PROGRAM TITLE:  	TOPEX/Poseidon
ACTIVITY STREAM:  	Integrative Modeling and Prediction
SCIENCE ELEMENT: 	Climate and Hydrologic Systems
				Global Observing Systems
				Biogeochemical Dynamics
				Solar Influences
				Data and Information Management

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

SCIENTIFIC MERIT:  TOPEX/Poseidon (launched August 10, 1992), a 
joint U.S. and French mission, is providing scientists with a detailed, 
global description of the ocean's topography and currents.  Radar 
altimeters on-board TOPEX/Poseidon are measuring the sea-surface 
height with an unprecedented accuracy of 3 cm from which can be 
calculated the speed and direction of ocean currents.  Researchers 
will use these data to develop models for extended weather and 
climate prediction, global ocean tides, local and global sea-surface 
variations, and study the interaction between the oceans and 
the earth's atmosphere.  The study of ocean circulation as it is 
affected by the rotation of the earth and winds which not only drive 
the ocean surface currents but raise the sea level downwind will 
provide more insight into the speed and direction of ocean currents.  
These currents provide global transport for warm and cold water 
which effect the global climate.  An example of this is El Nino which 
is a transport of warm Asian waters eastward towards South 
America;  the effects of which have been devastating.  More reliable 
prediction of such events can be had through improved knowledge 
of the ocean circulation.

STAKEHOLDERS:  TOPEX/Poseidon is a joint U.S. NASA and French 
CNES mission.  It is a core element of the WOCE and TOGA 
measurement programs.

POLICY RELEVANCE:	
Primary:	Climate change and global warming.
		Seasonal and Interannual Prediction 
		i.e. ,Predicting extreme anomalies such as El Nino.

Secondary:	International Cooperation
		Ecological Change and Biodiversity

PROGRAM CONTACTS: Michael Van Woert, Program Scientist
				Office of Mission to Planet Earth
				NASA Headquarters, Code YS
				Washington, D.C.  20546
				tel:   202-488-5150
				fax:  202-479-2613

				Patricia K. Liggett, Program Advisor
 				Office of Mission to Planet Earth
				NASA Headquarters, Code YDO
				Washington, D.C.  20546
				tel:    202-358-0755
				fax:  202-358-3098