Temperature distribution on the surface of the seas and oceans of the world, which cover roughly about three-fourths of the earth’s surface, is of great significance from the geographical viewpoint.
Essentially all of the energy available to the oceans, like the land, comes from the sun. Energy radiated by the sun covers the full electromagnetic spectrum. However, most of the energy that reaches the earth’s surface is contained in the wavelengths close to and including the visible portion of the spectrum.
Almost all the physical and chemical properties of sea water are determined by its temperature conditions. Temperature of the ocean water plays the most significant role in controlling its biological properties/characteristics.
The role of the sea water temperature in causing the ocean currents and other movements of water cannot be overemphasized. Since oceans have greater capacity for the storage of the solar energy, they play major role in maintaining the equilibrium in the heat budget of the earth.
The specific heat of water being more than that of land, it (water) heats up and cools down more slowly. On the contrary, land surface is heated more quickly and to a greater extent than the water surface when subjected to an equal amount of insolation, and it also cools more rapidly.
In other words, water tends to store the heat it receives, whereas land quickly returns it to the atmosphere. It is the differential heating of land and water that accounts for the distinct types of marine and continental types of climates found on the surface of the earth.
The oceans because of this characteristic property of heating and cooling in a relatively longer period of time tend to exercise moderating influence on the climate of such regions as come under their influence.
Thus, the coastal regions experience cool summers and less severe winters. It is worthwhile to remember that the above-mentioned characteristics of the temperatures of ocean water are of great importance to the geographers.