Follow this link to skip to the main content
NASA Jet Propulsion Laboratory California Institute of Technology
JPL - Home Page JPL - Earth JPL - Solar System JPL - Stars and Galaxies JPL - Science and Technology
Bring the Universe to You: JPL Email News JPL RSS Feed JPL Podcast JPL Video
MISR - Multi-angle Imaging SpectroRadiometer
 Get Data
Latest MISR Imagery
A Collection of MISR Imagery
Suggest an Image
MISR Instrument
AirMISR Instrument
AIrMISR Flight Imagery
 News and Events
 Ask a Question
 About Us
 Other Resources
A Collection of MISR Imagery
Aerosols over Houston and Galveston Bay
Larger images available View high-res tiff

Aerosols over Houston and Galveston Bay

In the year 2000 Houston officially exceeded Los Angeles as the city with the worst air quality in the United States. Since then, major research has been underway to characterize the type, extent and sources of air pollutants in and around Houston. The Multi-angle Imaging SpectroRadiometer (MISR) is participating in work underway to study Houston's air quality (see These MISR views portray Houston and Galveston Bay on September 12, 2002, and display data from three of MISR's nine cameras along with a map of retrieved aerosol optical thickness.

The left-hand panel is a natural-color view from MISR's vertical-viewing (nadir) camera. The center images cover the same geographic area, from the perspectives of the 70-degree forward-viewing and 70-degree backward viewing cameras. The appearance of haze is enhanced in these oblique views, and the overall area appears significantly brighter in the oblique forward view because the atmospheric particles scatter more sunlight into the forward direction. Due to geometric parallax, clouds appear to move relative to the ground as the view angle changes.

At right is a map of aerosol optical depth, a measure of the amount of aerosol present in the atmosphere and one of several key variables used to characterize their climatic and environmental influence. The extent of haze across Galveston Bay can be identified by the presence of light blue and green pixels, and places where clouds or other factors precluded a retrieval are shown in dark grey. MISR uses the changes in the atmosphere's ability to transmit light and the variation in scene brightness at different viewing angles to retrieve aerosol optical depth, and to deduce some information about particle properties, such as size, shape and composition.

These data are being used as part of the Houston regional air quality study. Airborne pollution particles that contribute to the poor air quality come in part from upwind power plants and petrochemical manufacturing facilities. Over a dozen local observing stations are scattered across the area to monitor air qualtiy. The MISR aerosol data help provide a context into which the particulate pollution sources, the monitoring site observations, and locations downwind, can all be placed.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 14553. The panels cover an area of 380 kilometers x 704 kilometers, and utilize data from blocks 65 to 69 within World Reference System-2 path 25.

Credit: Image credit: NASA/GSFC/LaRC/JPL, MISR Team.
Text acknowledgment: Clare Averill (Acro Service Corporation/Jet Propulsion Laboratory), Ralph Kahn (Jet Propulsion Laboratory).