ice-rime deposits

When observing atmospheric processes occurring on the MS and within the visible neighborhood, the following characteristics are determined:

– type of atmospheric phenomenon, determined visually by the external signs of the phenomenon in accordance with the list and description of phenomena compiled on the basis of the classification adopted by WMO;

– start and end time, which is marked by GMT; the duration of the AE, defined as the difference between the start and end times of the phenomenon during a meteorological day;

– the intensity of AE is determined visually by the external signs of the phenomenon, taking into account the general state of the weather;

– the state of the weather is determined by continuous observations of the AP, taking into account changes in the state of the sky.

The classification and description of AEs, which are observed on the MS, are made according to the following groups:

– hydrometeors, which are accumulations of liquid or solid particles of water falling in the atmosphere, suspended in it, deposited on objects, on the surface of the Earth or in the atmosphere, or

lifted by the wind from the surface of the Earth;

Lithometeors are accumulations of solid particles of sand or dust that

rise from the surface of the Earth by the wind, are transported to a certain distance, or remain in the air in suspension;

– electrical phenomena are visible or audible manifestations of the action of atmospheric electricity;

– optical phenomena in the atmosphere resulting from the reflection, refraction or diffraction of sunlight or moonlight;

– unclassified phenomena in the atmosphere, which are difficult to attribute to one of the listed types.

Each group is divided into several types and varieties.

The state of the weather during and between periods of observation

The characteristic of the state of the weather is given by the observer on the basis of continuous observations of the AP, taking into account the state of the sky and the development of clouds.

To characterize the weather at the time of observation, AH and cloudiness are taken into account, which occurred within 10 minutes and the last hour before the observation time. This weather has 100 different characteristics, which are divided into groups depending on the presence of certain phenomena at the station or in the field of view of the observer and are determined by the current code KN-01.

When characterizing the past weather, AO and cloudiness in

within six and three hours for the main and intermediate dates, respectively. Past weather is encoded by two characteristics.

Observations of ice-frost deposits

The MS performs visual and instrumental observations of ice-frost deposits. This defines the following characteristics:

– view of ice-rime deposits on the wire;

– duration of icing (time of the beginning and end of the phenomenon);

– the size of the deposits on the wire;

– mass of deposits per meter of wire length;

– the course of development of the process of ice-frost deposition.

Icing of the wires of an icing machine from the moment a deposit appears on at least one of the wires until it completely disappears is called an icing case. The duration of one case of icing can reach up to several days. The time of the end of the case is taken as the time of that inspection of the wires of the machine, when

it was found that there was no deposit on any of them.

Observations of icy-hoarfrost deposits are made according to the SGW, the record is made in special books KM-4.

Ice machine, its device and installation

The icing machine is permanently installed on the meteorological platform, in its northern part at a distance of at least 4 m from the place of installation of other devices.

The ice machine consists of three wooden or metal racks with two pairs of wires fixed on them, which serve as receivers for ice deposition. Racks are installed vertically at a distance of 90 cm from each other so that a right angle is formed in the plan, one side of which is directed from north to south, and the other from west to east.

The wires are four pieces of wire with a diameter of 5 mm, which are attached to the racks with help. The lower wires (latitudinal and meridional) are suspended on long brackets, and the upper wires on short ones so that they are at a height of 190 and 220 cm from the Earth’s surface, respectively.

The lower wires are not removed during observations, they are called permanent, and the size of deposits is measured on them. The top wires are removed to determine the mass of deposits and are called removable.

In order to distinguish frost from hoarfrost during observations, an iceoscope is installed next to the icing machine, which can be mounted on the racks of the icing machine. Icescope is

auxiliary installation for visual observations.

