AIS Ship Tracking Data Shows False Vessel Tracks Circling Above Point Reyes, Near San Francisco

Analysis from SkyTruth and Global Fishing Watch shows ship tracks jumping thousands of miles from their true locations.

Bjorn Bergman works with SkyTruth and with the Global Fishing Watch research team to track vessels broadcasting false automatic identification system (AIS) locations and to investigate new sources of satellite data for vessel tracking and for detecting dark targets at sea. In this blog post, Bjorn spots an unusual pattern of false AIS broadcasts concentrated at one location, Point Reyes, northwest of San Francisco on the California coast. Why would vessels thousands of miles away be suddenly popping up in circles over Point Reyes? Could this reflect an intentional disruption of the underlying global positioning system (GPS) that AIS relies on, or is there some other explanation for this pattern?

In December 2019, SkyTruth reported on a number of locations on the Chinese coast (mostly oil terminals) where ship tracking positions from the automatic identification system (AIS)  became scrambled as soon as ships approached within a few miles of a point on shore. Importantly, we knew that this was actual disruption of the underlying global positioning system (GPS) — or more broadly the Global Navigation Satellite System — and not just a shipboard AIS malfunction. We determined this because another source of GPS data, Strava’s heat map of fitness trackers, showed the same ring pattern. A quick recent check of the data showed that this GPS manipulation is ongoing at oil terminals in four of the cities (Shanghai, Dalian, Fuzhou, and Quanzhou) where we had detected it last year. We still don’t know if this manipulation is specifically intended to mask ship traffic or if there is some other reason for disrupting GPS.

Following the findings last year on the Chinese coast, I began looking globally for any similar patterns in AIS tracking data around the world. While I haven’t found the precise pattern observed at the Chinese oil terminals outside of China, I did find a somewhat different false AIS broadcast pattern which, strangely enough, appears concentrated above Point Reyes northwest of San Francisco, California in the United States. Although the circling tracks look similar in both locations, the vessels on the Chinese coast were at most a few miles from the circling tracks, while the vessels broadcasting tracks above Point Reyes are actually thousands of miles away. So far I’ve found vessels in nine locations affected. Some of these locations are near oil terminals or where GPS disruption has been reported before, but there is no clear pattern linking all of the affected areas.  

Image 1: AIS tracks from a number of vessels have appeared circling over Point Reyes near San Francisco even though the ships can be confirmed to be thousands of miles away. False circling tracks from five vessels are shown here. AIS data courtesy of Global Fishing Watch / Orbcomm / Spire.

The AIS positions being broadcast over Point Reyes are obviously false (some of them are over land and they show a constant speed and oval pattern we wouldn’t see with a real ship track). But how can we be sure where the ship really is? The most important indication is the location broadcast just prior to the jump to Point Reyes and then where the vessel reappears after the apparent circling finishes. The duration of the circling pattern varies, from less than an hour for one ship in the Indian Ocean, to as much as two weeks for some of the other vessels. However, besides seeing the true locations before and after the jump to Point Reyes, it’s also possible to look at where the AIS receiving satellites were while the vessels were broadcasting positions around Point Reyes.

Image 2: The colored lines show AIS tracks from five of the ships whose broadcast positions jumped suddenly to Point Reyes, California, northwest of San Francisco. The time of the tracking disruption varies from less than one hour for one vessel to about two weeks for some others. Two of the vessels (Princess Janice and Alkahfi Maryam) also have tracks appearing over land in North America. The reason for this displacement is unknown although some of the vessels are in areas where GPS disruption has been reported (Eastern Mediterranean and Sea of Azov). AIS data courtesy of Global Fishing Watch / Orbcomm / Spire.

To get an approximate location for one vessel’s real position during the two weeks it broadcast over Point Reyes and the Western United States, SkyTruth analyst Christian Thomas and I analyzed the footprints of the satellites receiving the AIS positions. This was possible thanks to data Spire Global, Inc. provided to Global Fishing Watch. Spire’s data gives the identity of the receiving satellite with each AIS position. This allowed the Global Fishing Watch research team to access orbit information, which they used to calculate exactly the point above the surface of the earth where each satellite was when it received an AIS position and then calculate the distance from the satellite position to the ship’s broadcast AIS position. Because AIS broadcasts are only received within an approximately 5,000 kilometer (3,100 mile) diameter footprint, we know that the vessel was somewhere within this area. We can even narrow down the location further based on successive passes of AIS receiving satellites. 

