During the summer of 1977, an intensive density mapping 

 will also be conducted in this area, using CTDs (to measure 

 salinity, temperature and pressure) for about 40 days. Two 

 U.S. and two U.S.S.R. ships will be involved in an effort to 

 describe the structure of the flow over several eddies, to reveal 

 fine scale features of the flow, and to obtain local dynamical 

 balances via objective mapping techniques. 



Elements of the Complementary Program 



( 1 ) Local Dynamics Experiment: Northern Synoptic Experi- 

 ment. The U.S.S.R. will maintain for 10 months, starting in 

 Summer 1977, 19 surface moorings with current meter in- 

 strumentation at tive levels down to 1,500 depth, with extensive 

 density sampling from research vessels, near 35 ^N, 43 °W. 

 The moorings will be deployed in a multiantenna array. U.S. 

 participation will include some part of Array III (mentioned 

 above), technical contributions to the U.S.S.R. mooring sys- 

 tem, and possibly a supply of XBTs to enable the density- 

 temperature program sampling to be optimized. 



(2) Eastern Basin Mooring Sites. The United Kingdom, 

 Federal Republic of Germany, and France will deploy about 

 seven instrumented moorings for up to 2 years in the northern 

 half of the Eastern North Atlantic basin, for gathering statistics 

 over a wide geographical region. 



(3) Neighborhood of the Gulf Stream. A pilot experiment 

 to study downstream scales of Gulf Stream meanders using 

 deep mooring and inverted echo sounders is planned. Three 

 moorings (Canada) will be maintained north of the Stream. 

 Detailed studies of Gulf Stream rings are also scheduled. 



(4) Small-Scale Processes. Evidence of coupling of the 

 POLYMODE eddies with high frequency and microstructure 

 phenomena is to be studied further through several small 

 experiments. 



(5) Near-Surface Experiments. Thirty satellite-tracked drifters 

 with thermistor chains will be launched in the Bay of Biscay 

 (France). An experiment with free-drifting cyclesondes (for 

 obtaining vertical profiles of velocity) has been proposed for 

 the region of the Southern Local Dynamics Experiment. Satel- 

 lite surveillance by infrared thermometry and microwave altim- 

 etry, for remote temperature, sea-state, and surface geopotential 

 topography have been proposed. 



(6) Near-Bottom Experiments. Modern general circulation 

 numerical models suggest it is important to study the connection 

 of bottom mixed-layer dynamics with that of the overlying 

 low frequency eddy phenomena, and the coupling with bottom 

 topography during POLYMODE. Small arrays of bottom in- 

 struments are planned. 



80° 70" 60° 50 



Figure 2. — Mesoscale experiments prior to spring 1976 



