No abstract

Natural crude-oil seepages, together with the oil released into seawater as a consequence of oil exploration/production/transportation activities, and operational discharges from tankers (i.e., oil dumped during cleaning actions) represent the main sources of sea oil pollution. Satellite remote sensing can be a useful tool for the management of such types of marine hazards, namely oil spills, mainly owing to the synoptic view and the good trade-off between spatial and temporal resolution, depending on the specific platform/sensor system used. In this paper, an innovative satellite-based technique for oil spill detection, based on the general robust satellite technique (RST) approach, is presented. It exploits the multi-temporal analysis of data acquired in the visible channels of the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the Aqua satellite in order to automatically and quickly detect the presence of oil spills on the sea surface, with an attempt to minimize "false detections" caused by spurious effects associated with, for instance, cloud edges, sun/satellite geometries, sea currents, etc. The oil spill event that occurred in June 2007 off the south coast of Cyprus in the Mediterranean Sea has been considered as a test case. The resulting data, the reliability of which has been evaluated by both carrying out a confutation analysis and comparing them with those provided by the application of another independent MODIS-based method, showcase the potential of RST in identifying the presence of oil with a high level of accuracy.

No abstract

Total suspended solids (TSSs) can affect primary production through influencing light penetration and nutrient availability in aquatic environments. In this study, novel algorithms were developed for TSS in the Pearl River estuary using Landsat‐derived reflectance corrected for Rayleigh scattering (Rrc). Comparisons between in situ and estimated TSS using the calibration and validation data sets resulted in R2s > 0.8 and mean absolute percentage errors < 35%. Landsat‐derived annual TSS between 1987 and 2018 in the Pearl River estuary ranged from 16.5 to 41 mg L−1. It indicated a statistically significant decreasing trend with an annual rate of 0.26 mg L−1 and decreased by 58.5% from 1987 to 2018. It showed a higher decreasing rate after than before the construction of the Hong Kong‐Zhuhai‐Macau Bridge. Nonetheless, TSS 2 km upstream from the Hong Kong‐Zhuhai‐Macau Bridge on the western side increased after the construction of the bridge related to the change of flow influenced by piers and artificial islands.