geocam2s.jpg (16528 bytes)

The View from Space

Photographic analyses of land use practices give insight into changes. Linear functions can be used to project the rate of future change. As growing human population requires an ever-increasing share of the Earth's surface on which to live, human activities change the distribution of plants and animals, alter drainage patterns, and modify natural boundaries. In doing so, mankind changes either the reflective or emissive properties of the surface. Such changes are detectable from space. Human actions that change the reflectance or color of the Earth's surface can be recorded with space photography. Activities include:

apollo8.jpg (17929 bytes)

On the Way to the Moon, Man Discovered the Earth

Earthrise from Apollo 8

  • DEFORESTATION. Forests are optically dense, green areas. The cutting of the trees produces a more reflective surface and exposes a different color. Deforestation scars are seen in the rain forests throughout the world. Forests are often cleared by setting fire to the vegetation, and smoke from these fires is visible from space.
  • URBANIZATION. Urban areas are delineated by highly reflective paved surfaces. Because the growth of cities is at the expense of vegetated surfaces, the increase in reflectivity can be measured.
  • FLUVIAL SEDIMENT LOADS. Clear cut forestry practices in many tropical countries have altered the sedimentary load of the rivers that drain the forest. Rivers loaded with sediment have a different color than "clean" rivers that drain forested areas. Sediment laden rivers, such as the Betsiboka River of Madagascar, are now red-brown when seen from space.
  • DESERTIFICATION. The reflective surface of deserts and eolian sediment patterns are also visible from space. The encroachment of deserts over once vegetated surfaces will register a shift in the optical and textural character.
  • COASTAL EROSION. Analysis of the position of the coastal features can be used to determine the rate and location of large-scale coastal changes. Dramatic rates of erosion can be seen on the edge of the Nile and Ganges river deltas.
  • LAKE LEVELS. Changes in boundary relations can detect variation in water levels in lakes (e. g., Lake Chad) or inland seas (e.g., Aral Sea).
  • WETLANDS. The delineation of wetlands is sometimes difficult. Changes in vegetation color and the sea land boundary are sometimes needed to detect loss.
globals.jpg (14138 bytes)

sect4.jpg (1938 bytes)

Last Section

Next Section

sect6.jpg (3166 bytes)

Payload Design

Earth Observation & Education

geocam2t.jpg (5419 bytes)

Back to Table of Contents

info.gif (2143 bytes)