Basic meteorological factors. Meteorological factors and their effect on the body

METEOROLOGICAL FACTORS - a group of natural environmental factors affecting, along with cosmic (radiation) and telluric (terrestrial), the human body. Physical and chemical factors of the atmosphere have a direct impact on humans.

Chemical factors include gases and various impurities. Gases whose content in the atmosphere is almost constant include nitrogen (78.08 vol.%), oxygen (20.95), argon (0.93), hydrogen (0.00005), neon (0.0018), helium (0.0005), krypton (0.0001), xenon (0.000009). The content of other gases in the atmosphere varies significantly. Thus, the carbon dioxide content ranges from 0.03 to 0.05%, and near some industrial enterprises and carbon dioxide mineral springs it can increase to 0.07-0.16%. The formation of ozone is associated with thunderstorms and the oxidation of certain organic substances, so its content at the Earth's surface is negligible and very variable. Ozone is mainly formed at an altitude of 20-40 km under the influence of UV rays from the Sun and, by delaying the short-wave part of the UV spectrum (UV-C with wavelengths shorter than 280 nm), protects living matter from death, i.e. plays the role of a giant filter protecting life on Earth. Due to its chemical activity, ozone has pronounced bactericidal and deodorizing properties. Atmospheric air may also contain small amounts of other gases: ammonia, chlorine, hydrogen sulfide, carbon monoxide, various nitrogen compounds, etc., which are mainly the result of air pollution from industrial waste. The emanation of radioactive elements and gaseous metabolic products of soil bacteria enter the atmosphere from the soil. The air may contain aromatic substances and phytoncides released by plants. Many of them have bactericidal properties. The air of forests contains 200 times less bacteria than the air of cities. Finally, the air contains suspended particles in liquid and solid states: sea salts, organic substances (bacteria, spores, pollen, etc.), mineral particles of volcanic and cosmic origin, smoke, etc. The content of these substances in the air is determined by various factors - features of the underlying surface, the nature of vegetation, the presence of seas, etc.

Chemicals contained in the air can actively affect the body. Thus, sea salts contained in the seaside air, aromatic substances released by plants (monarda, basil, rosemary, sage, etc.), garlic phytoncides, etc. have a beneficial effect on patients with diseases of the upper respiratory tract and lungs. Volatile substances released by poplar, oak, and birch help to increase redox processes in the body, and volatile substances from pine and spruce inhibit tissue respiration. Volatile substances from dope, hops, magnolia, bird cherry and other plants have a toxic effect on the body. High concentrations of terpenes in the air of pine forests can have adverse effects on patients with cardiovascular diseases. There is evidence that the development of negative reactions depends on the increase in ozone content in the air.

Of all the chemical factors in the air, oxygen is of absolute vital importance. When going uphill, the partial pressure of oxygen in the air decreases, which leads to symptoms of oxygen deficiency and the development of various kinds of compensatory reactions (increased respiration volume and blood circulation, red blood cell and hemoglobin content, etc.). In plain conditions, relative fluctuations in the partial pressure of oxygen are very insignificant, but relative changes in its density are more significant, since they depend on the ratio of pressure, temperature and air humidity. An increase in temperature and humidity and a decrease in pressure lead to a decrease in the partial density of oxygen, and a decrease in temperature, humidity and an increase in pressure lead to an increase in oxygen density. Changes in temperature from -30 to +30°C, pressure in the range of 933-1040 mbar, relative humidity from 0 to 100% lead to a change in the partial density of oxygen in the range of 238-344 g/m 3, while the partial pressure of oxygen in these conditions fluctuates between 207-241 mbar. According to V.F. Ovcharova (1966, 1975, 1981, 1985), a change in partial oxygen density can cause biotropic effects of a hypoxic and hypotensive nature when it decreases, and tonic and spastic effects when it increases. Weak change in partial oxygen density ±5 g/m3, moderate ±5.1-10 g/m3, pronounced ±10.1-20 g/m3, sharp ±20 g/m3.

Physical meteorological factors include air temperature and humidity, atmospheric pressure, cloudiness, precipitation, and wind.

Air temperature is determined primarily by solar radiation, and therefore periodic (daily and seasonal) temperature fluctuations are observed. In addition, there may be sudden (non-periodic) temperature changes associated with general atmospheric circulation processes. To characterize the thermal regime in climate therapy, the values ​​of average daily, monthly and annual temperatures, as well as maximum and minimum values, are used. To determine temperature changes, a value such as inter-day temperature variability is used (the difference in the average daily temperature of two adjacent days, and in operational practice, the difference in the values ​​of two consecutive morning measurement periods). A slight cooling or warming is considered to be a change in the average daily temperature by 2-4°C, a moderate cooling or warming - by 4-6°C, a sharp one - more than 6°C.

The air is heated by transferring heat from the earth's surface, which absorbs the sun's rays. This heat transfer occurs mainly by convection, i.e., the vertical movement of air heated by contact with the underlying surface, in place of which cooler air from the upper layers descends. In this way, a layer of air about 1 km thick is heated. Higher up, in the troposphere (lower layer of the atmosphere), heat exchange is determined by turbulence on a planetary scale, i.e., mixing of air masses; in front of the cyclone, warm air is carried from low latitudes to high latitudes; in the rear of cyclones, cold air masses from high latitudes invade low latitudes. The temperature distribution along height is determined by the nature of convection. In the absence of condensation of water vapor, the air temperature decreases at the HS with an increase for every 100 m, and with condensation of water vapor - only by 0.4 °C. As you move away from the Earth's surface, the temperature in the troposphere decreases by an average of 0.65 °C for every 100 m of altitude (vertical temperature gradient).

The air temperature of a given area depends on a number of physical and geographical conditions. In the presence of vast expanses of water, daily and annual temperature fluctuations in coastal areas are reduced. In mountainous areas, in addition to the altitude above sea level, the location of mountain ranges and valleys, the accessibility of the area to winds, etc. are important. Finally, the nature of the landscape plays a role. A surface covered with vegetation heats up during the day and cools less at night than an open surface. Temperature is one of the important factors in characterizing the weather and seasons. According to the Fedorov-Chubukov classification, three large groups of weather are distinguished based on the temperature factor: frost-free, with the air temperature passing through 0°C and frosty.

