Meteorological station: types, instruments and devices, observations made. Meteorological instruments. Meteorological instruments - instruments and installations for measuring and recording the values of meteorological elements. For comparison. "Research and production

Observations at meteorological stations are mainly of the nature of measurements and are carried out using special measuring instruments. devices; only a few meteorological elements are quantified without instruments (cloudiness degree, visibility range and some others). Qualitative assessments, such as determining the nature of clouds and precipitation, are made without instruments.

For network devices it is necessary sameness, facilitating the operation of the network and ensuring comparability of observations.

Meteorological instruments are installed on site open air stations. Only instruments for measuring atmospheric pressure (barometers) are installed indoors at the station, since the difference between the air pressure in the open air and indoors is negligible (virtually absent).

Instruments for determining air temperature and humidity are protected from solar radiation, precipitation and gusts of wind, and for this they are placed in booths special design. Instrument readings are made by the observer within the established observation periods. Stations are also equipped with self-writing instruments that provide continuous automatic recording of the most important meteorological elements (especially air temperature and humidity, atmospheric pressure and wind). Recording instruments are often designed in such a way that their receiving parts, located on the site or on the roof of a building, have electrical transmission to the writing parts installed inside the building.

The principles of a number of meteorological instruments were proposed back in the 17th-19th centuries. Currently, rapid progress is being made in meteorological instrumentation. New designs of devices are being created using the capabilities of modern technology: thermal and photoelements, semiconductors, radio communications and radar, various chemical reactions, etc. Especially noteworthy is the use in recent years for meteorological purposes radar. On the radar screen you can detect clusters of clouds, areas of precipitation, thunderstorms and even large atmospheric eddies (tropical cyclones) at a considerable distance from the observer and trace their evolution and movement.

As mentioned above, great strides have been made in the design automatic stations, transmitting their observations over a more or less long period of time without human intervention.

Aerological observation methods

The simplest type of aerological observations is wind sounding, i.e., observations of the wind in a free atmosphere using pilot balloons. This is the name given to small rubber balloons filled with hydrogen and released into free flight. By observing the flight of a pilot balloon through theodolites, it is possible to establish the speed and direction of the wind at the altitudes at which the balloon flies. Currently, in aerological observations of the wind, radio detection methods are increasingly being used, i.e. radio direction finding of radiosondes and radar (radio wind sounding), providing information about the wind in the presence of cloud cover. Wind observations, in addition to their scientific role, have a direct bearing on aviation operations. The temperature probing described below has the same meaning.

Temperature probing are called regular (usually twice a day) releases into the high layers of the atmosphere balloons with rubber shells of a sufficiently large size, to which automatic instruments are attached to record temperature, pressure and air humidity. Until the thirties, these devices - meteorographers- they only provided a recording of the observed values on the recorder tape. At one height or another, the balloon, inflating, burst, and the device descended to the ground on a second, additional balloon or on a parachute. However, the return of the device to the place of release depended on chance, and there could be no talk of urgent use of observations. Since 1930 the method has spread radiosonde(first used in the USSR). The device attached to the ball is radiosonde, while still in flight, it sends radio signals from which the values of meteorological elements in high layers can be determined.

The radio sounding method created a revolution in the methods of aerological observations and in all modern meteorology. Radiosonde observations can be used for weather services without any delay, which particularly increases their value. Thanks to radio sounding, our knowledge about the layers of the atmosphere has increased incomparably to a height of 30-40 km. However, the accuracy of the readings of modern radiosondes is still not high enough.

Radio sounding has replaced other methods of temperature sounding - the rise of meteorographs on kites, tethered balloons, airplanes, etc. Airplane remains, however, an important tool for special complex observations that require the participation of an observer, for example, for studying the physical structure of clouds, for actinometric and atmospheric-electric observations. For the same purposes they are used balloons, and occasionally stratospheric balloons with hermetically sealed gondolas. The latest stratospheric balloon altitude record in the United States is close to 35 km.

