HUMAN. PHYSICAL, AND FISCAL RESOURCES 1(55 



A mission to determine Earth's gravity field is still needed. 

 No gravity mission is firmly in any space agency's plans, but 

 design studies are being conducted. Of particular interest are the 

 joint U.S./ESA (European Space Agency) plans for a gravity mis- 

 sion, called Applications and Research Involving Space Technolo- 

 gies Observing the Earth's Field froni Low Earth Orbiting Satel- 

 lites (ARISTOTELES). The ARISTOTELES spacecraft would include 

 both a gravity gradiometer for highly accurate gravity measure- 

 ments and a magnetometer for geomagnetic studies. It is impor- 

 tant that the geomagnetic mission begin before 1998 to avoid the 

 next sunspot maximum, which would hamper the low-altitude 

 initial portion of the satellite's mission. 



It is clear from Table 4-6 that many objectives of the original 

 Space, A Research Strategy for the Decade 1985-1995 (TOT, 1985) 

 report are being met. Yet successful completion of many mis- 

 sions requires more than just NASA support; new partnerships 

 are needed. Healthy relationships between U.S. and non-U.S. space 

 agencies and with private industry are also needed. Some of these 

 relationships appear to be working v/ell, for example, in Earth 

 Resources Satellite- 1 data sharing through the Alaska synthetic 

 aperture radar facility and in the joint design of TOPEX/Poseidon 

 with the French. Future partnerships, such as those in ocean 

 color with the Orbital Sciences Corporation's SeaWiFS, are yet to 

 be tested. It is clear that developing and maintaining these part- 

 nerships require strong leadership at NASA headquarters, so that 

 U.S. participation in the process from sensor design to data analy- 

 sis is guaranteed. The oceanographic community must not find 

 itself wholly dependent on international agreements and data from 

 non-U.S. sensors and missions during the late 1990s and beyond. 



There is a need for continuing research in the development of 

 mathematical techniques to correct satellite data for the effects of 

 clouds, water vapor, and other atmospheric aerosols, to relate sat- 

 ellite measurements to observations at the ocean surface, and to 

 relate the surface signal to processes occurring at depth. If cali- 

 bration errors in the satellite data time series can be avoided, it 

 will be possible to create a time series that is long enough to 

 investigate low-frequency phenomena in the record of upper ocean 

 temperatures and other variables. 



Numerical Ocean Modeling 



Numerical ocean modeling has reached a degree of sophistica- 

 tion whereby it can affect the study of present ocean circulation 



