Eventually these hypothetical models must be tested. Great care 

 must be exercised to select the proper kinds of experiments and experi- 

 mental data. One must set phenomenon traps capable of catching the 

 unexpected as well as the expected. To take into account important 

 phenomena of small size and short duration, as well as those of large 

 scale and long duration, the simulation models must repeatedly examine 

 adequately fine-mesh grids in the ocean. There must be such horizontal 

 grids stacked one above the other closely enough to resolve important 

 phenomena in all three dimensions. Finally, the computer must have a 

 large enough capability to accept and process a mountain of data every 

 day if such requirements are to be met on a scale even approaching 

 that of an entire ocean basin. 



Experiments of this magnitude are not very easily undertaken by 

 one academic institution or by a single country. The two largest 

 oceanographic institutions in the United States, the Scripps Insti- 

 tution of Oceanography and the Woods Hole Oceanographic Institution, 

 presently lack the facilities and organization necessary to sustain an 

 ambitious multi-element field experiment, as a continuous commitment, 

 without jeopardizing the rest of the institutions' research program. So 

 it is necessary, as well as desirable, to encourage cooperation among 

 many institutions and countries. 



Five major cooperative projects are presently under way in the 

 Environmental Forecasting program of the U.S. IDOE. 



26 MID-OCEAN DYNAMICS EXPERIMENT (MODE) 



An important element of the Environmental Forecasting Program 

 of the U.S. IDOE is the Mid-Ocean Dynamics Experiment project, Phase 

 I of which is already under way. It is a cooperative effort, an important 

 portion of which is supported by the National Institute of Ocean- 

 ography in England. The long-range goal of MODE is to invest i- 

 gate the role of medium-scale, geostrophic eddies in the general circula- 

 tion of the oceans. The immediate purpose of MODE-I is to provide a 

 kinematic description of these eddies. It is estimated that geostrophic ed- 

 dies, if indeed they are ubiquitous, would contain at least as much kinetic 

 energy as the mean oceanic circulation, and possibly ten times more. 

 Where the energy comes from, how much there is, what it does, and where 

 it goes are serious questions presently being asked by those who are de- 

 vising descriptive numerical models. It is known that such eddies actually 

 do exist in the atmosphere, that their kinetic energy content is comparable 

 to that of the mean flow, and that this is enough to prevent successful de- 

 scriptive or predictive numerical simulation unless it is properly taken 

 into account. Such knowledge may be even more important in modeling 

 oceans; In any case, it is certain that this energy must be accounted for ac- 

 curately in the dynamics of the oceanic models. 



MODE-I will be conducted in a small area 200 kilometers on a side 

 and 5 kilometers deep, near the Tropic of Cancer south of Bermuda, as 

 shown in Figures 10 & 11. Scientists participating in MODE-I are from 

 eight different U.S. universities, two U.S. Federal laboratories, the Na- 

 tional Institute of Oceanography and Cambridge University in England, 

 and the Woods Hole Oceanographic Institution. 



