We’ve been using the new Landsat-8 satellite imagery to help monitor pollution events in the Gulf of Mexico. With a spatial resolution of 25 meters, this imagery is much more detailed than the twice-daily MODIS imagery (250 meters) that we used throughout the BP / Deepwater Horizon spill. But it takes a lot more Landsat images to cover the entire Gulf, and although we’re getting about 8-15 images of the Gulf region per day between Landsat-8 and Landsat-7, that’s not enough for complete daily coverage.
But hey, it’s free.
A Landsat-8 image taken yesterday shows a small, unreported slick in the Eugene Island area about 26 kilometers (15 miles) from the Louisiana coast. About 10 km (6 mi) across, the slick covers about 33 km2. Using our rule of thumb that, to be visible, a slick must be at least 1 micron thick on average, that amounts to about 8,700 gallons of oil or some oily substance:
|Detail from a Landsat-8 satellite image (inset) taken on July 18, 2013, showing a small apparent oil slick (orange outline) in the Eugene Island area off the Louisiana coast. Oil and gas platforms shown as small red dots.|
There are five oil and gas platforms (red dots) within the area of the slick. They all lie within lease blocks 44, 45 and 51. As far as we can tell, no reports of a slick were filed with the National Response Center yesterday, even though this was probably visible to anyone on those platforms (these could all be unmanned — we haven’t checked). See our Alerts map for the NRC reports in this part of the Gulf.
This doesn’t seem to be related to the incident we posted on Facebook yesterday, where a work boat came to port covered with drilling mud from a problem at an Apache drill rig in the Eugene Island Block 136. That’s about 37 km (23 mi) south of this slick.
By the way, here is the MODIS/Aqua satellite image for the same area as shown above, taken the same day at 2:15 pm local time. Heavy clouds obscure the site. This is another advantage of Landsat: it crosses overhead earlier in the day, at about 10:00 am local time. In many places, clouds build up as the day wears on:
|Detail from a MODIS/Aqua satellite image (same area as shown above), taken about 4 hours later on July 18, 2013. Slick outline (orange) shown for reference.|