Heat transfer through conduction, convection, and mantle circulation

¶ … Heat and Temperature

Although there is a difference between heat and temperature, the correlation which exists between them is very significant (Campbell, 2009). Temperature is the degree of vibration of particles in a system. High temperature therefore implies a high degree of vibration of particles. Heat is a type of energy which is usually changed into kinetic energy. As long as an object is heated, its temperature will increase. While heat is a form of energy, temperature is the effect of heat (Campbell, 2009). Intrinsically, the relationship between heat and the temperature is associated with change in the state, from solid to liquid and then gas.

Convection and conduction

Convection as a process involves the transfer of heat is from one region to another by actual motion of matter (Convection, 2013). Therefore, convection is only possible in fluids. In convection, temperature differences in the fluids drive currents. When fluids are heated, they expand, lowering the densities of the heated material. This causes the heated fluid to rise through the cooler fluids. Convection can either be natural or forced. Natural convection involves the force of gravity (Convection, 2013). When fluids are heated from below, the hot parts expand becoming less dense. Because of this, the hot fluid rise and replaces the less hot fluid above. The less hot fluid above is forced down as it is denser. It again gets heated and rises up. This process is continuous, and it creates uniformity in temperature of the fluid. In forced convection, materials are forced to move up by physical means. For instance, heat can be transferred through liquids by brisk stirring.

Convection greatly differs from conduction by the fact that conduction involves the transfer of heat through collision of particles (Campbell, 2009). On this, transfer of energy takes place locally. In conduction, heat moves through the bodies themselves as opposed to convection where there is transfer of heat by bulk motion (Campbell, 2009). In addition, conduction usually takes place in all forms of matter such as gases, solids and liquids. Nevertheless, it is more pronounced in solids than other forms of matter.

Locations where Convection Occurs

Monsoonal Circulation Convection

Monsoonal circulation involves large scale sea breezes occurring when the temperature on the land is greatly warmer or colder than that of the sea. These disproportions in temperatures occur due to the different ways in both sea and land absorbs heat. During the warmer season, the sun heats both the land and sea surfaces but the temperature of the land rises faster than that of the sea (Convection, 2013). This forces the sea breeze to blow from the sea to the land through convection. During the cold season, this cycle is reversed. The land cools more quickly than the sea leading to the creation of high pressure on the air over land. This forces the breeze to flow from the land to the sea. This causes precipitation on the sea.

Offshore and Onshore Wind Convection

In offshore and onshore wind convection, local differences in air pressure as temperature leads to the creation of localized winds. These variations occur mostly in coastal regions. In these regions, there is unequal heating of the land as well the adjacent sea regions. This leads to the creation of land and sea breezes. Land breeze (offshore winds) occurs at night while the sea breeze (onshore winds) occurs during the day (Convection, 2013). During the day, the land becomes heated more than the sea. This makes the air on the land to become less dense hence rising. These forces the air above the sea to occupy the space created. This happens through convection creating onshore winds or sea breeze (Convection, 2013). At night, the sea is more is usually warmer than the land. As a result, the air above it becomes heated and rise as its density becomes less. Consequently, this forces air from the land to occupy the space created. This movement of air from the earth to the sea is via convection and is what that is referred to as land breeze (offshore winds).

Onshore and offshore winds have a large impact due to the formation of land and sea breezes. In most situations, it causes heavy rainfall on the nearby land as well as on the sea. This is because the moist breezes lead to the formation of clouds leading to rainfall. This rainfall is usually accompanied by thunderstorms. However, the amount and location of the thunderstorms vary depend on the overall weather patterns of the region.

Mantle Convection