1. The Environment
1.1
The Unique Situation in the Environment
of the Indian Ocean
G. DIETRICH
There were two reasons why the Indian Ocean was chosen for the largest international
oceanographic investigation ever made. First, the Indian Ocean is the least-known ocean.
To make real progress in the knowledge of this ocean an investigation was needed, not by
one ship, not evert by one nation with several ships, but by numerous research vessels
acting in concert. Before 1957 nobody knew if an international cooperation involving
dozens of ships would work. But in 1957, which is really a remarkable date in the history
of marine sciences, the first multinational program took place during the International
Geophysical Year (lGY). The various oceanographic surveys made in the North Pacific
and North Atlantic oceans proved that several nations had a great willingness and
capability for scientific cooperation. The IGY meeting in Gothenburg (Sweden) 1957, the
meeting of the so-called CSAGI (Conseil Scientifique Annee Geophysique Internationale),
was the beginning of the HOE. In the same year the international body, SCOR (Scientific
Committee on Oceanic Research), was founded and its first great task became the
International Indian Ocean Expedition (HOE).
Little was known of the oceanographic conditions in the Indian Ocean, which was the
main reason why the HOE was planned. But there was also a second reason: the Indian
Ocean has a unique position among the oceans because the surface circulation in the
northern part reverses every half year. In winter we have the NE, and in summer the SW
monsoon circulation. There is no better place on earth to study the reaction of an ocean
with the atmosphere than the northern Indian Ocean.
Both the general survey of the Indian Ocean and the investigation of the monsoon
circulation were to be carried out in the same program. Now, 6 years after the expedition,
in which 20 nations with 40 research vessels participated, we can say it was successful.
It is true that not all expectations were fulfilled, mainly because the observations in large
areas were not very extensive. Perhaps there would be no criticisms if the expedition had
followed the plan made by weST (1959), which is based on a schematic grid system of
sections with repeated observations in different seasons. Such a plan is ideal but unrealistic.
The HOE had to be worked out by scientists from many countries who took part
voluntarily and were interested in a variety of scientific programs. Some regions are
extremely rich in problems, e.g. the monsoon effect which can be studied only in certain
areas of the Indian Ocean, and some regions lack specific problems, like the southern
Westerlies in the Circumpolar Current. The ocean was not investigated in a manner
resembling a military manoeuvre, but according to the demands of scientific problems in
selected regions (see map oposite title page). As a result the observations are unevenly
distributed. Therefore we congratulate RAMAGE on the great cooperative work in meteorology (RAMAGE et aI., 1972) and WYRTKI on his Oceanographic Atlas of the Indian Ocean
1.1
The Unique Situation in the Environment
of the Indian Ocean
G. DIETRICH
There were two reasons why the Indian Ocean was chosen for the largest international
oceanographic investigation ever made. First, the Indian Ocean is the least-known ocean.
To make real progress in the knowledge of this ocean an investigation was needed, not by
one ship, not evert by one nation with several ships, but by numerous research vessels
acting in concert. Before 1957 nobody knew if an international cooperation involving
dozens of ships would work. But in 1957, which is really a remarkable date in the history
of marine sciences, the first multinational program took place during the International
Geophysical Year (lGY). The various oceanographic surveys made in the North Pacific
and North Atlantic oceans proved that several nations had a great willingness and
capability for scientific cooperation. The IGY meeting in Gothenburg (Sweden) 1957, the
meeting of the so-called CSAGI (Conseil Scientifique Annee Geophysique Internationale),
was the beginning of the HOE. In the same year the international body, SCOR (Scientific
Committee on Oceanic Research), was founded and its first great task became the
International Indian Ocean Expedition (HOE).
Little was known of the oceanographic conditions in the Indian Ocean, which was the
main reason why the HOE was planned. But there was also a second reason: the Indian
Ocean has a unique position among the oceans because the surface circulation in the
northern part reverses every half year. In winter we have the NE, and in summer the SW
monsoon circulation. There is no better place on earth to study the reaction of an ocean
with the atmosphere than the northern Indian Ocean.
Both the general survey of the Indian Ocean and the investigation of the monsoon
circulation were to be carried out in the same program. Now, 6 years after the expedition,
in which 20 nations with 40 research vessels participated, we can say it was successful.
It is true that not all expectations were fulfilled, mainly because the observations in large
areas were not very extensive. Perhaps there would be no criticisms if the expedition had
followed the plan made by weST (1959), which is based on a schematic grid system of
sections with repeated observations in different seasons. Such a plan is ideal but unrealistic.
The HOE had to be worked out by scientists from many countries who took part
voluntarily and were interested in a variety of scientific programs. Some regions are
extremely rich in problems, e.g. the monsoon effect which can be studied only in certain
areas of the Indian Ocean, and some regions lack specific problems, like the southern
Westerlies in the Circumpolar Current. The ocean was not investigated in a manner
resembling a military manoeuvre, but according to the demands of scientific problems in
selected regions (see map oposite title page). As a result the observations are unevenly
distributed. Therefore we congratulate RAMAGE on the great cooperative work in meteorology (RAMAGE et aI., 1972) and WYRTKI on his Oceanographic Atlas of the Indian Ocean