Image 3: Broadcast AIS positions from Princess Janice. The track makes multiple jumps between a real location in an oil terminal on the coast of Nigeria (inset lower right) and false positions over the United States. Over two weeks in June 2019 the false track initially circles over Point Reyes northwest of San Francisco before veering over the Pacific and over the interior of the United States. More circling is seen around Salt Lake City Utah (inset upper right). AIS data courtesy of Global Fishing Watch / Orbcomm / Spire.

This vessel, the Princess Janice, is a crew boat traveling to offshore oil installations. It broadcasts a normal track out of a Nigerian oil terminal until June 5, 2019. For the following two weeks the vessel then broadcasts a false location track circling above Point Reyes and eventually veering off above Utah (during this time the track occasionally jumped back briefly to the Nigerian oil terminal). Unlike other false AIS broadcasts we have documented, which have a constant location offset or flipped coordinate values (producing a mirror image of the actual position), these circling tracks appear to not reflect the true movements of the vessel in any way. 

When we looked at the footprint of the satellite receiving AIS positions from Princess Janice, it’s clear that the vessel remained on a stretch of the central Nigerian coast or in nearby waters in the Gulf of Guinea (see Image 4) throughout the two-week period when false locations were being broadcast. 

Image 4: Princess Janice broadcasts an AIS track over Point Reyes near San Francisco and over the Western United States from June 5 – 21, 2019 (see Image 3). Analysis of the footprints for the satellites receiving these positions demonstrates that the vessel was actually within a region on the central Nigerian coast and adjacent Gulf of Guinea. Frame 1: Location over the Earth’s surface (red dots) of satellites receiving false position messages. Frame 2: Extent of satellite footprints for AIS reception (large red circles). Frame 3: Density of satellite coverage overlap, areas of increasing density shown as Blue → Green → Yellow → White. Frame 4: Area where all satellite footprints overlap (maximum coverage) shown in white. The white shaded region on the central Nigerian coast contains the true location of the Princess Janice during the period when the vessel was broadcasting a false location track. Analysis was done in Google Earth Engine using approximate satellite footprints of 5,000 km (3,100 miles) diameter.

Both the manipulated GPS positions seen on the Chinese coast and these new examples over Point Reyes are characterized by rings of positions. The rings have similar shapes, somewhat wider east to west than north to south. However circles appearing over Point Reyes vary greatly in size and the broadcast vessel courses may be oriented clockwise or counterclockwise around the ring. All speeds are exactly 20 knots. In contrast, the rings on the Chinese vessels last year had positions that were 21 or 31 knots with the 31 knot positions always oriented counterclockwise. Critically, while we could confirm that GPS interference caused the rings of AIS positions on the Chinese coast, we don’t yet know if that is the case with the positions over Point Reyes. An alternative is that this is simply a malfunction affecting the individual ships’ AIS systems. We were able to confirm that the false circling positions over Point Reyes occur in data from all available AIS providers (Orbcomm, Spire, and ExactEarth) and in AIS positions received by both satellites and terrestrial receivers.

The list of affected vessels below (Table 1) shows that many types of vessels in different geographic locations have displayed this same pattern of AIS disruption. Some were in areas where GPS problems have been reported by others (the Eastern Mediterranean, Sea of Azov, Libyan coast); other locations are seemingly random. A number of the vessels, but not all, appear near oil terminals and are involved in supporting offshore platforms. 


Table 1: Vessels showing a pattern of false circling AIS positions. Reported locations are where circling tracks appeared (mainly at Point Reyes near San Francisco). Real locations are where the vessel was determined to be while broadcasting the false circling AIS track. AIS data courtesy of Global Fishing Watch / Orbcomm / Spire.

The presence of three of these vessels in areas of documented GPS interference is intriguing. The cargo ship Berezovets shown below was operating in one such area in the Sea of Azov, north of the Black Sea. Following the Russian annexation of Crimea in 2014 and the takeover of Eastern Ukraine by Russian-backed separatists, the front line in the ongoing civil war has cut through Eastern Ukraine north of the Sea of Azov. There have also been conflicts on the water and a Russian blockade of the Kerch Strait leading north from the Black Sea.