Sharp sudden temperature fluctuations and extreme (maximum and minimum) temperatures that cause pathological conditions (frostbite, colds, overheating, etc.) can have an adverse effect on a person. A classic example of this is the massive flu outbreak (40,000 people) in St. Petersburg, when on one January night in 1780 the temperature rose from -43.6 to +6 °C.

Atmospheric pressure is measured in millibars (mbar), pascals (Pa) or millimeters of mercury (mmHg). 1 mbar=100 Pa. In mid-latitudes at sea level, air pressure averages 760 mmHg. Art., or 1013 mbar (101.3 kPa). As you rise, the pressure decreases by 1 mmHg. Art. (0.133 kPa) for every 11 m of height. Air pressure is characterized by strong non-periodic fluctuations associated with weather changes, with pressure fluctuations reaching 10-20 mbar (1-2 kPa), and in sharply continental areas - up to 30 mbar (3 kPa). A weak change in pressure is considered to be a decrease or increase in its average daily value by 1-4 mbar (0.1-0.4 kPa), moderate - by 5-8 mbar (0.5-0.8 kPa), sharp - more than 8 mbar ( 0.8 kPa). Significant changes in atmospheric pressure can lead to various pathological reactions, especially in patients.

Air humidity is characterized by vapor pressure (in mbar) and relative humidity, that is, the percentage ratio of the pressure (partial pressure) of water vapor in the atmosphere to the pressure of saturating water vapor at the same temperature. Sometimes the water vapor pressure is called absolute humidity, which is actually the density of water vapor in the air and, when expressed in g/m3, is close in value to the vapor pressure in mmHg. Art. The difference between the fully saturated and actual elasticity of water vapor at a given temperature and pressure is called the moisture deficit (lack of saturation). In addition, the so-called physiological saturation is distinguished, i.e. the elasticity of water vapor at human body temperature (37 °C). It is equal to 47.1 mmHg. Art. (6.28 kPa). The physiological saturation deficit will be the difference between the water vapor pressure at 37 °C and the water vapor pressure in the outside air. In summer, the vapor pressure is much higher, and the saturation deficit is smaller than in winter. Weather reports usually indicate relative humidity, since changes in humidity can be directly felt by humans. The air is considered dry at a humidity of up to 55%, moderately dry at 56-70%, humid at 71-85%, very humid (damp) at over 85%. Relative humidity changes in the opposite direction to seasonal and diurnal temperature variations.

Air humidity in combination with temperature has a pronounced effect on the body. The most favorable conditions for humans are conditions under which the relative humidity is 50%, the temperature is 17-19 °C, and the wind speed does not exceed 3 m/s. An increase in air humidity, preventing evaporation, makes heat painful (stuffy conditions) and enhances the effect of cold, promoting greater heat loss through conduction (humid-frost conditions). Cold and heat are more easily tolerated in dry climates than in humid climates.

When the temperature drops, the moisture in the air condenses and fog forms. It also occurs when warm, moist air mixes with cold, moist air. In industrial areas, fog can absorb toxic gases, which react chemically with water to form sulfur compounds (toxic smog). This could lead to mass poisoning of the population. In humid air, the danger of airborne infection is higher, since droplets of moisture, which may contain pathogens, have a greater ability to diffuse than dry dust, and therefore can get into the most remote areas of the lung.

Cloudiness is formed over the earth's surface by condensation and sublimation of water vapor contained in the air. The resulting clouds may consist of water droplets or ice crystals. Cloudiness is measured on an 11-point scale, according to which 0 corresponds to the complete absence of clouds, and 10 points to completely cloudy. The weather is regarded as clear and partly cloudy with 0-5 points of low cloudiness, cloudy - with 6-8 points, cloudy - with 9-10 points. The nature of clouds at different altitudes is different. The clouds of the upper tier (with a base above 6 km) consist of ice crystals, light, transparent, snow-white, almost not blocking direct sunlight and at the same time, diffusely reflecting them, significantly increasing the influx of radiation from the vault of heaven (scattered radiation). Middle-tier clouds (2-6 km) consist of supercooled drops of water or a mixture of it with ice crystals and snowflakes; they are denser, acquire a grayish tint, the sun shines through them weakly or does not shine through at all. The clouds of the lower tier look like low gray heavy ridges, shafts or a veil that covers the sky with a continuous cover; the sun usually does not shine through them. Daily changes in cloudiness are not of a strictly regular nature, and its annual course depends on the general physical and geographical conditions and landscape features. Cloudiness affects the light regime and causes precipitation, which sharply disrupts the daily variation of temperature and air humidity. These two factors, if pronounced, can have an adverse effect on the body in cloudy weather.

Precipitation can be liquid (rain) or solid (snow, pellets, hail). The nature of precipitation depends on the conditions of its formation. If rising air currents with high absolute humidity reach high altitudes, which are characterized by low temperatures, then water vapor sublimates and falls in the form of cereals, hail, and melted water vapor in the form of heavy rain. The distribution of precipitation is influenced by the physical and geographical features of the area. Within continents, precipitation is usually less than on the coast. There are usually more of them on the mountain slopes facing the sea than on the opposite ones. Rain plays a positive sanitary role: it purifies the air and washes away dust; droplets containing microbes fall to the ground. At the same time, rain, especially prolonged rain, worsens climate therapy conditions. Snow cover, having a high reflectivity (albedo) to short-wave radiation, significantly weakens the processes of solar heat accumulation, increasing winter frosts. The albedo of snow to UV radiation is especially high (up to 97%), which increases the effectiveness of winter heliotherapy, especially in the mountains. Often, short-term rain and snow improve the condition of weather-sensitive people and help stop previously existing weather-related complaints. The weather is considered without precipitation if the total amount per day does not reach 1 mm.

