Temperature Distribution on Earth
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:
Latitude
Altitude
Land And Sea Contrast
Ocean Currents
Passage of Air Masses
Vegetation Cover
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
Local Aspects
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.
Conclusion
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FAQs on Temperature Distribution
1. What does the term 'distribution of temperature' mean in geography?
In geography, the distribution of temperature refers to how temperature levels vary across different parts of the Earth. This is studied in two main ways: horizontally, which looks at temperature changes from the equator to the poles, and vertically, which examines how temperature changes with increasing altitude in the atmosphere.
2. What are the main factors that control the temperature of a place?
The temperature of any place is primarily controlled by a combination of factors. The most significant ones include:
- Latitude: The angle at which the sun's rays hit the Earth.
- Altitude: The height of a place above sea level.
- Distance from the sea: Coastal areas have moderate temperatures compared to inland areas.
- Ocean currents: Warm and cold currents can heat or cool the coasts they flow past.
- Prevailing winds: Winds can carry warm or cold air to a region.
3. What is the difference between horizontal and vertical distribution of temperature?
The main difference lies in the direction of measurement. Horizontal distribution refers to the variation of temperature across the Earth's surface, like moving from a warm country to a cold one. Vertical distribution refers to the change in temperature as you move upwards from the Earth's surface into the atmosphere, where it generally gets colder.
4. Why is it generally colder on a mountain top than at sea level?
It is colder at higher altitudes because the atmosphere becomes thinner and less dense. The Earth's surface absorbs solar radiation and heats the air closest to it. As you move higher, you are farther from this primary heat source, and the thin air is less able to retain heat. This phenomenon is known as the normal lapse rate.
5. What are isotherms and how do they help in studying temperature?
Isotherms are lines drawn on a map that connect places having the same temperature at a given time. They are very useful because they help us visualise temperature patterns across large areas. Closely spaced isotherms show a rapid temperature change, while widely spaced isotherms indicate a more gradual change.
6. How do land and sea affect local temperature distribution?
Land and sea absorb and release heat at different rates. Land heats up and cools down quickly, leading to extreme temperatures (very hot days, very cold nights). Water, on the other hand, heats up and cools down slowly, which results in more moderate temperatures. This is why coastal areas often have milder climates than places located far inland. This effect is known as the land-sea differential.
7. What is a 'temperature inversion' and why is it an exception to the normal pattern?
A temperature inversion is a situation where the air temperature increases with altitude, which is the opposite of the normal pattern. It happens when a layer of warm air settles over a layer of cooler air near the ground. This often occurs on calm, clear nights and can trap pollutants, leading to the formation of smog or fog in valleys and cities.
8. Why are the hottest places on Earth not located exactly on the equator?
While the equator receives direct sunlight, the hottest temperatures are typically found in the sub-tropical desert regions. This is because these areas often have clear, cloudless skies and low humidity, allowing for maximum solar radiation to reach and heat the ground. The equatorial region, in contrast, often has significant cloud cover and rainfall, which helps to moderate its temperatures.