Image 5: The Russian flagged cargo ship Berezovets transits through the Sea of Azov in June 2019 and has its AIS track jump suddenly to Point Reyes near San Francisco (inset). Incidents of documented GPS disruption occurred in March 2019 east of the Bilosarai Spit and in July 2019 in the city of Starohnatvka. AIS data courtesy of Global Fishing Watch / Orbcomm / Spire.

The Russian flagged Berezovets transited through the Kerch Strait on June 3, 2019 then headed northeast passing south of the conflict zone towards Russian ports. As the vessel enters Russian waters (location 1 in Image 5) and anchors, its June 4-8 positions broadcast by the AIS system are scrambled, some appearing scattered 20 miles from the vessel’s anchor point. The vessel track then moves east towards port before jumping 20 miles north to a point on land (2) and then jumping about 11,000 miles west to circle above Point Reyes (3). This circling continues for about 60 hours from June 11 – 14, including some irregular positions extending about 40 miles into the Pacific. As with the Princess Janice track, it’s unclear why the false track would jump to California and what accounts for the individual variations in the different tracks we see appearing at this location. On June 14, 2019 the Berezovets AIS track jumps back to the vessel’s real location, now in the Russian port of Azov (4) and can then be seen to proceed eastward up the River Don.  

The unusual disruption in the Berezovets broadcast AIS track was both preceded and followed by similar reported disruptions in GPS in the same region. On March 7, 2019 a Ukrainian military website reported that three vessels on the Sea of Azov experienced failures in their navigation systems. One of these failures occurred the day before, east of Bilosarai Spit (see Image 5). The other two reported disruptions were in the preceding month at other locations in the Sea of Azov. On July 23, 2019 according to a report from the Organization for Security and Co-operation in Europe’s Special Monitoring Mission to Ukraine a UAV (unmanned aerial vehicle) flying over the city of Starohnativka in Ukraine, was one of several UAVs that experienced GPS interference assessed to be likely from jamming. While not conclusive, the proximity of these other reported incidents makes it possible that the disruption seen in the Berezovets track was a result of the GPS interference known to be occuring in the area. 

Two other vessels were also in areas with documented GPS disruptions, Suha Queen II approaching the coast of Libya, and Haj Sayed I transiting from the Suez canal to Eastern Turkey. However, in searching for vessels showing the same circling pattern seen over Point Reyes, I have not yet found that multiple vessels in areas like the Sea of Azov were similarly affected. Global AIS data does show a few vessels with tracks circling over other locations. Two pilot vessels on the Chilean coast had their broadcast positions suddenly jump to circling tracks over Madrid. The Suha Queen II approaching the coast of Libya had its track jump to the Chinese city of Shanwei. The most recent vessel to appear circling over Point Reyes is the Ting Yuk, a tugboat operating in Hong Kong, which had its AIS track disrupted for a few hours at the end of March. 

So far it remains a mystery why these circling AIS tracks are appearing specifically at Point Reyes and a few other locations. It’s tempting to speculate that there might be some connection to a major U.S. Coast Guard communication station in Point Reyes which was an important historic location for developing maritime communications technology. While the Coast Guard left the area several years ago, volunteers continue to maintain at Point Reyes the only operational ship-to-shore maritime radio station. Still, it’s unclear why this location would somehow appear on AIS trackers. The fact that individual vessels in many different locations have been affected is puzzling and it’s unknown if any of these examples reflect actual disruptions of the GPS system. However some studies, such as a yearlong cruise by researchers of the German Aerospace Center which measured instances of GPS interference even during high seas transits, indicate that we may still have a great deal to learn about the true extent of global disruptions to this critical navigation system.

Systematic GPS Manipulation Occuring at Chinese Oil Terminals and Government Installations

Analysis reveals precise location and timing of GPS interference but purpose remains unclear.

Last month, an article in MIT Technology Review described strange GPS anomalies  in Shanghai. I began investigating, and have now found evidence of a novel form of GPS manipulation occuring at at least 20 sites on the Chinese coast during the past year. The majority of these sites are oil terminals, but government installations in Shanghai and Qingdao also show the same striking pattern of interference in GPS positioning. We don’t know the reason for this interference. It may simply be a general security or anti-surveillance system but it is also possible that it is intended to avoid scrutiny of imports of Iranian crude which have recently come under U.S. sanctions. Whatever the intention, we are able to demonstrate here, through analysis of vessel tracking data, that this GPS interference can be pinpointed very precisely in both time and location.

