Analyzing the distribution and variation of Suspended Particulate Matter (SPM) in the Yellow River Estuary (YRE) using Landsat 8 OLI

Abstract

Yellow River Estuary (YRE) as well as its adjacent coastal areas are famous for its high concentration of Suspended Particulate Matter (SPM). The distribution of SPM and its variations in the estuary area promoted the carbon, oxygen and nutrient cycles in coastal areas and nearby sea areas. This study took advantage of Landsat 8 Operational Land Imager (Landsat 8 OLI) data to estimate SPM in the YRE from 2013 to 2019. Remote sensing reflectance (Rrs) from Landsat 8 OLI bands has been proved to be effective through cross-validate with Rrs from Geostationary Ocean Color Imager (GOCI) bands. A simple empirical algorithm (NIR band ratio green band and add red band) was developed to map the SPM distribution and concentration, with the Average Percentage Difference (APD) 33.12% and R2 0.93 based on in-situ data. Annual average distribution of SPM shows that highly turbid areas with SPM greater than 103 mg/L are mostly found surrounding the estuary of Yellow River, in the northwest part of the Laizhou Bay and south part of Bohai bay. High variations of SPM distributions are consistent with high SPM, and vice versa. The influences of river runoff is mainly concentrated in the estuary area, and outside 4.5 km the variability of SPM effected by river discharge is not obvious. Significant difference is observed in seasonal SPM distribution. Higher SPM in winter is observed both in range and intensity compared to summer. Significant seasonal variations are mainly controlled by sediment resuspension processes driven by wind-wave forces. The results of this study indicate that Landsat8 OLI is an effective mean to retrieve SPM in YRE and its adjacent areas.