Wind is characterized by direction and speed. The direction of the wind is determined by the side of the world from which it blows (north, south, west, east). In addition to these main directions, intermediate ones are distinguished, amounting to a total of 16 directions (northeast, northwest, southeast, etc.). Wind strength is determined on the 13-point Simpson-Beaufort scale, on which 0 corresponds to calm (anemometer speed 0-0.5 m/s), 1 to quiet wind (0.6-1.7), 2 to light wind (1 ,8-3.3), 3 - weak (3.4-5.2), 4 - moderate (5.3-7.4), 5 - fresh (7.5-9.8), 6 - strong (9.9-12.4), 7 - strong (12.5-15.2), 8 - very strong (15.3-18.2), 9 - storm (18.3-21.5), 10 - strong storm (21.6-25.1), 11 - severe storm (25.2-29), 12 - hurricane (more than 29 m/s). A sharp short-term increase in wind up to 20 m/s or more is called a squall.

Wind is caused by pressure differences: air moves from an area of ​​high pressure to an area of ​​low pressure. The greater the pressure difference, the stronger the wind. Air circulations are created with varying frequency, which are of great importance for the formation of the microclimate and have a certain impact on humans. The heterogeneity of pressure in horizontal directions is due to the heterogeneity of the thermal regime on the earth's surface. In summer, the land heats up more than the water surface, as a result of which the air above the land expands from heating, rises, where it spreads in horizontal directions. This leads to a decrease in the total mass of air and, consequently, to a decrease in pressure at the earth's surface. Therefore, in the summer, relatively cool and humid sea air in the lower layers of the troposphere rushes from the sea to the land, and in the winter, dry cold air flows from the land to the sea. Such seasonal winds (monsoons) are most pronounced in Asia, on the border of the largest continent and the ocean. Within the USSR, they are more often observed in the Far East. The same change in winds is observed in coastal areas during the day - these are breezes, i.e. winds blowing from sea to land during the day, and from land to sea at night, spreading 10-15 km on both sides of the coastline. In southern coastal resorts in the summer during the daytime, they reduce the feeling of heat. In the mountains, mountain-valley winds arise, blowing up the slopes (valleys) during the day, and down from the mountains at night. They occur mainly in the warm season, in clear, calm weather and have a beneficial effect on humans. In mountainous areas, when there are mountains in the path of the air flow with a large pressure difference between one side and the other of the mountain range, a kind of warm and dry wind blowing from the mountains is formed - a foehn. In this case, as the air rises, it loses moisture in the form of precipitation and cools somewhat, and when it crosses the mountain range and descends, it heats up significantly. As a result, the air temperature during a hairdryer can increase by 10-15 °C or more in a short period of time (15-30 minutes). Hair dryers usually occur in winter and spring. Most often among the resort areas of the USSR they are formed in Tskhaltubo. Strong hair dryers cause a depressed, irritated state and worsen breathing. When air moves horizontally from hot and very dry areas, dry winds arise, during which humidity can drop to 10-15%. Bora is a mountain wind observed in the cold season in areas where low mountain ranges come close to the sea. The wind is gusty, strong (up to 20-40 m/s), duration is 1-3 days, often causes meteopathic reactions; happens in Novorossiysk, on the coast of Lake Baikal (Sarma), on the Mediterranean coast of France (Mistral).

At low temperatures, the wind increases heat transfer, which can lead to hypothermia. The lower the air temperature, the harder the wind is to bear. In hot weather, the wind increases skin evaporation and improves well-being. A strong wind has an adverse effect, it tires, irritates the nervous system, makes breathing difficult, while a small wind tones and stimulates the body.

The electrical state of the atmosphere is determined by the electric field strength, air conductivity, ionization, and electrical discharges in the atmosphere. The earth has the properties of a negatively charged conductor, and the atmosphere has the properties of a positively charged one. The potential difference between the Earth and a point located at a height of 1 m (electric potential gradient) is on average 130 V. The voltage of the electric field of the atmosphere has great variability depending on meteorological phenomena, especially precipitation, cloudiness, thunderstorms, etc., as well as depending on the time of year, geographic latitude and altitude. When clouds pass through, atmospheric electricity changes within significant limits within 1 minute (from +1200 to -4000 V/m).

The electrical conductivity of air is determined by the amount of positively and negatively charged atmospheric ions (aeroions) it contains. In 1 cm 3 of air, an average of 12 pairs of ions are formed every second, as a result of which about 1000 pairs of nones are constantly present in it. The unipolarity coefficient (the ratio of the number of positively charged ions to the number of negatively charged ones) in all zones except mountainous ones is above 1. Positive ions accumulate before a thunderstorm, and negative ions accumulate after a thunderstorm. During condensation of water vapor, positive ions predominate; during evaporation, negative ions predominate.

The parameters of atmospheric electricity have daily and seasonal periodicity, which, however, is very often overlapped by more powerful non-periodic fluctuations caused by changes in air masses.

Atmospheric processes change in time and space, being one of the main factors in weather and climate formation. The main form of general atmospheric circulation in extratropical latitudes is cyclonic activity (the emergence, development and movement of cyclones and anticyclones). In this case, the pressure changes sharply, causing a circular movement of air from the periphery to the center (cyclone) or from the center to the periphery (anticyclone). Cyclones and anticyclones also differ in the parameters of atmospheric electricity. With increasing pressure, especially on the ridge, which is the peripheral part of the anticyclone, the potential gradient increases sharply (up to 1300 V/m). Electromagnetic pulses travel at the speed of light and are detected from long distances. In this regard, they are not only a sign of the development of processes in the atmosphere, but also a certain link in its development. Anticipating changes in the main meteorological factors during the passage of fronts, they can be the first irritants, causing various kinds of meteoropathic reactions before a visible change in the weather.

The main meteorological climate-forming factors are the mass and chemical composition of the atmosphere.

The mass of the atmosphere determines its mechanical and thermal inertia, its capabilities as a coolant capable of transferring heat from heated areas to cooled ones. Without an atmosphere, Earth would have a “lunar climate”, i.e. climate of radiant equilibrium.

