Application of the Geostationary Ocean Color Imager to Mapping the Diurnal and Seasonal Variability of Surface Suspended Matter in a Macro-Tidal Estuary

Abstract

Abstract:Total suspended particulate matter (TSM) in estuarine and coastal regions usually exhibits significant natural variations. The understanding of such variations is of great significance in coastal waters. The aim of this study is to investigate and assess the diurnal and seasonal variations of surface TSM distribution and its mechanisms in coastal waters based on Geostationary Ocean Color Imager (GOCI) data. As a case study, dynamic variations of TSM in the macro-tidal Yalu River estuary (YRE) of China were analysed. With regard to diurnal variability, there were usually two peaks of TSM in a tidal cycle corresponding to the maximum flood and ebb current. Tidal action appears to play a vital role in diurnal variations of TSM. Both the processes of tidal re-suspension and advection could be identified; however, the diurnal variation of TSM was mainly affected by a re-suspension process. In addition, spring-neap tides can affect the magnitude of TSM diurnal variations in the YRE. The GOCI-retrieved TSM results clearly showed the seasonal variability of surface TSM in this area, with the highest level occurring in winter and the lowest in summer. Moreover, although river discharge to the YRE was much greater in the wet season than the dry season, TSM concentrations were significantly higher in the dry season. Wind waves were considered to be the main factor affecting TSM seasonal variation in the YRE.

Multi-temporal dynamics of suspended particulate matter in a macro-tidal river Plume (the Gironde) as observed by satellite data

“…But, since all of them are aggregate and the plume is considered as a whole, their effect if negligible. Compared to other studies using GOCI data (He et al, 2013;Choi et al, 2014;Cheng et al, 2016;Eom et al, 2016), the same type of results were obtained also using SEVIRI for the Girone area. Nevertheless, thanks to its better spatial and spectral capabilities, GOCI has the potential to resolve more fine patterns of SPM dynamics and can perform better in clear waters.…”

“…This assures the identification of patterns otherwise not distinguishable. Nonetheless, there is an obvious need for future geostationary sensors with improved capabilities, as it was shown as well by other studies using geostationary data (He et al, 2013;Choi et al, 2014;Cheng et al, 2016;Eom et al, 2016), that such information can be very useful for coastal applications. Only through such technological advances, dynamic areas, such as the Gironde river mouth, will be properly monitored.…”

“…Nevertheless, thanks to its better spatial and spectral capabilities, GOCI has the potential to resolve more fine patterns of SPM dynamics and can perform better in clear waters. The Yalu River macro-tidal estuary is a good example of a similar area (compared to Gironde) analyzed based on GOCI data (Cheng et al, 2016). Nevertheless, the forcing factors of SPM dynamics are different, with wind stress playing a more important role.…”

“…The spectral bands configuration is much more suited for ocean color applications, compared to SEVIRI, with 8 channels that cover the visible and near-infrared regions. Therefore, the studies using GOCI concerning water quality and especially SPM dynamics are more numerous and cover multiple coastal areas, from shallow waters dominated by resuspension processes to estuaries (He et al, 2013;Choi et al, 2014;Cheng et al, 2016;Eom et al, 2016). It comes to show the true potential of an ocean color satellite sensor and sets up the target for future possible studies in the European regions.…”

“…GOCI was successfully used in highly turbid coastal areas and daily to seasonal observations were drawn (Choi et al, 2014). A micro-tidal estuary was also analyzed -Yalu River (Cheng et al, 2016) and high quality conclusions regarding the diurnal and seasonal SPM cycles were revealed.…”