APPENDIX C 



GENERALIZED FLOW AT THE SURFACE 

 AND AT SUBSURFACE AND INTERMEDIATE DEPTHS 



Figures C-1 through C-7 show generalized surface circulation during 

 the northeast and southwest monsoons, generalized flow of subsurface water 

 masses (PGIW and SSW), and generalized flow of intermediate water masses 

 (RSIW, AAIW, and BIW). The various figures show direction of flow only, and 

 are not meant to indicate current magnitudes. Figures C-3 through C-7 

 (subsurface and intermediate flows) were derived by analyzing salinity maxima 

 and minima core depths. The effects of circulation and water masses on sound 

 velocity structures appears in the main body of the text. Therefore, the follow- 

 ing comments are supplementary and not necessarily related to any previous 

 discussion. 



Figures C-1 and C-2 (surface circulation during northeast and southwest 

 monsoons, respectively) are highly generalized and closely resemble those of 

 Matthews, Oct 1967. Since the two figures represent composite seasons (Nov- 

 Apr and May-Oct, respectively), they only generally resemble dynamic topo- 

 graphy charts for winter (Dec-Feb) and late summer (Jul-Sep) shown by Duing, 

 1970. However, Figures C-1 and C-2 are adequate for use in explaining sound 

 velocity variations at the surface and in the near-surface layer. 



Figure C-3 (PGIW flow) shows substantial modification from that of 

 Rochford, 1964 and is based on much more data. This figure indicates a lesser, 

 seasonal flow in the Somali Basin; a preferential, aseasonal flow along the 

 west coast of India; and a larger, aseasonal flow into the Bay of Bengal and 

 Andaman Sea. A lesser occurrance of PGIW in the Somali Basin is in agreement 

 with the findings of Hamon, 1967 and the occurence off the west coast of India 

 with the findings of Duing and Koske, 1967. Available data indicate that PGIW 

 flow is aseasonal off the west coast of India and in the region north of the Equator 

 between Ceylon and the northern tip of Sumatra. 



Figure C-4 (SSW flow) is highly schematic, particularly south of the 

 Equator in regions where RSIW is substantially diluted and/or occurs only 

 sporadically. In the region south of the Equator between about 80° and 100° 

 E. longitude, SSW flow could not be determined by T-S analysis because RSIW 

 is most often absent. The sporadic flow of SSW into the Gulf of Aden is 

 questionable. 



Figure C-5 (RSIW flow) is similar to that of Rochford, 1964 in the Somali 

 Basin, but substantially different throughout the rest of the area. More extensive 

 data now available indicate a preferential flow across the southern Arabian 



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