In addition to racks and wires, the icing machine kit includes:

– a ladder, which is installed in such a way that it does not touch the racks;

– bath for thawing ice deposits;

– a saw designed for sawing cuts in dense types of deposits when applying a bath;

– tongs and a scraper used to clean the wires from ice deposits;

– vernier caliper and Ponamorev’s templates for measuring the size of deposits;

– measuring glass.

test questions

1. What groups of atmospheric phenomena are there?

2. How are the type and intensity of an atmospheric phenomenon determined?

3. What is the case of ice-frost deposition?

4. The principle of operation of the ice machine.

5. What is an iceoscope for?

Glossary

In Russian in Kazakh In English
ice machine ice machine ice machine tool
For observations of ice-rime deposits
Icescope Icescope Icecope
A device for determining the difference between frost and frost

SRS Topics

Description of atmospheric phenomena, [L1], pp. 271-288, [L3], pp. 179-185, 235-241, 318-321, 333-334, 394-395.

Conditions for the production of observations of ice-frost deposits, determination of the mass of deposits [L1], pp. 317-322, 329-336.

Topics of the TSIS

Recording in the KM-4 book of the results of monitoring ice-frost deposits. [L1], pp. 452-453.

Weather coding within and between periods of observation [L2], pp. 8, 42-53,

Basic and additional literature

1. Manual for hydrometeorological stations and posts, part 1, Almaty 2002

2. CODE for the operational transmission of data from surface hydrometeorological observations, Leningrad, Gidrometizdat 1989.

3. I. I. Guralnik, G. P. Dubinsky, V. V. Larin, S. V. Mamikonova, Meteorologiya, Leningrad, Gidrometizdat, 1982

Lectures No. 17 Measuring Atmospheric Pressure

The atmosphere surrounding the globe exerts pressure on the surface of the Earth and on all objects above the earth. In an atmosphere at rest, the pressure at any point is equal to the weight of the overlying column of air extending to the outer periphery of the atmosphere.

Atmospheric pressure is measured by the height of the mercury column in the barometer, which balances this pressure.

At the MS during observations, the following pressure characteristics are determined: – pressure at the station level;

– pressure reduced to sea level for stations located at an altitude of up to 1000 m above sea level;

– the height of the isobaric surface closest to the level of the station when the station itself is more than 1000 m above sea level;

– barometric trend values;

– characteristic of the barometric trend.

The basic SI unit of measurement is the hectopascal (hPa), but millibars (Mb) and millimeters of mercury can be used as needed.

The height of the isobaric surface is determined in geopotential meters.

Atmospheric pressure instruments

The MS uses the following instruments to measure pressure:

– station cup mercury barometer;

– mercury-free barometer BRS-1;

– meteorological barograph M-22AN.

For special purposes, as well as for measurements in expeditionary and field conditions, inspector barometers and aneroid barometers are used.

The inspection barometer is used to measure the pressure in the range from 570 to 1070 hPa. It is much stronger than station cup mercury barometers and is more convenient for transportation. Therefore, it is used as a control during inspection at the MS, for continuous measurements at high-mountain stations, in expeditionary and other conditions.

Barometer, barograph. Device, installation, principle of operation

The barometer consists of the following main parts:

– a barometric glass tube, sealed at the top end and filled under vacuum with purified mercury;

– a cup consisting of three screwed parts, the middle part of which has a diaphragm with holes that protect the tube from air entering it; for communicating the barometer with the outside air, there is a hole in the lid of the cup, closed with a screw;

– a metal frame on which the scale is applied.

In the slot of the frame there is a movable index with a vernier, which moves with the help of a rack, a thermometer is fixed on the frame to determine the temperature of the barometer, and a cap with a ring is screwed on top of it for hanging it.

The barograph consists of:

– a block of membrane aneroid boxes;

– a transmission mechanism consisting of a system of arc patterns with axes;

– registering part – arrows with a pen and a drum with a clockwork;

– a body consisting of a base and a hinged lid.

With an increase in atmospheric pressure, the corrugated boxes are compressed, the column of boxes is shortened, the upper

the free end of the column and with it an arrow with a pen up. When the pressure decreases, the opposite occurs. By recording on the chart form, the characteristic and magnitude of the barometric trend is determined.

