Measuring the Rising Seas   
       
   Jan. 26, 2016:  Earth is enveloped by a vast ocean that covers about 71   
   percent of our planet. Even tiny changes in this body of water can add up to   
   enormous effects on climate and weather.   
       
   The Jason-3 satellite, launched on January 17, 2016, will allow scientists to   
   continue a 23-year record aimed at studying Earth's ocean to better understand   
   and forecast our climate, months and years into the future.   
       
   Jason-3 project scientist Josh Willis of NASA's Jet Propulsion Laboratory in   
   Pasadena, California says, "Jason-3 will measure the rising oceans and   
   changing climate for the next five years."   
       
       
   Jason-3 is the latest in a series of satellites that accurately measure the   
   height of the ocean surface dating back to the launch of Topex/Poseidon in   
   1992. Next came Jason-1 (launched in 2001) and then Jason-2 (launched in   
   2008). Jason-3 will be joining Jason-2 in orbit. For Jason-2 and Jason-3, the   
   National Oceanic and Atmospheric Administration, or NOAA, and the European   
   Organisation for the Exploration of Meteorological Satellites, or EUMETSAT   
   joined an international partnership with NASA and the French space agency,   
   CNES.   
       
   Willis adds that "from one mission to the next, we want to overlap our Jason   
   data and stitch it together to give us a consistent story of how our climate   
   is warming and our oceans are changing. Global sea level rise measured by   
   these satellites is one of the clearest indicators of how humans are changing   
   the climate."   
       
   This line of data-collecting ancestors have all measured sea surface height   
   using a radar altimeter -- an instrument similar to weather radars here on   
   Earth.   
       
   Here's how it works: The satellite emits a pulse of radar waves that travel   
   down toward Earth, bounce off the surface of the water, and return toward   
   space. Once the satellite detects the return signal, the altimeter calculates   
   the round-trip travel time. The longer the round trip, the lower the waters   
   are below. The height of the water also tells us about how warm the waters may   
   be between the surface and the bottom, because warm water expands and causes a   
   rise in sea surface height. The opposite is true for colder waters.   
       
   Ocean temperatures are making big news right now as a massive band of warm   
   water builds up and moves from west to east across the equatorial Pacific   
   Ocean.  This phenomenon, called "El Ni¤o," causes abnormal weather patterns   
   around the globe. Ripple effects could include rainy and cooler weather in the   
   southern United States and a chance to put a dent in California's current   
   drought. A reverse of the El Ni¤o phenomenon, called La Ni¤a, is associated   
   with the drought in the Southwest.   
       
   Willis says, "El Ni¤o is here. We have launched Jason-3 right into the biggest   
   El Ni¤o since the turn of the millennium, and the Jason data will allow us to   
   see whether it goes quietly or slingshots the Pacific into a huge La Ni¤a,   
   like the last big one in 1998."   
       
   The Topex/Poseidon and Jason satellites have a history of measuring climate   
   change and monitoring El Ni¤o.  Soon, Jason-3 could be making history of its   
   own.   
       
   For updates from the Pacific and around the world, stay tuned to   
   science.nasa.gov.   
       
       
   Regards,   
       
   Roger   
      
   --- DB 3.99 + Windows 10   
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