Studies of the Planet Earth
Oceanographic Studies and Applications
Launched in August 1992, the joint U.S./French satellite TOPEX/Poseidon demonstrated a new way of monitoring global mean sea-level variations. The satellite used a radar altimeter to measure sea-surface height very precisely and made global observations of the sea level every 10 days. The satellite not only monitored the mean sea-level change, it also told scientists where the change occurred, allowing researchers their first opportunity to study the natural causes for short-term sea-level variations and distinguish them from broader effects. On the basis of 3 years' worth of continuous measurements, the satellite detected sea-level rise at a rate of 4 millimeters per year. This is a critical new observational capability for climate research.
A major study used new computer models and data from the 10-year Tropical Ocean Global Atmosphere-Coupled Ocean-Atmosphere Response Experiment, an international research program that studies how Earth's oceans and atmosphere affect one another to make yearly predictions of equatorial Pacific sea-surface temperatures and related changes in precipitation patterns. One of the main targets of this research has been the El Niño, a climate disturbance that occurs every 2 to 5 years in the Pacific Ocean. Recent El Niño events may have played a key role in sea-level rise over the past 3 years. This effort also has helped explain the rise in sea levels.
The NOAA Satellite Ocean Remote Sensing (NSORS) program was begun during FY 1995 and is an integrated effort involving ocean data from NOAA polar and geostationary satellites, as well as several other space-based systemsthe Defense Satellite Meteorological Program, Canada's Radarsat, classified DoD data, and Japan's Advanced Earth Observing Satellite (ADEOS). NSORS involves data acquisition, algorithm development, calibration/validation, product development, product operations, user access/exploitation, and archival activities. During FY 1995, NOAA created an NSORS Implementation Plan and an Internet home page. In addition, NOAA personnel prepared hardware and communications equipment for the reception of Radarsat and ADEOS data; developed experimental ocean-surface wind products for operational customers; contracted for four instruments to be flown on NOAA aircraft for ADEOS validation; and electronically provided remapped GOES visible imagery prototype products in near real time for the U.S. east coast, Great Lakes, and Gulf of Mexico. NOAA scientists began developing new products from future ocean color sensors, initially limiting these products to the ocean areas around the coastal waters of the United States.
During FY 1995, NOAA increased by 30 percent the number of CoastWatch applications (now approximately 250) signed with users of CoastWatch data. CoastWatch, a long-standing NOAA program now under NSORS, uses high-resolution, near-real-time polar satellite data, covering all U.S. coastal areas, to measure sea-surface temperature and reflectance for monitoring river outflow and tracking oceanic features, including "red tide" events and locations of temperature-sensitive fisheries.
Following the launch of NOAA-14 during FY 95, NOAA defined new algorithms for the computation of global sea-surface temperature observations from the AVHRR. Researchers increased global sea-surface temperature observations by improving cloud detection in the areas of the ocean affected by glare from the Sun.
Also in the area of oceanographic studies, work continued on the multi-agency Comprehensive Ocean-Atmosphere Data Set project to provide an updated reference data set covering the world's ocean environment. Specific FY 1995 accomplishments included entering data for 3.5 million U.S. Merchant Marine observations for the 1912-1946 period and the establishment of an agreement with China to enter data for the U.S. Maury Collection, which consists of 19th century ship observations.
NASA, NOAA, and the Navy held discussions on the possible merger of the NASA/French space agency (CNES) TOPEX/Poseidon Follow-On (TPFO) mission with the second Navy Geodetic/Geophysical satellite (Geosat) mission. NASA and the Navy agreed to proceed with the NASA TPFO mission, modified to meet the Navy's tactical requirements. The Navy completed the critical design review for the Geosat Follow-On satellite in August 1995. Researchers expect this radar altimeter satellite to provide timely, worldwide, and very accurate measurements of ocean topography via direct readout to ships at sea and selected shore sites.
Curator: Lillian Gipson|
Last Updated: September 5, 1996
For more information contact Steve Garber, NASA History Office,