When making observations, the following conditions must be met:

– the barometer must be hung vertically in the office of the station in a barometric cabinet mounted on the main wall, and the barograph – horizontally on a special shelf;

– the barometer should hang freely, without touching the cupboard walls;

– the air temperature in the station room should be maintained close to normal;

– the screw for communicating the barometer cup with the atmosphere must be unscrewed by one or two turns;

– a ceramic or glass vessel should be installed under the cup of the barometer to collect mercury;

– the clock mechanism of the barograph is wound up regularly once a week and the chart blank is also changed.

To calculate the atmospheric pressure at sea level, a correction is added to the atmospheric pressure at the station level, which is found in the tables calculated for each station.

The height of the isobaric surface above the station level in

geopotential meters is determined from tables, atmospheric

pressure and virtual temperature at station level. The height of the station above sea level is added to the obtained value and the result is converted into geopotential meters according to the table.

Corrections to barometer readings, their physical essence

Normal atmospheric pressure is a pressure equal to the weight of a mercury column 760 mm high at a temperature of 0 0 C at sea level and a latitude of 45 0 . Therefore, a constant correction is introduced into the barometer reading and a correction for bringing the barometer readings to a temperature of 0 0 С; a certification correction is introduced into the thermometer reading.

The constant correction is the sum of the instrumental correction and the correction for bringing the barometer readings to normal gravity, depending on the geographical latitude and station height above sea level. The correction for bringing the barometer readings to a temperature of 0 0 С is determined according to the table.

test questions

1. What instruments are used to measure pressure?

2. What is the difference between an inspection barometer and a station barometer?

3. Why is a barograph needed on the MS?

4. Rules for installing a barometer and a barograph on the MS.

5. What corrections are made to barometer readings?

Glossary

In Russian in Kazakh In English
Barometer Barometer barometer
For measuring atmospheric pressure
Barograph Barograph barograph
Barometric Trend Recorder

SRS Topics

The device and principle of operation of the barometer and the recording part of the barograph .. [L1], pp. 33-40, [L2], pp. 68-71.

Measurement conditions [L1], pp.40-44.

Topics of the TSIS

Preparation of measuring instruments before the observation period. Measurement production. Processing and recording of measurement results. [L1], pp. 44-58, [L3], pp. 260-261.

List of basic and additional literature

1. Manual for hydrometeorological stations and posts, part 1, Almaty, 2002

2. Manual for hydrometeorological stations and posts, issue 3, part 111, Gidrometeizdat, Leningrad, 1962.

3. I. I. Guralnik, G. P. Dubinsky, V. V. Larin, S. V. Mamikonova, Meteorology, Leningrad, Gidrometizdat, 1982

Lectures #18 Measuring Wind Characteristics

Wind is the horizontal movement of air masses relative to the earth’s surface, characterized mainly by two quantities:

direction (where the wind is blowing on the horizon) and speed. Wind occurs due to the difference in atmospheric pressure at different points in the atmosphere.

During observations on the MS, the following wind characteristics are determined:

– average wind speed in m/s;

– average wind direction, i.e. angular degree or rhumb;

– maximum wind speed in time, wind speed with gusts, m/s;

– maximum wind speed between observation periods, maximum gust for 3 hours, m/s.

Wind speed measurement is based on the use of a rotating anemometer with automatic determination of the average and maximum wind speed; the measurement of wind direction is determined by the position of the wind vane, which is installed in the stream under the action of the air stream itself. It is allowed to use a weather vane with a flat board to measure the wind speed, which deviates under the influence of the flow by an angle proportional to the flow speed.

Anemorumbometer network

When making wind observations, a network anemorumbometer is used, which provides automatic measurement of the average wind speed for 10 minutes with a turn-on time of at least 10 minutes before the start of measurements.

The anemorumbometer consists of a block of wind speed and direction sensors, a measuring console and a power supply unit.

Measuring transducers of wind speed and direction are designed as a single sensor unit consisting of a horizontal streamlined body, the rear part of which ends with a tail unit – a wind vane. The transducer housing, together with the outer tube, freely rotates around the vertical column.

In front of the horizontal housing there is a propeller, which is installed in the direction of the air flow using a wind vane so that the plane of rotation of the screw is always perpendicular to the direction of the flow.