Atmospheric air is a mixture of gases, some of which have an almost constant concentration, others have a variable concentration. In addition, the atmosphere contains various liquid and solid aerosols, which also play a significant role in climate formation.

The main components of atmospheric air are nitrogen, oxygen and argon. The chemical composition of the atmosphere remains constant up to approximately 100 km altitude; above that, gravitational separation of gases begins to take effect and the relative content of lighter gases increases.

Particularly important for climate are thermodynamically active impurities that vary in content and have a great influence on many processes in the atmosphere, such as water, carbon dioxide, ozone, sulfur dioxide and nitrogen dioxide.

A striking example of a thermodynamically active impurity is water in the atmosphere. The concentration of this water (specific humidity, to which specific water content in the clouds is added) is highly variable. Water vapor makes a significant contribution to air density, atmospheric stratification, and especially to fluctuations and turbulent entropy flows. It is capable of condensing (or sublimating) on ​​particles (nuclei) existing in the atmosphere, forming clouds and fogs, as well as releasing large amounts of heat. Water vapor and especially cloudiness dramatically affect the fluxes of short-wave and long-wave radiation in the atmosphere. Water vapor also causes the greenhouse effect, i.e. the ability of the atmosphere to transmit solar radiation and absorb thermal radiation from the underlying surface and underlying atmospheric layers. Due to this, the temperature in the atmosphere increases with depth. Finally, colloidal instability may occur in clouds, causing coagulation of cloud particles and precipitation.

Another important thermodynamically active impurity is carbon dioxide, or carbon dioxide. It makes a significant contribution to the greenhouse effect by absorbing and re-emitting long-wave radiation energy. There may have been significant fluctuations in carbon dioxide levels in the past, which would have affected the climate.

The influence of solid artificial and natural aerosols contained in the atmosphere has not yet been well studied. Sources of solid aerosols on Earth are deserts and semi-deserts, areas of active volcanic activity, as well as industrialized areas.

The ocean also supplies small amounts of aerosols - particles of sea salt. Large particles fall out of the atmosphere relatively quickly, while the smallest particles remain in the atmosphere for a long time.

Aerosol influences the flux of radiant energy in the atmosphere in several ways. First, aerosol particles facilitate cloud formation and thereby increase albedo, i.e. the share of solar energy reflected and irretrievably lost for the climate system. Second, the aerosol scatters a significant portion of solar radiation, so that some of the scattered radiation (very small) is also lost to the climate system. Finally, some of the solar energy is absorbed by aerosols and reradiated both to the Earth's surface and into space.

Over the long history of the Earth, the amount of natural aerosol has fluctuated significantly, since periods of increased tectonic activity and, conversely, periods of relative calm are known. There were also periods in the history of the Earth when much larger land masses were located in hot, dry climatic zones and, conversely, the oceanic surface predominated in these zones. Currently, as in the case of carbon dioxide, artificial aerosol, a product of human economic activity, is becoming increasingly important.

Ozone is also a thermodynamically active impurity. It is present in the layer of the atmosphere from the Earth's surface to an altitude of 60–70 km. In the lowest layer of 0–10 km its content is insignificant, then it quickly increases and reaches a maximum at an altitude of 20–25 km. Further, the ozone content quickly decreases, and at an altitude of 70 km it is already 1000 times less than even at the surface. This vertical distribution of ozone is associated with the processes of its formation. Ozone is formed mainly as a result of photochemical reactions under the influence of high-energy photons belonging to the extreme ultraviolet part of the solar spectrum. In these reactions, atomic oxygen appears, which then combines with an oxygen molecule to form ozone. At the same time, ozone decomposition reactions occur when it absorbs solar energy and when its molecules collide with oxygen atoms. These processes, together with the processes of diffusion, mixing and transport, lead to the equilibrium vertical ozone profile described above.

Despite such insignificant content, its role is extremely great and not only for the climate. Due to the exceptionally intense absorption of radiant energy during the processes of its formation and (to a lesser extent) decay, strong heating occurs in the upper part of the layer of maximum ozone content - the ozonosphere (the maximum ozone content is located somewhat lower, where it enters as a result of diffusion and mixing). Of all solar energy falling on the upper boundary of the atmosphere, ozone absorbs about 4%, or 6·10 27 erg/day. In this case, the ozonosphere absorbs the ultraviolet part of radiation with a wavelength of less than 0.29 microns, which has a detrimental effect on living cells. In the absence of this ozone screen, apparently, life could not have arisen on Earth, at least in the forms known to us.

The ocean, which is an integral part of the climate system, plays an extremely important role in it. The primary property of the ocean, as well as the atmosphere, is mass. However, it is also important for the climate on what part of the Earth’s surface this mass is located.

Among the thermodynamically active impurities in the ocean are salts and gases dissolved in water. The amount of dissolved salts affects the density of sea water, which at a given pressure depends not only on temperature, but also on salinity. This means that salinity, along with temperature, determines density stratification, i.e. makes it stable in some cases, and in others leads to convection. The nonlinear dependence of density on temperature can lead to a curious phenomenon called mixing compaction. The temperature of the maximum density of fresh water is 4°C, warmer and colder water has a lower density. When mixing two volumes of such lighter waters, the mixture may turn out to be heavier. If there is lower density water below, the mixed water may begin to sink. However, the temperature range at which this phenomenon occurs in fresh water is very narrow. The presence of dissolved salts in ocean water increases the likelihood of such a phenomenon.

Dissolved salts change many of the physical characteristics of seawater. Thus, the coefficient of thermal expansion of water increases, and the heat capacity at constant pressure decreases, the freezing point and maximum density decrease. Salinity somewhat reduces the pressure of saturating vapor above the water surface.

An important ability of the ocean is the ability to dissolve large amounts of carbon dioxide. This makes the ocean a capacious reservoir that, under some conditions, can absorb excess atmospheric carbon dioxide, and under others, release carbon dioxide into the atmosphere. The importance of the ocean as a reservoir of carbon dioxide is further enhanced by the existence in the ocean of the so-called carbonate system, which absorbs huge amounts of carbon dioxide contained in modern limestone deposits.

