This is the first global map of ocean surface topography produced with data from the new interleaved tandem mission of the Jason-1 and Ocean Surface Topography Mission (OSTM)/Jason-2 satellites.
In January 2009, Jason-1 was maneuvered into orbit on the opposite side of Earth from its successor, OSTM/Jason-2 satellite. It takes 10 days for the satellites to cover the globe and return to any one place over the ocean. So, in this new tandem configuration, Jason-1 flies over the same region of the ocean that OSTM/Jason-2 flew over five days earlier. Its ground tracks fall mid-way between those of Jason-2, which are about 315 kilometers (195 miles) apart at the equator.
Working together, the two spacecraft measure the surface topography of the ocean twice as often as would be possible with one satellite, and over a 10-day period, they return twice the amount of detailed measurements. Combining data from the two satellites makes it possible to map smaller, more rapidly changing features than one satellite could alone.
This image shows sea-level anomaly data from the first 14 days of the interleaved orbit of Jason-1 and OSTM/Jason-2, the period beginning on Feb. 20, 2009. An anomaly is a departure from a value averaged over a long period of time.
Red and yellow are regions where sea levels are higher than normal. Purple and dark blue show where sea levels are lower. A higher-than-normal sea surface is usually a sign of warm waters below, while lower sea levels indicate cooler than normal temperatures. The small-sized patches of highs and lows are ocean eddies, the storms of ocean weather that carry most of the energy of ocean circulation. These are not well observed with only one satellite.
Jason-1 is a joint mission of NASA and the French space agency, CNES. The U.S. portion of the Jason-1 mission is managed by JPL for NASA's Science Mission Directorate, Washington, D.C.
OSTM/Jason 2 is an international endeavor with responsibility for satellite development and launch shared between NASA and CNES. The U.S. National Oceanic and Atmospheric Administration (NOAA) is responsible for satellite operations, and JPL is managing the mission for NASA. Data processing is being carried out by CNES, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and NOAA.