TEMPO.CO, Jakarta - A team of researchers has created an animated simulation of the currents in the Sunda Strait waters to find out the possible path of the missing journalists and three crew members who lost contact en route to Mount Anak Krakatau on September 7, 2026.
According to the researchers at the Climate and Atmosphere Research Center of the National Innovation and Research Agency (BRIN), the missing journalists are believed to have been carried by the ocean currents towards the west of Sumatra.
Two Diverged Paths
The BRIN team used two scenarios for locations at which all contact was lost with the crew, based on news articles. "They were 29.9 kilometers or approximately 16 nautical miles apart," said Widodo Setiyo Pranowo, a researcher in applied oceanography and coastal management, subdivision hydrodynamic modeling and transport, to Tempo on Sunday, September 20, 2026.
The modeled simulation assumes that the victims were still wearing life jackets, making it easy for them to be carried away by the currents. The first point, marked red on the simulation map, is located at the coordinates 6°14'40.52" South Latitude and 105°40'49.48" East Longitude. Its location is west of the waters of Banten, departing from the point in Carita, Serang Regency.
This simulation sees the victims carried by the current across the waters south of Mount Anak Krakatau, then carried to the waters east of Enggano Island on the west coast of Bengkulu. According to the simulation, by the 14th day, the victims' presence is likely to have stretched from the waters southwest and south of Pagai Island to the waters off Bengkulu's west coast.
The second point, marked in blue, has coordinates of 6°00'02.70" South Latitude and 105°34'00.87" East Longitude. Its location is closer to Sebesi Island.
In this simulation, the victims were carried by the current across the waters north Anak Krakatau in Tanjung Belimbing Lampung, and the southern part of the western waters of Bengkulu. By days 11-14, the victims reached the waters between the east, south, and southwest of Enggano Island.
Widodo said the coordinates from the news reports were the only information available to the public when the study began. "From a modeling perspective, we cannot determine which of the two initial points is correct; that's up to the investigation, not the scientific modeling we are doing," said Widodo.
Nevertheless, he added that in scientific terminology, the difference between the two initial points is expected to provide a wider range of possibilities for the search target locations.
How BRIN Simulates the Missing Journalists' Paths
In creating the simulation model of particle transport using the Euler-Lagrangian method, Widodo and his team relied on the archive of the Copernicus Marine Service's global model data, which is a marine monitoring service owned by the European Union. The data includes surface currents, tides, and wave information with a spatial data interval of approximately nine kilometers and a time interval of one hour.
One result of this method is the total current, which is the sum of three types of water movements (hydrodynamics) in the sea: regular ocean currents, currents generated by tidal dynamics, and wave thrust. The team also used inverse approaches to estimate wind speed based on wave dynamics because, theoretically, sea wave dynamics are generated by wind gusts.
Other data used includes sea depth maps from the General Bathymetric Chart of the Oceans (GEBCO) and coastlines according to the Base Map of Indonesia. According to Widodo, some of the data used are real conditions, while the others are forecasts. "For September 7 to about September 12, the data has been corrected with satellite observations, while for September 13 to 21, it is still a forecast," he said.
Widodo also explained that the wind speed is not directly measured but estimated from wave height. The data is used for simulations, which are planned to be conducted until September 22.
Using the drift velocity formula, Widodo and his team combined the Leeway factor or the wind thrust on the body parts that emerge above the water. Then the reduced stokes, which means the wave thrust is calculated smaller than on the surface because the human body is partially submerged.
Additionally, 2,000 particles or simulated individuals were placed in the Sunda Strait waters. The estimated weight per person is 60-70 kilograms. "The uncertainty point is the spread area," said Widodo, adding that a line is then drawn to represent the average path of all the particles.
Regarding the calculation or modeling method, according to Widodo, the picture using the Leeway formula is closer to reality. The reason is that individuals wearing life jackets are indeed affected by the wind. However, between the two locations of lost contact, he cannot state which one is stronger and reliable. "Both are equally likely as long as their initial coordinates have not been determined by the authorities."
Widodo claimed the error of the computer simulation to be very small. Nevertheless, he admitted that the actual uncertainty value is much larger and comes from other factors, such as the initial coordinates, ocean data that are not directly measured at the location, and the fact that this model remains untested.
Read: End of Search for Missing Journalists in Sunda Strait: What to Know
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