The measuring console is a desktop device, on the front panel of which there are: a light board, on which the value of the measured wind speed is displayed; keys “Vmax”, “Vavg” and “Vmgm” to enable the measurement of wind speeds; key “Vmax.reset” to reset the fixed value of the maximum wind speed; keys 2, 10 and “Vaverage on” to enable averaging

wind growth for the time interval set by the keys 2 or 10 minutes; light bulb “Measurement”; knob “Forecast” to set the time interval after which the measurement of the average wind speed will begin; toggle switch “Power” to turn on the device; two indicators; “Measure direction” key to register the wind direction.

Station weather vane

If there is no power supply at the station, the wind speed and direction are measured using a set of weather vanes: a wind vane with a light board for measuring wind speed from 0 to 10 m/s and a weather vane with a heavy board from 10 to 40 m/s.

The weather vane consists of a movable vertical rod with pins mounted on it indicating the direction of the wind and a movable part in the form of a tube put on it, on which the wind vane and the speed indicator are mounted.

The wind vane consists of two blades located at an angle to each other, from a counterweight-pointer, mounted on a tube. A sleeve with eight metal pins screwed into it is put on the lower thickened part of the fixed rod of the weather vane, designed to determine the position of the counterweight of the weather vane relative to the horizon. A metal letter C or N is attached to the north-facing pin.

The wind speed indicator is mounted on the top of the tube and consists of a metal plate-board and a frame with a sector on which there are eight pins for determining wind speed. The board can freely oscillate about the horizontal axis of the frame.

The weather vane board is 300 mm long and 150 mm wide. By weight, light (200 g) and heavy (800 g) boards are distinguished.

Other instruments for determining wind characteristics

Anemometer ARI-49

The manual induction anemometer is designed to determine the speed in the field within the range from 2 to 30 m/s at the installation level

device. The device keeps working capacity in the range of temperatures from-40 to +45gr.

The action of an induction anemometer is based on the principle of measuring the angular velocity of rotation of a three-cup meteorological vane using an electric induction tachometer.

The manual anemometer consists of: a sensing element that senses wind speed, an induction tachometer and a device body.

The sensing element is a turntable consisting of three cups fixed with rods on a bushing mounted on an axle that rotates on ball bearings.

Under the influence of wind, the turntable rotates along with the axis. The magnetic system fixed on the axis creates a rotating magnetic field, which induces eddy currents in the metal cap, causing the anemometer needle to deviate.

Before taking a reading on the instrument, it is necessary to hold for 10-15 seconds so that the spinner takes the rotation speed corresponding to the wind speed.

Anemometer MS-13

The manual anemometer is used to determine the average wind speed over a certain period of time, ranging from 1 to 20 m/s.

The sensitive element of the device is a cross with 4 cups, mounted on an axis, which, together with the cross, easily rotates in bearings. The crosspiece is protected by a frame from mechanical damage.

The anemometer has a counting mechanism showing the number of revolutions of the cross, for counting the revolutions of which there are three dials with arrows: a large arrow indicates units and tens of revolutions, small ones indicate hundreds and thousands. At the bottom of the device there is a locking lever for turning the anemometer counter on and off.

To determine the wind speed for a certain period of time, it is necessary: before turning on the device, remove the count from the dial, turn on the device at the desired time, after passing which, turn off the device and count the number of revolutions on the dial. The difference in revolutions must be divided by the time and

determine the wind speed from a special table.

Test questions.

1. What is wind?

2. What wind characteristics are determined on the MS?

3. Under what conditions should a wind vane be used?

4. What are ARI-49 and MS-13 anemometers used for?

Glossary

In Russian in Kazakh In English
Anemorumbometer Anemorumbometer anemorumbometer
Automatic Wind Measurement Instrument
Vane Vane weathercock
Wind speed and direction meter

SRS Topics

Anemorumbometer installation, inspection and maintenance. [L1], pp.65-68.

Wind near the earth’s surface, [L2], pp. 285-291.

