Monitoring red tide with satellite imagery and numerical models: a case study in the Arabian Gulf

Long-term study of desert dust deposition effects on phytoplankton biomass in the Persian Gulf using Google Earth Engine

Persian Gulf is surrounded by the most active dust source regions of the world. Every year, millions of tons of dust are deposited in this area causing significant adverse effects. This research aimed to fill the gap in the field of dust impact quantification regarding different and important regions in the Persian Gulf. We evaluated aerosol optical thickness (AOT) as dust, chlorophyll a (Chl a) as phytoplankton biomass, sea surface temperature (SST), and particulate organic carbon (POC) using Moderate Resolution Imaging Spectroradiometer (MODIS) data to quantify and analyze the impacts of dust. According to dust frequency maps over 21 years, 4 critical regions were selected including the Northern, Central, and Southern regions of the Persian Gulf and Strait of Hormuz. Slightly lower Chl a values were noted in the southern region and Strait of Hormuz compared to the Northern and Central regions. The Mann-Kendall (MK) test and Sen's slope estimator, which can determine trend parameters, were used to analyze 4 selected regions using 8 days, monthly, and yearly averaged data. The results of the MK test showed a significant positive trend for SST and a significant negative trend for POC. AOT and Chl a trends varied based on their locations. The cross-correlation test with a time lag showed maximum correlations between Chl a and dust (AOT) with a delay of 6-7 months. Also, to quantify the impacts of dust on phytoplankton biomass, R2 and analysis of variance (ANOVA) regression were used for data with a 6-7-month time lag. The results showed that the contribution of dust in the amount of Chl a variation was about 10 %-20 %. This study showed that the simultaneous use of remote sensing and statistical methods could provide necessary and timely warnings (regarding management) to prevent algal blooms and aquatic loss in this important and strategic area.

Synoptic view of an unprecedented red Noctiluca scintillans bloom in the Beibu Gulf, China

An unprecedented red Noctiluca scintillans (RNS) bloom in February 2021 in the Beibu Gulf, China was investigated using multi-sensor imagery. The location and spatial extent of the RNS patches were delineated based on the spectral signature. A combination of satellite remote sensing and numerical model data over the region was used to detect and monitor the development and progress of the RNS bloom and figure out the possible mechanism. Multi-sensor satellite imagery demonstrates a total coverage area of >20,000 km² for the two-phase bloom event from Feb 13 to 26, with abrupt dissipation on Feb 17 and reappearance on Feb 20. Analysis of the initialization mechanism of the bloom suggests that nutrients conveyed from the western coast of Guangdong through Qiongzhou Strait and from convective transport in the offshore area together stimulated the outbreak of the bloom. The most distinctive finding is the negative correlation between the area of RNS patches and wind speed. The abrupt disappearance of the RNS bloom deserves further study.

Rapid detection method of Skeletonema pseudocostatum and preparation of test strip

In eutrophic waters, harmful algal blooms (HAB) are particularly prone to occur, which will affect the ecological environment and public health and safety. How to quickly detect and monitor marine microalgae is the key to preventing and managing HAB. Our innovative application of colloidal gold immunochromatography (GICG) technology to detect the dominant species in red tide, Skeletonema pseudocostatum, to monitor the outbreak of red tide. The experimental results show that the method and the prepared test strips are extremely sensitive and can specifically detect the presence of Skeletonema pseudocostatum. The approximate concentration of algae cells is judged by establishing a fitting relationship between the degree of color development and the concentration of algae cells. This test strip provides a quick and easy method for routine environmental monitoring, fishery water quality monitoring, and field testing of red tide monitoring. It effectively warns of the outbreak of red tides and also provides a new application direction for GICG technology.

Algal blooms historical outbreaks in the northern coastal waters of the Persian Gulf and Oman Sea (1980-2015)

Harmful algal blooms (HABs) have been serious environmental problems in the Persian Gulf and Oman Sea in recent years. There has been an increase in occurrence of HABs in coastal waters of Hormuzgan Province (to the north of the Persian Gulf and Oman Sea) in recent decade, due to eutrophication as a result of human activities. In this review, HAB phenomena in coastal waters of Hormuzgan Province are summarized, including, causative species, timing and the location of blooms during a 35-year time span from 1980 to 2015. This review illustrates that 436 algal blooms have been recorded in the north of the Persian Gulf, formed by 17 species of phytoplankton; 270 of harmful dinoflagellate (Margalefidinium polykrikoides) blooms have led to huge catastrophic impacts on the economy, environment, and society. In addition, most algal blooms (49%) have occurred in the coasts of Bandar Abbas. The data in this review suggest supporting the establishment of an algal bloom monitoring and control program in the coastal waters of the northern part of the Persian Gulf and Oman Sea (Hormuzgan Province).