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The construction and operation of sea and river ports is carried out under constant influence of a number of external factors inherent in the main natural environments: atmosphere, water and land. Accordingly, external factors are divided into 3 main groups:

1) meteorological;

2) hydrological and lithodynamic;

3) geological and geomorphological.

Meteorological factors:

Wind mode. The wind characteristics of the construction area are the main factor determining the location of the port in relation to the city, the zoning of its territory, and the relative position of berths for various technological purposes. Being the main wave-forming factor, the regime characteristics of the wind determine the configuration of the coastal berth front, the layout of the port water area and external protective structures, and the routing of water approaches to the port.

As a meteorological phenomenon, wind is characterized by direction, speed, spatial distribution (acceleration) and duration of action.

Wind direction for the purposes of port construction and shipping is usually considered according to 8 main points.

Wind speed is measured at a height of 10 m above the surface of water or land, averaged over 10 minutes and expressed in meters per second or knots (knots, 1 knot = 1 mile/hour = 0.514 meters/second).

If it is impossible to meet these requirements, the results of wind observations can be corrected by introducing appropriate amendments.

Acceleration is understood as the distance within which the wind direction changed by no more than 300.

Wind duration is the period of time during which the direction and speed of the wind were within a certain interval.

The main probabilistic (regime) characteristics of wind flow used in the design of sea and river ports are:

· repeatability of directions and gradations of wind speeds;

· provision of wind speeds in certain directions;

· calculated wind speeds corresponding to specified return periods.

Water and air temperature. When designing, constructing and operating ports, information about air and water temperatures within the limits of their variation, as well as the likelihood of extreme values, is used. In accordance with temperature data, the timing of freezing and opening of pools is determined, the duration and working period of navigation is established, and the operation of the port and fleet is planned. Statistical processing of long-term data on water and air temperatures involves the following steps:

Air humidity. Air humidity is determined by the content of water vapor in it. Absolute humidity is the amount of water vapor in the air, relative humidity is the ratio of absolute humidity to its limit value at a given temperature.

Water vapor enters the atmosphere through evaporation from the earth's surface. In the atmosphere, water vapor is transported by ordered air currents and by turbulent mixing. Under the influence of cooling, water vapor in the atmosphere condenses - clouds are formed, and then precipitation falls on the ground.

A layer of water 1423 mm thick (or 5.14x1014 tons) evaporates from the surface of the oceans (361 million km2) during the year, and 423 mm (or 0.63x1014 tons) from the surface of the continents (149 million km2). The amount of precipitation on the continents significantly exceeds evaporation. This means that a significant mass of water vapor enters the continents from the oceans and seas. On the other hand, water that does not evaporate on the continents enters rivers and then seas and oceans.

Information about air humidity is taken into account when planning the transshipment and storage of certain types of cargo (eg tea, tobacco).

Fogs. The occurrence of fog is caused by the transformation of vapors into tiny water droplets with increasing air humidity. Droplets form when there are tiny particles in the air (dust, salt particles, combustion products, etc.).

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Medical climatology is the science of the influence of natural environmental factors on the human body.

Objectives of medical climatology:

1. Study of the physiological mechanisms of the influence of climate and weather factors on the human body

2. Medical assessment of weather conditions.

3. Development of indications and contraindications for the prescription of various types of climatic treatment methods.

4. Scientific development of methods for dosing climatotherapeutic procedures.

5. Prevention of meteopathic reactions.

Classification of climatological factors

There are three main groups of natural factors external environment affecting humans:

1. Atmospheric or meteorological.

2. Space or radiation.

3. Telluric or terrestrial.

For medical climatology, the lower layers of the atmosphere are mainly of interest - the troposphere, where the most intense heat and moisture exchange between the atmosphere and the earth's surface, the formation of clouds and precipitation occur. This layer of the atmosphere has a height of 10-12 km in mid-latitudes, 16-18 km in the tropics and 8-10 km in polar latitudes.

Characteristics of meteorological factors

Meteorological factors are divided into chemical and physical. Chemical factors atmosphere - gases and various impurities. Gases whose content in the atmosphere is constant include nitrogen (78.08 vol%), oxygen (20.95), argon (0.93), hydrogen, neon, helium, krypton, xenon. The content of other gases in the atmosphere is subject to significant changes. This applies, first of all, to carbon dioxide, the content of which ranges from 0.03 to 0.05%, and near some industrial enterprises and carbon dioxide mineral springs it can increase to 0.07-0.16%.

The formation of ozone is associated with thunderstorms and the oxidation of certain organic substances, so its content at the Earth's surface is negligible and very variable. Ozone is mainly formed at an altitude of 20-25 km under the influence of UV rays from the Sun and, by delaying the short-wave part of the UV spectrum - UVC (with a wavelength shorter than 280 nm), protects living beings from death, i.e. plays the role of a giant filter protecting life on Earth. Atmospheric air may also contain small amounts of other gases - ammonia, chlorine, hydrogen sulfide, various nitrogen compounds, etc., which are mainly the result of air pollution from industrial waste. Some gases enter the atmosphere from the soil. These include radioactive elements and gaseous metabolic products of soil bacteria. The air may contain aromatic substances and phytoncides released by plants. Finally, there are suspended liquid and solid particles in the air - sea salts, organic substances (bacteria, spores, pollen, etc.), mineral particles of volcanic and cosmic origin, smoke, etc. The content of these substances in the air depends on many factors (for example , on wind speed, time of year, etc.).

Chemicals contained in the air can actively affect the body. Thus, saturation of the air with sea salts turns the coastal coastal zone into a kind of natural salt inhalation, which has a beneficial effect on diseases of the upper respiratory tract and lungs. The air of pine forests with a high content of terpenes may be unfavorable for patients with cardiovascular diseases. Negative reactions from increasing ozone content in the air are observed.

Of all chemical factors, oxygen is of absolute importance for life. When climbing mountains, the partial pressure of oxygen in the air decreases, which leads to symptoms of oxygen deficiency and the development of various types of compensatory reactions (increased respiration and blood circulation volume, red blood cell and hemoglobin content, etc.).