According to the MIT Technology Review article, this phenomenon was first documented by the U.S. flagged container ship Manukai when the vessel entered the port of Shanghai in July. The captain noticed that the vessel’s AIS (Automatic Identification System) appeared to malfunction — vessels on the navigation screen appeared and disappeared without explanation and appeared to move when they were in fact stationary. AIS, originally designed for collision avoidance, transmits vessels’ GPS locations, courses, and speed every few seconds via VHF (very high frequency) radio. These signals are not only picked up by nearby vessels and terrestrial antennas, but some private companies have also launched satellites able to receive these signals. For this analysis we were able to use data made available by two of these companies, Spire and Orbcomm, through our research partnership with Global Fishing Watch.

An investigation by non-profit C4ADS (Center for Advanced Defence Studies) showed that AIS vessel locations from hundreds of ships navigating Shanghai’s Huangpu river were coming up at false locations. Strangely, vessels on the river would have their GPS location jump to a ring of positions appearing on land. And this was not just affecting ships; looking at the cycling and running app STRAVA’s tracking map of cyclists, C4ADS also confirmed that this strange pattern of interference was affecting all GPS receivers.

To further investigate the GPS manipulation documented in Shanghai, I examined AIS position broadcasts from ships in the area. A distinct pattern emerged. Upon approaching the area of interference, a vessel’s broadcast position jumps from the vessel’s true location to a point on land where false AIS broadcasts occur in a ring approximately 200 meters in diameter. Many of the positions within the ring had speeds of precisely 31 knots or 21 knots (much faster than vessels would be moving near dock) and showed a course varying depending on the position within the ring. The GPS anomaly appears to affect vessels once they are a few kilometers out from the center of the ring. Once affected, vessels begin broadcasting seemingly random positions within the ring or from other high speed positions scattered around it.

Image 1. The Chinese cargo ship Huai Hia Ji 1 Hao (yellow) transits southeast on the Huangpu river. Upon nearing the center of GPS interference area the track jumps to the ring on land and to other random positions nearby. Positions from other affected vessels are shown in red. AIS data courtesy Global Fishing Watch / Orbcomm / Spire.

Image 2. GPS interference can be pinpointed based on this ring of false AIS positions. Approximately 200 meters in diameter, many of the positions in the ring had reported speeds near 31 knots (much faster than a normal vessel speed) and a course going counterclockwise around the circle. AIS data courtesy Global Fishing Watch / Orbcomm / Spire.

Because the ring of false AIS broadcasts follows this very specific pattern, I was able to query AIS tracking data to check if there are other locations where these rings are also occurring. The results are striking. This GPS manipulation is occuring not only in Shanghai but has occurred in at least 20 locations in six Chinese cities within the past year. The focus of these apparent GPS manipulation devices is clearly oil terminals (where 16 of the 20 detected locations were observed). But three prominent office buildings in Shanghai and Qingdao are also affected: the Industrial and Commercial Bank of China in Shanghai, the Qingdao tax administration office, and the Qingdao headquarters of the Qingjian industrial group.

Image 3. A ring of false AIS positions marks an apparent GPS interference device deployed in an office building identified as the Qingdao tax administration office. AIS data courtesy Global Fishing Watch / Orbcomm / Spire.

Image 4. Locations of detected GPS manipulation occuring in six Chinese cities in 2019. Interference following this pattern was not found beyond the Chinese coast.

It seems likely that the centers of these rings of false AIS positions actually mark the physical location of some sort of GPS disrupting device. A device having precisely this effect on GPS receivers, including shipborne AIS systems, has not been previously documented, though there have been other cases of GPS blocking and manipulation. Earlier this year C4ADS published a report with details on GPS manipulation clearly being carried out by the Russian government. These Russian systems appeared to have the effect of making all receiving devices within range show some particular location, such as a nearby airport, rather than the true location of the device. This was seen in one striking example of vessels approaching Putin’s alleged palace on the Black Sea coast.

