Vertical Distribution Of Temperature In The Oceans

The maximum temperature of the oceans is always on the surface because it directly receives the insolation. The heat is transmitted to the lower sections of the oceans through the mechanism of conduction.

This can be shown as the temperature-depth profile.
The photic zone (extends from the upper surface to ~200 m) receives adequate solar insolation.
Aphotic zone (extends from 200 m to the ocean bottom) does not receive adequate sunrays.

Solar rays very effectively penetrate up to 20m depth and they seldom go beyond 200m depth. Consequently, the temperature decreases from the ocean surface with increasing depth but the rate of decrease of temperature with increasing depth is not uniform everywhere. The temperature falls very rapidly up to the depth of 200m and thereafter the rate of decrease of temperature is slowed down.

Three-Layer System

Vertically the oceans are divided into 3 layers from the stand point of thermal conditions of seawater, in the lower and middle latitudes as follows:
(1) The upper layer represents the top layer of warm water mass with a thickness of 500 meters with average temperature ranging between 20°C to 25°C.

This lighter ocean water mass floats over the thickest heavy water mass of the oceans extending up to the ocean bottoms.
This layer is present within the tropics throughout the year but it develops in middle latitudes only during summer
season.

(2)The lower layer extends beyond 1000 m depth up to the ocean bottoms. This layer is very cold and represents denser ocean water mass.
(3) A transitional zone called the thermocline, extending between a depth of 300 m to 1000 m, separates the upper and lower ocean water masses. In thermocline, water temperature decreases rapidly with increasing depth.

Thermocline

The profile shows a boundary region between the surface waters of the ocean and the deeper layers.
The boundary usually begins around 100 – 400 m below the sea surface and extends several hundred of meters downward.
The thermocline is the boundary region where there is a rapid decrease of temperature. In the deep ocean, temperatures approach 0°C, and about 90 percent of the total volume of water is found below the thermocline in this zone.

FAQs related with Vertical Distribution Of Temperature In The Oceans

Ques 1. What factors contribute to the vertical distribution of temperature in the oceans?

Answer. The vertical distribution of temperature in the oceans is influence by various factors. Solar radiation is a primary driver, as it heats the surface waters, creating a warm layer known as the upper mixed layer. Below this layer, temperature changes with depth due to processes like vertical mixing, upwelling, and downwelling. These processes are influence by factors such as wind, ocean currents, thermohaline circulation, and the geography of the ocean basin.

Ques 2. How does thermocline affect the vertical distribution of temperature in the oceans?

Answer. The thermocline is a layer in the ocean where there is a rapid decrease in temperature with depth. It separates the warm surface layer from the colder deep ocean. The depth and strength of the thermocline vary geographically and seasonally. In tropical regions, the thermocline is typically shallow, while in higher latitudes, it can be deeper. The thermocline plays a crucial role in the vertical distribution of temperature by creating a barrier that limits the exchange of heat between the surface and deep waters.

Ques 3. What is the role of upwelling and downwelling in the vertical distribution of temperature?

Answer. Upwelling and downwelling are important processes that influence the vertical distribution of temperature in the oceans. Upwelling occurs when deep, cold water rises to the surface, bringing colder temperatures from the deep ocean to the surface layers. This can happen along coastlines due to winds pushing surface waters offshore or as a result of ocean currents. Downwelling, on the other hand, is the sinking of surface waters to deeper layers. It often occurs in regions where surface waters become denser, such as in high latitudes. Both upwelling and downwelling contribute to redistributing heat vertically in the ocean, impacting the vertical temperature structure.

Vertical Distribution Of Temperature In The Oceans,Vertical Distribution Of Temperature In The Oceans