The Landsat 7 satellite was launched successfully on April 15, 1999. NASA and the U.S. Geological Survey (USGS) are jointly managing the program. Landsat 7 is extending the medium-resolution global land coverage that has been the hallmark of the Landsat program since 1972. A complete global archive of relatively cloud-free coverage was collected during the first 6 months of operation; such coverage has not been achieved in nearly a decade. All Landsat 7 data received at the primary ground station at the USGS Earth Resources Observation System (EROS) Data Center are being archived and made available to the public in digital format within 24 hours of collection.

The USGS EROS Data Center Earth Observing System Distributed Active Archive Center, which is funded by NASA, supported four missions in 1999, including the prelaunch, instrument checkout, and operations activities of Landsat 7 and the prelaunch and operations readiness activities in support of the Terra mission. USGS staff participated in the calibration of the Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer instrument that is collecting information on Earth's environment.

The USGS Astrogeology Program continued to make significant contributions to the exploration of the solar system. NASA's Galileo mission to Jupiter continued to return exceptional images of Io and other Jovian satellites that give major insight into the surficial processes at work on those moons. The Deep Space 1 spacecraft returned image and spectral data from a near-Earth asteroid, leading to new knowledge that perhaps the near-Earth asteroid Braille is related to the much larger and well-studied asteroid Vesta, perhaps as a "chip off Vesta's old block" or as a "sibling" from a larger body that has long since been destroyed.

USGS scientists contributed to all these astrogeology efforts. USGS scientists involved with the Mars Orbital Camera and the Thermal Emission Spectrometer teams of NASA's Mars Global Surveyor mission continue to make observations of surface landforms and composition through those instruments, and they also assist in the selection and monitoring of specific targets on Mars. Unfortunately, the Mars Exploration Program suffered a huge setback with the losses of the Mars Climate Orbiter and the Mars Polar Lander: Two USGS Astrogeology Program scientists have been asked to serve on the Mars Program Independent Assessment Team, which will make recommendations on future Mars exploration strategies.

DoI continued to utilize both the DoD Navstar GPS Precise Positioning Service (PPS) and augmented differential GPS for real-time positioning in wildland areas. Laser rangefinders have also been linked directly to GPS receivers to assist in field work for remote positioning in dangerous or inaccessible terrain. DoI continued to assist the DoT-DoD efforts to expand the Nationwide Differential GPS (NDGPS) by identifying project areas that are out of reach of current differential GPS methods. DoI GPS coordinators continued to identify DoI requirements for specifications of future improvements to military handheld GPS receivers.

The Multi-Resolution Land Characterization Project, a joint activity of the USGS, the Environmental Protection Agency (EPA), NASA, NOAA, and other agencies, had produced medium-resolution, land-cover data from Landsat data for 41 States by the end of FY 1999. The USGS Global Land Cover data base (known as the DISCover land cover layer), which is derived from AVHRR satellite data, is the first and only global land cover data base to have a statistically based accuracy assessment. Validation was completed in FY 1999 with an average accuracy of 73.5 percent per land-cover category.

The Office of Surface Mining Reclamation and Enforcement (OSMRE) employed GPS in various initiatives in FY 1999. OSMRE used GPS to locate acid seeps as part of its Appalachian Clean Streams Initiative. The Mountaintop Removal Task Force used GPS to locate mine features in the field. GPS mapping saved time and design costs at the Coal Basin reclamation project in cooperation with the State of Colorado. OSMRE and the State of Pennsylvania have monitored the surface effects of longwall mining with GPS techniques.

