The ultimate source of heat and energy is the Sun. The divergent heat received from the sun on the different regions on Earth is the utmost reason behind the different climate features. So understanding the pattern of temperature distribution on Earth in different seasons is important for understanding different climatic features such as precipitation, wind system, pressure system, etc.
In this article, we will discuss the horizontal and vertical distribution of temperatures along with the factors affecting and factors controlling the temperature distribution on Earth.
Horizontal Distribution of Temperature
The distribution of temperature across latitude over the Earth's surface is known as the horizontal distribution of temperatures. The horizontal distribution of temperature on Earth is shown by Isotherms. Isotherms are the line joining points that have an equal temperature. When the isotherm map is analyzed, it can be observed that the horizontal distribution of temperature is uneven.
Following are the Factors Accountable for the Uneven Horizontal Distribution of Temperature is:
Land And Sea Contrast
Passage of Air Masses
Vertical Distribution of Temperature
As we are aware, the temperature in the troposphere decreases with an increase in altitudes but the rate of decrease in the temperature changes according to seasons. The decrease of temperatures is known as the vertical temperature gradient or normal lapse rate which is 1000 times more than the horizontal lapse rate. The decrease of temperature upward in the atmosphere proves the fact that the atmosphere gets heat from the Earth's surface through the process of conduction, radiation, and convection. Hence, as the distance from the Earth’s surface ( the source of direct heat energy to the atmosphere) increases ( i.e as the altitude increases ), the air temperature decreases.
Factors Affecting Temperature Distribution
Some of the factors affecting the temperature distribution are:
Latitude: The temperature of the surface water decreases from the equator towards the poles because the sun rays become more and more inclined and hence the amount of insolation minimizes poleward.
Unequal Distribution of Land And Water: The oceans in the northern hemisphere receive more heat because of their contact with the larger extent of land than the equivalent parts in the southern hemisphere.
Prevailing Winds: The winds blowing from the land towards the ocean drive surface water away from the coasts resulting in an upwelling, in which deep cold water rises into the surface.
Ocean Current: Warm ocean current increases the temperature in cold areas whereas the cold current decreases the temperature in the warm ocean. For example: in a gulf stream, a warmer current increases the temperature of the Eastern coast of North America and the west coast of Europe.
Other factors affecting the temperature distribution are local weather conditions like storms and cyclones.
Factors Controlling Temperature Distribution
The factors controlling the temperature distribution on the Earth’s surface are discussed below:
The latitude of the Place
The altitude of the Place
Distance From The Sea
The presence of warm and cold ocean Currents
Global Distribution of Temperature
The global distribution of temperature can be effectively understood by considering the temperature distribution for January and July. The distribution of temperature is usually shown on the map using the isotherms. The isotherms are line joining places of equal temperature. Generally, the effects of latitude are well shown on the map as isotherms are generally parallel to the latitudes. The deviation from this trend is more generally observed in January rather than in July, especially in the northern hemisphere. The land surface is much larger in the northern hemisphere than in the southern hemisphere. Hence, the effects of land masses and ocean currents are well observed.
Temperature Distribution - January
In January, there is winter in the Northern hemisphere and summers in the southern hemisphere.
The western margins of continents in January are much higher than the Eastern counterparts as the westerlies can carry high temperatures into the landmasses.
The temperature gradient is much closer to the Eastern margins of continents. The isotherms observe more steady behavior in the southern hemisphere.
Temperature Distribution - July
During July, it is winter in the Southern hemisphere and summers in the Northern hemisphere. The isotherm behavior is the opposite of what it was in January.
The isotherms are generally parallel to the latitudes in July. The equatorial oceans record warmer temperatures more than 27 degrees celsius. More than 30 degrees celsius is noticed over the land in the subtropical continent region of Asia, along the 30 ° N latitude.
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