Beaufort scale, [L1], pp.81-83.

Topics of the TSIS

Production of wind observations for all instruments, [L1], pp.69-74, [L3], pp.61-65, pp.65-66

Recording in KM-1 books, coding according to the KN-01 code of the results of observations. [L1], pp.448-449, [L4], pp.7,26

List of basic and additional literature

1 Manual for hydrometeorological stations and posts, part 1, Almaty,

2002

2..I.Guralnik, G.P.Dubinsky, V.V.Larin, S.V.Mamikonova, Meteorology, Leningrad, Gidrometizdat, 1982.

3. Manual for hydrometeorological stations and posts, issue 3, part III, Gidrometeizdat, Leningrad, 1962

4. CODE for operational data transmission of surface hydrometeorological observations, Leningrad, Gidrometizdat, 1989

Lectures No. 19-20 Measurement of meteorological visibility range

The meteorological visibility range is the limiting distance beyond which, with a given transparency of the atmosphere, an absolutely black object of large angular dimensions merges with the sky background and becomes invisible because of this. The MWP is related to the transparency of the atmosphere, which is characterized by the transparency coefficient or its reciprocal, the transmittance.

MRV is measured in kilometers or points of the international scale, which is given in the form of a table. In it, each point of the MRV (from 0 to 9) corresponds to the interval of distances in which the value of the MRV is located.

Methods and means for determining the MW

On the MS network, the DMV is determined using the M-53 visibility meter during daylight hours and the M-71 nephelometric backscattering unit at night. In the absence of meters, the determination of the MDP is made visually.

The MDM is estimated according to the scale of the international synoptic code KN-01. For instrumental measurement of visibility, code numbers from 00 to 84 are used, and for visual measurement, from 90 to 99.

Determination of MRV by photometric comparison

To measure the MWP by this method, a polarizing visibility meter M-53A is used. In the central part of the body of the device, a polaroid and a birefringent prism are placed, which gives an optical bifurcation of the observed image, with one image of the object shifted relative to the other vertically.

When the polaroid is rotated, the brightness of the shifted

images: when the brightness of one of them increases, the brightness of the other decreases, up to the complete extinction of one of them.

The rotation of the polaroid, fixed inside the body of the device on a dial with a scale, is performed using a gear drum. The angle of rotation of the polaroid is measured on a scale through a magnifying glass, which is equipped with a diopter ring for focusing the image of the scale strokes. Observations are made through the eyepiece of the instrument, on the other hand

A hood is screwed into the housing to protect the optics from direct sunlight and precipitation, as well as to limit the field of view.

During operation, the device must be held by the handle, which is screwed to the body. For observation by the method of photometric comparison, it is necessary to select two natural objects on the ground and install two artificial ones – a shield and a shield.

Natural objects must meet the following requirements:

– must be dark;

– the minimum width must be 0.008 of the distance to them, the height – at least ½ of the width;

– objects should be selected at such distances from the place of observation that it would be possible to determine all the required ranges of MRV values from them.

An artificial object – a shield – is installed in the interval of distances found according to a special table.

At the observation point at a distance of 2-3 m from the observer towards the objects on a column 2 m high, a black box is strengthened with a hole towards the observer. The mounting height of the box should be such that, when viewed through the device, the upper image of the object and the lower

the images of the boxes were in the center of the field of view almost close to each other.

Rotating the scale of the device with the help of a toothed drum, the observer achieves equality in the apparent brightness of the lower image of the box and the upper image of the object located next to each other. After that, a reading is made on the scale of the device with an accuracy of 0.1 divisions. Then the reading is knocked down and observations are repeated two more times. Of the three readings, find the average value and add to it a correction for the zero position of the device. In addition, the nature of the illumination of the object, the presence of snow or frost on the trees, in the snowless period, the state of the crown of the trees are noted.

Measuring the visibility range by a complex method

The photometric comparison method is accurate and simple, but requires the presence of distant dark natural objects, since is based on comparing the brightness of two objects of observation located at different distances from the observer.