This Chinese system is clearly being deployed both at central government offices and at the much more remote locations of oil terminals. In the case of the government office buildings it seems likely that these GPS disrupting devices were activated as a security measure. Some are only active for a few days, perhaps to coincide with the visit of an important official. However,  the AIS manipulation occuring at oil terminals particularly interests us at SkyTruth: One possible motive for deploying GPS manipulation devices at oil terminals could be recent U.S. sanctions on Chinese companies importing Iranian crude. And the intentional disruption of a navigation safety system, in close proximity to crude oil storage, is a serious concern.

Almost half of the specific locations where these presumed GPS disrupting devices have been deployed are at oil terminals near Dalian in northeast China. In an August analysis, The New York Times matched Planet satellite imagery from June and July with AIS tracking data to show Iranian tankers delivering oil to China in violation of U.S. sanctions. The Financial Times also documented Chinese flagged tankers importing Iranian crude after ship to ship transfers with Iranian tankers.

I took a closer look at exactly how this GPS disruption is affecting vessel tracking in one oil terminal east of Dalian. Here I identified four locations where GPS disrupting devices appear to have been deployed in 2019. I compared AIS vessel position data from March 1, 2019  and September 5, 2019. The differences were dramatic.

These two days showed similar numbers of AIS positions in the area. But on September 5 approximately two-thirds of the vessel positions at dock disappeared and appeared to be replaced by positions orbiting the GPS disrupting devices or scattered randomly in the region. At the same time, it does appear that some normal AIS broadcasts are coming through and that the GPS disruption does not entirely mask all vessel movements in the area.

Image 5. On March 1, 2019 AIS vessel position data around an oil terminal east of Dalian China shows accurate vessel positions and speeds. On that date, none of the four locations of GPS interference were active. Consequently no vessel positions appear on land and stationary vessels are accurately shown with near 0 speeds (green). AIS data courtesy Global Fishing Watch / Orbcomm / Spire.

Image 6. On September 5, 2019 two GPS interference locations were active and this had a dramatic effect on scrambling vessel positions in the area. Many positions now appear orbiting the presumed GPS interference devices and others appear scattered on land. On the water many positions are appearing with very high speeds (over 25 knots, red) and it’s not possible to distinguish true and false locations. However some slow speed positions (green) are appearing at dock where they would be expected, so some AIS broadcasts appear to be unaffected. AIS data courtesy Global Fishing Watch / Orbcomm / Spire.

Image 7. The distribution of AIS speeds in the area is significantly altered by the activation of the GPS interference devices. Above AIS speed distributions are compared between March 1 (left, no GPS interference) and September 5 (right, active GPS interference). On Sept 5 the total number of slow speed positions from docked vessels is greatly reduced and spikes now appear at 21 and 31 knots from positions orbiting the presumed GPS interference devices.

I also examined one individual vessel track to see how it was affected by GPS interference. This is the Chinese flagged tanker Jin Nui Zou which entered the Dalian oil terminal on September 5. Initially a normal track is seen as the vessel approaches the terminal from the southeast. With closer proximity to the presumed interference device, scrambled positions — often with very high speeds — start to appear. Eventually almost all of the vessel’s AIS positions appear in the ring orbiting the interference device.

Image 8. The tanker Jin Niu Zuo approaches an oil terminal east of Dalian on September 5. Initially, positions with normal transit speeds appear (yellow). With closer proximity, scattered high speed positions begin to emerge (red) and eventually most positions appear in the ring surrounding the presumed AIS interference device. AIS data courtesy Global Fishing Watch / Orbcomm / Spire.

The timing of GPS interference at different sites on the Chinese coast can be inferred based on the appearance of AIS positions on land with 21 and 31 knot speeds. Of the 20 locations identified, interference appears earliest at office buildings in Qingdao but only over a couple days (April 17 – 18, 2019). The first GPS interference at oil terminals appears in June and has continued until recently but timing varies by location. Activation of interference at different terminals is intermittent and may be in response to specific events. For instance at an oil terminal near Quanzhou GPS interference appears to have been activated only between September 25th and 27th, 2019.