GIS-based framework for artificial aquifer recharge to secure sustainable strategic water reserves in Qatar arid environment peninsula

This study proposes a large-scale artificial aquifer recharge plan to increase the strategic water reserve to cope with future emergencies. The main aim of the plan is to restore groundwater levels to those of the 1980s through artificial recharge. Desalinated water or highly treated municipal sewage effluent could be artificially recharged into the aquifer to recharge it. Potentiometric surface of aquifers and Geographic Information Systems (GIS) analysis were used to assess change in the groundwater levels between 1980 and 2009. Zones that have experienced considerable decline in groundwater levels from their former “natural” status—when the aquifers were barely exploited, were identified. These zones are considered optimum recharge sites as they could provide ‘natural’ ground storage chosen by nature. Therefore, working with nature (not against it) by re-filling these natural spaces is the optimum approach. The artificial recharge of the main and principal upper aquifer in Qatar (Rus and Um er Radhuma) is targeted and recommended. It is estimated that up to 182.8 Million Cubic Meter (mcm) could be recharged and stored in these proposed zones, to increase the strategic water reserve of the country. This increase would sustain supplies of high quality for up to three months if consumption is maintained at the 2018 level. Moreover, this additional reserve could last for over one year, if emergency measures were put in place—in case of serious water-shortages, and disaster preparedness, for example by reducing the per capita consumption to the global average per capita consumption.

Spatiotemporal Variability of Chlorophyll-a and Sea Surface Temperature, and Their Relationship with Bathymetry over the Coasts of UAE

The catastrophic implication of harmful algal bloom (HAB) events in the Arabian Gulf is a strong indication that the study of the spatiotemporal distribution of chlorophyll-a and its relationship with other variables is critical. This study analyzes the relationship between chlorophyll-a (Chl-a) and sea surface temperature (SST) and their trends in the Arabian Gulf and the Gulf of Oman along the United Arab Emirates coast. Additionally, the relationship between bathymetry and Chl-a and SST was examined. The MODIS Aqua product with a resolution of 1 × 1 km2 was employed for both chlorophyll-a and SST covering a timeframe from 2003 to 2019. The highest concentration of chlorophyll-a was seen in the Strait of Hormuz with an average of 2.8 mg m−3, which is 1.1 mg m−3 higher than the average for the entire study area. Three-quarters of the study area showed a significant correlation between the Chl-a and SST. The shallow (deep) areas showed a strong positive (negative) correlation between the Chl-a and SST. The results indicate the presence of trends for both variables across most of the study area. SST significantly increased in more than two-thirds of the study area in the summer with no significant trends detected in the winter.

Red Sea MODIS Estimates of Chlorophyll a and Phytoplankton Biomass Risks to Saudi Arabian Coastal Desalination Plants