Fluctuations in the partial pressure of oxygen, which in the same area are a consequence of fluctuations in atmospheric pressure, are very small and cannot play a significant role in the occurrence of weather reactions. The human body is affected by the oxygen content in the air, which depends on atmospheric pressure, temperature and humidity. The lower the pressure, the higher the temperature and humidity of the air, the less oxygen it contains. Fluctuations in the amount of oxygen are more pronounced in continental and cold climates.

TO physical meteorological factors include air temperature, atmospheric pressure, air humidity, cloudiness, precipitation, and wind.

Air temperature is determined mainly by solar radiation, and therefore periodic (daily and seasonal) temperature fluctuations are noted. There may be sudden (non-periodic) temperature changes associated with general atmospheric circulation processes. To characterize the thermal regime in climatology, average daily, monthly and annual temperatures, as well as maximum and minimum values, are used. To determine temperature changes, a value called inter-day temperature variability is used (the difference between the average daily temperatures of two neighboring days, and in practice, the difference in the values ​​of two consecutive morning measurements). A slight cooling or warming is considered a change in the average daily temperature by 1-2°C, a moderate cooling or warming - by 3-4°C, a sharp one - more than 4°C.

The air is heated by transferring heat from the earth's surface, which absorbs the sun's rays. This occurs mainly through convection, i.e. vertical movement of air heated by contact with the underlying surface, in place of which cooler air from the upper layers descends. In this way, a layer of air 1 km thick is heated. Above is heat exchange in the troposphere; this is determined by turbulence on a planetary scale, i.e. mixing air masses; there is a movement of warm air from low to high latitudes in front of the cyclone and an invasion of cold air masses from high latitudes in the rear of the cyclones. The temperature distribution along height is determined by the nature of convection. In the absence of condensation of water vapor, the air temperature decreases by 1°C with an increase for every 100 m, and with condensation of water vapor - only by 0.4°C. As a result, as you move away from the Earth, the temperature decreases by an average of 0.65°C for every 100 m of altitude (vertical temperature gradient).

The air temperature of a given area depends on a number of physical and geographical conditions. The presence of vast expanses of water in coastal areas reduces daily and annual temperature fluctuations.

In mountainous areas, in addition to the altitude above sea level, the location of mountain ranges and valleys, the accessibility of the area to winds, etc. are important. The nature of the landscape also plays a role. A surface covered with vegetation heats up during the day and cools less at night than an open surface.

Temperature is one of the important characteristics of the weather and season. According to the classification of E.E. Fedorova - L.A. Chubukov, based on the temperature factor, distinguishes three large groups of weather: frost-free, with a temperature transition over 0°C and frosty weather.

Extreme (maximum and minimum) temperatures, which contribute to the development of a number of pathological conditions (frostbite, colds, overheating, etc.), as well as sharp fluctuations, can have an adverse effect on humans. A classic example of this is the case when, on one January night in 1780, in St. Petersburg, as a result of an increase in temperature from - 43.6°C to + 6°C, 40 thousand people fell ill with the flu.

Atmosphere pressure measured in millibars (Mb) or millimeters of mercury (mmHg). In mid-latitudes at sea level, the air pressure is 760 mmHg. Art. As you rise, the pressure decreases by 1 mmHg. Art. for every 11 m of height. Air pressure is characterized by strong non-periodic fluctuations that are associated with weather changes; in this case, pressure fluctuations reach 10-20 mb. A weak change in pressure is considered to be a decrease or increase in its average daily value by 1-4 mb, a moderate change by 5-8 mb, a sharp change by more than 8 mb.

Air humidity in climatology it is characterized by two quantities - vapor pressure ( in mb) and relative humidity, i.e. the percentage ratio of the pressure (partial pressure) of water vapor in the atmosphere to the pressure of saturating water vapor at the same temperature.

Sometimes the water vapor pressure is called absolute humidity, which is actually the density of water vapor in the air and, expressed in g/m 3, is numerically close to the vapor pressure in mmHg. Art.

The difference between the saturating and actual pressure of water vapor at a given temperature and pressure is called moisture deficiency or lack of saturation.

In addition, they highlight physiological saturation, i.e. water vapor pressure at a human body temperature of 37°C, equal to 47.1 mm Hg. Art.

Physiological saturation deficiency- the difference between the elasticity of water vapor at a temperature of 37°C and the elasticity of water vapor in the outside air. In summer, the vapor pressure is much higher, and the saturation deficit is smaller than in winter.

Weather reports usually indicate relative humidity because... its change can be directly felt by a person. Air is considered dry when humidity is up to 55%, moderately dry - at 56-70%, humid - at 71-85%, very humid (damp) - above 85%. Relative humidity is measured in the opposite direction to seasonal and daily temperature fluctuations.

Air humidity in combination with temperature has a pronounced effect on the body. The most favorable conditions for humans are when the relative humidity is 50% and the temperature is 16-18ºC. When air humidity increases, preventing evaporation, heat is difficult to tolerate and the effect of cold increases, contributing to greater heat loss through conduction. Cold and heat are more easily tolerated in dry climates than in humid climates.

When the temperature drops, the moisture in the air condenses and forms fog. This is also possible when warm, humid air mixes with cold, humid air. In industrial areas, fog can absorb toxic gases, which, when reacting chemically with water, form sulfur compounds. This could lead to mass poisoning of the population. In epidemic areas, fog droplets may contain pathogens. With humidity, the risk of airborne infection is higher, because... Moisture droplets have a greater ability to diffuse than dry dust, and therefore can reach the most remote areas of the lung.

Clouds, formed above the earth's surface by condensation of water vapor contained in the air, can consist of water droplets or ice crystals. Cloudiness is measured using an eleven-point system, according to which 0 corresponds to the complete absence of clouds, and 10 points to completely cloudy. The weather is considered clear and partly cloudy with 0-5 points of low cloudiness, cloudy - with 6-8 points and cloudy - with 9-10 points.

