Detailed introduction to operation of a marine environment forecast system for an oil spill in the Bohai Sea

In order to ensure the smooth automatic forecast of the entire system, the Shandong Maritime Safety Administration purchased and configured the Dawning high-performance server and 10 m fiber optic extranet access. The entire system begins forecast from 0:00 every morning, downloads and assimilates the data required in 25 minutes and completes the forecast of the atmospheric module in about 2.5 hours, the forecast of the marine module in about 2 hours and all forecasts before 8:00 in the morning, which can ensure the smooth advancement of daytime work. The download of current field data from the server is shown in Figure 4.15. The wind-field data is downloaded in the same way.

Currently, the system has been integrated with the OILMAP software (Figure 4.16). According to the needs of OILMAP software, the internationally advanced NetCDF data format is accepted as the output format of marine numerical model and wind-field results. This data format has a

FIGURE 4.14: Forecast results of sea-surface wind field on April 14. 2010 (the legend represents different wind speed levels in meters per second)

FIGURE 4.15: Download of current field data from the server (the size of one-day current field data is about 350 M)

FIGURE 4.16: Data interface carefully worked out by the research group

FIGURE 4.17: Import of current field data of three consecutive days into OILMAP (the arrow represents the current velocity field)

FIGURE 4.18: Import of wind field data of three consecutive days into OILMAP (the black weather vane represents the wind field)

FIGURE 4.19: Diagram of basic information acquisition for oil spill simulation self-explanatory function, takes up small storage place, has good versatility and is convenient for subsequent visualized data processing. After researching and testing, the output of the wind field and marine dynamic model can be quickly and accurately imported into the OILMAP software to carry out oil spill-related simulation.

After the current field and wind field calculated by the model are imported into the OILMAP and the database is set up, the preparations for the oil-spill drift model are completed and the forecast can be performed.

First, the basic information required for oil-spill simulation, such as location and time (time zone) of oil-spill pollution, simulation duration, trace- ability/forecasting and water temperature, should be provided (Figures 4.17 through 4.19).

Select the type of pollutants in an oil-spill accident. For instance, a light diesel system provides the basic information of nearly 2000 kinds of oil stored in the ADIOS database and OILMAP database. It is shown in Figure 4.20.

Then, carry out difference-value calculation of the previous^ introduced current field and wind field, as shown in Figures 4.21 and 4.22.

Then, input the parameters related to oil-spill simulation, such as the time interval of forecast and simulation, wind-force coefficient, number of oil particles, deflection angle of wind and uncertainty ratio. See Figure 4.23. Till this point, the entire automatic operation of the system is completed, as shown in Figure 4.24.

FIGURE 4.20: Selection of oil types and quantity of pollutants

FIGURE 4.21: Importing wind field data

FIGURE 4.22: Carrying out difference-value calculation after importing current field data

FIGURE 4.23: Parameter settings for oil-spill simulation

FIGURE 4.24: Overview of environmental dynamic-field and simulation

cases

Model verification with cases and operational application

The system has been applied in offshore oil spill accident many times since its development . In case of emergency, more reliable forecasting results have been obtained with the system in the shortest time, which provides important reference for the handling of the accident.

1) Performance of such system in “4.19 accident” [95, 96]

In 2010, we found a clear anomalous zone between Liaodong Peninsula and North Huangcheng Island from the satellite image, and upon identification, we thought that it was likely to be oil-spill pollutants. Table 4.2 shows the related satellite-monitoring information based on satellite images.

According to the information obtained from the satellite images, the source of pollutants is traced back by using the “Marine Environment Forecast system for oil spill in Bohai Sea.” Tracing back from 07:00 on April 20, 2010 to 22:00 on April 19, 2010, the results show that the pollutants may have come from the area in north by west of Laotieshan Waterway, as shown in Figure 4.25.

According to the accident report received by the Shandong Maritime Safety Administration, at 21:35 on April 19, 2010, “Shengzhou 5” collided with “AAA” ship sank and the 2 tons diesel machine in the ship overrun. If the collision occurred at point A, the traceability result is about 1 nautical mile away from the collision location.

TABLE 4.2: Remote-sensing monitoring information of satellite

FIGURE 4.25: Distribution of anomalous zone shown on the Radarsat satellite images at 06:56 on April 20

FIGURE 4.26: Details of the anomalous zone

FIGURE 4.27: Traceability results of the system

Although the traceability result is slightly different from the reality, it is on the whole reasonable and accurate (Figure 4.27). Analysis suggests that the causes of deviation may be: (a) the specific location where the ship sank is not clear (the traceability is based on the collision location); (b) the accurate time of oil spill is not clear (the traceability is based on 30 minutes after the collision); (c) the wind field and current field are somewhat different from the reality.