Harmful algal blooms (HABs) and the high biomass associated with them have afflicted marine desalination plants along coastal regions around the world. Few studies of HABs have been conducted in the Red Sea, where desalination plants along the Saudi Arabian Red Sea coast provide drinking water for millions of people. This study was conducted along the Saudi Arabian Red Sea coast from 2014 to 2015 to assess the potential for using Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing of chlorophyll a (Chl a) or fluorescence line height (FLH) to identify risks for biofouling at these desalination plants. Ship-based surveys of phytoplankton were conducted along the Saudi Arabian coastline offshore of desalination plants at Jeddah, Al Shoaibah and Al Qunfudhuh to assess the density of phytoplankton populations and identify any potential HAB species. Ship-based surveys showed low to moderate concentrations of phytoplankton, averaging from 1800–10,000 cells L−1 at Jeddah, 2000–11,000 cells L−1 at Al Shoaibah and 1000–20,500 cells L−1 at Al Qunfudhuh. Sixteen different species of potentially toxigenic HABs were identified through these surveys. There was a good relationship between ship-based total phytoplankton counts and monthly averaged coastal MODIS Chl a (R2 = 0.49, root mean square error (RMSE) = 0.27 mg m−3) or FLH (R2 = 0.47, RMSE = 0.04 mW m−2 µm−1 sr−1) values. Monthly average near shore Chl a concentrations obtained using MODIS satellite imagery were much higher in the Red Sea coastal areas at Al Qunfudhuh (maximum of about 1.3 mg m−3) than at Jeddah or Al Shoaibah (maximum of about 0.4 and 0.5 mg m−3, respectively). Chlorophyll a concentrations were generally highest from the months of December to March, producing higher risks of biofouling desalination plants than in other months. Concentrations decreased significantly, on average, from April to September. Long-term (2005–2016) monthly averaged MODIS Chl a values were used to delineate four statistically distinct zones of differing HAB biomass across the entire Red Sea. Sinusoidal functions representing monthly variability were fit to satellite Chl a values in each zone (RMSE values from 0.691 to 0.07 mg m−3, from Zone 1 to 4). December to January mean values and annual amplitudes for Chl a in these four sinusoidal functions decreased from Zones 1–4. In general, the greatest risk of HABs to desalination occurs during winter months in Zone 1 (Southern Red Sea), while HAB risks to desalination plants in winter months are low to moderate in Zone 2 (South Central Red Sea), and negligible in Zones 3 (North Central) and 4 (Northern).

Spatio-Temporal Variability in Bio-Optical Properties of the Southern Caspian Sea: A Historic Analysis of Ocean Color Data

Currently, satellite ocean color imageries play an important role in monitoring of water properties in various oceanic, coastal, and inland ecosystems. Although there is a long-time and global archive of such valuable data, no study has comprehensively used these data to assess the changes in the Caspian Sea. Hence, this study assessed the variability of bio-optical properties of the upper-water column in the Southern Caspian Sea (SCS) using the archive of the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and the Moderate Resolution Imaging Spectroradiometer (MODIS). The images acquired from SeaWiFS (January 1998 to December 2002) and MODIS Aqua (January 2003 to December 2015) satellites were used to investigate the spatial–temporal variability of bio-optical properties including Chlorophyll-a (Chl-a), attenuation coefficient, and remote sensing reflectance, and environmental parameters such as sea surface temperature (SST), wind stress and the El Nino-southern oscillation (ENSO) phenomena at different time lags in the study area. The trend analysis demonstrated an overall increase of 0.3358 mg m−3 in the Chl-a concentration during 1998–2015 (annual increase rate of 0.018 mg m−3 year−1) and four algal blooms and in turn an abnormal increase in Chl-a concentration were occurred in August 2001, September 2005, 2009, and August 2010. The linear model revealed that Chl-a in the northern and middle part of the study area had been influenced by the attenuation coefficient after a one-month lag time. The analysis revealed a sharp decline in Chl-a concentration during 2011–2015 and showed a high correlation with the turbidity and attenuation coefficient in the southern region, while Kd_490nm and remote sensing reflectance did a low one. Generally, Chl-a concentration exhibited a positive correlation with the attenuation coefficient (r = 0.63) and with remote sensing reflectance at the 555 nm (r = 0.111). This study can be used as the basis for predictive modeling to evaluate the changes of water quality and bio-optical indices in the Southern Caspian Sea (SCS).

Correlation between concentrations of chlorophyll-a and satellite derived climatic factors in the Persian Gulf

Monthly mean satellite derived Chl-a, aerosols, wind, SST, PAR, and turbidity datasets were used to investigate the possible factors regulating phytoplankton variability in the Persian Gulf. The spatial correlation analysis revealed two distinct regions of SST and PAR, and a relatively uniform spatial correlation pattern of the other parameters. The cross correlation between aeolian dusts and Chl-a was significantly positive with 1-3 months offset. The pattern of spatial correlation between Chl-a and SST was positive in the shallow regions without time lag, and was negative with time offset of 3-5 months in deeper regions. The cross correlation between Chl-a and north-ward winds were positive with time lags of 1-3 months. Vertical mixing under the influence of north-ward winds in the deeper region, availability of light and nutrients in the shallow regions, and dust fertilizations over the whole area were suggested to be the major controlling factors regulating phytoplankton growth.

