This image shows the land cover types of the United States in different
colors. Each land cover type plays a different role in carbon, climate, and
water cycles. Land cover maps help scientists understand how human and
natural activities affect the Earth system.
Midwest
Grasslands that once covered much of the central United States have been
converted to agricultural land. Expanding human populations will increase
pressure on grassland ecosystems, and land cover mapping will be necessary
to monitor both the extent and quality of farmland as well as to protect
important plant and animal habitat.
Northeast
Urban growth is a key land cover issue for the Northeast. Baltimore and
Washington appear to be growing into a single urban corridor, replacing the
few remaining patches of forest and mixed vegetation landscapes. Recent
evidence that urbanization alters climate and rainfall patterns means
mapping the urban areas will be important for land use planning and regional
weather forecasting.
Northwest
The expansive forests of the Pacific Northwest are an important ecological
and commercial asset. Land cover mapping helps assess forest extent and
quality. While urban sprawl may be the concern near Seattle, on the eastern
slopes of the mountains, water availability for dry-land farming across the
Columbia River Plateau is key.
Rocky Mountains
Evergreen forests cover the slopes of the Rockies, while lowlands receive
less moisture and support grasslands to the east and open shrublands to the
west. Land use planners are battling urban sprawl along the Front Range in
Colorado. Although dominated by Denver, other areas north and south hint at
a rapidly expanding urban corridor. Land-cover mapping at the wildland-urban
interface is important for resource management in fire-prone areas.
Southeast
Farmlands and forests dominate the Southeast. Mapping land cover along
coastal regions will become increasingly more important if sea levels
continue to rise. In southern Florida, a blue patch of land marks one of the
U.S.' largest remaining wetlands-the Florida Everglades. Its proximity to
the Miami urban corridor to the east means land cover and land use must be
carefully observed to maintain ecosystem quality.
Southwest
Open shrubland dominates the semi-arid Southwest, with considerable amounts
of barren or sparsely vegetated land as well. Different land cover types
have varied influences on the regional water cycle. In an area where
moisture is in short supply, large urban areas such as Los Angeles and
agricultural areas must carefully plan water use. Accurate mapping of land
cover is critical to regional climate models that forecast water resources,
as well as for resource management in fire-prone areas, particularly at the
wildland-urban interface.
South-central US
The Mississippi River Valley looks vastly different than it would have three
hundred years ago. Millions of acres of wetlands have been lost as humans
have altered the river and its flood plain to create agricultural land along
the river, contributing to catastrophic floods. Mapping land cover along
river systems helps scientists predict where floods are likely to occur and
to plan land cover change carefully.
Launched December 18, 1999, Terra is the flagship of the Earth Observing
System series of satellites and is a central part of NASA’s Earth Science
Enterprise. The mission of the Earth Science Enterprise is to develop a
scientific understanding of the Earth system and its response to natural and
human-induced changes to enable improved prediction capability for climate,
weather, and natural hazards.
Images by Boston University and NASA Goddard Space Flight Center
For more information and images, see: http://geography.bu.edu/landcover/index.html
Lynn Chandler
Goddard Space Flight Center, Greenbelt, Md.
(Phone: 301/286-2806)
Lynn.Chandler.1@gsfc.nasa.gov
Bob Zalisk
Boston University, Boston, Mass.
(Phone: 617/353-7628)
bzalisk@bu.edu |