In recent years, they have begun to practice releasing balloons without people not only with radiosondes, but also with more complex automatic instruments for various types of observations. Such large diameter balls with a polyethylene shell (transoceanic probes) reach heights of about 30-40 with a significant load of instruments km. They can fly at a certain given altitude (more precisely, on a given isobaric surface, i.e. in a layer with the same atmospheric pressure), while being in the air for many days in a row and transmitting radio signals. Determining the flight trajectories of such balloons is important for studying air transport in high layers of the atmosphere, especially over the oceans and at low latitudes, where the network of aerological stations is insufficient.

To study even higher layers of the atmosphere, releases are made meteorological And geophysical rockets with instruments whose readings are transmitted via radio. The lifting ceiling of rockets has now become unlimited.

In 1957-1958 In the USSR, and then in the USA, they managed to launch the first Earth satellites with automatic instruments into the upper layers of the atmosphere. Now a large number of such satellites revolve around the Earth, and the orbits of some of them reach heights of tens of thousands of kilometers. Since 1960, so-called weather satellites, designed to study the underlying layers of the atmosphere. They photograph and transmit via television the distribution of clouds around the globe, and also measure the radiation coming from the earth's surface.

In addition, an important method for studying the higher layers is observations of the propagation of radio waves.

The era of great discoveries and inventions, which marked the beginning of a new period in human history, also revolutionized the natural sciences. The discovery of new countries brought information about a huge number of physical facts previously unknown, starting with experimental evidence of the sphericity of the earth and the concept of the diversity of its climates. Navigation of this era required great development of astronomy, optics, knowledge of the rules of navigation, the properties of the magnetic needle, knowledge of the winds and sea currents of all oceans. While the development of merchant capitalism served as an impetus for increasingly distant travel and the search for new sea routes, the transition from old craft production to manufacture required the creation of new technology.

This period was called the Age of the Renaissance, but its achievements went far beyond the revival of ancient sciences - it was marked by a real scientific revolution. In the 17th century the foundations of a new mathematical method for analyzing infinitesimals were laid, many basic laws of mechanics and physics were discovered, a spotting scope, microscope, barometer, thermometer and other physical instruments were invented. Using them, experimental science quickly began to develop. Announcing its emergence, Leonardo da Vinci, one of the most brilliant representatives of the new era, said that “... it seems to me that those sciences are empty and full of errors that do not end in obvious experience, i.e. unless their beginning or middle or end passes through one of the five senses.” God's intervention in natural phenomena was considered impossible and non-existent. Science came out from under the yoke of the church. Along with the church authorities, Aristotle was also consigned to oblivion - from the middle of the 17th century. His creations were almost never republished and were not mentioned by naturalists.

In the 17th century science began to be created anew. That new science

had to win the right to exist, aroused great enthusiasm among scientists of that time. Thus, Leonardo da Vinci was not only a great artist, mechanic and engineer, he was a designer of a number of physical instruments, one of the founders of atmospheric optics, and what he wrote about the visibility range of colored objects remains of interest to this day. Pascal, a philosopher who proclaimed that human thought will allow him to conquer the powerful forces of nature, an outstanding mathematician and creator of hydrostatics, was the first to experimentally prove the decrease in atmospheric pressure with altitude. Descartes and Locke, Newton and Leibniz - the great minds of the 17th century, famous for their philosophical and mathematical research - made major contributions to physics, in particular to atmospheric science, which was then almost inseparable from physics.

This revolution was led by Italy, where Galileo and his students Torricelli, Maggiotti and Nardi, Viviani and Castelli lived and worked. Other countries also made major contributions to meteorology at the time; it is enough to recall F. Bacon, E. Mariotte, R. Boyle, Chr. Huygens, O. Guericke - a number of outstanding thinkers.