In the absence of suitable natural objects, the MLE is determined only by black shields in a complex way: up to 4 km – by the method of photometric comparison on two shields, more than 4 km – by the relative brightness method on the far shield located at a distance of 300 m from the observer.

At the observation point, two black inclined shields, a diaphragm shield with a rectangular hole in the center, and a pole with an instrument holder should be installed. Shields and shield-diaphragm are painted with black matte paint and should not have through holes.

Distances: from the pole with the device holder to the diaphragm shield should be 3 m, from the diaphragm shield to the first shield – 40-60 m, to the second shield – 300 m. Dimensions: diaphragm shield 70×100 mm, its central hole – 15×21 mm; the first shield – 0.6×0.4 m, the second – 3.2×2.4 m. The size ratio is chosen so that after

inclined installation of shields and a diaphragm flap, the visible shape was a square. The shield-diaphragm must be equipped with a side flag, which is used for observations by the method of photometric comparison.

Conducting observations. Entry in the KM-1 book

When observing using the complex method, it is necessary to roughly estimate the MDL visually – it is more than 4 km or less.

For photometry, the side flag of the diaphragm shield is used. Holding the device in your hands and observing the shield and the flag through it, you need to choose such a position that there is located above the upper image of the shield

the bottom image of the checkbox. Further observations are made as described

higher.

For observations using the relative brightness method, the handle of the instrument is placed on the holder’s pin. Observing the surface of the shield through the device and the opening of the shield-diaphragm, rotate the scale of the device from zero division with the help of a drum. At the same time, the lower image of the sky area near the horizon is superimposed on the upper image of the diaphragm shield and the shield surface observed through its hole, so the contrast between the diaphragm shield and the shield surface decreases. The scale is turned until the contrast becomes indistinguishable – the contrast is extinguished by the sky background. A reading is made on a scale with an accuracy of 0.1 division, observations are repeated three times and the average value is found from three readings, adding to it a correction for the place of zero.

Next, remove the device from the pin, set the scale to zero and, holding the device in hand, observe through it and through the opening of the aperture shield a homogeneous section of the sky near the horizon. By turning the scale from zero division, the image of the sky background is superimposed on the upper image of the diaphragm shield and the sky area visible through its hole. The scale is turned until the contrast becomes indistinguishable and at this moment the reading is taken. Observations are repeated three times and the average reading is calculated with the introduction of a correction for the place of zero.

With a complex method of observations, lighting does not need to be taken into account, because the shield-diaphragm and the observed object are illuminated in the same way.

When observing by the complex method, the KM-1 book is written:

a) when observing by the method of photometric comparison: in the first cell of the upper line – the designation of the object (there will be two of them: the near shield – sh.b. and the far shield – sh.d.), in the second and third cells – a dash;

b) during observations by the relative brightness method: in the first and

a dash is put in the third cell of the top line, the average reading over the sky is written in the second.

In both cases, the average corrected reading is recorded in the first cell of the second line, and the MDL found from the auxiliary table is recorded in the second and third cells of the second line (in km and code digits).

To facilitate the processing of observational results, special auxiliary tables are compiled, according to which it is possible to go directly from the readings to the MDM.

Determination of MPE in the dark

To determine the MW at night, the M-71 nephelometric unit is used, the principle of operation of which is based on the relationship between the MW and the brightness of light scattered by particles that cloud the atmosphere towards the light source. The more clouded the atmosphere, the smaller the MDR and the more light is scattered in all directions, including backwards. By measuring the brightness of the backscattered light, one can determine

MDV. Measurements are made using the M-53M instrument mounted on the M-71 setup.

The device and the principle of operation of the installation are as follows: a light source – a lamp-headlight – gives a powerful light beam. Part of the backscattered light enters the lower through semicircular hole of the light box. The upper semicircular hole, facing the observer, is illuminated by the light of the headlamp scattered in the light box. The illumination of the upper hole does not depend on the state of the atmosphere and creates a reference brightness. The observer using the M-53A device compares the brightness of the backscattered light with the reference brightness. To do this, by rotating the scale of the M-53A instrument,

equalize the apparent brightness of both semicircular holes and at the moment of equality take a reading on the scale. By the value of the reference using a calibration table, the MDM is determined.

