Bilge Dumping? Busted Using Satellite Images and AIS Data

Remember that 92-mile-long bilge dump off Congo and Angola that caught our attention back in April?

Envisat ASAR satellite radar image showing bilge-dump slick (long dark streak) off Angola on April 6, 2012. Image courtesy European Space Agency.

The bright spot at the left end of the slick is likely the vessel that caused it.  But the ASAR imagery left an important question unanswered: Who was responsible for this pollution?

With the generous help of our new partners, SpaceQuest, new information has surfaced that helps put a name on that bright spot:  the Dona Liberta, a refrigerated cargo ship owned by NaviFruit LTD. This vessel has made unfortunate news in the past.  On July 4, 2011, the ship's captain dumped two Tanzanian stowaways in Liberia’s territorial waters, strapped to empty barrels. One of the stowaways died while receiving medical treatment after washing up on shore. In November 2011 the vessel was laid up in the River Fal in England, stranding two Romanian watchmen on board in unsanitary conditions who were rescued by a charitable organization. And in February 2012, the Dona Liberta spilled 70-90 gallons of oil in the River Fal, prompting a cleanup response from local authorities.

The Dona Liberta, courtesy of Shipspotting.com © Juan B

So how did we figure this out?

Read all about it after the jump....

Playing Hide-and-Seek! With an Oil Tanker.

Supertankers loaded with crude have been making the news recently, mostly because they can't find a place to sell the stuff. These tankers departed from Kurdistan, but Iraq claims the oil they carry is their property and the Kurds don't have the right to sell it.  This global political dispute is playing out on the water in an interesting, albeit risky, way: the tankers are unable to come into port, so are lingering offshore, fully loaded, waiting for some kind of resolution.

Late in July, we tracked the tanker United Leadership as it roamed across the Mediterranean and loitered in the Atlantic off the coast of Morocco.

Now we're following one that's a little closer to home:  the United Kalavrvta has been parked in a holding pattern in the northern Gulf of Mexico about 50 nautical miles southeast of Galveston. A few days ago Reuters noted that the tanker had "disappeared" from satellite tracking data, speculating they may be trying to offload their 42-million-gallon cargo of crude onto another vessel.  The US Coast Guard weighed in with this comment: 

A Coast Guard official said the vessel in the Gulf of Mexico might have turned off its beacon, sailed beyond antennas that monitor transponders, or perhaps some antennas might have been taken out of service.

Um, that's not quite right: tankers are required by international maritime law, AND by US Coast Guard regulations, to continually broadcast their position, heading, speed and other information using a Class A AIS system when they are between ports. There should be no threat of piracy in the US Gulf of Mexico, so the captain has no legal justification for turning the system off, until the vessel is safely in port.  Which it is not.  And the AIS signals sent by the relatively powerful Class A transmitters on tankers and other large cargo vessels are readily picked up by AIS satellites, which can cover the entire ocean.  If the captain turned off his AIS, perhaps the US Coast Guard needs to go pay him a visit and enforce US law.  

So where is the United Kalavrvta?  Right where it's been for weeks, since it showed up on July 27.  See below for the details: our vessel-tracking expert Bjorn prepared this series of maps and info yesterday, using our satellite AIS data feed from exactEarth.  We hope the Coast Guard can make use of this to resolve the inconsistencies in broadcasting by this loaded supertanker.  After all, it's hurricane season in the Gulf, and a fully loaded tanker that is not broadcasting its location to all the vessels in the vicinity is a hazard to navigation, and a potentially colossal environmental disaster waiting to happen.  
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Latest Position at: 2014-09-02 19:23:57 UTC
Latitude: 28.585117 Longitude: -94.249783
Course: 252.0°

Speed: 0.0kn

The United Kalavrvta is at anchor in the same location off Galveston. They resumed AIS broadcast but with some unusually long gaps between positions. Their last position was about 32 hours ago. Between the 26th and the 28th there was a 47 hour gap, between the 28th and the 30th there was a 53 hour gap. 

