Mid-Ocean Dynamics Experiment (MODE) 



MODE, initiated in 1971, is an investigation of the role of meso- 

 scale eddies in the ocean circulation. It is jointly funded with 

 ONR, and includes some NOAA participation. These mesoscale 

 eddies are believed to contain at least as much kinetic energy as 

 the mean ocean circulation, and possibly as much as ten times 

 more. Whejre the energy comes from, how much is present, and 

 what it does are questions which must be answered in order to 

 refine the numerical models that are the basis of environmental 

 prediction. 



An observational program in a region south of Bermuda has 

 yielded new techniques and devices for measuring mesoscale mo- 

 tions, a mass of data constituting a case history of the kinetics 

 of a single eddy, a series of synoptic maps indicating the possible 

 nature of the eddy field, and a preliminary estimate of the statis- 

 tics characterizing the eddy field. MODE results are expected to 

 provide guidance in the interpretation of historical or incomplete 

 data from other regions, and to be of value in computer simula- 

 tion of eddy motions. 



MODE is now embarking on a new phase, called POLYMODE, 

 which is jointly planned by the United States and the U.S.S.R. 

 to follow up on many of the earlier measurements in MODE 

 and in a similar Russian study called POLYGON, but on a 

 larger scale in time and space, and in a different region of the 

 Atlantic. 



North Pacific Experiment (NORPAX) 



NORPAX grew out of an ongoing study, funded by ONR, of 

 the relation between areas of anomalous sea surface temperature 

 in the North Pacific and anomalous weather and climate occur- 

 rences over North America. Taken on as an IDOE project in 

 1972, and jointly funded by ONR and IDOE, NORPAX is an 

 investigation of long-period, large-scale ocean-atmosphere coupling, 

 aimed at discovering how oceanic processes in the upper layers 

 of the North Pacific relate to the weather and climate of the 

 Pacific and the continents to the east. 



One dramatic aspect of NORPAX has been the description of a 

 pattern of large-scale oceanic and atmospheric anomalies which 

 appear to be associated with El Nino ^ conditions, and which may 



1 Under normal conditions, southeasterly winds blowinc; along the Peru coast drive 

 the surface waters of the Peru Current away from shore, bringing about upwelling 

 of cool, nutrient-rich waters from greater depths. These waters sustain sizeable bird 

 and fish populations and support the Peruvian anchovy fishery, which is one of the 



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