Air masses. Atmospheric circulation. air currents in the atmosphere Movement of air masses in the atmosphere

Air mass movements

The air is in constant motion, especially due to the activity of cyclones and anticyclones.

A warm air mass that moves from warmer regions to colder regions causes sudden warming when it arrives. At the same time, from contact with a colder earth's surface, the moving air mass from below is cooled and the layers of air adjacent to the earth may turn out to be even colder than the upper layers. The cooling of the warm air mass coming from below causes the condensation of water vapor in the lowest layers of the air, resulting in the formation of clouds and precipitation. These clouds are low, often dropping to the ground and causing fog. In the lower layers of the warm air mass, it is quite warm and there are no ice crystals. Therefore, they cannot give heavy rainfall, only occasionally a fine, drizzling rain falls. Clouds of warm air mass cover the entire sky with an even cover (then they are called stratus) or a slightly wavy layer (then they are called stratocumulus).

Cold air mass moves from cold regions to warmer regions and brings cooling. Moving to a warmer earth's surface, it is continuously heated from below. When heated, not only does condensation not occur, but the already existing clouds and fogs must evaporate, nevertheless, the sky does not become cloudless, just clouds form for completely different reasons. When heated, all bodies heat up and their density decreases, so when the lowest layer of air heats up and expands, it becomes lighter and, as it were, floats up in the form of separate bubbles or jets, and heavier cold air descends in its place. Air, like any gas, heats up when compressed and cools when it expands. Atmospheric pressure decreases with height, so the air, rising, expands and cools by 1 degree for every 100m of ascent, and as a result, at a certain height, condensation and the formation of clouds begin in it. The descending jets of air from compression heat up and not only nothing condenses in them , but even the remnants of clouds that fall into them evaporate. Therefore, clouds of cold air masses are clubs piling up in height with gaps between them. Such clouds are called cumulus or cumulonimbus. They never descend to the ground and do not turn into mists, and, as a rule, do not cover the entire visible sky. In such clouds, ascending air currents carry water droplets with them into those layers where ice crystals are always present, while the cloud loses its characteristic "cauliflower" shape and the cloud turns into a cumulonimbus cloud. From that moment on, precipitation falls from the cloud, although heavy, but short-lived due to the small size of the clouds. Therefore, the weather of cold air masses is very unstable.

atmospheric front

The boundary of contact between different air masses is called an atmospheric front. On synoptic maps, this border is a line that meteorologists call the "front line". The boundary between warm and cold air mass is an almost horizontal surface, imperceptibly descending towards the front line. Cold air is under this surface, and warm air is above. Since air masses are constantly in motion, the boundary between them is constantly shifting. An interesting feature: a front line necessarily passes through the center of an area of low pressure, and a front never passes through the centers of areas of increased pressure.

A warm front occurs when a warm air mass moves forward and a cold air mass retreats. Warm air, as lighter, creeps over cold air. Due to the fact that the rise of air leads to its cooling, clouds form above the surface of the front. Warm air climbs up quite slowly, so the cloudiness of the warm front is an even veil of cirrostratus and altostratus clouds, which has a width of several hundred meters and sometimes thousands of kilometers in length. The farther ahead of the front line the clouds are, the taller and thinner they are.

A cold front is moving towards warmer air. At the same time, cold air crawls under warm air. The lower part of the cold front, due to friction against the earth's surface, lags behind the upper part, so the surface of the front protrudes forward.

Atmospheric vortices

The development and movement of cyclones and anticyclones leads to the transfer of air masses over considerable distances and the corresponding non-periodic weather changes associated with a change in wind directions and speeds, with an increase or decrease in cloudiness and precipitation. In cyclones and anticyclones, air moves in the direction of decreasing atmospheric pressure, deviating under the action of various forces: centrifugal, Coriolis, friction, etc. As a result, in cyclones, the wind is directed towards its center with counterclockwise rotation in the Northern Hemisphere and clockwise in the Southern Hemisphere, in anticyclones, vice versa, from the center with opposite rotation.

Cyclone- an atmospheric vortex of huge (from hundreds to 2-3 thousand kilometers) diameter with reduced atmospheric pressure in the center. There are extratropical and tropical cyclones.

Tropical cyclones (typhoons) have special properties and occur much less frequently. They are formed in tropical latitudes (from 5° to 30° of each hemisphere) and are smaller (hundreds, rarely more than a thousand kilometers), but larger baric gradients and wind speeds reaching hurricanes. Such cyclones are characterized by the "eye of the storm" - a central area with a diameter of 20-30 km with relatively clear and calm weather. Around are powerful continuous accumulations of cumulonimbus clouds with heavy rains. Tropical cyclones can transform into extratropical cyclones during their development.

Extratropical cyclones are formed mainly on atmospheric fronts, most often located in subpolar regions, and contribute to the most significant weather changes. Cyclones are characterized by cloudy and rainy weather, and most of the precipitation in the temperate zone is associated with them. The center of an extratropical cyclone has the most intense precipitation and the most dense clouds.

Anticyclone- area of high atmospheric pressure. Usually the anticyclone weather is clear or partly cloudy. Small-scale whirlwinds (tornadoes, blood clots, tornadoes) are also important for the weather.

