What is the diurnal variation of temperature. The diurnal variation of water vapor pressure. Motivation of educational activity. Announcement of the topic of the lesson and setting tasks

The daily course of air temperature is called the change in air temperature during the day - in general, it reflects the course of the temperature of the earth's surface, but the moments of the onset of maxima and minima are somewhat late, the maximum occurs at 14 o'clock, the minimum after sunrise.

Daily amplitude of air temperature(the difference between the maximum and minimum air temperatures during the day) is higher on land than over the ocean; decreases when moving to high latitudes (the greatest in tropical deserts - up to 40 0 ​​C) and increases in places with bare soil. The magnitude of the daily amplitude of air temperature is one of the indicators of the continentality of the climate. In deserts, it is much greater than in areas with a maritime climate.

Annual variation of air temperature(change in the average monthly temperature during the year) is determined primarily by the latitude of the place. Annual amplitude of air temperature- the difference between the maximum and minimum average monthly temperatures.

The geographical distribution of air temperature is shown using isotherms- lines connecting points on the map with the same temperature. The distribution of air temperature is zonal; annual isotherms generally have a sublatitudinal strike and correspond to the annual distribution of the radiation balance.

On average for the year, the warmest parallel is 10 0 N.L. with a temperature of 27 0 C is thermal equator. In summer, the thermal equator shifts to 20 0 N, in winter it approaches the equator by 5 0 N. The shift of the thermal equator in SP is explained by the fact that in SP the land area located at low latitudes is larger compared to the SP, and it has higher temperatures during the year.

Heat on the earth's surface is distributed zonal-regional. In addition to geographic latitude, the distribution of temperatures on Earth is influenced by: the nature of the distribution of land and sea, relief, altitude above sea level, sea and air currents.

The latitudinal distribution of annual isotherms is disturbed by warm and cold currents. In the temperate latitudes of the NP, the western shores, washed by warm currents, are warmer than the eastern shores, along which cold currents pass. Consequently, the isotherms at the western coasts are bent towards the pole, at the eastern coasts - towards the equator.

The average annual temperature of SP is +15.2 0 С, and SP is +13.2 0 С. In SP, minimum temperatures are much lower; at the stations "Sovetskaya" and "Vostok" the temperature was -89.2 0 С (absolute minimum of SP). The minimum temperature in cloudless weather in Antarctica can drop to -93 0 С. The highest temperatures are observed in the deserts of the tropical zone, +58 0 С in Tripoli, +56.7 0 С in California, in Death Valley.

Maps give an idea of ​​how much continents and oceans affect the distribution of temperatures. isonomal(isonomals are lines connecting points with the same temperature anomalies). Anomalies are deviations of actual temperatures from mid-latitude ones. Anomalies are positive and negative. Positive anomalies are observed in summer over heated continents. Over Asia, temperatures are 4 0 C higher than the mid-latitude ones. In winter, positive anomalies are located above warm currents (above the warm North Atlantic Current off the coast of Scandinavia, the temperature is 28 0 C above the norm). Negative anomalies are pronounced in winter over chilled continents and in summer over cold currents. For example, in Oymyakon in winter the temperature is 22 0 C below the norm.

The following thermal zones are distinguished on Earth (isotherms are taken beyond the boundaries of thermal zones):

1. Hot, is limited in each hemisphere by an annual isotherm of +20 0 С, passing near 30 0 s. sh. and y.sh.

2. Two temperate belts, which in each hemisphere lie between the annual isotherm +20 0 C and +10 0 C of the warmest month (July or January, respectively).

3. two cold belts, the boundary passes along the 0 0 isotherm from the warmest month. Sometimes there are regions eternal frost, which are located around the poles (Shubaev, 1977)

Thus:

1. The only source of heat that is of practical importance for the course of exogenous processes in GO is the Sun. Heat from the Sun enters the world space in the form of radiant energy, which then, absorbed by the Earth, turns into thermal energy.

2. The sunbeam on its way is subjected to numerous influences (scattering, absorption, reflection) from the various elements of the medium it penetrates and the surfaces on which it falls.