At the Dalian oil terminals GPS interference appears to have begun in late June 2019. It is possible that this was a reaction to increased scrutiny of crude imports after the U.S. ended exemptions for purchase of Iranian oil on May 2nd. In fact, Dalian is the headquarters of two subsidiaries of Cosco shipping which were sanctioned on September 25 for importing Iranian crude. Based on what can be seen with vessel activity in Dalian, it is clear that GPS interference is not able to entirely mask vessels approaching the terminal. However, it likely would make it impossible to reliably link a vessel’s AIS track with satellite imagery of a vessel discharging crude at dock. While it is not at all clear that GPS interference was intended to obscure shipping activity, we do see that it had a significant impact on AIS tracking and that the interference was specifically concentrated at oil terminals.

In the November article first documenting the strange GPS anomaly in Shanghai, the question was posed whether this was the work of the Chinese state or some other actor like a mafia engaged in smuggling river sand. Based on the very specific characteristics of the GPS manipulation observed and its deployment at high level installations, it seems very likely that the Chinese state is responsible. It remains to be seen whether this is simply a security measure or if GPS manipulation is also being deployed specifically to prevent monitoring of oil imports.

Unusual Behavior by Tankers Near Brazil Oil Spill

The source of the massive oil spill affecting Brazil remains unclear, but unusual tanker activity raises questions.

For months now, oil has been washing up on the beaches of northeast Brazil. The quantity of oil, the large area affected, and the length of time oil has appeared, have generated international news coverage and concern. Government officials, scientists and non-governmental organizations around the world — including SkyTruth — have been trying to identify the source of the pollution; so far, unsuccessfully. Brazilian researchers have identified a likely location for the origin of the spill based on ocean currents. The oil is a heavy consistency that floats below the surface of the water and Brazilian researchers and government officials have claimed that it is likely from Venezuela, although they haven’t published the chemical analysis data to support this.

Photo 1. Heavy oil has been sullying the beaches of northeastern Brazil since early September. The cause remains elusive. [Photo courtesy tvBrasil via Creative Commons license]

At SkyTruth we have been examining available satellite imagery and evaluating some of the theories put forward on the origin of the spill. We haven’t seen any convincing evidence of oil slicks or sources on the images, and we don’t agree with analyses published by others (here and here) that claim to have solved the mystery. I recently decided to take a look at AIS (Automatic Identification System) ship-tracking data in the region that Brazilian researchers identified to be the likely origin of the spill. When I examined the AIS data, I found some unusual behavior by oil tankers passing through the area. 

AIS is a system in which vessels at sea transmit their location at regular intervals via VHF radio. Initially designed for collision avoidance, this location data is also picked up by satellites and provides a global record of vessel movements. I was aided by Global Fishing Watch’s automated modeling of AIS tracks, developed by data scientist Nate Miller, which identifies loitering events, that is, locations where vessels have essentially come to a stop, and are drifting out at sea. Tankers and cargo ships normally maintain a relatively constant transit speed as they are moving from their point of origin to their destination port. Ships may stop out at sea for a number of reasons, including engine problems, waiting for entry authorization at a port, or even at-sea transfers of cargo or refueling. But spending more than 24 hours adrift at sea represents a financial loss for a tanker and would suggest unusual circumstances.

Of hundreds of tankers that moved through the area in the months before the oil was reported, a handful stood out for having lengthy loitering events near the likely area of origin for the spill. One particular tanker, rather than proceeding directly on a course from Spain to Argentina, stopped for two extended periods (each for approximately 14 hours) just within Brazil’s Exclusive Economic Zone (the EEZ area extends up to 200 nautical miles from shore). The tanker I identified with these unusual loitering events is The Amigo, a 133-meter vessel listed as an Asphalt/Bitumen tanker and flagged to the Marshall Islands. 

Figure 1. Tanker loitering events (yellow circles) detected by Global Fishing Watch analytical tools on the coast of northeast Brazil in July and August 2019 (filtered to events longer than 8 hours). Five loitering events near the area thought to be the likely origin of the spill are shown as larger circles and listed in the table below. The AIS track of tanker The Amigo is shown in red. The EEZ boundary marking Brazil’s waters is in green.

We checked for satellite imagery in the area where the vessel was drifting (July 24 – 26) and unfortunately didn’t turn anything up. So any possible association between this tanker and the oil spill is purely speculative. However, some of the circumstances of the vessel’s operation fit with theories on the source of the spill, so we think its activities should be scrutinized further.