Weather - a set of values of meteorological elements and atmospheric phenomena observed at a certain point in time at a particular point in space. Weather refers to the current state of the atmosphere, as opposed to Climate, which refers to the average state of the atmosphere over a long period of time. If there are no clarifications, then the term "Weather" means the weather on Earth. Weather phenomena occur in the troposphere (lower part of the atmosphere) and in the hydrosphere. The weather can be described by air pressure, temperature and humidity, wind strength and direction, cloudiness, atmospheric precipitation, visibility range, atmospheric phenomena (fogs, snowstorms, thunderstorms) and other meteorological elements.

Climate(ancient Greek κλίμα (genus p. κλίματος) - slope) - a long-term weather regime characteristic of a given area due to its geographical location.

Climate is a statistical ensemble of states through which the system passes: hydrosphere → lithosphere → atmosphere over several decades. By climate it is customary to understand the average value of weather over a long period of time (of the order of several decades), that is, climate is the average weather. Thus, the weather is an instantaneous state of some characteristics (temperature, humidity, atmospheric pressure). The deviation of the weather from the climatic norm cannot be considered as climate change, for example, a very cold winter does not indicate a cooling of the climate. To detect climate change, a significant trend in the characteristics of the atmosphere over a long period of time of the order of ten years is needed. The main global geophysical cyclical processes that form the climatic conditions on Earth are heat circulation, moisture circulation and general circulation of the atmosphere.

Distribution of precipitation on Earth. Atmospheric precipitation on the earth's surface is distributed very unevenly. Some areas suffer from excess moisture, others from its lack. Very little precipitation is received by the territories located along the Northern and Southern tropics, where temperatures are high and the need for precipitation is especially great. Huge areas of the globe, which have a lot of heat, are not used in agriculture due to lack of moisture.

How can one explain the uneven distribution of precipitation on the earth's surface? You probably already guessed that the main reason is the placement of low and high atmospheric pressure belts. So, at the equator in the low pressure zone, constantly heated air contains a lot of moisture; as it rises, it cools and becomes saturated. Therefore, in the region of the equator, a lot of clouds form and there are heavy rains. A lot of precipitation also falls in other areas of the earth's surface (see Fig. 18), where the pressure is low.

Climate-forming factorsIn high-pressure belts, descending air currents predominate. Cold air, descending, contains little moisture. When lowered, it shrinks and heats up, making it drier. Therefore, in areas of high pressure over the tropics and near the poles, there is little precipitation.

CLIMATIC ZONING

The division of the earth's surface according to the generality of climatic conditions into large zones, which are parts of the surface of the globe, having a more or less latitudinal extent and distinguished by certain climatic indicators. Z. to. does not necessarily have to cover the entire hemisphere in latitude. In climatic zones, climatic regions are distinguished. There are vertical zones distinguished in the mountains and lying one above the other. Each of these zones has a specific climate. In different latitudinal zones, the vertical climatic zones of the same name will be different in terms of climate features.

Ecological and geological role of atmospheric processes

The decrease in the transparency of the atmosphere due to the appearance of aerosol particles and solid dust in it affects the distribution of solar radiation, increasing the albedo or reflectivity. Various chemical reactions lead to the same result, causing the decomposition of ozone and the generation of "pearl" clouds, consisting of water vapor. Global change in reflectivity, as well as changes in the gas composition of the atmosphere, mainly greenhouse gases, are the cause of climate change.

Uneven heating, which causes differences in atmospheric pressure over different parts of the earth's surface, leads to atmospheric circulation, which is the hallmark of the troposphere. When there is a difference in pressure, air rushes from areas of high pressure to areas of low pressure. These movements of air masses, together with humidity and temperature, determine the main ecological and geological features of atmospheric processes.

Depending on the speed, the wind produces various geological work on the earth's surface. At a speed of 10 m/s, it shakes thick branches of trees, picks up and carries dust and fine sand; breaks tree branches at a speed of 20 m/s, carries sand and gravel; at a speed of 30 m/s (storm) tears off the roofs of houses, uproots trees, breaks poles, moves pebbles and carries small gravel, and a hurricane at a speed of 40 m/s destroys houses, breaks and demolishes power line poles, uproots large trees.

Squall storms and tornadoes (tornadoes) have a great negative environmental impact with catastrophic consequences - atmospheric vortices that occur in the warm season on powerful atmospheric fronts with a speed of up to 100 m/s. Squalls are horizontal whirlwinds with hurricane wind speeds (up to 60-80 m/s). They are often accompanied by heavy showers and thunderstorms lasting from a few minutes to half an hour. The squalls cover areas up to 50 km wide and travel a distance of 200-250 km. A heavy storm in Moscow and the Moscow region in 1998 damaged the roofs of many houses and knocked down trees.

Tornadoes, called tornadoes in North America, are powerful funnel-shaped atmospheric eddies often associated with thunderclouds. These are columns of air narrowing in the middle with a diameter of several tens to hundreds of meters. The tornado has the appearance of a funnel, very similar to an elephant's trunk, descending from the clouds or rising from the surface of the earth. Possessing a strong rarefaction and high rotation speed, the tornado travels up to several hundred kilometers, drawing in dust, water from reservoirs and various objects. Powerful tornadoes are accompanied by thunderstorms, rain and have great destructive power.

