Civil Space Missions
Only from space can we observe Earth’s vast oceans on a truly global scale, to monitor critical changes in ocean currents, heat storage, and other characteristics that tell us how the oceans moderate Earth’s climate. The National Oceanic and Atmospheric Administration and other sponsors rely on JPL synoptic observation capabilities.
NASA, NOAA (National Oceanic and Atmospheric Administration), and our European partners track global ocean surface topography: the shape of the sea surface. This information helps us understand and foresee the relationship between ocean changes and hurricane intensity, weather-driving patterns such as El Niño and La Niña, and climate.
JPL brings NASA radar technology into operational use for a NOAA–European partnership that has monitored sea-surface height and shape from space for many years.
These agencies’ joint sea surface monitoring began with TOPEX (Ocean Topography Experiment)/Poseidon in 1992. It continues today from 1336 km overhead with Ocean Surface Topography Mission/Jason-2, and Jason-3 will continue this altimeter satellite series. A radar altimeter measures the distance between satellite and sea by precisely monitoring the round-trip travel time of microwave pulses reflected off the sea surface. The sea surface figure is calculated to ranges of a few millimeters to a few centimeters from measurements of the satellite’s orbit altitude by a global network of ground receivers. In addition, the detailed shape of the returned radar pulses yields information on wind speed and wave height.
FORMOSAT-7/COSMIC-2 (Constellation Observing System for Meteorology, Ionosphere, and Climate) is a collaborative mission among the U.S. Air Force, NOAA, JPL, and Taiwan’s National Space Organization. The mission comprises a constellation of 12 satellites collecting atmospheric temperature and water-profile data. Using the highly accurate radio occultation measurement technique, it will improve weather prediction and advance research into the Earth’s ionosphere, climate, and weather.
JPL’s participation is the TriG (Tri–Global Navigation Satellite System) instrument, which uses all three international navigation signals (Global Positioning System, Galileo, and Global Navigation Satellite System) to enable precision orbit determination for the satellites. NASA funds TriG development for COSMIC-2; the Air Force procures the TriG units and the constellation’s launches; and Taiwan’s National Space Organization procures the spacecraft and integrates the TriG instruments onto them. The first launch of six satellites is planned for 2015, with the remaining six in 2017.