The Amigo is an unusual tanker in that it is outfitted to maintain its cargo at high temperature to keep it from solidifying. When the tanker passed through Brazilian waters off Brazil’s northeast coast, it was en route from Cadiz, Spain to a port near Buenos Aires, Argentina. The loitering events occurred between July 24 and July 26 before the vessel proceeded to Argentina. Port records show that on August 10 the vessel delivered 14,000 tons of bitumen (or at least it was scheduled to offload that quantity of product). AIS confirms that the tanker reached dock in Campana, Argentina on August 10. 

The tanker was coming from Cadiz, Spain though we don’t know if the asphalt was actually from Spain or what quantity was loaded at the port facility in Cadiz. Earlier this year the vessel visited Venezuelan ports and imported Venezuelan asphalt to the US. This article from March mentions The Amigo in the context of US sanctions against Venezuela that were coming into force. Could The Amigo have been carrying a cargo of asphalt that originated in Venezuela?

Figure 2. Movements of The Amigo since January 2019. The tanker’s current location in Turkey is shown.

The terms asphalt and bitumen appear to be used interchangeably to describe a semi-solid form of petroleum. High heat tankers like The Amigo must maintain their cargo at an elevated temperature so that it does not solidify, and can be pumped out of the vessel. Problems with heating might result in product remaining in one of the ship’s tanks and needing to be flushed out. Even under normal operations, heavy oil residue can build up in the cargo tanks and needs to be washed out or removed to free up usable space. International law requires that this be done in port where the oily sludge can be treated, but many ports lack the necessary treatment facilities. If somehow asphalt did end up being discharged directly into the ocean it would be expected to drift below the surface in warm equatorial waters. This might not generate a large surface oil slick that could be seen on satellite images, possibly explaining our frustration here at SkyTruth. 

As mentioned, there are some legitimate reasons for a tanker to be drifting out at sea. But we think it is fair to pose some further questions about this vessel given the severity of the spill in Brazil. What prompted the vessel to halt its normal transit off Brazil? What was the origin of the asphalt carried by the vessel and what quantities were loaded and offloaded? Could the chemical properties of the oil found on Brazilian beaches match this cargo, or any oily residue remaining in The Amigo’s cargo tanks?

But it’s not just The Amigo that’s raising questions for us. We’ve detected loitering events by other tankers in recent months (as shown on the map above and in the table below). We’ve found evidence of likely bilge-dumping by a few vessels in the area. And we’ve noticed that more than a dozen tankers operating in this area turn their AIS off while at sea, apparently in violation of international maritime safety law.

Table 1. Table showing the five tanker loitering events detected near the likely source of origin of the Brazil oil spill, shown as large yellow circles on the map at top.

We hope to find out answers to some of these questions soon, and we will continue to investigate all available data that might help to identify the origin of this devastating oil spill. One problem is very clear: we don’t know everything we need to know about the tanker activity near Brazil, and in many other parts of the ocean. 

Update 19 Nov 2019 – Since posting this last week I’ve had a chance to get some input regarding the Bitumen tanker I identified as of particular interest, The Amigo. The 14,000 tons they were scheduled to offload in Argentina would represent close to the full carrying capacity of the vessel. With estimates of at least 2,000 tons of material recovered from the beaches it seems that the vessel could not be responsible if they delivered a full cargo. 

We remain puzzled by the properties of oil coming up on the beach. It has been clearly reported as floating below the surface which fits with the fact that no large slick has so far shown up on satellite imagery. It has been questioned whether any of the asphalt carried by a vessel like The Amigo would really remain in the water column and be able to float ashore, rather than sinking to the seafloor. So some sort of heavy crude seems to be the most likely source. 

We are continuing to investigate any possible leads on the source of the spill and will share any more information that comes up. 

Bilge Dumping off the Coast of Brazil

The cause of the massive oil spill plaguing Brazil’s beaches is still unknown, but monitoring reveals a potential new bilge dumping incident

We still haven’t found the cause of the massive oil spill that’s been plaguing Brazil’s beaches since early September.  