Tornadoes rarely occur in subpolar or equatorial regions, where it is constantly cold or hot. Few tornadoes in the open ocean. Tornadoes occur in Europe, Japan, Australia, the USA, and in Russia they are especially frequent in the Central Black Earth region, in the Moscow, Yaroslavl, Nizhny Novgorod and Ivanovo regions.

Tornadoes lift and move cars, houses, wagons, bridges. Particularly destructive tornadoes (tornadoes) are observed in the United States. From 450 to 1500 tornadoes are recorded annually, with an average of about 100 victims. Tornadoes are fast-acting catastrophic atmospheric processes. They are formed in just 20-30 minutes, and their existence time is 30 minutes. Therefore, it is almost impossible to predict the time and place of occurrence of tornadoes.

Other destructive, but long-term atmospheric vortices are cyclones. They are formed due to a pressure drop, which, under certain conditions, contributes to the occurrence of a circular movement of air currents. Atmospheric vortices originate around powerful ascending currents of humid warm air and rotate at high speed clockwise in the southern hemisphere and counterclockwise in the northern hemisphere. Cyclones, unlike tornadoes, originate over the oceans and produce their destructive actions over the continents. The main destructive factors are strong winds, intense precipitation in the form of snowfall, downpours, hail and surge floods. Winds with speeds of 19 - 30 m / s form a storm, 30 - 35 m / s - a storm, and more than 35 m / s - a hurricane.

Tropical cyclones - hurricanes and typhoons - have an average width of several hundred kilometers. The wind speed inside the cyclone reaches hurricane force. Tropical cyclones last from several days to several weeks, moving at a speed of 50 to 200 km/h. Mid-latitude cyclones have a larger diameter. Their transverse dimensions range from a thousand to several thousand kilometers, the wind speed is stormy. They move in the northern hemisphere from the west and are accompanied by hail and snowfall, which are catastrophic. Cyclones and their associated hurricanes and typhoons are the largest natural disasters after floods in terms of the number of victims and damage caused. In densely populated areas of Asia, the number of victims during hurricanes is measured in the thousands. In 1991, in Bangladesh, during a hurricane that caused the formation of sea waves 6 m high, 125 thousand people died. Typhoons cause great damage to the United States. As a result, dozens and hundreds of people die. In Western Europe, hurricanes cause less damage.

Thunderstorms are considered a catastrophic atmospheric phenomenon. They occur when warm, moist air rises very quickly. On the border of the tropical and subtropical zones, thunderstorms occur for 90-100 days a year, in the temperate zone for 10-30 days. In our country, the largest number of thunderstorms occurs in the North Caucasus.

Thunderstorms usually last less than an hour. Intense downpours, hailstorms, lightning strikes, gusts of wind, and vertical air currents pose a particular danger. The hail hazard is determined by the size of the hailstones. In the North Caucasus, the mass of hailstones once reached 0.5 kg, and in India, hailstones weighing 7 kg were noted. The most hazardous areas in our country are located in the North Caucasus. In July 1992, hail damaged 18 aircraft at the Mineralnye Vody airport.

Lightning is a hazardous weather phenomenon. They kill people, livestock, cause fires, damage the power grid. About 10,000 people die every year from thunderstorms and their consequences worldwide. Moreover, in some parts of Africa, in France and the United States, the number of victims from lightning is greater than from other natural phenomena. The annual economic damage from thunderstorms in the United States is at least $700 million.

Droughts are typical for desert, steppe and forest-steppe regions. The lack of precipitation causes drying up of the soil, lowering the level of groundwater and in reservoirs until they dry up completely. Moisture deficiency leads to the death of vegetation and crops. Droughts are especially severe in Africa, the Near and Middle East, Central Asia and southern North America.

Droughts change the conditions of human life, have an adverse impact on the natural environment through processes such as salinization of the soil, dry winds, dust storms, soil erosion and forest fires. Fires are especially strong during drought in taiga regions, tropical and subtropical forests and savannahs.

Droughts are short-term processes that last for one season. When droughts last more than two seasons, there is a threat of starvation and mass mortality. Typically, the effect of drought extends to the territory of one or more countries. Especially often prolonged droughts with tragic consequences occur in the Sahel region of Africa.

Atmospheric phenomena such as snowfalls, intermittent heavy rains and prolonged prolonged rains cause great damage. Snowfalls cause massive avalanches in the mountains, and the rapid melting of the fallen snow and prolonged heavy rains lead to floods. A huge mass of water falling on the earth's surface, especially in treeless areas, causes severe erosion of the soil cover. There is an intensive growth of ravine-beam systems. Floods occur as a result of large floods during a period of heavy precipitation or floods after a sudden warming or spring snowmelt and, therefore, are atmospheric phenomena in origin (they are discussed in the chapter on the ecological role of the hydrosphere).

