75° E. meridian by NORSEL in 1956, on the 90° E. meridian by DISCOVERY 

 II in 1951, near the 86° E. meridian by ALBATROSS in 1945, and at 56° E. 

 longitude on a line running from west of Madagascar to Cape Guardaful by 

 NORSEL In 1955. In 1933, MABAHISS ran a section from the equator at 

 about 63° E. longitude to the Gulf of Oman. Between the years 1959 and 

 1962, H .M.A.S . DIAMANTINA, operated by the Australian Commonwealth 

 Scientific and Industrial Organization, Division of Fisheries and Oceanography 

 (C.S.I.R.O., 1962, and 1962a), participated In a series of cruises that covered 

 most of the waters to the south, west, and northwest of Australia. Three of her 

 tracks ran along the 32° S. parallel, one of which continued to 95° E. longitude 

 In 1960, the Lament Geological Observatory research vessel VEMA ran a 

 track which zig-zagged across the 32° S . parallel and which extended as far 

 west as Mauritius Island . In 1959 and 1960, the U .S .S .R . research vessel 

 VITYAZ covered a large portion of the Indian Ocean with her cruises, of 

 which one leg was slightly north of the 32° S . parallel . Other VITYAZ cruises 

 paralleled the south-north profile of EASTWIND on both eastern and western 

 sides along the 72°, 83°, and 90° meridians. A preliminary account of the 

 results of these cruises Is reported upon in Okeanologlya (Bezrukov, 1961). 

 The Scripps Institution of Oceanography's research vessel ARGO, In 1960, 

 ran cruise tracks south and north of the 32° S. parallel as far west as Mauritius. 

 By far the most comprehensive of the recent works on the Indian Ocean Is that 

 of Muromtsev on "The Basic Pattern of the Hydrology of the Indian Ocean" 

 (Muromtsev, 1959). An extensive data compilation from all available sources, 

 as well as vertical sections, and areal distribution charts of temperature, 

 salinity, density, and dissolved oxygen, accompanys Muromtsev's report . 

 The International Indian Ocean Expedition plans call for an extensive and 

 practically complete coverage of all parts of the Indian Ocean between the 

 years 1963 and 1965 or 1966. 



B. General Discussion of Oceanography of Indian Ocean 



The Indian Ocean has long been believed to be similar to the Atlantic, 

 and Indeed there are several striking resemblances. Both bodies of water have 

 midridges which join south of the Cape of Good Hope . Both ridges have a 

 rift valley and are centers of seismic activity. The continuity of the two 

 ridges and their rift valleys was recently confirmed from crossings made by 

 VEMA In 1959 and 1960 (Ewing and Heezen, 1960). The Mediterranean 

 feeds water of high salinity into the AtlantlCjOnd the Arabian and Red Seas 

 feed high salinity water Into the Indian Ocean. The more Important source 

 of high salinity Intermediate water for the Indian Ocean Is the Arabian Sea; 

 the Persian Gulf is too shallow to furnish much water southward. However, 

 in the Red Sea, a salinity as high as 40<%„ Is caused by intensive evaporation 

 and almost complete lack of run off from the land. This water at Intermediate 

 depths may be traced In the western portion of the Indian Ocean as far south 



