Multiple cameras on JPL's MISR instrument on NASA's Terra spacecraft were used to create two unique views of oil moving into Louisiana's coastal wetlands. The images cover an area measuring 110 by 119 kilometers (68 by 74 miles).
Image Credit: NASA /GSFC/LaRC/JPL, MISR Team
Dark filaments of oil are seen approaching the shores of Blind Bay and Redfish Bay at the eastern edge of the Mississippi River delta, and also nearing Garden Island Bay and East Bay farther to the south. These areas are home to many varieties of fish. To the north, the arc-shaped pattern of land and runoff is associated with the Chandeleur Islands, which are part of the Breton National Wildlife Refuge. This refuge is the second oldest in the United States and is a habitat for dozens of seabird, shorebird and waterfowl species. Oil is reported to have reached the islands on May 6. Eighteen days later, this image shows filaments of oil crossing the island barrier -- which had been heavily eroded by Hurricane Katrina in 2005 -- and entering the Breton and Chandeleur Sounds.
The left-hand image contains data from MISR's vertical-viewing camera. It is shown in near-true color, except that data from the instrument's near-infrared band, where vegetation appears bright, have been blended with the instrument's green band to enhance the appearance of vegetation.
The Mississippi River delta is located below the image center. The slick is seen approaching the delta from the lower right, and filaments of oil are also apparent farther to the north (towards the top). The oil is made visible by sun reflecting off the sea surface at the same angle from which the instrument is viewing it, a phenomenon known as sunglint. Oil makes the surface look brighter under these viewing conditions than it would if no oil were present. However, other factors can also cause enhanced glint, such as reduced surface wind speed. To separate glint patterns due to oil from these other factors, additional information from MISR's cameras is used in the right-hand image.
Previous MISR imagery of the spill shows that the contrast of the oil against the surroundings is enhanced by using a combination of vertical views and oblique-angle views. The right-hand panel was constructed by combining data from several MISR channels. In this false-color view, oil appears in shades of inky blue to black; silt-laden water due to runoff from the Mississippi River shows up as orange, red and violet; and land and clouds appear in shades of cyan.
Oil from the Deepwater Horizon rig lingered off the Mississippi Delta on July 4, 2010. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image the same day. The oil appears as an uneven light gray shape east-southeast of the delta. The oil was visible to MODIS on July 4 thanks to sunglint. Oil smoothes the surface of the water, making it a better mirror of sunlight. As a result, close to the Sun’s reflection, the oil is lighter than surrounding water. This is especially true between the Mississippi Delta and the Deepwater Horizon rig. East of the rig, however, sunglint lightens most of the water, making it difficult to distinguish a possible oil slick from oil-free water.
Image credit: NASA's Goddard Space Flight Center, MODIS Rapid Response TeamNASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) flew over the Gulf of Mexico to image the Deepwater Horizon oil spill on June 22-23, 2010. The airborne radar, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., currently flies aboard NASA's Gulfstream-III aircraft from NASA's Dryden Flight Research Center, Edwards, Calif. UAVSAR imaged the Gulf coastline from the Florida Keys to Corpus Christi, Texas, and collected data over several areas of open ocean throughout the Gulf. The coastal data will be used in several ways: scientists will study how L-band radars can track the extent that oil from such spills intrudes into coastal and wetland environments. They will assess the impact of oil on different types of vegetation. In addition, they will monitor how ecosystems recover after oil has impacted an area.
Text credit: Michon Scott, NASA's Earth Observatory
Text credit: Michon Scott, NASA's Earth Observatory
The UAVSAR data will be combined with data collected from other remote sensing instruments, such as the JPL-built and managed Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) optical/infrared instrument , to gain complementary and more comprehensive information about the oil spill and its long-term effects on Gulf ecosystems.This false-color composite UAVSAR image from June 23, 2010, shows the southern Louisiana coastline, covering the area around Grande Isle and the entrance to Barataria Bay. The colors in the image reflect the three different UAVSAR radar polarizations: HH (horizontal transmit, horizontal receive) is colored red; VV (vertical transmit, vertical receive) is colored blue; and HV (horizontal transmit, vertical receive) is colored green. Like a pair of Polaroid sunglasses, these images are sensitive to different parts of the radar signal that is parts of the radar signal that is reflected back from Earth's surface. The HV polarization is sensitive to multiple scattering that typically occurs in vegetation. VV polarization is sensitive to scattering from surfaces -- this gives a bluish tint to water and non-vegetated soil. Finally, HH polarization is sensitive to structures and vertical tree trunks -- this gives some urban areas and vegetated regions a reddish tint. Dark areas on the water surface are caused by something that smooths the surface and damps wave activity, such as oil.
For more information on UAVSAR, visit http://uavsar.jpl.nasa.gov/. Image Credit: NASA/JPL--GoogleSource: NASA for complete set of new images visit here.
Jet Propulsion Laboratory, Pasadena, Calif.