AIS data track showing path of United Kalavrvta over the past 90 days.

AIS data from September 2 showing position of United Kalavrvta at anchor about 60 miles southeast of Galveston.

Zoomed-in detail showing AIS data for United Kalavrvta since August 24; the tight circular path indicates it's anchored (probably by the bow) and drifting around the anchor point as it gets pushed by wind and current.

Just for grins, we thought we'd see if this vessel shows up on Landsat-8 satellite imagery.  The most recent cloud-free image of this area was taken on August 4.  Sure enough, the faint pattern of a large oceangoing vessel appears exactly where the AIS data say the tanker was located on that day.  

It's tough to hide a supertanker:

Part of a Landsat-8 satellite image taken on August 4, showing a vessel in the reported AIS position for the United Kalavrvta.

Detail from Landsat-8 image showing a large vessel (pale elongated blob) at the AIS position reported by the United Kalarvrvta on August 4, 2014. Vessel appears to be roughly 240 meters long. FleetMon data indicate United Kalarvrvta is 275 meters long.  This is within the error of Landsat-8 imagery, which has 30-meter pixels.  Note another, similar-size vessel at center left.

Sanctions on Russia to Freeze ExxonMobil's Arctic Drilling Efforts

Last week the U.S. Treasury Dept. issued new sanctions that are expected to force ExxonMobil to halt its current Arctic drilling operations, a $700 million dollar partnership with Russian energy company Rosneft. Earlier sanctions only applied to new financial transactions and therefore did not stop the energy giants from moving the West Alpha drilling rig hundreds of miles north of the Arctic Circle to begin drilling for oil in the Kara Sea. On August 9, Vladimir Putin gave the go-ahead to start drilling in the Universitetskaya (Университетская) Prospect, making this venture the northernmost oil well in Russia. However, ExxonMobil now has just until the end of the month to wrap up their operations.

ExxonMobil and Rosneft planned to complete the project during the brief ice-free season between August and October. In early July, barely a month before the West Alpha rig arrived from Norway, the Kara Sea was still covered in ice (above). 

As we've written before, there are a number of reasons to be concerned about drilling in the Arctic. We've seen the devastation caused by a blowout in the relatively calm waters of the Gulf of Mexico, and this drilling operation is 385 miles northeast of Gazprom's controversial Prirazlomnaya platform that Greenpeace activists boarded last year.

What is so worrying about drilling in the Arctic? Aside from the unforgiving weather that can tear a 28,000 ton drill rig from its support vessels and drive it ashore, there are no technologies proven to clean up spilled oil from the ice that covers the region most of the year. And this ice is always moving: consider what the Kara Sea looked like in July (above) compared to August (below). At 68² km, the 11 km long chunk of ice identified above is larger than Manhattan.  According to Rosneft, the West Alpha rig is outfitted with sensors to track advancing sea ice, and they claim to be able to shut-in the well and move the rig if necessary.

(Above) As of August 22 the ice had retreated. 

Clouds often block the view of electro-optical satellites like Landsat, but synthetic aperture radar on satellites like the European Space Agency's Sentinel 1-A can peer through clouds and collect data on vessel locations, oil slicks, and sea ice, day or night. While we wait for Sentinel to begin routine data collection, we are watching vessel activity around the West Alpha rig using satellite AIS tracking data. (To read more about our work with satellite AIS, click here)

(Above): AIS data show the path taken by the West Alpha rig as it was towed from Norway to its current location in the Kara Sea.

(Above): With our AIS data viewer we can "see" all of the broadcasting vessels operating around the West Alpha. This may also allow us to see if vessels appear to engage in oil-spill clean up operations. 

Looking at Landsat's 15-meter panchromatic band (Band 8), we can just make out the rig and several support vessels. We've been able to definitely identify the two vessels east of the rig. The furthest vessel to the east is the REM Supporter and the vessel in the middle is the Loke Viking. The identity of the vessel right beside the rig is unknown. 

