Life on planet Earth is impossible without an atmosphere, the gases of which are breathed by all living beings, including humans. This air shell consists of several layers, the most important and most studied of which is the troposphere. Its significance is very great, because it is here that the life of people and most living beings 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
Troposphere - Earth's atmosphere, the lowest air layer in which there is flora and fauna, including humans. It is located between the surface of the planet and the stratosphere. Between them is the tropopause - the transition layer.
80% of all atmospheric air is concentrated in the troposphere, moreover, over 50% of breathable air is located up to five kilometers above the ground. For this reason, it becomes difficult for an untrained person to breathe at this level.
With a relatively low height of this layer, it is greatly influenced by the processes occurring on the ground. This isreturn to the atmosphere of the Earth's thermal energy, as well as moisture and suspension (dust, sea s alt, plant spores, and so on). Almost all of the steam is here, clouds are formed bringing rain, snow and hail, and wind is generated.
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 considered layer is:
- over the poles 8-12 kilometers;
- in mid-latitudes 10-12 km;
- at the equator about 18 km.
In this interval, there is a continuous movement of air flows, which can move both horizontally and vertically. As you can see, the thickness decreases from the equator to the poles.
The composition of atmospheric gas does not change and is represented by oxygen and nitrogen. Air pressure and density, as well as the concentration of moisture in it, decrease with height. Water vapor appears as a result of volatilization of liquid from the seas and oceans.
The air changes with altitude: it cools and becomes thinner. The temperature decreases at a rate of 0.65 degrees/100 meters and reaches -55° at the upper boundary of the troposphere. The stop of the decrease in temperature serves as the upper boundary of this layer. Thus, as the temperature rises, 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 increasedhumidity, 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. Heat radiated by the earth accumulates in the troposphere, while carbon dioxide, methane and water vapor retain heat. This process of heating the earth and air and retaining heat in the troposphere is called the greenhouse effect.
In recent decades, the world community has been concerned about this problem, as it leads to global warming. Knowing what phenomena occur in the troposphere, humanity can try to reduce the negative impact on the environment, including the atmosphere.
Characteristic phenomena
Theme "What phenomena occur in the troposphere" - 6th grade of the school curriculum. It is in secondary school that students begin to understand that the troposphere is an extremely important atmospheric layer in which natural phenomena are formed 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 there are various weather changes, which are observed, among other things, through weather stations and weather balloons.
Processes common to this area are represented by the formation of winds, clouds and precipitation. In addition, there are thunderstorms, fogs, dust storms and snowstorms. Catastrophic events occur less frequently: floods, hurricanes and other weather events.anomalies.
What phenomena occur in the troposphere can be seen on the example of ordinary dew, which forms in the warm season in the morning. When it gets colder, a thin layer of ice crystals appears instead.
When the soil cools, the surface layer of air begins to cool. In contact with the upper layer of soil, the 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, since there is very high humidity and the duration of nights during which the earth's surface is actively cooling. As a result, morning moisture condenses very intensely.
Also, a characteristic meteorological phenomenon is fog: the accumulation of condensate products near the surface of the earth. It results from the contact of cool air with warm air. It is important that the relative humidity of the air must be very high - more than 85%.
Movement of air masses
Among the phenomena that occur in the troposphere, one of the most common is the wind - a stream of air moving rapidly along the earth's surface. The source of the appearance of wind lies in the uneven distribution of atmospheric pressure. When air currents increase, tornadoes, tornadoes and hurricanes can form.
Colossal volumes of air in 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. When in contact, different air flows react with each other. These two features determine the weather conditions in different areas. The impact of air currents on each other gives rise to the appearance of moving atmospheric vortices in the height - cyclones and anticyclones.
A cyclone is a huge whirlwind with low atmospheric pressure in the center. The diameter of a cyclone can reach several thousand kilometers. When a cyclone is usually bad weather with strong winds and precipitation. An anticyclone is a giant vortex with high atmospheric pressure that brings good weather: few clouds, little wind, no precipitation.
Hazardous Atmospheric Phenomena
What phenomena occur in the troposphere can also be considered on 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 in general. In addition, natural disasters threaten the lives and he alth of people and animals.
For example, a thunderstorm is a dangerous atmospheric phenomenon. This is a phenomenon in which electrical discharges appear among clouds or between a cloud and the earth's surface - lightning, accompanied by thunder.
Lightning is a spark discharge of electricity accumulated in the air. Thunder, on the other hand, is formed as a result of a process when air that is very hot and instantly expanding near lightning provokes the birth of sound waves. Reflecting from various obstacles (cloudsand objects on the ground), these waves create an echo - a thunderclap. Usually a thunderstorm occurs in massive cumulus clouds and is dangerous with heavy rain, hail, storm wind intensification, lightning.
Rainbow
In nature, there are not only dangerous atmospheric phenomena, but also beautiful, pleasing to the eye phenomena. For example, a rainbow is a phenomenon that can be seen when the Sun illuminates a large number of raindrops. It appears to the observer as a multi-colored arc or circle, in which there are seven colors, gradually flowing into each other. The cause of a rainbow is sunlight broken down into its components.
Rainbows can be seen when the sun shines with the rain. But you need to be exactly between the sun and the rain, and the heavenly body should be behind, and the rain in front. You cannot see the sun and the rainbow at the same time. The intensity of the colors and the size of the stripes of the seven-color miracle are determined by the size and number of water drops. The larger the drop, the narrower and brighter the rainbow. Therefore, after a thunderstorm with rain, a bright and narrow rainbow appears.