But SkyTruth’s continued surveillance of the coast of northeastern Brazil, in response to one of the country’s worst oil-related environmental disasters ever, has uncovered what appears to be another previously unreported bilge dumping incident off the coast of Joao Pessoa in the state of Paraiba. Located about 20 km offshore, a 25 km-long slick appears to originate from the Grajau, a Brazil-flagged liquefied petroleum gas (LPG) tanker. Slicks such as this are a hallmark of the intentional dumping of untreated, oily bilge wastes from vessels underway at sea, although there may be other explanations for this slick (for example, the ship was experiencing a serious mechanical problem). The slick (a long, dark streak) and vessel (a bright spot at the south end of the slick) are shown on this Sentinel-1 radar satellite image taken on the 19th of July. We identified the vessel using their public AIS tracking broadcasts, extracted from the ShipView vessel-tracking platform. The image was captured at 07:53 UTC; a careful look at the AIS broadcasts from Grajau just before and after the image was taken show that the vessel we can see on the radar image is very likely Grajau.

Recent discoveries of bilge dumping in the Atlantic Ocean along Brazil’s coast reveal that this is a persistent problem that — as in many places — lacks effective enforcement. None of the slicks we’ve seen appear big enough to be the source of the oil plaguing Brazil’s beaches. This potential bilge slick from Grajau is no exception: it’s a modest-sized slick compared with the dozens of bilge slicks we’ve seen from other places around the world that are occasionally more than 100 km long. And this slick, just 20 km offshore, probably would have dissipated or washed ashore several weeks before the thick globs of heavy oil began to appear on the beaches in early September.

Nevertheless, bilge dumping is a chronic source of oil pollution in the ocean that has been hidden for too long. Now that we can see it, and can identify the likely polluters, it’s time for governments to take action to bring this illegal practice to an end.

AIS ship-tracking broadcasts (red dots) from the Brazil-flagged LPG tanker Grajau, overlain on a Sentinel-1 radar satellite image showing an apparent bilge-dumping slick (dark streak) and the vessel that appears to be responsible (bright spot, indicated within the red circle). Based on the AIS data, we think this vessel is likely the Grajau. See inset map at upper right for detail. Image was collected at 07:53 on July 19.

The location of the boat, relative to Brazil’s coastline.

Bilge Dumping Caught in Indonesia – Again!

SkyTruth identified the bulk carrier Lumoso Aman as the likely polluter via AIS and satellite imagery.

On October 10, 2019, SkyTruth discovered yet another likely bilge dumping incident in Southeast Asian waters. At 10:25:26 UTC (Coordinated Universal Time), Sentinel-1 Imagery captured this oily pollution during routine monitoring of the Makassar Strait. Lingering off the southwest coast of Sulawesi, Indonesia, this oil slick measures approximately 33 kilometers long. The slick and the suspected responsible vessel (circled in red in Figure 1 below) appear roughly 100 kilometers west of the coast of Makassar, the capital of Sulawesi. Makassar is a port city with active commerce and tourism.

Figure 1: A vessel suspected of bilge dumping.

We identified the potential culprit through AIS (Automatic Identification System) broadcasts from the Lumoso Aman (Figure 2), a bulk cargo carrier operating under the flag of Indonesia. 

Figure 2: A picture of the Lumoso Aman, courtesy of Vessel Finder.

Bilge dumping is the disposal of waste water from a ship’s lower hull. Bilge water is supposed to be treated before it’s discharged, but sometimes vessel operators will bypass the pollution control equipment and flush oily, untreated bilge into the ocean – in direct violation of international marine pollution law. You can learn more about this ongoing source of ocean pollution, and how SkyTruth identifies perpetrators, in our recent post about bilge dumping in Southeast Asia.

Our motto at SkyTruth is “If you can see it, you can change it.” We tirelessly monitor the ocean with this vision in mind, to be watchdogs and defenders of our Earth’s waters. No matter how remote these areas of pollution appear to be, we can see them with satellite images. These seemingly remote bodies of water are connected to waters throughout the world. Just as air pollution migrates between contiguous countries or states, oil pollution can find its way to any coastline and harm coastal environments and communities. With continued monitoring, we hope that nations, communities, and enforcement agencies can hold ship operators accountable, making it clear that bilge pollution is an unacceptable threat to the world’s ocean ecosystems. 

Figure 3: SkyTruth intern Tatianna Evanisko tracks polluting vessels around the world from the SkyTruth offices in Shepherdstown WV. Photo credit: Johnna Armstrong.