It is worth noting that the West Alpha rig has not broadcast its location since August 14. It is not to clear to us from the IMO regulations if they are required to continually broadcast their location until they are safely back in port, but it is not uncommon for drill rigs to stop broadcasting when they are "on-station" and not moving.

According to Rosneft, drilling began in early August and was expected to take two months. But under these new sanctions Exxon has to wind down their activity and secure the well by the end of September. 

Oil Spill Causes Shipping Backup in Gulf of Mexico

The 168,000-gallon fuel oil spill that happened Saturday near Galveston, Texas caused the Coast Guard to temporarily close the Houston Ship Channel.  That's a very busy, narrow waterway connecting the Port of Houston with the Gulf of Mexico and overseas ports.  In addition to the environmental consequences of this heavy oil spill, including the threat to shorebirds at the peak of their spring migration, this closure has caused a big-time backup of shipping traffic.  

Here at SkyTruth we track vessels with satellite imagery, and also with other satellite-collected data.  Here's a view of the situation using satellite Automated Information System (AIS) data, radio-frequency tracking information that vessels continually broadcast so they can avoid running into each other at sea:

AIS map on March 24, 2014 showing ship traffic backed up as a result of an oil spill in the Houston Ship Channel. Colored triangles mark the locations of vessels of different types. Port of Houston is at upper left.

Detail from above, showing large offshore holding area where dozens of cargo ships and tankers lie at anchor, awaiting clearance to enter the ship channel (marked by dashed pink line).

This shows a large "waiting room" in the Gulf just outside the entrance to the channel where dozens of vessels -- mostly oil tankers and cargo ships -- are anchored, waiting for clearance to proceed into port.  There are also quite a few vessels bottled up in port, waiting to get out, including a few large cruise ships.  

You can see some of the AIS data yourself, and query individual vessels, at the cool Marine Traffic ship-tracking site.

Pollution Response Activity in Campos Basin off Brazil?

We're still trying to figure out what caused that big smoke plume we saw in the Marlim Sul oil field of the Campos Basin, about 70 miles off the coast of Brazil, on a December 31 satellite image.  So far, we've looked at data showing the locations of active exploration wells (where we would expect to see a drill rig at work); active oil production platforms, including FPSOs; and vessels broadcasting an AIS signal; and we can't identify anything at the location where the smoke plume originates: 
 

Detail from December31, 2013 MODIS satellite image showing smoke plume off coast of Brazil in the Campos Basin oil field. Source of smoke plume shown by red marker.  Nearby / notable drill rigs and platforms shown by yellow markers.  Other oil platforms shown as purple dots.

So we are still stumped by this incident.  If any of you want to lend a hand, the smoke plume's point of origin is here:

latitude -22.604346° / longitude -40.065453°  ( 22°36'15.65"S /  40° 3'55.63"W)

Meanwhile, our investigation has turned up something else of interest. 

We're using global satellite AIS data to track vessels around the world, as part of our work to monitor marine protected areas and detect illegal commercial fishing activity.  We spotted an oil spill response vessel, the Mar Limpo II, operating in the Campos Basin about 45 miles southwest of the smoke-plume location. Judging by its repeated back-and-forth track, it looks like the vessel is actively engaged in oil spill response, possibly skimming oil and/or applying chemical dispersant to an oil spill:

Map of Campos Basin off Brazil, showing vessel AIS data. Track of the oil pollution response vessel, the Mar Limpo II, is shown in blue.

Detail from above showing the back-and-forth motion of the Mar Limpo II. Current position (January 9) of the vessel is indicated by square white brackets. Vessel appears to be engaged in oil spill response.

 If anyone has information about a possible spill here, please let us know.

UPDATED: Oil-Laden Cargo Vessel Without Power & Drifting Toward Canadian Coastline

UPDATED OCT. 18, 2014 at 9:42 AM: Canadian Coast Guard patrol vessel Gordon Reid has gained control of the "Симушр" and is towing it out to sea. As of 6:00 am, the Reid had put 14 miles between the stricken tanker and the coast of Haida Gwaii. USCG Spar is arriving on the scene, but the American tugboat Barbara Foss was still over 200 miles out.

