Editing Jason-1 (section)

== Use of information ==
[[TOPEX/Poseidon]] and Jason-1 have led to major advances in the science of [[physical oceanography]] and in climate studies.<ref>{{cite web|url=http://www.eumetsat.int/idcplg?IdcService=GET_FILE&dDocName=PDF_JASON2_SCIENCE_OP_REQ&RevisionSelectionMethod=LatestReleased|title=OSTM/JASON-2 SCIENCE AND OPERATIONAL REQUIREMENTS|publisher=EUMETSAT|url-status=dead |archive-url=https://web.archive.org/web/20070928020851/http://www.eumetsat.int/idcplg?IdcService=GET_FILE&dDocName=PDF_JASON2_SCIENCE_OP_REQ&RevisionSelectionMethod=LatestReleased|archive-date=2007-09-28}}</ref> Their 15-year data record of ocean surface topography has provided the first opportunity to observe and understand the global change of ocean circulation and sea level. The results have improved the understanding of the role of the ocean in climate change and improved weather and climate predictions. Data from these missions are used to improve ocean models, forecast hurricane intensity, and identify and track large ocean/atmosphere phenomena such as [[El Niño]] and [[La Niña]]. The data are also used every day in applications as diverse as routing ships, improving the safety and efficiency of offshore industry operations, managing fisheries, and tracking marine mammals.<ref>{{cite web|url=http://www.eumetsat.int/idcplg?IdcService=GET_FILE&dDocName=PDF_JASON2_SCIENCE_OP_REQ&RevisionSelectionMethod=LatestReleased|title=OSTM/JASON-2 SCIENCE AND OPERATIONAL REQUIREMENTS|publisher=EUMETSAT|url-status=dead|archive-url=https://web.archive.org/web/20070928020851/http://www.eumetsat.int/idcplg?IdcService=GET_FILE&dDocName=PDF_JASON2_SCIENCE_OP_REQ&RevisionSelectionMethod=LatestReleased|archive-date=2007-09-28}}</ref> Their 15-year data record of ocean surface topography has provided the first opportunity to observe and understand the global change of ocean circulation and sea level. The results have improved the understanding of the role of the ocean in climate change and improved weather and climate predictions. Data from these missions are used to improve ocean models, forecast hurricane intensity, and identify and track large ocean/atmosphere phenomena such as El Niño and La Niña. The data are also used every day in applications as diverse as routing ships, improving the safety and efficiency of offshore industry operations, managing fisheries, and tracking marine mammals.

TOPEX/Poseidon and Jason-1 have made major contributions<ref>{{cite web|url=http://jpl.nasa.gov/news/press_kits/jason-2.pdf|title="The Legacy of Topex/Poseidon and Jason 1", page 30. Ocean Surface Topography Mission/Jason 2 Launch Press Kit, June 2008|publisher=NASA/JPL}} {{PD-notice}}</ref> to the understanding of:

=== Ocean variability ===
[[Image:Sealevel chart.jpg|upright=1.3|right|thumb|290px|Although the 1993–2005 [[TOPEX|Topex/Poseidon]] satellite (on the left) measured an average annual Global Mean Sea Level rise of 3.1 mm/year, Jason-1 is measuring only 2.3 mm/year GMSL rise, and the [[Envisat]] satellite (2002–2012) is measuring just 0.5 mm/year GMSL rise. In this graph, the vertical scale represents globally averaged mean sea level. Seasonal variations in sea level have been removed to show the underlying trend. (Image credit: University of Colorado)]]

The missions revealed the surprising variability of the ocean, how much it changes from season to season, year to year, decade to decade and on even longer time scales. They ended the traditional notion of a quasi-steady, large-scale pattern of global ocean circulation by proving that the ocean is changing rapidly on all scales, from huge features such as El Niño and La Niña, which can cover the entire equatorial Pacific, to tiny eddies swirling off the large Gulf Stream in the Atlantic.

=== Sea level change ===
{{further|Sea level change}}

Measurements by Jason-1 indicate that mean sea level has been rising at an average rate of 2.28&nbsp;mm (0.09 inch) per year since 2001. This is somewhat less than the rate measured by the earlier [[TOPEX |TOPEX/Poseidon]] mission, but over four times the rate measured by the later [[Envisat]] mission. Mean sea level measurements from Jason-1 are continuously graphed at the [http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/products-images/index.html Centre National d'Études Spatiales] web site, on the [http://www.aviso.oceanobs.com/fileadmin/images/news/indic/msl/MSL_Serie_J1_Global_IB_RWT_NoGIA_Adjust.png Aviso page]. A composite sea level graph, using data from several satellites, is also available on [http://www.aviso.oceanobs.com/msl/ that site].

The data record from these altimetry missions has given scientists important insights into how global sea level is affected by natural climate variability, as well as by human activities.

=== Planetary Waves ===
TOPEX/Poseidon and Jason-1 made clear the importance of planetary-scale waves, such as [[Rossby wave|Rossby]] and [[Kelvin wave|Kelvin]] waves. No one had realized how widespread these waves are. Thousands of kilometers wide, these waves are driven by wind under the influence of Earth's rotation and are important mechanisms for transmitting climate signals across the large ocean basins. At high latitudes, they travel twice as fast as scientists believed previously, showing the ocean responds much more quickly to climate changes than was known before these missions.

=== Ocean tides ===
{{further|Tides}}

The precise measurements of TOPEX/Poseidon's and Jason-1 have brought knowledge of ocean tides to an unprecedented level. The change of water level due to tidal motion in the deep ocean is known everywhere on the globe to within 2.5 centimeters (1 inch). This new knowledge has revised notions about how tides dissipate. Instead of losing all their energy over shallow seas near the coasts, as previously believed, about one third of tidal energy is actually lost to the deep ocean. There, the energy is consumed by mixing water of different properties, a fundamental mechanism in the physics governing the general circulation of the ocean.

=== Ocean models ===
TOPEX/Poseidon and Jason-1 observations provided the first global data for improving the performance of the numerical ocean models that are a key component of climate prediction models. TOPEX/Poseidon and Jason-1 data are available at the University of Colorado Center for Astrodynamics Research,<ref>{{cite web|url=http://argo.colorado.edu/~realtime/welcome/|title=CCAR Near Real-time Altimetry Data Homepage |publisher=University of Colorado|url-status=dead|archive-url=https://web.archive.org/web/20080515212403/http://argo.colorado.edu/~realtime/welcome/|archive-date=2008-05-15}}</ref> NASA's Physical Oceanography Distributed Active Archive Center,<ref>{{cite web|url=http://podaac.jpl.nasa.gov/|title=Physical Oceanography DAAC|publisher=NASA}} {{PD-notice}}</ref> and the French data archive center AVISO.<ref>{{cite web |url=http://www.aviso.oceanobs.com/|title=Aviso Altimetry|publisher=CNES}}</ref>