The nature of clouds at different altitudes is different. The upper level clouds (with a base greater than 6 km) consist of ice crystals; they are light, transparent, snow-white, almost do not retain direct sunlight and at the same time, reflecting them diffusely, noticeably increase the influx of radiation from the vault of heaven (scattered radiation). Middle-tier clouds (2-6 km) consist of supercooled drops of water or a mixture of ice crystals and snowflakes, are denser, have a grayish tint, the sun shines through them weakly or not at all. The clouds of the lower tier look like low gray heavy ridges, shafts or a veil that covers the sky with a continuous cover; the sun usually does not shine through them. Daily changes in cloudiness do not have a strictly regular character, and the annual variation largely depends on the general physical and geographical conditions and landscape features. Cloudiness affects the light regime and causes precipitation, which sharply disrupts daily temperature and air humidity. It is these two factors, if they are pronounced, that can have an adverse effect on the body in cloudy weather.

Precipitation can be liquid (rain) or solid (snow, grain, hail). The nature of precipitation depends on the conditions of its formation. If rising air currents with high absolute humidity reach high altitudes, which are characterized by low temperatures, then water vapor freezes and falls in the form of cereals, hail, and melted water vapor - in the form of heavy rain. The distribution of precipitation is influenced by the physical and geographical features of the area. On the continent, rainfall is usually less than on the coast. There are usually more of them on the mountain slopes facing the sea than on the opposite ones. Rain plays a positive sanitary role: it purifies the air and washes away dust; droplets containing microbes fall to the ground. At the same time, rain, especially prolonged rain, worsens climate therapy conditions.

Snow cover, due to its high reflectivity (albedo) to short-wave radiation, significantly weakens the processes of solar heat accumulation, increasing winter frosts. The albedo of snow to UV radiation is especially high (up to 97%), which increases the effectiveness of winter heliotherapy, especially in the mountains. Often short-term rain and snow improve the condition of weather-sensitive people, contributing to the disappearance of previously existing weather-related complaints. If the total amount of precipitation per day does not exceed 1 mm, the weather is considered without precipitation.

Wind characterized by direction and speed. The direction of the wind is determined by the side of the world from which it blows (north, south, west, east). In addition to these main directions, intermediate components are distinguished, totaling 16 directions (northeast, northwest, southeast, etc.). Wind strength is determined using the thirteen-point Simpson-Beaufort scale, according to which:

0 corresponds to calm (speed according to the anemometer 0-0.5 m/s),

1 - quiet wind,

2 - light wind,

3 - weak wind,

4 - moderate wind,

5-6 - fresh wind,

7-8 - strong wind,

9-11 - storm,

12 - hurricane (more than 29 m/s).

A sharp short-term increase in wind up to 20 m/s and above is called a squall.

Wind is caused by differences in pressure: air moves from an area of ​​high pressure to an area of ​​low pressure. The greater the difference in pressure, the stronger the wind. The inhomogeneity of pressure in horizontal directions is due to the inhomogeneity of the thermal regime on the Earth's surface. In summer, the land heats up more than the water surface, as a result of which the air above the land expands from heating, rises, and spreads in horizontal directions. This leads to a decrease in the total mass of air and, consequently, to a decrease in pressure at the Earth's surface. Therefore, in summer, relatively cool and humid sea air in the lower layers of the troposphere rushes from sea to land, and in winter, on the contrary, dry cold air moves from land to sea. Such seasonal winds ( monsoons) are most pronounced in Asia, on the border of the largest continent and ocean. They are also observed in the Far East. The same change in winds is observed in coastal areas during the day - this breezes, i.e. winds blowing from sea to land during the day, and from land to sea at night, spreading over 10-15 km on both sides of the coastline. In southern coastal resorts in the summer during the daytime, they reduce the feeling of heat. In mountainous areas, mountain-valley winds arise, blowing up the slopes (valleys) during the day, and down from the mountains at night. Mountainous areas are characterized by a peculiar warm, dry wind blowing from the mountains - hairdryer It is formed if there are mountains in the path of the air flow with a large difference in pressure between the two sides of the mountain range. Rising air leads to a slight decrease in temperature, and lowering leads to a significant increase. As a result, cold air, falling from the mountains, heats up and loses moisture, so the air temperature during a hairdryer can increase by 10-15°C or more in a short (15-30 minutes) period of time. When air moves horizontally from hot and very dry areas, dry winds arise, during which humidity can drop to 10-15%.

At low temperatures, the wind increases heat transfer, which can lead to hypothermia. The lower the air temperature, the harder the wind is to bear. In hot weather, the wind increases skin evaporation and improves well-being. A strong wind has an adverse effect, it tires, irritates the nervous system, and makes breathing difficult; a small wind has a tonic and stimulating effect.

Electrical state of the atmosphere determined by the electric field strength, air conductivity, ionization, and electrical discharges in the atmosphere. The earth has the properties of a negatively charged conductor, and the atmosphere has the properties of a positively charged one. The potential difference between the Earth and a point located at a height of 1 m (electric potential gradient) is 130 V. Electrical conductivity of air is determined by the amount of positively and negatively charged atmospheric ions (aeroions) contained in it. Aeroions are formed by ionization of air molecules due to the removal of electrons from them under the influence of cosmic rays, radioactive radiation from the soil and other ionizing factors. The released electrons immediately join other molecules. This is how positively and negatively charged molecules (aeroions) are formed, which have greater mobility. Small (light) ions, settling on suspended air particles, form medium, heavy and ultra-heavy ions. In humid and polluted air, the number of heavy ions increases sharply. The cleaner the air, the more light and medium ions it contains. The maximum concentration of light ions occurs in the early morning hours. The average concentration of positive and negative ions ranges from 100 to 1000 per 1 cm 3 of air, reaching several thousand per 1 cm 3 in the mountains. The ratio of positive to negative ions is unipolarity coefficient. Near mountain rivers and waterfalls, where water splashes, the concentration of negative ions increases sharply. The unipolarity coefficient in coastal areas is less than in areas remote from the sea: in Sochi - 0.95; in Yalta - 1.03; in Moscow - 1.12; in Almaty - 1.17. Negative ions have a beneficial effect on the body. Negative ionization is one of the healing factors during cascade bathing.