In comprehensive consideration of the above factors, it is really commendable for the system to obtain the precision traceability results and find the approximate location of the source of spilled oil with important reference value in a short time.

2) Application of the system in traceability of the “4.16” oil spill accident at the mouth of Kiaochow Bay [95, 96]

At 14:00 on April 16, 2010, a marine oil spill occurred at the mouth of Kiaochow Bay. The research group immediately applied this system to trace back the oil pollutants. The results show that the oil spill occurred at Huang- dao Oil Terminal (Figure 4.28). Upon investigation, it was determined that it came from the discharge of the water used to wash the oil tank at Huangdao Oil Terminal. The successful traceability this time proved again the reliability of the system.

3) Oil spill forecasting after collision between the Bright Century ship and the Sea Success ship [97]

On May 1, 2010, two ships collided in Chengshan Cape sea area in Wei- hai. The DWT bulk carrier Bright Century carrying 150,000 tons of iron ore sank after the collision and the head of the other handymax general cargo ship carrying 30,000 tons coiled steel was seriously damaged. Oil spill occurred after the collision. To better cooperate with the spilled-oil cleanup, the system was applied to forecast the drift path. The oil spill occurred at 37°38'30^,,N/123°09'00"E, and 100 tons fuel oil was spilled. The forecast period

FIGURE 4.28: Traceability of oil spill at the mouth of Kiaochow Bay on April 16, 2010

FIGURE 4.29: Location of the spilled oil 36 hours after collision

is 7:00 on May 2 to 19:00 on May 3. The wind field used for forecast was WRF real-time forecast-wind field (with resolution of 10 km), and the current field was the tidal current and wind current automatically forecast with FVCOM (with maximum resolution less than 50 m).

The forecasting results of the system are shown in Figure 4.29. Thirty- six-hours after the oil spill, the pollutants drifted to the area in the vicinity of 38°02'57"N and 123°23'20"E (location in the north and 26 nautical miles away from the collision location). The drift trajectory is represented by the solid lines in the Figure 4.29: the spilled oil drifted towards northeast first, then it drifted eastwards and then turned to northwest, finally it kept drifting towards northeast for a considerable long distance. Compared with its initial location, after 36 hours the spilled oil drifted to the location in the northeast of and 26 nautical miles away from the location where oil spill occurred.

• 4) Application of the system in “7.16” oil spill accident in Dalian [98, 99,
• 100]

Around 18:00 on July 16, 2010, the pipeline in the crude oil tank area of Dalian PetroChina International Warehousing & Transportation Co., Ltd., located near Dalian New Port, Liaoning Province, exploded, causing a fire and some crude oil to leak into the sea. The preliminary estimate was that the explosion caused 1500 tons of crude oil to flow into the sea. By 13:30 on the 19th, the surveillance results of Chinese ship patrols showed that the polluted sea area was as much as 430 square kilometers, causing heavy damage to local fisheries, aquaculture and tourism. The economic losses were very serious, and the clean-up fee alone was more than one billion Chinese yuan. It can be said that this explosion was the most serious marine oil spill accident

FIGURE 4.30: Clean-up on the sea surface of Nantuo Fishing Port

in China. After investigation, the Ministry of Communications said that the cause was the explosion of 300,000 tons crude oil from the vessel Yuzhoubaoshi when adding catalyst to land pipelines of a crude oil reserve tank during the unloading of crude oil reserve of Dalian PetroChina International Warehousing fc Transportation Co., Ltd., which is near Dalian New Port. Figure 4.30 shows the clean-up on the sea surface of Nantuo Fishing Port after occurrence of oil spill.

When the accident happened, “the Marine Environment Forecast System for oil spill in Bohai Sea and North Yellow Sea” had been operating for about half a year. The Maritime Safety Administration of China used such a system to simulate the distribution of spilled oil in Dayao Bay and Dalian Bay (a) at 18:00 on .July 19 (about 72 hours after the accident). The simulation results are in good agreement with the satellite image (b) (Figure 4.31), providing forceful technical forecasting and early-warning support for the emergency response to the major oil spill accident.

In these cases, relatively reasonable and accurate results were obtained effectively in a short time after forecasting or traceability with the system. Hence, the system is an environmental forecast system with higher reliability and can provide valuable reference for prevention, control and emergency response of marine oil spills, thus saving the manpower and material input and minimizing the damages of oil-spill pollution to marine and human health.

Currently, the system is being constantly improved. The ultimate goal is to construct forecasting and early-warning systems of oil-spill pollution in major oil terminals and water regarding and create the information-service platform for early-warning decisions oil-spill pollution in coastal waters of China so as to provide information services for minimizing the damages of oil spills and maintaining the sustainable development of the marine economy.

FIGURE 4.31: The “7.16” major oil spill accident in Dalian