Weathering- destruction and change of rocks under the influence of temperature, air, water. A set of complex processes of qualitative and quantitative transformation of rocks and their constituent minerals, leading to the formation of weathering products. Occurs due to the action of the hydrosphere, atmosphere and biosphere on the lithosphere. If rocks are on the surface for a long time, then as a result of their transformations, a weathering crust is formed. There are three types of weathering: physical (ice, water and wind) (mechanical), chemical and biological.

physical weathering

The greater the temperature difference during the day, the faster the weathering process. The next step in mechanical weathering is the entry of water into the cracks, which, when frozen, increases in volume by 1/10 of its volume, which contributes to even greater weathering of the rock. If blocks of rocks fall, for example, into a river, then they are slowly ground down and crushed under the influence of the current. Mudflows, wind, gravity, earthquakes, volcanic eruptions also contribute to the physical weathering of rocks. Mechanical grinding of rocks leads to the passage and retention of water and air by the rock, as well as a significant increase in surface area, which creates favorable conditions for chemical weathering. As a result of cataclysms, rocks can crumble from the surface, forming plutonic rocks. All the pressure on them is exerted by side rocks, due to which the plutonic rocks begin to expand, which leads to the scattering of the upper layer of rocks.

chemical weathering

Chemical weathering is a combination of various chemical processes that result in further destruction of rocks and a qualitative change in their chemical composition with the formation of new minerals and compounds. The most important chemical weathering factors are water, carbon dioxide and oxygen. Water is an energetic solvent of rocks and minerals. The main chemical reaction of water with minerals of igneous rocks - hydrolysis, leads to the replacement of cations of alkaline and alkaline earth elements of the crystal lattice with hydrogen ions of dissociated water molecules:

KAlSi3O8+H2O→HAlSi3O8+KOH

The resulting base (KOH) creates an alkaline environment in the solution, in which further destruction of the orthoclase crystal lattice occurs. In the presence of CO2, KOH transforms into the carbonate form:

2KOH+CO2=K2CO3+H2O

The interaction of water with minerals of rocks also leads to hydration - the addition of water particles to mineral particles. For example:

2Fe2O3+3H2O=2Fe2O 3H2O

In the chemical weathering zone, the oxidation reaction is also widespread, to which many minerals containing oxidizable metals undergo. A striking example of oxidative reactions during chemical weathering is the interaction of molecular oxygen with sulfides in the aquatic environment. Thus, during the oxidation of pyrite, along with sulfates and hydrates of iron oxides, sulfuric acid is formed, which is involved in the creation of new minerals.

2FeS2+7O2+H2O=2FeSO4+H2SO4;

12FeSO4+6H2O+3O2=4Fe2(SO4)3+4Fe(OH)3;

2Fe2(SO4)3+9H2O=2Fe2O3 3H2O+6H2SO4

radiation weathering

Radiation weathering is the destruction of rocks under the action of radiation. Radiation weathering affects the process of chemical, biological and physical weathering. Lunar regolith can serve as a characteristic example of a rock significantly affected by radiative weathering.

biological weathering

Biological weathering is produced by living organisms (bacteria, fungi, viruses, burrowing animals, lower and higher plants). In the course of their life, they act on rocks mechanically (destruction and crushing of rocks by growing plant roots, when walking, digging holes by animals). Especially Microorganisms play an important role in biological weathering.

weathering products

Kurums are the product of weathering in a number of areas of the Earth on the day surface. Weathering products under certain conditions are crushed stone, gruss, "slate" fragments, sandy and clay fractions, including kaolin, loess, individual rock fragments of various shapes and sizes, depending on the petrographic composition, time and weathering conditions.

air masses- these are the moving parts of the troposphere, differing from each other in their properties - temperature, transparency. These properties of air masses depend on the territory over which they are formed under the condition of a long stay. Depending on the formation, 4 main types of air masses are distinguished: (), tropical and. Each of these four types is formed over the expanse of land and sea. Since land and sea heat up to different degrees, subtypes can also form in each of these types - continental and sea air masses.

Arctic (Antarctic) air is formed over the ice surface of polar latitudes; It is characterized by low temperatures, low moisture content, while the maritime Arctic air is more humid than the continental one. Invading low latitudes, Arctic air significantly lowers the temperature. The flat relief contributes to its penetration far into the interior of the mainland. A similar phenomenon can be observed. As you move south, the Arctic air heats up and contributes to the formation of dry winds, which cause frequent in this area.

Moderate air masses form in temperate latitudes. Continental temperate air masses are strongly cooled in winter. They have a low moisture content. With the invasion of continental air masses, a clear frost is established. In summer, the continental air is dry and very hot. Marine air masses of temperate latitudes are humid, temperate; in winter they bring thaws, in summer - cloudy weather and cooling.

Tropical air masses form throughout the year in the tropics. Typically, their marine variety is characterized by high humidity and temperature, and the continental variety is dusty, dry and even higher temperature.

Equatorial air masses are formed in the equatorial zone. around its axis contributes to the movement of air masses to the Northern Hemisphere, then to the Southern. These air masses are characterized by high temperature and high humidity, and for them there is no clear division into maritime air masses and continental air masses.