The Bureau of Indian Affairs (BIA) used remote sensing and GPS to support BIA and tribal initiatives to map land use, inventory natural resources, and conduct environmental assessments. Digital orthophotography and National Aerial Photography Program (NAPP) aerial photography were used as backdrops to model potential flood inundation zones caused by the failure of BIA-managed dams and to delineate the extent of irrigated agricultural lands within BIA irrigation districts on Indian reservations in the Western United States. Digital orthophotography and color-infrared NAPP photography were used to create maps to support the clearing of military ordnance from the Badlands Bombing Range, Pine Ridge Reservation, South Dakota. Landsat 7 data were enhanced to map the perimeter and relative burn intensity of several large wildfires in Nevada as part of a joint BIA-Bureau of Land Management firefighting effort. The BIA also expanded the applications of both civilian and military (encrypted) GPS receivers in natural resource planning, inventory, and mapping.

The National Park Service (NPS) used Landsat and Satellite Pour l'Observation de la Terre (SPOT) data, along with conventional aerial photography and digital orthophotography, to map and monitor land cover, vegetation, cultural features, and other specific features in many National Parks, from Alaska to Florida. Approximately 400 GPS units were used to support mapping and navigation needs for a variety of resource management and maintenance applications.

The USGS cooperated with the NPS in FY 1999 to use aerial photography and extensive field data to classify and map vegetation communities in Fort Laramie National Historic Site, Wyoming; Agate Fossil Beds National Monument, Nebraska; and Wind Cave National Park, South Dakota. The Gap Analysis Program cooperated with State and local partners to complete its analysis of the conservation status of vertebrates and plant communities in 14 States, using Landsat data, wildlife habitat surveys, and extensive field sampling. Other research efforts employed various types of telemetry to track terrestrial and marine wildlife and assess habitat use and availability. Hyperspectral imaging was used to detect and map invasive plants.

The Minerals Management Service (MMS) used GPS as part of a U.S.-Mexico boundary survey to identify shoreline points to calculate the part of a proposed offshore boundary that is not already legally defined. The MMS also supported the analysis of AVHRR data and altimetry data from the Ocean Topography Experiment (TOPEX) and European Remote-Sensing Satellite-1 (ERS-1). Partners included the Scripps Institution of Oceanography (La Jolla, California), Louisiana State University, the University of South Florida, and Texas A&M University.

Remotely sensed data from satellites and aircraft sensors and GPS technology continued to play an important role in the Bureau of Land Management's efforts to sustain the health, diversity, and productivity of the public lands. The data provided critical information to resource specialists for their inventory, assessment, modeling, and monitoring efforts. Data from traditional and digital aerial cameras and multispectral and hyperspectral sensors were supplemented by Geographic Information System (GIS) technology to support management activities associated with wildlife habitat, wilderness, recreation, rangeland, timber, fire, minerals, and hazardous materials.

The U.S. Fish and Wildlife Service (FWS) found innovative ways to use GPS and aircraft for the rapid creation of data bases from field data for wildlife and habitat inventories. For example, the Office of Migratory Bird Management has implemented a data recording system that automatically incorporates GPS locations for all aerial waterfowl survey observations and generates a ground track of the aerial flight path. FWS offices regularly use GPS units for navigation, both on water bodies and in roadless areas. GPS units are also used to create data layers for use in GIS programs, particularly marking facility locations and boundaries of management activities such as controlled burns, wildfires, and hunting units.

The USGS National Civil Applications Program (NCAP) provides secure facilities for Federal civil agencies to acquire and process classified satellite data for applications such as land and resource management, global change research, environmental monitoring, and disaster detection and mitigation. In 1999, NCAP staff and the Department of Defense continued to test the prototype Hazard Support System, which will provide near-real-time warnings of wildland fires in the United States, and to monitor and report on volcanic activity and associated volcanic ash clouds worldwide. The Global Fiducials Library became operational, providing the scientific community with digital classified satellite data collected over selected worldwide sites for long-term environmental monitoring.