The herald of the new scientific method was F. Bacon (1561 - 1626) - “the founder of English materialism and all experimental science of our time,” according to Karl Marx. Bacon rejected the speculations of scholastic “science”, which, as he rightly said, neglected natural science, was alien to experience, was shackled by superstition and bowed to the authorities and dogmas of faith, which tirelessly spoke of the unknowability of God and his creations. Bacon proclaimed that science would be led forward by the union of experience and reason, purifying experience and extracting from it the laws of nature interpreted by the latter.

In Bacon's New Organon we find a description of a thermometer, which even gave some reason to consider Bacon the inventor of this device. Bacon also wrote ideas about the general system of the winds of the globe, but they did not find a response in the works of authors of the 17th - 18th centuries who wrote on the same topic. Bacon's own experimental works, in comparison with his philosophical studies, are, however, of secondary importance.

Galileo did the most for experimental science in the first half of the 17th century, including meteorology. What he gave to meteorology previously seemed secondary in comparison, for example, with Torricelli's contribution to this science. Now we know, however, that in addition to the ideas he first expressed about the weight and pressure of air, Galileo came up with the idea of the first meteorological instruments - a thermometer, a barometer, a rain gauge. Their creation laid the foundation for all modern meteorology.

Rice. 1. Types of mercury barometers: a - cup, b - siphon, c - siphon-cup.

Rice. 2. Station cup barometer; K is the ring on which the barometer is suspended.

Meteorological booth

Purpose. The booth serves to protect meteorological instruments (thermometers, hygrometers) from rain, wind and sunlight.

Materials:

- wooden blocks 50 x 50 mm, length up to 2.5 m, 6 pcs.;
- plywood plates 50-80 mm wide, up to 450 mm long, 50 pcs.;
- hinges for vents, 2 pcs.;
- boards no thicker than 20 mm for making the bottom and roof of the booth;
- white paint, oil or enamel;
- material for the ladder.

Manufacturing. The body is knocked together from the bars. The corner bars should form the high legs of the booth. Shallow cuts are made in the bars at an angle of 45°, plywood plates are inserted into them so that they form the side walls and no gaps are visible through the opposite walls of the booth. The frame of the front wall (door) is made of slats and hung on hinges. The back wall of the booth and the door are mounted from plywood plates in the same way as the side walls. The bottom and roof are made from boards. The roof must overhang on each side of the booth by at least 50 mm; it is installed obliquely. The booth is painted white.

Installation. The booth is installed so that its bottom is 2 m above the ground. Near it, a permanent ladder is constructed from any material of such a height that the face of the observer standing on it is at the height of the middle of the booth.

Eclimeter

Purpose. Measuring vertical angles, including the heights of celestial bodies.

Materials:

- metal protractor;
- thread with a weight.

Manufacturing. The edges of the base of the protractor are bent at right angles; small sighting holes are punched on the bent parts at the same distance from the horizontal diameter of the protractor. The digitization of the protractor scale changes: 0° is placed where 90° usually stands, and 90° is written in the places 0° and 180°. The end of the thread is fixed in the center of the protractor, the other end of the thread with a weight hangs freely.

Working with the device. Through two sighting holes, we point the device at the desired object (a celestial body or an object on Earth) and read the vertical angle along the thread. You cannot look at the Sun even through small holes; to determine the height of the Sun, you need to find a position such that the sun's ray passes through both sighting holes.

Hygrometer

Purpose. Determination of relative air humidity without the help of tables.

Materials:

- board 200 x 160 mm;
- slats 20 x 20 mm, length up to 400 mm, 3--4 pcs.;
- 5--7 light human hair 300--350 mm long;
- a weight or other weight weighing 5-7 g;
- light metal pointer 200--250 mm long;
- wire, small nails.

Women's hair is needed, it is thinner. Before cutting off 5-7 hairs, you need to thoroughly wash your hair with shampoo for oily hair (even if your hair is non-greasy). There must be a counterweight on the arrow so that the arrow, when placed on a horizontal axis, is in indifferent equilibrium.