The resulting air masses inevitably begin to move. The reason for this is the uneven heating of the earth's surface and, as a result, the difference. If there were no movement of air masses, then at the equator the average annual temperature would be 13 ° higher, and at latitudes of 70 ° - 23 ° lower than at present.

Invading areas with different thermal properties of the surface, the air masses are gradually transformed. For example, temperate marine air, entering the land and moving deep into the mainland, gradually heats up and dries up, turning into continental air. The transformation of air masses is especially characteristic of temperate latitudes, which from time to time are invaded by warm and dry air from the latitudes and cold and dry air from the circumpolar ones.

The movement of air masses should lead, first of all, to the smoothing of baric and temperature gradients. However, on our rotating planet with different heat capacity properties of the earth's surface, different heat reserves of land, seas and oceans, the presence of warm and cold ocean currents, polar and continental ice, the processes are very complex and often the heat content contrasts of various air masses not only do not smooth out, but vice versa , increase.[ ...]

The movement of air masses above the Earth's surface is determined by many reasons, including the rotation of the planet, the uneven heating of its surface by the Sun, the formation of zones of low (cyclones) and high (anticyclones) pressure, flat or mountainous terrain, and much more. In addition, at different heights, the speed, stability and direction of air flows are very different. Therefore, the transfer of pollutants entering different layers of the atmosphere proceeds at different rates and sometimes in other directions than in the surface layer. With very strong emissions associated with high energies, pollution entering high, up to 10-20 km, layers of the atmosphere can move thousands of kilometers within a few days or even hours. Thus, the volcanic ash thrown out by the explosion of the Krakatau volcano in Indonesia in 1883 was observed in the form of peculiar clouds over Europe. Radioactive fallout of varying intensity after testing especially powerful hydrogen bombs fell on almost the entire surface of the Earth.[ ...]

The movement of air masses - the wind resulting from the difference in temperature and pressure in different regions of the planet affects not only the physical and chemical properties of the air itself, but also the intensity of heat transfer, changes in humidity, pressure, chemical composition of air, reducing or increasing the amount pollution.[ ...]

The movement of air masses can be in the form of their passive movement of a convective nature or in the form of wind - due to the cyclonic activity of the Earth's atmosphere. In the first case, the settlement of spores, pollen, seeds, microorganisms and small animals is ensured, which have special adaptations for this - anemochores: very small sizes, parachute-like appendages, etc. (Fig. 2.8). All this mass of organisms is called aeroplankton. In the second case, the wind also carries aeroplankton, but over much longer distances, while it can also carry pollutants to new zones, etc.[ ...]

The movement of air masses (wind). As is known, the reason for the formation of wind currents and the movement of air masses is the uneven heating of different parts of the earth's surface, associated with pressure drops. The wind flow is directed towards lower pressure, but the rotation of the Earth also affects the circulation of air masses on a global scale. In the surface layer of air, the movement of air masses affects all meteorological factors of the environment, i.e., the climate, including temperature, humidity, evaporation from land and sea surfaces, as well as plant transpiration.[ ...]

ANOMALOUS CYCLONE MOVEMENT. The movement of a cyclone in a direction sharply divergent from the usual, i.e., from the eastern half of the horizon to the western or along the meridian. A.P.C. is associated with the anomalous direction of the leading flow, which in turn is due to the unusual distribution of warm and cold air masses in the troposphere.[ ...]

AIR MASS TRANSFORMATION. 1. A gradual change in the properties of the air mass during its movement due to changes in the conditions of the underlying surface (relative transformation).[ ...]

The third reason for the movement of air masses is dynamic, which contributes to the formation of high pressure areas. Due to the fact that the most heat comes to the equatorial zone, air masses rise up to 18 km here. Therefore, intensive condensation and precipitation in the form of tropical showers are observed. In the so-called "horse" latitudes (about 30° N and 30° S), cold dry air masses, descending and heating adiabatically, intensively absorb moisture. Therefore, in these latitudes, the main deserts of the planet naturally form. They mainly formed in the western parts of the continents. The westerly winds coming from the ocean do not contain enough moisture to transfer to the descending dry air. Therefore, there is very little rainfall.[ ...]

The formation and movement of air masses, the location and trajectory of cyclones and anticyclones are of great importance for making weather forecasts. A synoptic map provides a visual representation of the state of the weather at the moment over a vast territory.[ ...]

WEATHER TRANSFER. The movement of certain weather conditions along with their "carriers" - air masses, fronts, cyclones and anticyclones.[ ...]

In a narrow border strip separating air masses, frontal zones (fronts) arise, characterized by an unstable state of meteorological elements: temperature, pressure, humidity, wind direction and speed. Here, with exceptional clarity, the most important principle in physical geography of the contrast of environments is manifested, which is expressed in a sharp activation of the exchange of matter and energy in the zone of contact (contact) of natural complexes of different properties and their components (F. N. Milkov, 1968). The active exchange of matter and energy between air masses in the frontal zones is manifested in the fact that it is here that the origin, movement with a simultaneous increase in power and, finally, the extinction of cyclones take place.[ ...]

