Life on planet Earth is impossible without an atmosphere, the gases of which breathe all living things, including humans. This air envelope consists of several layers, the most important and most studied of which is the troposphere. Its value is very great, because it is here that the life of people and most living creatures flows, and almost all atmospheric air is concentrated. What is the troposphere, and what phenomena occur in it?
Definition of the troposphere: location and features
The troposphere is the atmosphere of the Earth, the lowest air layer in which the flora and fauna exist, including humans. It is located between the surface of the planet and the stratosphere. Between them is the tropopause - the transition layer.
In the troposphere, 80% of all atmospheric air is concentrated, more than 50% of which is breathable is up to five kilometers above the ground. For this reason, at this level, an untrained person has difficulty breathing.
With a relatively small height of this layer, it is very affected by processes on the ground. This is the return to the atmosphere of the Earth’s thermal energy, as well as moisture and suspended matter (dust, sea salt, plant spores, and so on). Almost all of the steam is here, clouds are formed that carry rain, snow and hail, and wind appears.
Physical parameters
The height, composition and temperature of the troposphere, as well as humidity and pressure are its most important physical parameters.
The height of the layer in question is equal to:
- over the poles of 8-12 kilometers;
- in middle latitudes 10-12 km;
- at the equator about 18 km.
In this interval, there is a continuous movement of air flows that can move both horizontally and vertically. As you can see, the thickness decreases in the direction from the equator to the poles.
The composition of the atmospheric gas does not change and is represented by oxygen and nitrogen. The pressure and density of air, as well as the concentration of moisture in it, decrease with height. Water vapor appears due to the escape of fluid from the seas and oceans.
Air changes with height: it cools and becomes more rarefied. The temperature decreases at a speed of 0.65 degrees / 100 meters and reaches -55 ° at the upper boundary of the troposphere. The stop of the temperature drop serves as the upper boundary of this layer. Thus, with increasing temperature, the temperature gradually decreases, and the air heats up from the ground (from bottom to top).
Greenhouse effect
The surface layer of the atmosphere is the habitat of people, flora and fauna. Here the weakest wind and high humidity, contains a large amount of dust, flying microorganisms and various suspended particles.
The rays of the Sun easily pass through the air and heat the soil. The heat radiated by the earth is accumulated in the troposphere, and carbon dioxide, methane and water vapor retain heat. Such a process of heating the earth and air and heat retention in the troposphere is called the greenhouse effect.
In recent decades, the world community is concerned about this problem, as it leads to global warming. Knowing what phenomena occur in the troposphere, mankind can try to reduce the negative impact on the environment, including the atmosphere.
Characteristic phenomena
The theme “What phenomena occur in the troposphere” is the 6th grade of the school curriculum. It is in high school that students understand that the troposphere is an extremely important atmospheric layer in which natural phenomena form and occur that affect the existence of people and other living organisms. Therefore, this layer of the atmosphere is carefully studied by world experts. It is in the troposphere that various weather changes occur, which are observed, among other things, through weather stations and weather balloons.
The processes familiar to this area are represented by the formation of winds, clouds and precipitation. In addition, thunderstorms, fogs, dust storms and blizzards occur. Catastrophic events are less common: floods, hurricanes and other weather anomalies.
What phenomena occur in the troposphere can be considered with the example of ordinary dew, which forms in the warm season in the morning. During cooling, a thinnest layer of ice crystals appears instead.
When the soil cools, cooling of the surface air layer begins. In contact with the upper layer of soil, water vapor present in the troposphere begins to condense and dew appears. The rate of its occurrence is directly proportional to the decrease in soil temperature. The most abundant dew occurs in the tropical zone, because there is very high humidity and the duration of nights during which the earth's surface is actively cooled. As a result, morning moisture condenses very intensely.
Also, a characteristic meteorological phenomenon is fog: the accumulation of condensate products at the surface of the earth. It occurs as a result of contact of chilled air with warm. It is important that the relative humidity should be very high - more than 85%.
Air mass movement
Among the phenomena that occur in the troposphere, one of the most common can be called wind - a stream of air rapidly moving along the earth's surface. The source of the appearance of wind is the uneven distribution of atmospheric pressure. As airflow speeds increase, tornadoes, tornadoes, and hurricanes can form.
The colossal air volumes of the troposphere, which have the same characteristics, are called air masses. They are dependent on the areas where they are formed. When moving, air masses do not change their characteristics for a long time. In contact, different air flows react with each other. These two features determine the weather conditions in different places. The influence of air flows on each other gives rise to the appearance of moving atmospheric vortices in the heights - cyclones and anticyclones.
A huge whirlwind with low atmospheric pressure in the center is called a cyclone. The diameter of the cyclone can reach several thousand kilometers. With a cyclone, it is usually inclement with strong winds and precipitation. An anticyclone is a giant whirlwind with high atmospheric pressure that carries good weather: few clouds, little wind, no precipitation.
Hazardous atmospheric phenomena
What phenomena occur in the troposphere can also be considered by the example of dangerous weather phenomena. The danger lies in the fact that they can cause significant damage to agricultural land, the well-being of countries and the natural environment as a whole. In addition, natural disasters threaten the life and health of people and animals.
For example, a thunderstorm is a dangerous atmospheric phenomenon. This is a phenomenon in which, among clouds or between a cloud and the surface of the earth, electrical discharges appear - lightning, accompanied by thunder.
Lightning is a spark of electricity that has accumulated in the air. Thunder is formed as a result of a process when very heated and instantly expanding near lightning air provokes the birth of sound waves. Reflecting from various obstacles (clouds and objects on the ground), these waves create an echo - thunder. Typically, a thunderstorm occurs in massive cumulus clouds and is dangerous by heavy rain, hail, stormy wind amplification, and lightning.