The situation looks more promising, but winds are picking up again and more inclement weather is anticipated. More from the CBC... 

ORIGINAL POST: Canadian media and the Council of the Haida Nation are reporting that a 443 foot Russian cargo vessel lost power early this morning in gale-force winds, and is now slowly drifting towards the Canadian coastline. The Симушр (pronounced "Simushir") is a cargo vessel, but is also laden with over 110,000 gallons of "bunker fuel" (a heavy fuel oil) and 13,000 gallons of diesel fuel (500 and 60 metric tonnes, respectively). 

From MarineTraffic.com - The СИМУШР in port in Busan, S. Korea.

According to satellite AIS data, the vessel is 10 miles SE of the coast, and slowly drifting almost due north at an average speed of 2.87 knots (3.3 mph) over the last 9 hours. Weather reports referenced by the Haida Nation stated, "Thirty-five to forty-five [MPH?] south-east winds are blowing the vessel to shore in a 7-10 metre sea." However the release also stated that the winds are expected to turn westerly in the afternoon. 

Timeline of the СИМУШР's drift since Oct. 16, 2014 based on satellite AIS data. The vessel is currently 10 miles from the nearest point of land.

A weather buoy off the coast of Haida Gwaii is reporting that the wave height is down to 4.5 meters, but the winds are still coming from the southwest at 16-19 knots (~18-22 MPH). We cannot say with any certainty how the currents or winds will effect the vessel as it gets closer to shore, but a few straight-line calculations may put the risk in perspective.

If we plot a straight line from where the Симушр reported it was no longer under command, through the vessel's last reported location, all the way to landfall with the coast; we find it has drifted approximately 29 miles in just under 9 hours. On this trajectory, it could reach the northern part of Haida Gwaii in 26 miles during the early hours of October 18th.

Fortunately, the last few reports show the path is shifting slightly toward the west. If we plot a straight line between the last two reported locations...

This trajectory clears the coastline by 4 miles, again in the early hours of tomorrow morning. 

However, ocean currents and winds do not follow straight lines, so reality will almost certainly be somewhat different than these projections. Thankfully, nearby vessels like the North Star, an 839 foot American container ship, are closing in on the stricken ship to assist it. Additionally, the Gordon Reid, a Coast Guard Patrol Vessel, is only 21 miles away and closing fast. The Reid was originally reported to be 750 km (466 mi) away. This post will be updated as details unfold.

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SkyTruth Uses Satellites to Track – a Bicycle?!

[Update - July 28, 2014: Tony successfully completed the challenge and we have switched the map from a live view of his most recent location to a static overview of the whole journey.]

Shepherdstown, WV –  On Friday, July 25th, SkyTruth will turn our attention from aimless oil tankers and drilling sites in America's Heartland to an unlikely suspect - a bicycle. Technically we're more interested in the man riding the bicycle – Tony Long, Director of the Ending Illegal Fishing campaign at the Pew Charitable Trusts. 

Long, a former commander in Her Majesty's Royal Navy (UK), is taking part in the Action London-to-Paris ride, a 24 hour, ~240 mile challenge to raise money for children's medical research. Along the way Tony will be carrying a SPOT personal tracker provided by SkyTruth in order to demonstrate how remarkably simple and inexpensive it is to deploy a satellite monitoring system, whether it's for a bicycle winding through the hills of Northern France or a 608-ton fishing vessel plying the waters of the South Pacific for tuna. 
   
SkyTruth CTO Paul Woods is the brains behind putting Tony's path on the map. "It's a nice example of how easy it is for anyone willing to be transparent about their actions with a trivial investment of time and money."  

Some fishing vessels already employ AIS transmitters as a way of broadcasting their location to avoid deadly collisions at sea, but the use of AIS is not mandatory everywhere. 