3. The distribution of solar radiation is affected by: the distance between the earth and the Sun; the angle of incidence of the sun's rays; the shape of the Earth (predetermines the decrease in the intensity of radiation from the equator to the poles). This is the main reason for the allocation of thermal zones and, consequently, the reason for the existence of climatic zones.

4. The influence of the latitude of the area on the distribution of heat is corrected by a number of factors: relief; distribution of land and sea; influence of cold and warm sea currents; atmospheric circulation.

5. The distribution of solar heat is further complicated by the fact that the regularities and features of the vertical distribution are superimposed on the regularities of the horizontal (along the earth's surface) distribution of radiation and heat.

Air temperature and diurnal temperature variation

Target: To form an idea of ​​the distribution of heat on the surface of the Earth, the average daily temperature, the amplitude of temperature fluctuations (daily, annual).

Equipment: thermometer textbook.

During the classes.

I .Organizing time. Rapport.

II . Checking homework

Test.

Which gas is predominant in the atmosphere:

a) oxygen; b) hydrogen; c) carbon dioxide; d) nitrogen.

Which layer of the atmosphere contains most of the air?

At what latitudes is the troposphere thicker?

a) above the equator b) in polar latitudes; c) in temperate latitudes.

What layer of the atmosphere is above the troposphere?

a) exosphere; b) stratosphere; c) mesosphere.

In which layer does the weather change occur:

a) in the stratosphere b) in the troposphere; c) in the upper atmosphere.III . Learning new material. How is the air heated?

How much of the solar energy do you think will heat the air in the troposphere?

Describe how temperature changes in the troposphere and with height. Why is the temperature dropping?

Reveal patterns :

The sun's rays pass through the atmosphere without heating it.

The sun's rays heat the earth's surface

Atmospheric air is heated by the Earth's surface

Air temperature decreases with altitude. For every km, the temperature drops by 6°C.

What is the reason for the unequal heating of air during the day? Look at the picture on the slide, try to formulate a pattern.

regularity : the higher the Sun above the horizon, the greater the angle of incidence of the sun's rays, therefore, the surface of the Earth warms up better, and the air from it.

The daily course of air temperature.

At what time of the day is the temperature the highest and lowest? Explain.

How does temperature change throughout the year?

Think about why the warmest and coldest months are not June and December, when the sun's rays have the largest and smallest angles of incidence on the earth's surface.

Air temperature - the degree of air heating, determined with a thermometer.

Air temperature is one of the most important characteristics of weather and climate.

The temperature of air, as well as soil and water in most countries is expressed in degrees of the international temperature scale, or scaleCelsius (WITH). Zero of this scale falls on the temperature at which ice melts, and +100 ˚С - on the boiling point of water. However, in the United States and a number of other countries, the scale is still used not only in everyday life, but also in meteorology.fahrenheit (F). In this scale, the interval between the melting points of ice and the boiling point of water is divided by 180˚, with the melting point of ice assigned a value of +32 ˚F. Zero Celsius corresponds to +32 ˚F, and +100 ˚С = +212 ˚F.

In addition, in theoretical meteorology, an absolute temperature scale is used (scaleKelvin ), K. The zero of this scale corresponds to the complete cessation of the thermal motion of molecules, that is, the lowest possible temperature. On the Celsius scale, this will be -273 ˚С

To identify the general patterns of temperature changes, an indicator of average temperatures is used: average daily, average monthly, average annual.

Determine the average annual temperature in Ust-Kamenogorsk

Examination:

Negative: -10°+(-7°)+(-2°)+(-2°)+(-6°)= -27°С

Positive: 6°+13°+17°+18°+16°+12°+5°=+87°С

Average dailyt: 87° - 27°= 60°: 12=+5°С

Determining the change in temperature, usually note its highest and lowest rates. The difference between the highest and lowest scores is calledamplitude temperatures. Write down the definition.

Determine the temperature amplitude according to the table and diagrams on the slide .

Exercise : according to fig. 86, p.94 determine the amplitude of the air temperature, using the readings of the third pair of thermometers.

Educational practical work.

Drawing up a graph of the daily course of temperature (under the guidance of a teacher)

Isotherms - these are lines connecting points with the same average air temperature for a certain period of time.

Usually show isotherms of the warmest and coldest months of the year, i.e. July and January.