Towards Monitoring of Nutrient Pollution in Coastal Lake Using Remote Sensing and Regression Analysis

The last few decades have witnessed a tremendous increase in nutrient levels (phosphorus and nitrogen) in coastal water leading to excessive algal growth (Eutrophication). The presence of large amounts of algae turns the water’s color into green or red, in the case of algal blooms. Chlorophyll-a is often used as an indicator of algal biomass. Due to increased human activities surrounding Dubai creek, there have been eutrophication concerns given the levels of nutrients in that creek. This study aims to map chlorophyll-a in Dubai Creek from WorldView-2 imagery and explore the relationship between chlorophyll-a and other eutrophication indicators. A geometrically- and atmospherically-corrected WorldView-2 image and in-situ data have been utilized to map chlorophyll-a in the creek. A spectral model, developed from the WorldView-2 multispectral image to monitor Chlorophyll-a concentration, yielded 0.82 R2 with interpolated in-situ chlorophyll-a data. To address the time lag between the in-situ data and the image, Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images were used to demonstrate the accuracy of the WorldView-2 model. The images, acquired on 20 May and 23 July 2012, were processed to extract chlorophyll-a band ratios (Band 4/Band 3) following the standard approach. Based on the availability, the 20 May image acquisition date is the closest to the middle of Quarter 2 (Q2) of the in-situ data (15 May). The 23 July 2012 image acquisition date is the closest to the WorldView-2 image date (24 July). Another model developed to highlight the relationship between spectral chlorophyll-a levels, and total nitrogen and orthophosphate levels, yielded 0.97 R2, which indicates high agreement. Furthermore, the generated models were found to be useful in mapping chlorophyll-a, total nitrogen, and orthophosphate, without the need for costly in-situ data acquisition efforts.

Numerical study on the summertime patches of red tide in the adjacent sea of the Changjiang (Yangtze) River Estuary, China

High incident rates of red tide have occurred off the coast of the Changjiang (Yangtze) River Estuary in summer, resulting from a magnified population growth discharging substantial nutrient loads into this vicinity. The presence of elevated Chlorophyll-a concentrations (≥36.3 μg/l), low suspended sediment concentrations in surface and mid-layers (<10 mg/l), a strong saline front and surface water temperature gradient, veering surface winds, and a bimodal shape to the Changjiang Diluted Water (CDW) revealed two red tide patches appearing between August 6-13, 2010. Two distinguishable hydrodynamic driving mechanisms, connected to these incidents, are diagnosed. Field observations and numerical simulations determined a red tide patch in the northeastern offshore area is caused by a northeast transport of the CDW truncated by a northwest intrusion of the Taiwan Warm Current (TWC) as winds deviated. Red tide occurrence in the southern nearshore area originated from a plume front where CDW interfaces with the TWC.

Remotely sensing harmful algal blooms in the Red Sea

Harmful Algal Blooms (HABs) are of global concern, as their presence is often associated with socio-economic and environmental issues including impacts on public health, aquaculture and fisheries. Therefore, monitoring the occurrence and succession of HABs is fundamental for managing coastal regions around the world. Yet, due to the lack of adequate in situ measurements, the detection of HABs in coastal marine ecosystems remains challenging. Sensors on-board satellite platforms have sampled the Earth synoptically for decades, offering an alternative, cost-effective approach to routinely detect and monitor phytoplankton. The Red Sea, a large marine ecosystem characterised by extensive coral reefs, high levels of biodiversity and endemism, and a growing aquaculture industry, is one such region where knowledge of HABs is limited. Here, using high-resolution satellite remote sensing observations (1km, MODIS-Aqua) and a second-order derivative approach, in conjunction with available in situ datasets, we investigate for the first time the capability of a remote sensing model to detect and monitor HABs in the Red Sea. The model is able to successfully detect and generate maps of HABs associated with different phytoplankton functional types, matching concurrent in situ data remarkably well. We also acknowledge the limitations of using a remote-sensing based approach and show that regardless of a HAB’s spatial coverage, the model is only capable of detecting the presence of a HAB when the Chl-a concentrations exceed a minimum value of ~ 1 mg m^-3. Despite the difficulties in detecting HABs at lower concentrations, and identifying species toxicity levels (only possible through in situ measurements), the proposed method has the potential to map the reported spatial distribution of several HAB species over the last two decades. Such information is essential for the regional economy (i.e., aquaculture, fisheries & tourism), and will support the management and sustainability of the Red Sea’s coastal economic zone.