Manufacturing. The board serves as the base of the device. A U-shaped frame with a height of 250-300 and a width of 150-200 mm is mounted on it. The crossbar is attached horizontally at a height of about 50 mm from the base. The arrow axis is installed in the middle of it; this could be a nail. The arrow should be put on it with a sleeve. The bushing should rotate freely on the axis. The outer surface of the bushing should not be slippery (a short piece of thin rubber tube can be placed on it). Hair is attached to the middle of the top crossbar of the frame, and a weight is suspended from the other end of the hair bundle. The hair should touch the side surface of the sleeve; you need to make one full turn with it. An arc-shaped scale is cut out of cardboard or any other material and attached to the frame. The zero division of the scale (complete air dryness) can, with a certain degree of convention, be applied where the needle of the device stops after being placed in the oven for 3-4 minutes. Mark the maximum humidity (100%) according to the arrow reading of the device, placed in a bucket covered with plastic wrap, with boiling water poured into the bottom. Divide the interval between 0% and 100% into 10 equal parts and label the tens of percentages. It’s good if you can control the readings of the hygrometer by checking it with the psychrometer at the weather station.

Installation. It is convenient to keep the device in a meteorological booth; if you want to know the humidity in the room, place it in the room.

Equatorial sundial

Purpose. Determination of true solar time.

Materials:

- square board with a side from 200 to 400mm;
- a wooden or metal stick, you can take a 120mm nail;
- compass;
- protractor;
- oil paints of two colors.

Manufacturing. Board - the base of the clock is painted in one color. A dial is drawn on the base using paint of a different color - a circle divided into 24 parts (15° each). 0 is written at the top, 12 at the bottom, 18 at the left, 6 at the right. A gnomon is fixed in the center of the clock - a wooden or metal pin; it needs to be strictly perpendicular to the dial. Installation. The clock is placed at any height in a place as open as possible, not protected from sunlight by buildings or trees. The base of the watch (bottom of the dial) is located in the east-west direction. The upper part of the dial is raised so that the angle between the plane of the dial and the horizontal plane is 90° minus the angle corresponding to the latitude of the place. Working with the device. The time is read on the dial by the shadow cast by the gnomon. The hours will run from the end of March to September 20-23.

The clock shows true solar time, do not forget that it differs from the one by which we live, in some places quite significantly. If you want the clock to work in winter, make sure that the gnomon passes through the base board, it will serve as a support in its inclined position, and draw a second dial on the underside of the base; only on it the number 6 will be on the left, and 18 on the right. -- Note ed.

Purpose. Determination of wind direction and strength.

Materials:

- wooden block;
- tin or thin plywood;
- thick wire, 5-7 mm;
- plasticine or window putty;
- Oil paint;
- small nails.

Manufacturing. The weather vane body is made of a wooden block 110-120 mm long, which is shaped into a truncated pyramid with bases 50 x 50 mm and 70 x 70 mm. Two tin or plywood wings in the form of trapezoids about 400 mm high, with bases of 50 mm and 200 mm, are nailed to the opposite side faces of the pyramid; tin fenders are better, they do not warp from dampness.

A hole with a diameter slightly larger than the diameter of the pin on which the weather vane will rotate is drilled in the center of the block (not through!). It would be good to insert something solid inside the hole, at the very end, so that when the weather vane rotates, the hole does not drill out. A wire is driven into the end part of the weather vane, on the side opposite the wings, so that it protrudes 150-250 mm, and a ball of plasticine or window putty is placed on its end. The weight of the ball is selected so that it balances the wings so that the weather vane does not tip back or forward. It would be good if, instead of plasticine or putty, you could select and secure another, more reliable counterweight to the wire. It is bent from wire and inserted vertically into the upper surface of the weather vane bar, above the axis of its rotation, a rectangular frame 350 mm high. and 200mm wide. The frame must be located perpendicular to the longitudinal axis of the weather vane. A tin or plywood board weighing 200 g and measuring 150 x 300 mm is hung on the frame on loops (wire rings). The board should swing freely, but should not move from side to side. A plywood or tin scale of wind strength in points is attached to one of the side posts of the frame. All wooden and plywood parts (and others if desired) are painted with oil paint.