"Imagine if every commercial fishing vessel were as trackable as Tony's bicycle. Overnight we could make it infinitely harder to hide illegal fishing," Woods said. 

Long agrees. "Tracking fishing vessels is a vital element of ending illegal activity – the only thing that is missing is the will to make it mandatory globally."

“I am pleased to have SkyTruth’s emblem on my shirt,” Long said in an email several days before the challenge. "Having seen the great work SkyTruth are doing advancing tracking of fishing vessels from space I jokingly said 'Track my ride to Paris?' – I wasn’t expecting a reply of, 'of course!'"

You can see Tony's track on the map below. And you can sponsor Tony's cause by clicking here. 

All Oiled Up... And Nowhere to Go

SkyTruth has been doing a lot of work recently on the problem of tracking vessels way out in the ocean, and figuring out what they're doing.  A useful level of "maritime domain awareness" is key to effectively managing marine protected areas, enforcing fisheries laws to reduce the global scourge of illegal fishing, and mitigating pollution and other health and environmental impacts of the inexorable increase in vessel traffic everywhere. Sometimes we see interesting things going on out in the ocean...

Yesterday an article in the Wall Street Journal caught my eye, about an oil tanker full of crude from Kurdistan that has been wandering around in the Mediterranean Sea and eastern Atlantic Ocean in search of a buyer.  Back in June they almost had a deal, but it fell through.  I thought you'd like to see what the tracking data look like for this vessel's peregrinations.  Bjorn, our vessel-tracking expert, prepared these maps using satellite-collected AIS radio-frequency data that tankers are required, by international maritime law, to broadcast.  

I hope this tanker finds a safe port soon to offload this potentially dangerous cargo.  

90-day AIS track (red dots) for oil tanker United Leadership, as of July 22. 

Detail from above.

Detail showing attempted port call in Morocco on July 3 (not June 3, as indicated by the Wall Street Journal), followed by "holding pattern" offshore as the United Leadership operators  ponder their next move.

Smoke Plume in Campos Basin off Brazil - Mystery Solved?

We may now know what caused the large smoke plume we observed on a December 31 satellite image off the coast of Brazil.  We learned that repair operations were being done on a pipeline in the Marlim Sul field between two platforms about 10 miles north of the point of origin of the smoke plume.  We're told it is not unusual for a large volume of flaring to be necessary during a pipeline repair operation.  

Using satellite AIS data, David spotted a pipelay vessel, the Normand Seven (here's a painting of the vessel), working in the area on December 31, supporting this information that a pipeline repair project was being conducted.

Teri made this map showing the track of the Normand Seven in late December through early January:

Satellite AIS data (courtesy ExactEarth) showing the track of the Normand Seven in the area where we observed a large smoke plume on December 31.

So... one mystery possibly solved.  Meanwhile, we're still wondering about the oil pollution response activity some 45 miles to the southwest. 

Possible Bilge Dumping, Offshore Brazil

We've been looking at satellite imagery of offshore Brazil regularly since Chevron's November 2011 blowout and spill in the Campos Basin.  Yesterday Teri noticed what appears to be a 40-mile-long, thin slick about 50 miles offshore in the southern part of the Campos oil field, playing hide-and-seek between the clouds and cloud shadows, on a MODIS/Terra satellite image: 

Detail from MODIS/Terra satellite image taken on February 25, 2014, showing apparent bilge-dumping slick from a vessel operating in or passing through the Campos Basin oil field, offshore Brazil. Oil platforms and FPSOs shown as purple dots. Image courtesy of NASA/MODIS Rapid Response Team. 

Given the location, one might suspect this is a leak from one of the many oil platforms or FPSOs in this area, shown as purple dots in the image above.  Petrobras platform Namorado-2 is located close to the north end of this slick. But we think, given it's length and consistent width, this is more likely a bilge-dumping slick or leak from a passing vessel than a leak from a platform.

