition between 2001 and 2006. Our estimation reveals that impervious surface increased 416 km² with a growth rate of 5.8% between 2001 and 2006. Approximately 1110.1 km² of non-urban lands were converted into urban land, resulting in a 3.2% increase in the region. Hay/pasture, woody wetland, and evergreen forest represented the three most common land cover classes that transitioned to urban. Among these land cover transitions, more than 50% of the urbanization occurred within 50 km of the coast. Our analysis shows that the close-to-coast land cover transition trend, especially within 10 km off the coast, potentially imposes substantial long-term impacts on regional landscape and ecological conditions.     

Some aspects of geomorphic processes along the Goa coast through remote sensing

This paper deals with the processes operating on the beaches of Goa, interpreted from imagery, followed by ground-truth collection and field checks. Studies on Landsat imagery bring out two distinct coastal geomorphological features, one north and the other south of Vasco-da-Gama. The beaches to the south indicate the prograding shoreline with deposition being the dominant phenomenon. The beaches to the north of Vasco-da-Gama reveal a retrograding shoreline where erosion is dominant. The presence of chimneys and stacks to the north of Vasco-da-Gama are characteristic of intensive erosional action while to the south a wide regular beach backed by a palaeo-strand line points to deposition. The pattern of the sediment load (in Band 4) is used as an index of longshore current movement. The action of erosion as against that of deposition in the two regions can be surmised from the diffused pattern vis-a-vis the uniformly wide even tone. Sand samples from the northern portion give a sorting coefficient of 1.100 while the southern portion shows a value of 0.712. It is hypothesised that the promontory on which Vasco-da-Gama lies is responsible for the formation of two different geomorphic zones.     

Shoreline and coral reef ecosystem changes in gulf of Mannar, Southeast coast of India

Changes in shoreline, coral reef and seafloor have been mapped using remote sensing satellite data of IRS LISS-III (1998), IRS LISS-II (1988), Survey of India Topographic sheet (1969), Naval Hydrographic Chart (NHO) 1975 and bathymetry data (1999) with ARC-INFO and ARC-VIEW GIS. The analysis of multi-date shoreline maps showed that 4.34 and 23.49 km2 of the mainland coast and 4.14 and 3.31 km² areas of island coast have been eroded and accreted, respectively, in the Gulf of Mannar. The analysis of multi-date coral reef maps showed that 25.52 km² of reef area and 2.16 km² of reef vegetation in Gulf of Mannar have been lost over a period of ten years. The analysis of multi-date bathymetry data indicates that the depth of seafloor has decreased along the coast and around the islands in the study area. The average reduction of depth in seafloor has been estimated as 0.51m over a period of twenty four years. The increased suspended sediment concentration due to coastal and island erosion, and raised reef due to emerging of coast by tectonic movement are responsible for coral reef degradation in the Gulf of Mannar. Validation by ground truth has confirmed these results.     

TOPSAR wave spectra model and coastal erosion detection

This paper presents work done utilizing TOPSAR data to detect shoreline change along the Terengganu coast (Malaysia). TOPSAR data were used to extract information on wave spectra. This wave spectra information was then used to model shoreline changes by investigating the wave refraction patterns. From these patterns, the volume transport at several locations was estimated. The shoreline change model developed was designed to cover a 20 km stretch of shoreline of Kuala Terengganu. The model utilized data from aerial photographs, TOPSAR data and ground truth data. The location of sedimentation and erosion along the shoreline of Kuala Terengganu was estimated. The wave spectra extracted from TOPSAR data showed wavelengths ranging from 20 m to 175 m. The main direction of the waves given by the spectra was from the northeast. The wave refraction patterns varied, showing both convergence and divergence, indicating erosion and sedimentation locations, respectively. A comparison between the TOPSAR shoreline change model and aerial photographs and ground truth data showed a significant relationship. Finally, the regression model showed that erosion occurred particularly at Sultan Mahmed Airport, at a rate of −1.5 m/year. The maximum rate of sedimentation along the 20 km stretch was 1 m/year.     