Installation. According to the standard, the weather vane is installed on a pole dug into the ground or on a tower above the roof of a building at a height of 10 m above ground level. It is quite difficult to comply with this requirement; you will have to proceed from the possibilities, taking into account the visibility of the device from a height of human height. The axis of the weather vane must be installed vertically on a pole, on the sides of which there should be pins indicating eight directions: N, NE, E, SE, S, SW, W, NW. Of these, only one, directed to the north, should have a clearly visible letter C.

Working with the device. Wind direction is the direction from which the wind is blowing, so it is read by the position of the counterweight, not the wings of the weather vane. The strength of the wind in points is read by the degree of deflection of the weather vane board. If the board oscillates, its average position is taken into account; when isolated strong gusts of wind are observed, the maximum wind force is indicated. So, the entry “SW 3 (5)” means: southwest wind, force 3, gusts up to force 5.

Meteorological stations

Hair hygrometer: 1 -- hair; 2 -- frame; 3 -- arrow; 4 -- scale.

Film hygrometer: 1 -- membrane; 2 -- arrow; 3 -- scale.

Meteorological instruments used by R. Hooke in the middle of the 17th century: barometer ( A), anemometer ( b) and compass ( V) determined the pressure, speed and direction of the wind as a function of time, of course, if there was a clock. In order to understand the causes and properties of the movement of atmospheric air, numerous and fairly accurate measurements were needed, and therefore, fairly cheap and accurate instruments. Image: Quantum

Internal structure of an aneroid.

Location of weather stations on Earth

Images from space weather stations

The weather forecast is made both on the basis of readings from ship instruments and information transmitted by coastal meteorological services.

The main element in weather forecasting is atmospheric pressure. Normal atmospheric pressure is the mass of a mercury column with a height of 760 mm over an area of 1 cm2. To measure pressure under ship conditions, an aneroid barometer and a barograph are used (Fig. 1).

A device that continuously records atmospheric pressure on a special paper barogram tape. This allows us to judge changes in atmospheric pressure over time and make appropriate predictions.

Rice. 1 Instruments for measuring atmospheric pressure: aneroid barometer and barograph

To measure the speed and direction of the true wind, an anemometer, a stopwatch and a CMO circle are used (Fig. 2).

Rice. 2 Instruments for determining wind speed and direction: 1 - SMO circle, anemometer and stopwatch 2 - automatic weather station

Used to measure the average wind speed over a certain period of time. The anemometer counter has three dials: a large one, divided into one hundred parts, giving units and tens of divisions, and two small ones - for counting hundreds and thousands of divisions. Before determining the wind speed, it is necessary to record the scale reading. Then stand on the upper bridge on the windward side in a place where the wind flow is not distorted by ship structures. Holding the anemometer in your outstretched hand, turn it on at the same time as the stopwatch. After 100 seconds, turn off the anemometer and record a new reading. Find the difference in readings and divide by 100. The result obtained is the wind speed, measured in meters per second (m/s).

If the ship is underway, then the apparent (observed) direction and speed of the wind are measured, i.e., the resultant speeds of the true wind and the ship. When determining the apparent direction of the wind, it should be remembered that the wind always “blows into the compass.”

To determine the true direction and speed of the wind on a moving ship, the SMO (Sevastopol Marine Observatory) circle is used. The calculation procedure is given on the back of the circle.

Modern ships are equipped with automatic weather stations. Measuring equipment is mounted on the upper bridge; indicators are displayed on the bridge, showing the direction and speed of the true wind at a given moment.

To measure humidity on ships, an aspiration psychrometer is used (Fig. 3), consisting of two thermometers inserted into a nickel-plated metal frame, on top of which an aspirator (fan) is screwed. When the aspirator is running, air is sucked in from below through double tubes that protect the thermometer reservoirs. Flowing around the tanks of thermometers, the air imparts its temperature to them. The right tank is wrapped in cambric, which is moistened with a pipette 4 minutes before the fan starts. Measurements are taken on the bridge wing on the windward side. Readings are taken first from a dry thermometer, then from a wet one.