Solar energy causes planetary movements of air masses as a result of their uneven heating. There are grandiose processes of atmospheric circulation, which are of a rhythmic nature.[ ...]

If in a free atmosphere with turbulent movements of air masses this phenomenon does not play a noticeable role, then in a stationary or low-moving indoor air, this difference should be taken into account. In close proximity to the surface of various bodies, we will have a layer with some excess of negative air ions, while the surrounding air will be enriched with positive air ions.[ ...]

Non-periodic weather changes are caused by the movement of air masses from one geographical area to another in the general atmospheric circulation system.[ ...]

Due to the fact that at high altitudes the speed of movement of air masses reaches 100 m/s, ions moving in a magnetic field can be displaced, although these displacements are insignificant compared to the transfer in a flow. For us, it is important that in the polar zones, where the lines of force of the Earth's magnetic field are closed on its surface, the distortions of the ionosphere are very significant. The number of ions, including ionized oxygen, in the upper layers of the atmosphere of the polar zones is reduced. But the main reason for the low ozone content in the region of the poles is the low intensity of solar radiation, which falls even during the polar day at small angles to the horizon, and is completely absent during the polar night. In itself, the screening role of the ozone layer in the polar regions is not so important precisely because of the low position of the Sun above the horizon, which excludes the high intensity of UV radiation of the surface. However, the area of the polar "holes" in the ozone layer is a reliable indicator of changes in the total ozone content in the atmosphere.[ ...]

The translational horizontal movements of water masses associated with the movement of significant volumes of water over long distances are called currents. Currents arise under the influence of various factors, such as wind (i.e. friction and pressure of moving air masses on the water surface), changes in the distribution of atmospheric pressure, uneven distribution of the density of sea water (i.e. horizontal pressure gradient of waters of different densities at equal depths), the tide-forming forces of the Moon and the Sun. The nature of the movement of masses of water is also significantly influenced by secondary forces, which themselves do not cause it, but manifest themselves only in the presence of movement. These forces include the force that arises due to the rotation of the Earth - the Coriolis force, centrifugal forces, friction of the waters on the bottom and coasts of the continents, internal friction. The distribution of land and sea, the topography of the bottom and the outlines of the coasts have a great influence on sea currents. Currents are classified mainly by origin. Depending on the forces that excite them, the currents are combined into four groups: 1) frictional (wind and drift), 2) gradient-gravitational, 3) tidal, 4) inertial.[ ...]

Wind turbines and sailing ships are propelled by the movement of air masses due to heating it by the sun and creating air currents or winds. one.[ ...]

MOTION CONTROL. The formulation of the fact that the movement of air masses and tropospheric disturbances mainly occurs in the direction of the isobars (isohypses) and, consequently, the air currents of the upper troposphere and lower stratosphere.[ ...]

This, in turn, may lead to a violation of the movement of air masses near industrial areas located next to such a park and increased air pollution.[ ...]

Most weather phenomena depend on whether air masses are stable or unstable. With stable air, vertical movements in it are difficult, with unstable air, on the contrary, they develop easily. The stability criterion is the observed temperature gradient.[ ...]

Hydrodynamic, closed type with adjustable air cushion pressure, with pulsation dampener. Structurally, it consists of a body with a lower lip, a collector with a tilting mechanism, a turbulator, an upper lip with a mechanism for vertical and horizontal movement, mechanisms for fine adjustment of the outlet slot profile with the ability to automatically control the transverse profile of the paper web. The surfaces of the parts of the box that come into contact with the mass are carefully polished and electropolished.[ ...]

The potential temperature, in contrast to the molecular temperature T, remains constant during dry adiabatic movements of the same air particle. If in the process of moving the air mass its potential temperature has changed, then there is an inflow or outflow of heat. The dry adiabat is a line of equal potential temperature.[ ...]

The most typical case of dispersion is the movement of a gas jet in a moving medium, i.e., during the horizontal movement of air masses of the atmosphere.[ ...]

The main reason for short-period OS oscillations, according to the concept put forward in 1964 by the author of the work, is the horizontal movement of the ST axis, which is directly related to the movement of long waves in the atmosphere. Moreover, the direction of the wind in the stratosphere over the place of observation does not play a significant role. In other words, short-term OS fluctuations are caused by a change in air masses in the stratosphere above the observation site, since these masses separate ST.[ ...]

The state of the free surface of reservoirs, due to the large area of their surface, is strongly influenced by the wind. The kinetic energy of the air flow is transferred to the masses of water through friction forces at the interface between two media. One part of the transferred energy is spent on the formation of waves, and the other part is used to create a drift current, i.e. progressive movement of the surface layers of water in the direction of the wind. In reservoirs of limited size, the movement of water masses by a drift current leads to a distortion of the free surface. At the windward coast, the water level drops - a wind surge occurs, at the leeward coast the level rises - a wind surge occurs. At the Tsimlyansk and Rybinsk reservoirs, level differences of 1 m or more were recorded near the leeward and windward shores. With a long wind, the skew becomes stable. The masses of water that are brought to the lee coast by the drift current are diverted in the opposite direction by the near-bottom gradient current.[ ...]