Meteorological conditions have a significant impact on the transfer and dispersion of harmful impurities entering the atmosphere. Modern cities usually occupy territories of tens and sometimes hundreds of square kilometers, so changes in the content of harmful substances in their atmosphere occur under the influence of meso- and macro-scale atmospheric processes. The greatest influence on the dispersion of impurities in the atmosphere is exerted by the wind and temperature regime, especially its stratification.

The influence of meteorological conditions on the transport of substances in the air manifests itself differently, depending on the type of emission source. If the gases emanating from the source are superheated relative to the surrounding air, then they have an initial rise; In this regard, a field of vertical velocities is created near the emission source, promoting the rise of the torch and the carryover of impurities upward. In weak winds, this rise causes a decrease in the concentrations of impurities near the ground. The concentration of impurities near the ground also occurs during very strong winds, but in this case it occurs due to the rapid transfer of impurities. As a result, the highest concentrations of impurities in the surface layer are formed at a certain speed, which is called dangerous. Its value depends on the type of emission source and is determined by the formula

where is the volume of the emitted gas-air mixture, is the temperature difference between this mixture and the surrounding air, and is the height of the pipe.

With low emission sources, an increased level of air pollution is observed in weak winds (0-1 m/s) due to the accumulation of impurities in the ground layer.

Undoubtedly, the duration of wind at a certain speed, especially weak winds, is also important for the accumulation of impurities.

The direction of the wind has a direct impact on the nature of air pollution in the city. A significant increase in the concentration of impurities is observed when winds from industrial facilities predominate.

The main forms that determine the dispersion of impurities include atmospheric stratification, including temperature inversion (i.e., an increase in air temperature with height). If the temperature increase begins directly from the surface of the earth, the inversion is called surface, but if from a certain height above the surface of the earth, then it is called elevated. Inversions make vertical air exchange difficult. If the elevated inversion layer is located at a sufficiently high altitude from the pipes of industrial enterprises, then the concentration of impurities will be significantly lower. The inversion layer, located below the level of emissions, prevents their transfer to the earth's surface.

Temperature inversions in the lower troposphere are determined mainly by two factors: cooling of the earth's surface due to radiation and advection of warm air onto the cold underlying surface; often they are associated with cooling of the surface layer due to the expenditure of heat on the evaporation of water or the melting of snow and ice. The formation of inversions is also facilitated by downward movements in anticyclones and the flow of cold air into lower parts of the relief.

As a result of theoretical studies, it was established that at high emissions the concentration of impurities in the surface layer increases due to increased turbulent exchange caused by unstable stratification. The maximum surface concentration of heated and cold impurities is determined, respectively, by the formulas:

Where; and - the amount of substance and volumes of gases emitted into the atmosphere per unit time; - diameter of the emission source mouth; , - dimensionless coefficients that take into account the rate of deposition of harmful substances in the atmosphere and the conditions for the release of the gas-air mixture from the mouth of the emission source; - overheating of gases; - coefficient that determines the conditions for vertical and horizontal dispersion of harmful substances and depends on the temperature stratification of the atmosphere. The coefficient is determined under unfavorable meteorological conditions for the dispersion of impurities, with intense vertical turbulent exchange in the surface layer of air, when the surface concentration of impurities in the air from a high source reaches a maximum. Thus, in order to know the value of the coefficient for various physical-geographical regions, information is needed on the spatial distribution of the values ​​of the turbulent exchange coefficient in the surface layer of the atmosphere

As a characteristic of the stability of the atmospheric boundary layer, the so-called “mixing layer height” is used, corresponding approximately to the height of the boundary layer. Intense vertical movements caused by radiative heating are observed in this layer, and the vertical temperature gradient approaches or exceeds the dry adiabatic one. The height of the mixing layer can be determined from data from aerological sounding of the atmosphere and the maximum air temperature near the ground during the day. An increase in the concentration of impurities in the atmosphere is usually observed with a decrease in the mixing layer, especially when its height is less than 1.5 km. When the mixing layer height is more than 1.5 km, practically no increase in air pollution is observed.

When the wind weakens to calm, impurities accumulate, but at this time the rise of superheated emissions into the upper atmosphere, where they are dissipated, increases significantly. However, if an inversion occurs under these conditions, a “ceiling” may form that will prevent emissions from rising. Then the concentration of impurities near the ground increases sharply.

The relationship between air pollution levels and meteorological conditions is very complex. Therefore, when studying the reasons for the formation of an increased level of atmospheric pollution, it is more convenient to use not individual meteorological characteristics, but complex parameters corresponding to a certain meteorological situation, for example, wind speed and thermal stratification indicator. For the state of the atmosphere in cities, a surface temperature inversion in combination with weak winds poses a great danger, i.e. air stagnation situation. It is usually associated with large-scale atmospheric processes, most often with anticyclones, in which weak winds are observed in the atmospheric boundary layer and surface radiative temperature inversions are formed.

The formation of the level of air pollution is also influenced by fogs, precipitation and radiation regime.

Fogs influence the content of impurities in the air in a complex way: drops of fog absorb impurities, not only near the underlying surface, but also from the overlying, most polluted layers of air. As a result, the concentration of impurities increases greatly in the fog layer and decreases above it. In this case, the dissolution of sulfur dioxide in fog droplets leads to the formation of more toxic sulfuric acid. Since the weight concentration of sulfur dioxide in the fog increases, 1.5 times more sulfuric acid can be formed during its oxidation.

Precipitation clears the air of impurities. After prolonged and intense precipitation, high concentrations of impurities are observed very rarely.

Solar radiation causes photochemical reactions in the atmosphere and the formation of various secondary products, which often have more toxic properties than substances coming from emission sources. Thus, in the process of photochemical reactions in the atmosphere, sulfur dioxide is oxidized with the formation of sulfate aerosols. As a result of the photochemical effect, photochemical smog is formed in polluted air on clear sunny days.

The above review allowed us to identify the most important meteorological parameters affecting the level of air pollution.