Air humidity is characterized by the content of water vapor in the air. The amount of water vapor in grams per cubic meter of humid air is called absolute humidity.

Relative humidity is the ratio of the amount of water vapor contained in the air to the amount of steam required to saturate the air at a given temperature, expressed as a percentage. When the temperature drops, the relative humidity increases, and when the temperature rises, it decreases.

When air containing water vapor is cooled to a certain temperature, it will be so saturated with water vapor that further cooling will cause condensation, i.e. the formation of moisture, or sublimation - the direct formation of ice crystals from water vapor. The temperature at which the water vapor contained in the air reaches saturation is called the dew point.

A thermometer is used to measure the ambient air temperature (Fig. 4).

Rice. 3 Aspiration psychrometer

Rice. 4 Device for measuring air temperature

Reading Fax Cards

Information about weather and sea conditions necessary to decide on the choice of course or work at sea can be obtained in the form of facsimile transmissions of various maps. This type of hydro-meteorological information is the most informative. It is characterized by great variety, efficiency and visibility.

Currently, regional hydrometeorological centers compile and broadcast a large number of different maps. Below is a list of charts most commonly used for navigation purposes:

surface weather analysis. The map is compiled on the basis of surface meteorological observations at key dates;
surface weather forecast. Shows the expected weather in the specified area in 12, 24, 36 and 48 hours;
short-lead surface forecast. The expected position of the pressure system (cyclones, anticyclones, fronts) in the surface layer for the next 3-5 days is given;
wave field analysis. This map gives a description of the wave field in the region - the direction of wave propagation, their height and period;
wave field forecast. Shows the forecasted wave field for 24 and 48 hours - the direction of the waves and the height of the prevailing waves;
ice conditions map. The ice situation in the given area (concentration, ice edge, polynyas and other characteristics) and the position of icebergs are shown.

Surface analysis maps contain data on actual weather in the lower layers of the atmosphere. The pressure field on these maps is represented by isobars at sea level. The main surface maps are for 00:00, 06:00, 12:00 and 5:00 hours Greenwich Mean Time.

Forecast maps are maps of the expected weather conditions (12, 24, 36, 48, 72 hours). On surface forecast maps, the expected positions of the centers of cyclones and anticyclones, frontal sections, and pressure fields are indicated.

When reading facsimile hydrometeorological maps, the navigator receives the initial information from the map header. The map header contains the following information:

card type;
the geographic area covered by the map;
hydrometeorological station call signs;
date and time of publication;
additional information.

The type and region of the map are characterized by the first four symbols, with the first two characterizing the type, and the next two characterizing the map region. For example:

ASAS - surface analysis (AS - analysis surface) for the Asian part (AS - Asia);
FWPN - wave forecast (FW - forecast wave) for the northern part of the Pacific Ocean (PN - Pacific North).

Common abbreviations are listed below:

Hydrometeorological situation analysis maps.
- AS - surface analysis (Surface Analysis);
- AU - Upper Analysis for various heights (pressures);
- AW - Wave/Wind Analysis;
Prognostic cards (for 12, 24, 48 and 72 hours).
- FS - surface forecast (Surface Forecast)
- FU - altitude forecast (Upper Forecast) for various heights (pressures).
- FW - wind/wave forecast (Wave/Wind Forecast).
Special cards.
- ST—ice forecast (Sea Ice Condition);
- WT - tropical cyclone forecast (Tropical Cyclone Forecast);
- CO - Sea Surface Water Temperature map;
- SO - map of surface currents (Sea Surface Current).
The following abbreviations are commonly used to indicate the area covered by the map:
- AS - Asia;
- AE - Southeast Asia
- PN—Pacific North;
- JP - Japan;
- WX - Equator zone, etc.

Four alphabetic characters may be accompanied by 1-2 numeric characters specifying the type of map, for example FSAS24 - surface analysis for 24 hours or AUAS70 - above-ground analysis for 700 hPa pressure.