Evaluation of Chlorophyll-a Estimation Approaches Using Iterative Stepwise Elimination Partial Least Squares (ISE-PLS) Regression and Several Traditional Algorithms from Field Hyperspectral Measurements in the Seto Inland Sea, Japan

Harmful algal blooms (HABs) occur frequently in the Seto Inland Sea, bringing significant economic and environmental losses for the area, which is well known as one of the world's most productive fisheries. Our objective was to develop a quantitative model using in situ hyperspectral measurements in the Seto Inland Sea to estimate chlorophyll a (Chl-a) concentration, which is a significant parameter for detecting HABs. We obtained spectra and Chl-a data at six stations from 12 ship-based surveys between December 2015 and September 2017. In this study, we used an iterative stepwise elimination partial least squares (ISE-PLS) regression method along with several empirical and semi-analytical methods such as ocean chlorophyll, three-band model, and two-band model algorithms to retrieve Chl-a. Our results showed that ISE-PLS using both the water-leaving reflectance (RL) and the first derivative reflectance (FDR) had a better predictive ability with higher coefficient of determination (R²), lower root mean squared error (RMSE), and higher residual predictive deviation (RPD) values (R² = 0.77, RMSE = 1.47 and RPD = 2.1 for RL; R² = 0.78, RMSE = 1.45 and RPD = 2.13 for FDR). However, in this study the ocean chlorophyll (OC) algorithms had poor predictive ability and the three-band and two-band model algorithms did not perform well in areas with lower Chl-a concentrations. These results support ISE-PLS as a potential coastal water quality assessment method using hyperspectral measurements.

Characteristics and sources of anthropogenic and biogenic hydrocarbons in sediments from the coast of Qatar

Surface sediment samples from the coastal zone of Qatar were collected and analyzed to determine the characteristics, and sources of anthropogenic and biogenic hydrocarbons. The main compounds in these surface sediments included n-alkanes, methyl n-alkanoates, diterpenoids, hopanes, steranes, phthalate esters, polycyclic aromatic hydrocarbons (PAHs) and unresolved complex mixture (UCM). Their total concentrations ranged from 18.7±3.7-81.1±7.5ng/g (3.7±0.6-10.4±4.8%) for n-alkanes, 8.3±2.3-51±3.4ng/g (3.0±2.0-5.6±2.0%) for methyl n-alkanoates, 1.8±0.1-10.5±1.0ng/g (1.0±0.5-0.4±0.1%) for diterpenoids, 0.0-79.3±7.4ng/g (0.0-7.9±0.6%) for hopanes, 0.0-32.9±7.9ng/g (0.0-6.5±1.0%) for steranes, 0.7±0.1-36.3±3.4ng/g (0.1±0.1-1.9±3.4%) for phthalates, 0.30±0.2-7.8±0.7ng/g (0.02±0.04-0.42±0.72%) for PAHs, and 38±9-609±57ng/g (38.5±13.4-56.5±13.4%) for UCM. The major sources of these lipids were anthropogenic petroleum residues and plasticizers (80-89%), with lesser amounts from natural higher plants and microbial residues (11-20%). Petroleum residues and plasticizer inputs to the coastal sediments of Qatar likely affect the marine ecosystems and associated species groups as well as shallow coastal nursery and spawning areas.

Analysis of bloom conditions in fall 2013 in the Strait of Hormuz using satellite observations and model simulations

In this study an algal bloom event in fall 2013 in the Strait of Hormuz was thoroughly investigated using satellite remote sensing and hydrodynamic modeling. The motivation of this study is to deduce ambient conditions prior to and during the bloom outbreak and understand its trigger. Bloom tracking was achieved by sequential MODIS imagery and numerical simulations. Satellite observations showed that the bloom was initiated in late October 2013 and dissipated in early June 2014. Trajectories of bloom patches were simulated using a Lagrangian transport model. Model-based predictions of bloom patches' trajectories were in good agreement with satellite observations with a probability of detection (POD) reaching 0.85. Analysis of ancillary data, including sea surface temperature, ocean circulation, and wind, indicated that the bloom was likely caused by upwelling conditions in the Strait of Hormuz. Combined with numerical models, satellite observations provide an essential tool for investigating bloom conditions.