The lamp headlight and the light box are placed in the installation case; the M-53A device is inserted into the opening of the housing and clamped with a screw. One of the five attachment lenses included in the installation kit is put on the eyepiece of the device. The lenses change according to the observer’s vision.

The lamp-headlight can be closed with a cover if necessary. The body of the device is pivotally mounted on a stand, which is screwed at the installation site.

The M-71 installation is placed on a meteorological platform on a small sturdy table with a cabinet in which the power supply is placed.

Observations are made similarly to observations by the method of photometric comparison, only the brightness equalization is carried out according to the semicircles visible in the device.

test questions

1. What is the meteorological visibility range?

2. What are the main parts included in the M-53A device?

3. Under what conditions is the MLV determined by the photometric comparison method and the complex method?

4. What is the M-71 unit used for?

Glossary

In Russian in Kazakh In English
Device M-53A Device M-53A Device M-53A
Polarizing MRV Meter
Installation M-71 Installation M-71 Mounting M-71
Device for determining MPE at night

SRS Topics

Observations of DMV by the visual method. [L1], pp. 419-428.

Installation, maintenance, periodic verification of instruments, [L2], pp. 195-201.

Topics of the TSIS

Compilation of auxiliary tables, [L1], pp. 376-377, 379, 385-387. [L3], pp.61-65, pp.65-66

Recording in KM-1 books, coding according to the KN-01 code of the results of observations. [L1], pp. 394-395, [L3], pp. 6,38

List of basic and additional literature

1. Manual for hydrometeorological stations and posts, part 1, Almaty, 2002

2. Manual for hydrometeorological stations and posts, issue 3, part 111, Gidrometeizdat, Leningrad, 1962

3. CODE for operational data transmission of surface hydrometeorological observations, Leningrad, Gidrometizdat, 1989

Lectures № 21-22 Actinometric observations

Key points

The main elements of the radiation regime measured at stations with actinometric observations are direct solar radiation, diffuse sky radiation, total solar radiation, radiation reflected by the earth’s surface, and residual radiation, or active surface radiation balance.

Direct solar radiation is called radiation coming directly from the Sun and the near-solar zone with a radius of 5 gr. Straight

radiation arriving at a horizontal surface is not directly measured, but is calculated by the formula S1 = Ssinh, where h is the height of the Sun above the horizon.

Scattered solar radiation is the radiation that enters the

the horizontal surface from all points of the firmament, with the exception of the solar disk and the near-solar zone with a radius of 5 g, as a result of the scattering of solar radiation by atmospheric gas molecules, water droplets or ice crystals of clouds and solid particles suspended in the atmosphere.

Total solar radiation is the total arrival of direct solar and diffuse radiation to a horizontal surface.

The total radiation reaching the active surface is not only absorbed, but also partially reflected. Part of the total radiation reflected from the active surface is called reflected radiation.

Based on the values of total and reflected radiation, the radiation characteristic of the active surface is calculated – its albedo –

the ratio of the radiation reflected from the surface to the incoming total radiation. The albedo value is expressed in fractions of a unit or as a percentage.

The difference between total and reflected radiation is called residual shortwave radiation or radiation balance.

The portion of atmospheric radiation directed downward and reaching a horizontal surface is called long-wave atmospheric radiation.

Long-wave radiation from the atmosphere is partly reflected from the earth’s surface back into the atmosphere. This part is called long-wave reflected radiation.

Devices, their description, principle of operation

An actinometer is designed to measure direct solar radiation, which consists of a housing with a receiver, a tube and a tripod. The receiver of the radiation is a suit made of silver foil, blackened on the side facing the Sun. A round hole is cut in the center of the disc. The internal junctions of a thermopile consisting of 36 thermoelements connected in series and arranged in the form of an asterisk are glued to the other side of the disk. Thermoelements consist of manganin and constantan strips and have two junctions each: external and internal.

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