The results obtained are based on solving the problem for stationary conditions. However, the considered scales of the area are relatively small and the time of movement of the air mass ¿ = l:/u is small, which allows us to limit ourselves to the parametric consideration of the characteristics of the oncoming air flow.[ ...]

But the icy Arctic creates difficulties in agriculture not only because of cold and long winters. Cold, and therefore dehydrated arctic: air masses do not warm up during spring-summer movement. The higher the temperature, the more! moisture is needed to saturate it. I. P. Gerasimov and K. K. Mkov noted that “at present, a simple increase in the ice coverage of the Arctic Basin causes. . . zas; in Ukraine and the Volga region” 2.[ ...]

In 1889, a giant cloud of locusts flew from the coast of North Africa across the Red Sea to Arabia. The movement of insects lasted the whole day, and their mass was 44 million tons. V.I. Vernadsky regarded this fact as evidence of the enormous power of living matter, an expression of the pressure of life, striving to capture the entire Earth. At the same time, he saw in this a biogeochemical process - the migration of elements included in the locust biomass, a completely special migration - through the air, over long distances, not consistent with the usual mode of movement of air masses in the atmosphere.[ ...]

Thus, the main factor determining the speed of katabatic winds is the temperature difference between the ice cover and the atmosphere 0 and the angle of inclination of the ice surface. The movement of the cooled air mass down the slope of the ice dome of Antarctica is enhanced by the effects of the fall of the air mass from the height of the ice dome and the influence of baric gradients in the Antarctic anticyclone. Horizontal baric gradients, being an element of the formation of katabatic winds in Antarctica, contribute to an increase in the outflow of air to the periphery of the continent, primarily due to its supercooling near the surface of the ice sheet and the slope of the ice dome towards the sea.[ ...]

The analysis of synoptic maps is as follows. According to the information plotted on the map, the actual state of the atmosphere at the time of observation is established: the distribution and nature of air masses and fronts, the location and properties of atmospheric disturbances, the location and nature of clouds and precipitation, temperature distribution, etc. for given conditions of atmospheric circulation. By compiling maps for different periods, you can follow them for changes in the state of the atmosphere, in particular, for the movement and evolution of atmospheric disturbances, the movement, transformation and interaction of air masses, etc. The presentation of atmospheric conditions on synoptic maps provides a convenient opportunity for information about the state of the weather.[ . ..]

Atmospheric macroscale processes studied with the help of synoptic maps and which are the cause of the weather regime over large geographic areas. This is the emergence, movement and change in the properties of air masses and atmospheric fronts; the emergence, development and movement of atmospheric disturbances - cyclones and anticyclones, the evolution of condensation systems, intramass and frontal, in connection with the above processes, etc.[ ...]

Until aerial chemical treatment is completely excluded, it is necessary to make improvements in its use by the most careful selection of objects, reducing the likelihood of “demolitions” - movements of sawing air masses, controlled dosage, etc. For primary care in clearings through the use of herbicides, it is advisable to use typological diagnostics to a greater extent clearings. Chemistry is a powerful means of forest care. But it is important that chemical care does not turn into poisoning of the forest, its inhabitants and visitors.[ ...]

In the nature around us, water is in constant motion - and this is just one of the many natural cycles of substances in nature. When we say “movement”, we mean not only the movement of water as a physical body (flow), not only its movement in space, but, above all, the transition of water from one physical state to another. In Figure 1 you can see how the water cycle works. On the surface of lakes, rivers and seas, water under the influence of the energy of sunlight turns into water vapor - this process is called evaporation. In the same way, water evaporates from the surface of the snow and ice cover, from the leaves of plants and from the bodies of animals and humans. Water vapor with warmer air currents rises to the upper layers of the atmosphere, where it gradually cools and again turns into a liquid or turns into a solid state - this process is called condensation. At the same time, water moves with the movement of air masses in the atmosphere (winds). From the resulting water droplets and ice crystals, clouds are formed, from which, in the end, rain or snow falls on the ground. Water returned to earth in the form of precipitation flows down the slopes and collects in streams and rivers that flow into lakes, seas and oceans. Part of the water seeps through the soil and rocks, reaches groundwater and groundwater, which also, as a rule, have a runoff into rivers and other water bodies. Thus, the circle closes and can be repeated in nature indefinitely.[ ...]

SYNOPTIC METEOROLOGY. Meteorological discipline, which took shape in the second half of the XIX century. and especially in the 20th century; the doctrine of atmospheric macroscale processes and weather forecasting based on their study. Such processes are the emergence, evolution and movement of cyclones and anticyclones, which are closely related to the emergence, movement and evolution of air masses and fronts between them. The study of these synoptic processes is carried out with the help of a systematic analysis of synoptic maps, vertical sections of the atmosphere, aerological diagrams and other auxiliary means. The transition from a synoptic analysis of circulation conditions over large areas of the earth's surface to their forecast and to the forecast of weather conditions associated with them is still largely reduced to extrapolation and qualitative conclusions from the provisions of dynamic meteorology. However, in the last 25 years, numerical (hydrodynamic) forecasting of meteorological fields has been increasingly used by numerically solving the equations of atmospheric thermodynamics on electronic computers. See also the weather service, weather forecast and a number of other terms. Common synonym: weather forecast.[ ...]