The type and area of the map are followed by the call sign of the radio station broadcasting the map (for example, JMH - Japan Meteorological and Hydrographic Agency). The second line of the title indicates the date and time the map was compiled. Date and time are in Greenwich Mean Time or UTC. To denote the given time, the abbreviations Z (ZULU) and UTC (Universal Coordinated Time) are used, respectively, for example, 240600Z JUN 2007 - 06/24/07, 06.00 GMT.

The third and fourth lines of the header decipher the card type and provide additional information (Fig. 5).

Pressure relief on facsimile maps is represented by isobars - lines of constant pressure. On Japanese weather maps, isobars are drawn through 4 hectopascals for pressures that are multiples of 4 (for example, 988, 992, 996 hPa). Every fifth isobar, i.e., a multiple of 20 hPa, is drawn by a thick line (980, 1000, 1020 hPa). Such isobars are usually (but not always) labeled with pressure. If necessary, intermediate isobars are also drawn through 2 hecto-pascals. Such isobars are drawn with a dotted line.

Pressure formations on weather maps of Japan are represented by cyclones and anticyclones. Cyclones are designated by the letter L (Low), anticyclones by the letter H (High). The center of pressure formation is indicated by an “x”. The pressure in the center is indicated next to it. An arrow near the pressure formation indicates the direction and speed of its movement.

Rice. 5 Surface weather analysis map for the Asian region

There are the following ways to indicate the speed of movement of pressure formations:

ALMOST STNR - almost stationary (almost stationary) - pressure formation speed less than 5 knots;
SLW - slowly (slowly) - pressure formation speed from 5 to 10 knots;
10 kT — pressure formation rate in knots with an accuracy of 5 knots; Text comments are given for the deepest cyclones, which give the characteristics of the cyclone, the pressure in the center, the coordinates of the center, the direction and speed of movement, the maximum wind speed, as well as the zone of winds with speeds exceeding 30 and 50 knots.

An example of a comment on a cyclone:

DEVELOPING LOW 992 hPa 56.2N 142.6E NNE 06 KT MAX WINDS 55 KT NEAR CENTER OVER 50 KT WITHIN 360 NM OVER 30 KT WITHIN 800 NM SE-SEMICIRCULAR 550 NM ELSEWHERE.

DEVELOPING LOW - a developing cyclone. There may also be DE-VELOPED LOW - a developed cyclone;
- pressure in the center of the cyclone - 992 hPa;
- coordinates of the cyclone center: latitude - 56.2° N, longitude - 142.6° E;
- the cyclone is moving at NNE at 6 knots;
- the maximum wind speed near the center of the cyclone is 55 knots.

A tropical cyclone goes through 4 main stages in its development:

TD — tropical depression (Tropical Depression) — an area of low pressure (cyclone) with a wind speed of up to 17 m/s (33 knots, 7 points on the Beaufort scale) with a pronounced center;
TS - tropical storm (Tropical Storm) - a tropical cyclone with a wind speed of 17-23 m/s (34-47 knots, 8-9 points on the Beaufort scale);
STS - severe (severe) tropical storm (Severe Tropical Storm) - a tropical cyclone with a wind speed of 24-32 m/s (48-63 knots, 10-11 on the Beaufort scale);
T - typhoon (Typhoon) - a tropical cyclone with a wind speed of more than 32.7 m/s (64 knots, 12 points on the Beaufort scale).

The direction and speed of movement of a tropical cyclone is indicated in the form of a probable sector of movement and circles of probable position after 12 and 24 hours. Beginning with the TS (tropical storm) stage, weather maps provide a text commentary on the tropical cyclone, and, beginning with the STS (severe tropical storm) stage, the tropical cyclone is given a number and name.