Is bilge dumping legal in Brazilian waters?  And who is the culprit? There is plenty of coastal shipping activity in this area, including cargo ships that we've caught dumping bilge elsewhere. There is also a lot of tanker traffic here, hauling oil from the FPSOs offshore to storage facilities and refineries onshore, occasionally causing spills here in Brazilian waters.  

If we had to place a bet, we would guess this is bilge dumping from a shuttle tanker serving the Campos Basin oil facilities. Teri is running through the AIS data now to see if she can identify the source of this slick.

Suspected Bilge Dumping off Corsica

We got a tip early this morning from a friend in France that an oil spill had been reported in the Mediterranean Sea off the northwest coast of Corsica.  Today's MODIS images showed nothing of interest.  But we did find a brand-new Landsat-8 satellite image that was taken yesterday (September 2), and it shows two parallel slicks that appear to be bilge-dumping incidents. We've really boosted the contrast in the images below, so you can more clearly see the slicks.

The largest slick is at least 90 km (56 miles) long; at the north end it disappears into clouds and haze. The smaller slick to its west is about 41km (25 miles) long.  Both are very sinuous, suggesting they are at least a day or so old and have been pushed around by the wind and current. 

Bilge-dumping is a definite no-no in the Mediterranean.  Hopefully the CleanSeaNet program is on top of this and will track down the offenders.  Careful study of AIS data might identify the likely culprits. 

Detail from a Landsat-8 satellite image taken on September 2, 2013 (inset) showing likely bilge-dumping slicks off the northwest coast of Corsica.

Detail from above. Bright spot at south end of slick to the west is a large vessel moving to the north; probably not associated with this pollution incident.

Chronic Oil Spill in the Gulf of Mexico Since 2004 - Still Spillin'

The 2013 hurricane season is now upon us, and it's predicted to be a doozy this year.  Which got us to thinking...

Remember that strange, persistent little oil slick about 12 miles offshore that SkyTruth discovered on satellite imagery during the BP oil spill in 2010, that was NOT related to the BP / Deepwater Horizon disaster?

Remember how SouthWings  flew photographer J. Henry Fair out there and came across a deepwater drill rig with a miles-long oil slick next to it?

Oil slick at the Taylor Energy chronic leak site in Gulf of Mexico, June 5, 2010.

When we published this, an interesting story emerged:  we had found a chronic, continuous oil spill in the Gulf emanating from oil wells that were serviced by a platform at this location.  "Platform 23051" as we called it (because that's how it was identified by government data), no longer existed: it had been hit by a seafloor mudslide triggered by Hurricane Ivan waaaay back in September 2004.  That's right, six years earlier.  And the damaged wells, now buried under the mud, were being slowly found, re-entered and plugged with cement by their owner -- an LLC named Taylor Energy Company -- using a leased drill rig called the Ocean Saratoga.

The rig disappeared for a while, then re-appeared in November 2010.  It was still on the scene in March 2011, when Greenpeace flew over the site and took some photos. But we had indications from AIS vessel-tracking data that the rig had departed by June 2011.  Periodic aerial overflights conducted by Gulf Monitoring Consortium and On Wings of Care, and radar satellite images acquired since June 2011, have shown no rig working to plug the wells since Ocean Saratoga's departure. The May 2013 status report from Diamond Offshore shows  the rig is contracted to work elsewhere.  

One thing, however, has remained constant at the site: it's still leaking oil and forming a persistent, miles-long slick that is routinely visible on satellite images. Occasionally it reaches out more than 20 miles from the source.

Taylor is required to report the size and location of their oil slick to the Coast Guard's National Response Center on a daily basis.  We've compiled all of their reports, as well as our own observations from overflights and satellite imagery.  What we see on satellite images consistently contradicts Taylor's own reports, suggesting they are systematically and significantly underreporting the size of the slick.  And our analysis shows that the total spill from the Taylor site may have exceeded 1 million gallons by February 2012. 