The USGS used satellite data to measure the volumetric changes of glaciers in Washington and Montana. These measurements enhanced the USGS Benchmark Glacier program that focuses on the response of glaciers to climate changes. The program continued to be carried out in cooperation with the NPS at North Cascades and Glacier National Parks. The USGS used RADARSAT and ERS-2 Synthetic Aperture Radar (SAR) images to monitor the catastrophic retreat under way at the Columbia Glacier in Prince William Sound, Alaska. Compared to Captain George Vancouver's observation from two centuries ago, Columbia Glacier is the only remaining tide water glacier in southern Alaska that had not retreated. In cooperation with glaciologists at the University of Colorado, the USGS used a combination of SAR images and vertical aerial photography to measure the glacier dynamics in the critical terminus region.

The USGS developed an algorithm that incorporates the effect of grain size growth to extract snow depth from the passive microwave observations obtained by the Special Sensor Microwave Imager (SSM/I) on the Defense Meteorological Satellite Program (DMSP) satellite. The brightness temperature of a snow pack in the microwave wavelength bands depends not only on the snow depth but also on the internal snow pack properties, particularly the grain size, which is highly variable through the winter. Previous algorithms did not include this effect and have yielded erroneous estimates of snow depth. This algorithm is being used in a joint USGS-NASA study of the fresh water input to the Arctic Ocean that results from the melting of the Siberian snow pack. Fluctuations in the snow pack may influence the response of the Arctic Sea ice cover to anticipated global warming.

Interferometric Synthetic Aperture Radar (InSAR) data were used to detect and measure land-surface displacements in the Las Vegas (Nevada) and Santa Clara (California) valleys caused by the deformation of ground-water aquifer systems caused by hydraulic stresses, such as seasonal and long-term changes in ground-water pumping. These data have also revealed the presence of previously unmapped faults in urban areas, such as an extension of the Silver Creek fault in downtown San Jose, California.

The USGS Volcano Hazards Program expanded its use of remotely sensed data in FY 1999. Applications include surface deformation monitoring, thermal monitoring, detection and tracking of volcanic ash clouds, and topographic mapping. Networks were expanded at two hazardous volcanoes sites, Long Valley, California, and Mauna Loa, Hawaii, that use GPS to monitor deformation. Hawaii Volcano Observatory scientists cooperated with scientists at the University of Hawaii to test the use of GOES thermal imagery from the Internet to monitor the ongoing eruption at Kilauea. Imagery was successfully acquired from classified sources to produce a new, detailed digital elevation model of Augustine Volcano.

USGS scientists applied satellite-based InSAR techniques to study volcanoes in Alaska by producing deformation measurement at tens-of-meter horizontal resolution with centimeter to subcentimeter vertical precision. Using this technique, scientists discovered that the center of Okmok Volcano subsided 140 centimeters as a result of the 1997 eruption. It was also demonstrated that Westdahl Volcano has been inflating with magma since 1992. Based on the timing of recent eruptions at Westdahl and the fact that it has been inflating for 7 years, a new eruption can be expected within the next several years. As we increase our understanding of the use of satellite interferometry to detect inflation at volcanoes that appear inactive, we will improve our ability to anticipate volcanic eruptions and, thus, to mitigate volcanic hazards.

The USGS Alaska Volcano Observatory continued to utilize up-to-the-minute satellite data and computer modeling techniques to monitor volcanic ash clouds that spread into the atmosphere thousands of feet above Earth's surface as a result of volcanic activity in the North Pacific region. The proximity of more than 40 active volcanoes in Alaska to the Anchorage International Airport, the largest cargo-handling facility in the United States, has created a potentially dangerous situation. In FY 1999, the Observatory provided information about airborne volcanic ash from several eruptions to the FAA, U.S. Air Force, and National Weather Service to assist in aircraft hazard mitigation and weather forecasting.

The USGS National Water Quality Assessment (NAWQA) program used color-infrared and black-and-white NAPP aerial photographs to create high-resolution rectified digital images to map land-use boundaries within a 500-meter buffer area around water wells that are part of the NAWQA ground-water quality monitoring network. USGS personnel continued to utilize the land-use delineations to define relationships between land-use characteristics and ground-water quality.