How do we explore the oceans?
The oceanographer addresses two questions: “What is going on in the oceans?” and “Why?” The former is answered by careful observations of the oceans, the latter by putting these observations in perspective with the help of an established theoretical framework.
Oceanographers use a variety of instruments to observe the oceans. A basic requirement for such observations is a platform that can support the equipment deployed in observations. At present there are three kinds of platforms in use. The first is a research ship. It is like a floating laboratory equipped with instruments (temperature and salinity profilers, bottles for collecting water samples at different depths, devices that can sense the ocean floor, etc.) to observe the ocean. It also has facilities (lodging, boarding, communication, etc.) for oceanographers to stay at sea for a few weeks. A research vessel is equipped with machinery to handle sampling equipment: nets for biological studies, autonomous and remotely-controlled underwater vehicles, profilers, photography, and video systems, etc. (Fig. 40).
The second kind of platform often utilised by oceanographers is called a “mooring”. It consists of a wire that is attached to the ocean floor, and kept taut with the help of floats. Instruments (current meters, temperature recorders, etc.) are then attached to the wire.
The third kind of platform is one that is used by oil and gas companies in offshore petroleum production. These stable structures are often used for measuring meteorological variables, water level, currents, etc.
During the last 25 years there has been significant improvement in our ability to study the oceans with sensors that are stationed on satellites. These sensors provide information only on properties of the ocean surface, but their ability to cover a large spatial area and repeat the observations at regular intervals has proved useful in exploring the oceans.