In 2013 the satellite experts at NOAA began to report their analyses of the Taylor slick to the NRC as well (the first report we noticed from NOAA came on April 7).  They, too, are reporting slicks significantly bigger than what Taylor is reporting.  The latest example:  on June 1 at 9:00am, Taylor reported a slick 200 feet wide and 6.5 miles long.  But NOAA reported a slick 1 mile wide and 20.2 miles long on a satellite image taken at 11:45am, less than three hours later.  NOAA's slick is more than 80 times bigger than what Taylor reported.  And if we assume the slick is, on average, only 1/1000th of a millimeter (1 micron) thick, that amounts to at least 13,800 gallons of oil on the water.  Yet the federal government has publicly stated that the leaking wells cumulatively spill only about 14 gallons per day.

We assume NOAA analysts were looking at this MODIS/Terra satellite image taken at 11:45am local time on June 1.  We measure the observable slick to be 21.4 miles long, reaching a maximum width of just over 5,100 feet but tapering to less than 1,500 feet at each end. Still, significantly bigger than Taylor reported:

Detail from MODIS/Terra satellite image taken at 11:45am on June 1, 2013, showing slick (bright line) apparently emanating from site of chronic leak since 2004.

Measurement shows slick extends more than 21 miles from the source.

Something's fishy here.  But no matter whose numbers you believe, one nagging question is begging to be answered:  When are these wells going to be permanently plugged?  As time goes by, it looks like the answer is "never -- we're going to let them leak until the reservoir effectively bleeds out." How can this be acceptable to federal government regulators and the politicians of Louisiana? 

Those rushing to embrace drilling in the waters off Virginia, Alaska and elsewhere in the US might want to slow down and take a good hard look at this ongoing travesty in the Gulf.  

95-Mile-Long Slick in the Gulf of Mexico?

This report on SkyTruth's handy pollution Alerts system caught my eye yesterday afternoon:

SUSPECTED SLICK IS SEEN AS LONG NARROW PLUME APPROXIMATELY 95 MILES LONG AND 1 MILE OR LESS WIDE.

That sounds like bilge-dumping from a passing vessel -- an activity that is illegal in US waters (and much of the rest of the world).   Intrepid SkyTruth intern Patrick busted somebody for bilge-dumping off Angola last year using satellite radar imagery and AIS data.  The report was submitted to the Coast Guard-operated National Response Center by image analysts at NOAA.  We're thrilled that they've started reporting their analyses of possible pollution incidents to the NRC, so we can easily incorporate them into our Alerts system.  (We like to think our Gulf Monitoring Consortium activity helped spur NOAA to get their experts into the game in a more public way.)

NOAA's analysts now think it's probably not oil; more likely it's natural surfactant caught in the convergence zone between two water masses.  I agree; this is close to the edge of a loop current now in the northeastern part of the Gulf.  And bilge-dump slicks usually look a lot sharper than this (see a slideshow of our examples from radar imagery). 

Here's detail from a MODIS/Terra satellite image taken at 16:50 UTC on April 14, 2013, showing the apparent slick.

Location map showing detail from MODIS/Terra satellite image taken on April 14, 2013.

Detail from MODIS/Terra satellite image of slick (dark, east-west trending streak) probably caused by natural surfactants accumulating along the convergence zone between ocean currents.

Bilge Dumping off Vietnam - February 22, 2012

We've posted about bilge dumping before - the practice of flushing the oily slop out of your vessel, straight into the ocean.  It's illegal in a lot of places, but it is very hard to enforce.  SkyTruth's daily offshore monitoring program just caught this fine (awful?) example of bilge dumping off the coast of Vietnam, in a major north-south shipping lane about 115 miles offshore: 

Envisat ASAR satellite radar image off Vietnam, February 22, 2012. Image courtesy European Space Agency.

Zooming in on those black streaks, and turning the image west-up, here's a closer look at this mess:

Envisat ASAR image courtesy European Space Agency.

More images and analysis after the jump....