Application of the Geostationary Ocean Color Imager (GOCI) to estimates of ocean surface currents

Abstract

The Geostationary Ocean Color Imager (GOCI) can be utilized efficiently to observe subtle changes in oceanic environments under cloud‐free conditions because it receives ocean color images around the Korean Peninsula hourly, for 8 h a day. Here we investigated the applicability of the GOCI for estimating hourly variations in ocean surface currents, which provide significant information on seawater circulation for fisheries, shipping controls, and more. Ocean surface currents were deduced from eight images of GOCI‐derived total suspended matter (TSM) from highly turbid coastal waters and images of chlorophyll concentration (CHL) for relatively clear waters. The results showed that GOCI TSM‐derived ocean surface currents can effectively estimate and represent fast tidal currents, as well as flood and ebb tides on the west coast of Korea, in comparison with in situ measurements. GOCI‐derived CHL scenes successfully illustrated currents moving along boundaries where warm and cold seawaters mix, in addition to mesoscale currents such as the East Korea Warm Current (EKWC) in the East Sea of Korea. Satellite‐based sea surface temperature and sea surface height images supported the reliability of GOCI‐derived ocean surface currents in the East Sea.

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

“…These invalid data nearshore correspond to tidal flats and reclamation area in the YRE (Figure 1), which prohibit the imager from observing valid ocean reflectance. In addition to tidal flats, the GOCI atmospheric correction is expected to fail in extremely turbid waters near the estuary [2,18,19]. Moreover, the cloud-masking threshold currently implemented by GDPS is too tight to reveal valid data in more turbid areas [16].…”

Diurnal Variability of Turbidity Fronts Observed by Geostationary Satellite Ocean Color Remote Sensing

“…The diurnal variations in TSM are frequently observed in other regions, for example, in the Bohai and ECS Seas [37,46], in the Southern North Sea [66,67]. The tide-induced turbulent mixing and wave-current interaction in the inner shelf region of YS are capable of stirring a large amount of sediment to the surface layer, resulting in TSM variations [46,49,68], which could further influence turbidity frontal patterns through sediment resuspension and deposition.…”

“…Additionally, the TSM images were simultaneously applied to estimate sea surface currents using the well-known maximum cross-correlation (MCC) method [37,57]. Using GOCI-derived TSM sequential images, previous studies suggested that the MCC technique could be widely used to accurately derive high-frequency surface currents in the YS and ECS [37,58,59].…”

“…Using GOCI-derived TSM sequential images, previous studies suggested that the MCC technique could be widely used to accurately derive high-frequency surface currents in the YS and ECS [37,58,59]. Specifically, we took a 10ˆ10 km box centered with a certain pixel from one TSM image, and searched the location of the match-up box from the next sequential TSM image using the maximum cross-correlation method.…”

“…In contrast, the world's first Geostationary Ocean Color Imager (GOCI), launched in 2010, can provide eight snapshots at a one-hour interval (i.e., from 00:15 to 07:45 GMT) with a high spatial resolution of 500 m [34]. Its unprecedented capability is of great benefit for the continuous monitoring of short-term finer oceanic phenomena and physical processes in near real time [35][36][37][38].…”