The case of jet propagation analyzed by us is not typical, since there are very few calm periods in almost any area. Therefore, the most typical case of scattering is the movement of a gas jet in a moving medium, i.e., in the presence of a horizontal movement of atmospheric air masses.[ ...]

It is obvious that simply the air temperature T is not a conservative characteristic of the heat content of the air. So, with a constant heat content of an individual volume of air (turbulent mole), its temperature can vary depending on the pressure (1.1). Atmospheric pressure, as we know, decreases with height. As a result, vertical movement of air leads to changes in its specific volume. In this case, the work of expansion is realized, which leads to changes in the temperature of air particles even in the case when the processes are isentropic (adiabatic), i.e. there is no heat exchange of an individual mass element with the surrounding space. Changes in the temperature of the air moving along the vertical will correspond to dry diabatic or wet diabatic gradients, depending on the nature of the thermodynamic process.

Condensation is the change in the state of a substance from gaseous to liquid or solid. But what is condensation in the mastaba of the planet?

At any given time, the atmosphere of the planet Earth contains over 13 billion tons of moisture. This figure is almost constant, as losses due to precipitation are eventually continuously replaced by evaporation.

Moisture cycle rate in the atmosphere

The rate of circulation of moisture in the atmosphere is estimated at a colossal figure - about 16 million tons per second or 505 billion tons per year. If suddenly all the water vapor in the atmosphere condensed and fell out as precipitation, then this water could cover the entire surface of the globe with a layer of about 2.5 centimeters, in other words, the atmosphere contains an amount of moisture equivalent to only 2.5 centimeters of rain.

How long does a vapor molecule stay in the atmosphere?

Since on Earth an average of 92 centimeters falls per year, therefore, moisture in the atmosphere is renewed 36 times, that is, 36 times the atmosphere is saturated with moisture and freed from it. This means that a water vapor molecule stays in the atmosphere for an average of 10 days.

Water molecule path

Once evaporated, a water vapor molecule usually drifts hundreds and thousands of kilometers until it condenses and falls with precipitation to the Earth. Water that falls as rain, snow or hail on the highlands of Western Europe travels about 3,000 km from the North Atlantic. Between the transformation of liquid water into steam and the precipitation on Earth, several physical processes take place.

From the warm surface of the Atlantic, water molecules enter warm, moist air, which then rises above the surrounding colder (more dense) and drier air.

If in this case a strong turbulent mixing of air masses is observed, then a layer of mixing and clouds will appear in the atmosphere at the border of two air masses. About 5% of their volume is moisture. Steam-saturated air is always lighter, firstly, because it is heated and comes from a warm surface, and secondly, because 1 cubic meter of pure steam is about 2/5 lighter than 1 cubic meter of clean dry air at the same temperature and pressure. It follows that moist air is lighter than dry air, and warm and humid air is even more so. As we shall see later, this is a very important fact for weather change processes.

Movement of air masses

Air can rise for two reasons: either because it becomes lighter as a result of heating and moisture, or because forces act on it, causing it to rise above some obstacles, such as masses of colder and denser air, or over hills and mountains.

Cooling

Rising air, having fallen into layers with lower atmospheric pressure, is forced to expand and at the same time cool. Expansion requires the expenditure of kinetic energy, which is taken from the thermal and potential energy of atmospheric air, and this process inevitably leads to a decrease in temperature. The cooling rate of a rising portion of air often changes if this portion is mixed with the surrounding air.

Dry adiabatic gradient

Dry air, in which there is no condensation or evaporation, as well as mixing, which does not receive energy in another form, cools or heats up by a constant amount (by 1 ° C every 100 meters) as it rises or falls. This value is called the dry adiabatic gradient. But if the rising air mass is moist and condensation occurs in it, then the latent heat of condensation is released and the temperature of the air saturated with steam falls much more slowly.

Wet adiabatic gradient

This amount of temperature change is called the wet-adiabatic gradient. It is not constant, but changes with the change in the amount of latent heat released, in other words, it depends on the amount of condensed steam. The amount of steam depends on how much the air temperature drops. In the lower layers of the atmosphere, where the air is warm and humidity is high, the wet-adiabatic gradient is slightly more than half of the dry-adiabatic gradient. But the wet-adiabatic gradient gradually increases with height and at a very high altitude in the troposphere is almost equal to the dry-adiabatic gradient.

The buoyancy of moving air is determined by the ratio between its temperature and the temperature of the surrounding air. As a rule, in the real atmosphere, the temperature of the air falls unevenly with height (this change is simply called a gradient).

If the mass of air is warmer and therefore less dense than the surrounding air (and the moisture content is constant), then it rises in the same way as a child's ball immersed in a tank. Conversely, when the moving air is colder than the surrounding air, its density is higher and it sinks. If the air has the same temperature as the neighboring masses, then their density is equal and the mass remains stationary or moves only together with the surrounding air.

Thus, there are two processes in the atmosphere, one of which promotes the development of vertical air movement, and the other slows it down.

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