Analysis of the spatio-temporal variability of seawater quality in the southeastern Arabian Gulf

In this study, seawater quality measurements, including salinity, sea surface temperature (SST), chlorophyll-a (Chl-a), Secchi disk depth (SDD), pH, and dissolved oxygen (DO), were made from June 2013 to November 2014 at 52 stations in the southeastern Arabian Gulf. Significant variability was noticed for all collected parameters. Salinity showed a decreasing trend, and Chl-a, DO, pH, and SDD demonstrated increasing trends from shallow onshore stations to deep offshore ones, which could be attributed to variations of ocean circulation and meteorological conditions from onshore to offshore waters, and the likely effects of desalination plants along the coast. Salinity and temperature were high in summer and low in winter while Chl-a, SDD, pH, and DO indicated an opposite trend. The CTD profiles showed vertically well-mixed structures. Qualitative analysis of phytoplankton showed a high diversity of species without anomalous species found except in Ras Al Khaimah stations where diatoms were the dominating ones.

Oman's coral reefs: A unique ecosystem challenged by natural and man-related stresses and in need of conservation

Oman contains diverse and abundant reef coral communities that extend along a coast that borders three environmentally distinct water bodies, with corals existing under unique and often stressful environmental conditions. In recent years Oman's reefs have undergone considerable change due to recurrent predatory starfish outbreaks, cyclone damage, harmful algal blooms, and other stressors. In this review we summarize current knowledge of the biology and status of corals in Oman, particularly in light of recent stressors and projected future threats, and examine current reef management practices. Oman's coral communities occur in marginal environmental conditions for reefs, and hence are quite vulnerable to anthropogenic effects. We recommend a focus on developing conservation-oriented coral research to guide proactive management and expansion of the number and size of designated protected areas in Oman, particularly those associated with critical coral habitat.

Spatio-temporal variability of SST and Chlorophyll-a from MODIS data in the Persian Gulf

Spatio-temporal variability of SST and Chl-a evaluated using MODIS products from 2002 to 2013 in the Persian Gulf. Wavelet Transform was utilized to analyze the spatio-temporal stability and abnormality of MODIS SST and Chl-a. The stationary level of SST decreases from west to the east during summer to early autumn, and increases from late autumn to spring. The stationary level of Chl-a is higher in the coastal areas, while its average ranged from 0.1 to 0.5mgm(-3). No meaningful major oscillating period observed in the abnormal variability of SST and Chl-a. The winter and summer peaks of SST and Chl-a were observed in the central parts and north-west regions. The timing of maximum SST was observed in August, which is not correlated with Chl-a maxima. The variability of SST and Chl-a in the whole Persian Gulf is seasonal, and related to river outflows, water circulation and climate regimes.

Exploring the potential of optical remote sensing for oil spill detection in shallow coastal waters--a case study in the Arabian Gulf

Remote sensing provides an effective tool for timely oil pollution response. In this paper, the spectral signature in the optical and infrared domains of oil slicks observed in shallow coastal waters of the Arabian Gulf was investigated with MODIS, MERIS, and Landsat data. Images of the Floating Algae Index (FAI) and estimates of sea currents from hydrodynamic models supported the multi-sensor oil tracking technique. Scenes with and without sunglint were studied as the spectral signature of oil slicks in the optical domain depends upon the viewing geometry and the solar angle in addition to the type of oil and its thickness. Depending on the combination of those factors, oil slicks may exhibit dark or bright contrasts with respect to oil-free waters. Three oil spills events were thoroughly analyzed, namely, those detected on May 26 2000 by Landsat 7 ETM + and MODIS/Terra, on October 21 2007 by MERIS and MODIS, and on August 17 2013 by Landsat 8 and MODIS/Aqua. The oil slick with bright contrast observed by Landsat 7 ETM + on May 26 2000 showed lower temperature than oil-free areas. The spectral Rayleigh-corrected reflectance (R(rc)) signature of oil-covered areas indicated higher variability due to differences in oil fractions while the R(rc) spectra of the oil-free area were persistent. Combined with RGB composites, FAI images showed potentials in differentiating oil slicks from algal blooms. Ocean circulation and wind data were used to track oil slicks and forecast their potential landfall. The developed oil spill maps were in agreement with official records. The synergistic use of satellite observations and hydrodynamic modeling is recommended for establishing an early warning and decision support system for oil pollution response.