The Spatial-Temporal Distribution of GOCI-Derived Suspended Sediment in Taiwan Coastal Water Induced by Typhoon Soudelor

Abstract

This paper discusses the use of a Geostationary Ocean Color Imager (GOCI) to monitor the spatial–temporal distribution of suspended sediment (SS) along the coastal waters of northern Taiwan which was affected by Typhoon Soudelor from 8 to 10 August 2015. High temporal resolution satellite images derived from GOCI were processed to generate four-day average images of SS for pre- and post-typhoon periods. By using these four-day average images, characteristics of SS along the north of Taiwan coastal water can be tracked. The results show that SS concentration increased in the four-day average image immediately after the typhoon (11–14 August), and then decreased in the four-day average image 9 to 12 days after the typhoon (19–22 August). The mouths of the Dajia River and Tamsui River were hotspots of SS, ranging from 9 to 15 g/m3 during the two post-typhoon periods. Moreover, the maximum suspended sediment (SSmax) and its corresponding time (tmax) can be computed using GOCI hourly images for the post-typhoon period from 08:30 on 11 August to 08:30 on 22 August. The results show that SSmax occurred in the west coastal water within 4 days post-typhoon, and SSmax occurred in the east coastal water 9 to 12 days post-typhoon. Furthermore, an exponential decay model was used to compute the time when 90% of typhoon-induced SS was dissipated after Typhoon Soudelor (t90). It was found that t90 in the mouths of the Tamsui River and Heping River was the longest among all coastal waters of our study area, with a range of 360–480 h. River discharge and ocean currents with suspended sediment concentration are discussed.

A New Algorithm for Monitoring Backflow from River to Lake (BRL) Using Satellite Images: A Case of Poyang Lake, China

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Investigation of the Kuroshio-coastal current interaction and marine heatwave trends in the coral habitats of Northeastern Taiwan

“…The variations in these oceanic characteristics directly impact the health, growth, and stability of coral ecosystems (Denis et al, 2019;Hsu et al, 2019;Kuo et al, 2023). Beyond SST and sea surface salinity (SSS), factors such as the speed of the Kuroshio Current (KC) and coastal currents, as well as their mixing, may contribute to nutrient transport and the load of suspended particulates (Hsu et al, 2018(Hsu et al, , 2020aTseng et al, 2019;Chau et al, 2021). Marine ecologists have extensively studied disturbances to Taiwan's coral reef ecosystems.…”

Changes in the Hydrological Characteristics of the Attabad Landslide-Dammed Lake on the Karakoram Highway

“…In terms of innovation, this paper is the first to study the sediment content of dammed lakes. With the development of remote sensing for lakes, remote sensing technology has been widely used for highland lake change and sea, estuarine and near-shore, lake suspended sediment monitoring studies, and many mature suspended sediment quantitative remote sensing inversion models have been established [27][28][29][30][31][32][33]. In the study of lake changes, multispectral optical remote sensing images such as Landsat MSS/TM/ETM+/OLI, Gaofen series satellites (GF-1/2), and Sentinel data (Sentine-2) have been used for the monitoring of lake area changes on the Qinghai-Tibet Plateau since the 1970s, among which, the Landsat data series are most widely used because they provide more high-quality free data [34].…”