An example of a tropical cyclone comment:

T 0408 TINGTING (0408) 942 hPa 26.2N 142.6E PSN GOOD NORTH 13 KT MAX WINDS 75 KT NEAR CENTER EXPECTED MAX WINDS 85 KT NEAR CENTER FOR NEXT 24 HOUR OVER 50 KT WITHIN 80 NM OVER 30 KT WITHIN 180 NM NE-SEMI CIRCULAR 270 NM ELSEWHERE.

T (typhoon) - stage of development of a tropical cyclone;

0408 - national number;
typhoon name - TINGTING;
(0408) - international number (eighth cyclone of 2004);
pressure in the center 942 hPa;
coordinates of the cyclone center are 56.2° N 6° E. The coordinates are determined with an accuracy of 30 nautical miles (PSN GOOD).

To indicate the accuracy of determining the coordinates of the cyclone center, the following notations are used:

PSN GOOD - accuracy up to 30 nautical miles;
PSN FAIR - accuracy 30-60 nautical miles;
PSN POOR - accuracy below 60 nautical miles;
moving at NORTH at 13 knots;
maximum wind speed of 75 knots near the center;
expected maximum wind speed of 85 knots for the next 24 hours.

Weather maps also indicate navigation hazards in the form of hydrometeorological warnings. Types of hydrometeorological warnings:

[W] - warning about wind (Warning) with a speed of up to 17 m/s (33 knots, 7 points on the Beaufort scale);
— warning of strong wind (Gale Warning) with a speed of 17-23 m/s (34-47 knots, 8-9 points on the Beaufort scale);
— warning about storm winds (Storm Warning) with a speed of 24-32 m/s (48-63 knots, 10-11 points on the Beaufort scale);
— warning about hurricane winds (Typhoon Warning) with a speed of more than 32 m/s (more than 63 knots, 12 points on the Beaufort scale).
FOG [W] - FOG Warning with visibility less than 4 miles. The boundaries of the warning area are indicated by a wavy line. If the warning area is small, its boundaries are not indicated. In this case, the area is considered to occupy a rectangle described around the warning sign.

Hydrometeorological data is plotted on weather maps according to a certain pattern, with symbols and numbers, around a circle indicating the location of a hydrometeorological station or ship.

Example of information from a hydrometeorological station on a weather map:

Information from the hydrometeorological station

In the center there is a circle depicting a hydrometeorological station. The shading of the circle shows the total number of clouds (N):

dd - wind direction, indicated by an arrow going to the center of the station circle from the side where the wind is blowing.

Signs and meaning of clouds

ff - wind speed, depicted as an arrow feather with the following symbols:

small feather corresponds to a wind speed of 2.5 m/s;
a large feather corresponds to a wind speed of 5 m/s;
the triangle corresponds to a wind speed of 25 m/s.

Wind speed

In the absence of wind (calm), the station symbol is depicted as a double circle.

VV is the horizontal visibility indicated by the code number according to the following table:

Horizontal visibility
Code	VV, km	Code	VV, km	Code	VV, km	Code	VV, km	Code	VV, km
90	<0,05	92	0,2	94	1	96	4	98	20
91	0,05	93	0,5	95	2	97	10	99	>50

PPP - atmospheric pressure in tenths of hectopascal. Numbers of thousands and hundreds of hectopascals are omitted. For example, a pressure of 987.4 hPa is plotted on the map as 874, and 1018.7 hPa as 187. The sign “xxx” indicates that the pressure was not measured.
TT - air temperature in degrees. The sign “xx” indicates that the temperature was not measured.
Nh is the number of low-level clouds (CL), and in their absence, the number of middle-level clouds (CM), in points.
CL, CM, CH - the shape of the clouds of the lower (Low), middle (Middle) and upper (High) tiers, respectively.
pp is the value of the pressure trend over the last 3 hours, expressed in tenths of hectopascal, the sign “+” or “-” before pp means, respectively, an increase or decrease in pressure over the last 3 hours.
a - characteristic of the pressure trend over the last 3 hours, indicated by symbols characterizing the course of pressure changes.
w is the weather between observation periods.
ww — weather at the time of observation.