Seasonality and Latitudinal Variation of Water Vapour and Aerosol Optical Thickness and Their relationship Over Tropical Indian Ocean

Aerosol and water vapour are very important element in the Earth’s climate system which has direct role in the Earth’s radiation budget. In this paper the seasonality, latitudinal distribution and the relationship of aerosol optical thickness (AOD) and water vapour (WV) using MODIS Level 3 monthly data from 2001 to 2008 are analysed. The analysis shows that AOD (0.55 μm) values reach maximum during southwest monsoon and remain minimum during northeast monsoon period. The Equatorial Indian Ocean shows minimum AOD (0.115 to 0.153) throughout the year compared to Arabian Sea (0.208 to 0.613) and Bay of Bengal (0.214 to 0.351). Arabian Sea shows high variation and maximum value of AOD compared to Bay of Bengal and Equatorial Indian Ocean. During southwest monsoon WV over Bay of Bengal was found higher in concentration compared to Arabian Sea and Equitorial Indian Ocean throughout the study period. Comparison between Arabian Sea (2.98 cm to 5.07 cm) and Bay of Bengal (3.49 cm to 5.94 cm) shows that WV concentration is less in Arabian Sea throughout the year. The analysis of correlation between WV and AOD was found to be inconsistent. However, AOD and WV shows a strong positive correlation for whole year (Mean R² =0.90) in the Equitorial Indian Ocean region except in the months of January, February and March. In general, the correlation between WV and AOD is found to be strongly positive for oceanic aerosol (sea salt) in low water vapour condition.     

Non-linear motions of Australian geodetic stations induced by non-tidal ocean loading and the passage of tropical cyclones

We investigate daily and sub-daily non-tidal oceanic and atmospheric loading (NTOAL) in the Australian region and put an upper bound on potential site motion examining the effects of tropical cyclone Yasi that crossed the Australian coast in January/February 2011. The dynamic nature of the ocean is important, particularly for northern Australia where the long-term scatter due to daily and sub-daily oceanic changes increases by 20–55 % compared to that estimated using the inverted barometer (IB) assumption. Correcting the daily Global Positioning System (GPS) time series for NTOAL employing either a dynamic ocean model or the IB assumption leads to a reduction of up to 52 % in the weighted scatter of daily coordinate estimates. Differences between the approaches are obscured by seasonal variations in the GPS precision along the northern coast. Two compensating signals during the cyclone require modelling at high spatial and temporal resolution: uplift induced by the atmospheric depression, and subsidence induced by storm surge. The latter dominates ( \(>\) 135 %) the combined net effect that reaches a maximum of 14 mm, and 10 mm near the closest GPS site TOW2. Here, 96 % of the displacement is reached within 15 h due to the rapid transit of cyclones and the quasi-linear nature of the coastline. Consequently, estimating sub-daily NTOAL is necessary to properly account for such a signal that can be 3.5 times larger than its daily-averaged value. We were unable to detect the deformation signal in 2-hourly GPS processing and show that seasonal noise in the Austral summer dominates and precludes GPS detection of the cyclone-related subsidence.     

Sea-Level Change Over the China Sea and Its Vicinity Derived from 25-Year T/P Series Altimeter Data

The characteristics of sea-level change in the China Sea and its vicinity are studied by combining TOPEX/Poseidon (T/P), Jason-1, Jason-2, and Jason-3 altimeter data. First, the sea-surface height is computed by using monthly data via collinear adjustment, regional selection, and crossover adjustment. The sea-level anomaly (SLA) from October 1992 to July 2017 is calculated based on the difference that is obtained by the value derived from the inverse distance weighting method to interpolate the CNES_CLS15 model value at a normal point. By analyzing the satellite data at the same time in orbit, three mean bias groups over the China Sea and its vicinity are obtained: the difference between T/P and Jason-1 is ??11.76 cm, the difference between Jason-1 and Jason-2 is 9.6 cm, and the difference between Jason-2 and Jason-3 is 2.42 cm. To establish an SLA series for 25 years in the study area, the SLAs are corrected. Mean rate of sea-level rise of the Bohai Sea, Yellow Sea, East China Sea, and South China Sea of 4.87 mm/a, 2.68 mm/a, 2.88 mm/a, and 4.67 mm/a, respectively, is found by analyzing the series of SLAs.