Remote Sensing Applications

Signatures a unique identifier

Computer Display of Remote Sensing ImagesIndividual bands of satellite data are mapped to the three color guns Color guns red, green, blueAt most, 3 bands can be displayed at once

Displaying multispectral (mulitiple bands) data:Different color gun (red, green, or blue) assigned to each bandCombination of red + green + blue for each pixel produces color image

Displaying panchromatic (single band) data: Single band sent to the each of the red/green/blue color guns produces greyscale image

3 for the price of 1

Heat Island Effect: Atlanta, GAMeasuring the effect the city has on its environment:Landsat TMLand use classification (bottom)Temperature map (top) computed from thermal bandIssue:Atlanta regularly exceeds the temperature of the surrounding environment by as much as 10 degrees.This extreme difference causes thunderstorms to be generated and promotes ground level ozone.http://svs.gsfc.nasa.gov/stories/Landsat/atlanta_heat.html

Monitoring Urban Growth LandSat image Urban growth in the Washington D.C. metropolitan region 1973-1996Red areas: New urban infrastructure built 1973-1985Yellow: 1985-1990Blue 1990-1996

Impervious Surface Mappinghttp://visibleearth.nasa.gov/view_rec.php?id=1792Baltimore/Washington area Shows extent of impervious surfaces. Red represents high concentrations of impervious surfaces. Blue represents moderate concentrations and green represents low concentrations of impervious surfaces.

Base image: LandSat Impervious surface mapping: Derived from both LandSat & IKONOS satellite data

Mt. Saint Helens1973198319881992Eruption: May 18, 1980 eruptionImages before and after can be used to assess forest regrowth

Finding Fossils from SpaceLandSat ImageRed: band 7 (shortwave infrared)Green: band 4 (near infrared)Blue: band 1 (blue) Vegetation & different rock types stand out clearly in this image target potential fossil sites http://visibleearth.nasa.gov/view_rec.php?id=188

Shell Canyon Ant HillsThe bright sandy patches are deposits from stream meanders that provide trout spawning beds. Wildlife HabitatsPositive Systems, Inc. Both ant hills and prairie dog mounds display a similar and distinct appearance in the imagery

Precision AgricultureWater Deficit Index (WDI): Indicates rate of evaporative water loss from cropped fieldsDetermined from measurements of field temperature and the spectral vegetation index measured by Landsat Thematic Mapper (TM)Tool for water conservation can be used to monitor the efficacy of irrigation and identify fields where evaporative water loss is greatest.

Noxious Weed MapsThe figure at left is an example of a mapping project in the Northwestern United States. The purple pixels represent the values that are within the spectrum of spotted knapweed.

Assessing and Monitoring Grass and Forest FiresASTER image (7/2001)13 years after fires burned > 1.6 million acres in Yellowstone National Park, the scars are still evident. Burned areas appear gray, unburned forests dark green.

http://asterweb.jpl.nasa.gov/gallery-detail.asp?name=yellowstonepark

1999 Landsat Image Yellowstone Park Boundary plainly visible in this 1999 Graphically represents differences in managerial policies among governmental agencies of the Greater Yellowstone Ecosystem

Monitoring Deforestation197519861992Light blue: Deforested land & urban areas Red: Healthy vegetation

Dust Storms

Polar Ozone HoleTOMS: Total Ozone Mapping SpectrometerSouth Polar ozone hole imageCentered on Antarctica

EM radiation interacts with physical matter; some wavelengths are absorbed & some are reflectedDetermine/estimate matter type by analyzing spectral signatures in satellite data

Land use types are classified in ten categories, with dark grey being urban areas, light grey for suburban areas, shades of green showing various evergreen and conifer tree coverage, grassy areas, golf courses, and agriculture, while orange shows deciduous trees, and blue shows water. In the thermal band "floating" over the city, blue represents cooler areas, shades of yellow express intermediate temperatures, and red shows hotter areas. Researchers used data from LandSat like this shown above to measure the effect the city has on its environment. The strong correlation between urban and suburban areas and enhanced temperatures is easily seen. New urban growth in the area tends to concentrate along existing transportation routes, particularly in the outer suburbs of Virginia and Maryland that were largely agricultural just a few decades ago.

Scientists are using a major advance in satellite-based land surface mapping to create more accurate and detailed maps of our cities. These maps provide urban planners with a better understanding of city growth and how rainfall runoff over paved surfaces impact regional water quality. These space-based maps of buildings and paved surfaces, such as roads and parking lots, which are impervious to water, can indicate where large amounts of storm water runs off. Concentrated runoff leads to erosion and elevated discharge of soil and chemicals into rivers, streams, and ground water.Andrew Smith, a faculty research assistant at the Mid-Atlantic Regional Earth Science Applications Center produced a map of the Washington-Baltimore area that quantifies how much impervious surface there is across the entire region. Baltimore and the counties that border it have at least 20 percent, and up to 40 percent, impervious surface area, indicating that pollution from runoff could be a problem. North is up in all these images. The 1973 LandSat 1 image used MSS bands 7, 5, and 4 (called MSS 4, 2, and 1 on the later LandSat satellites) displayed as red, green, and blue respectively. The other images mapped TM bands 4, 3, and 2 to red, green, and blue. This color combination is often referred to as "false color infrared" since it has a similar appearance and tone to color infrared photography. Reds represent vegetation, greys are exposed land, and light blues show snow on the peaks of Mt. St. Helens and neighboring Mt. Adams. The Columbia River snakes into view in the lower left corner, just north of Portland, Oregon.

In this image of WDI at the University of Arizona Maricopa Agricultural Center, one can determine that the cotton in the northern part of Field 7 was being irrigated during the overflight, resulting in the bright green color in contrast with the yellow color of the drier cotton and the red color of fallow fields.

These images show a portion of the state of Rondnia, Brazil, in which tropical deforestation has occurred. The 1975 and 1986 images are MSS data. The 1992 image is TM data. Approximately 30% (3,562,800 sq km) of the world's tropical forests are in Brazil. The estimated average deforestation rate from 1978 to 1988 was 15,000 sq km per year. Systematic cutting of the forest vegetation starts along roads and then fans out to create the "feather" or "fishbone" pattern shown in the eastern half of the 1986 image.Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project is to provide quantitative data on global ocean bio-optical properties to the Earth science community. Subtle changes in ocean color signify various types and quantities of marine phytoplankton (microscopic marine plants), the knowledge of which has both scientific and practical applications. Since an orbiting sensor can view every square kilometer of cloud-free ocean every 48 hours, satellite-acquired ocean color data constitute a valuable tool for determining the abundance of ocean biota on a global scale and can be used to assess the ocean's role in the global carbon cycle and the exchange of other critical elements and gases between the atmosphere and the ocean.