IV . Consolidation of what has been learned.

Textbook page 94

V . Homework.

§24, questions

On Sunday, mark the air temperature at 9:00, 12:00, 15:00, 18:00, 21:00. Enter data into a table

9 h

12 h

15 h

18 h

21 h

CHAPTERIIISHELLS OF THE EARTH

Topic 2 ATMOSPHERE

§thirty. DAILY CHANGE OF AIR TEMPERATURE

Remember what is the source of light and heat on Earth.

How is clear air heated?

HOW THE AIR HEATS. From the lessons of natural history, you know that transparent air transmits the sun's rays to the earth's surface and heats it up. It is the air that does not heat up with rays, but heats up from a heated surface. Therefore, the farther from the earth's surface, the colder it is. That is why when a plane is flying high above the ground, the air temperature is very low. At the upper boundary of the troposphere, it drops to -56 °C.

It has been established that after each kilometer of altitude, the air temperature drops by an average of 6 °C (Fig. 126). High in the mountains, the earth's surface receives more solar heat than at the foot. However, heat dissipates faster with height. Therefore, while climbing the mountains, you can notice that the air temperature gradually decreases. That is why snow and ice lie on the tops of high mountains.

HOW TO MEASURE THE AIR TEMPERATURE. Of course, everyone knows that air temperature is measured with a thermometer. However, it is worth remembering that a thermometer is incorrectly installed, for example, in the sun, it will show not the air temperature, but how many degrees the device itself has heated up. At meteorological stations, to obtain accurate data, the thermometer is placed in a special booth. Its walls are slatted. This allows air to freely enter the booth, together the grilles protect the thermometer of the wii. direct sunlight. The booth is installed at a height of 2 m from the ground. Thermometer readings are recorded every 3 hours.

Rice. 126. Air temperature change with height

Flying above the clouds

In 1862, two Englishmen flew in a balloon. At an altitude of 3 km, bypassing the clouds, the researchers were shivering from the cold. When the clouds disappeared and the sun came out, it got even colder. At the height of these 5 km, the water froze. It became difficult for people to breathe, it was noisy in their ears, and with a lack of strength, it was actually the axis. So slam the rarefied air on the body. At an altitude of 3 km, one of the survivors lost consciousness. At altitudes and 11 km it was -24°C (on Earth at that time the grass was green and flowers were blooming). Both daredevils were threatened with death. Therefore, they descended to Earth as quickly as possible.

Rice. 127. Graph of the daily course of air temperature

DAILY CHANGE OF TEMPERATURE. The sun's rays during the day heat the Earth unevenly (Fig. 128). At noon, when the sun is high above the horizon, the earth's surface heats up the most. However, high air temperatures are observed not at noon (at 12 o'clock), but two or three hours after noon (at 14-15 o'clock). This is because it takes time to transfer heat from the earth's surface. In the afternoon, despite the fact that the Sun is already descending to the horizon, the air continues to receive heat from the heated surface for another two hours. Then the surface gradually cools down, the air temperature decreases accordingly. The lowest temperatures are before sunrise. True, on some days such a daily temperature pattern may be disturbed.

Consequently, the reason for the change in air temperature during the day is a change in the illumination of the Earth's surface due to its rotation around its axis. A more visual representation of the change in temperature is given by the graphs of the daily course of air temperature (Fig. 127).

WHAT IS THE AMPLITUDE OF AIR TEMPERATURE VARIATION. The difference between the highest and lowest air temperatures is called the amplitude of the temperature fluctuation (A). There are daily, monthly, annual amplitudes.

For example, if the highest air temperature during the day was +25 °C, and +9 °C, then the amplitude of the fluctuations will be 16 °C (25 - 9 = 16) (Mat. 129). The nature of the earth's surface (it is called the underlying) affects the daily amplitudes of temperature fluctuations. For example, over the oceans, the amplitude is only 1-2 °C, over the steppes 15-0 °C, and in deserts it reaches 30 °C.

Rice. 129. Determination of the daily amplitude of fluctuations in air temperature

REMEMBER

The air is heated from the earth's surface; With altitude, its temperature drops by about 6 ° C for every kilometer of altitude.

The air temperature during the day changes due to changes in surface illumination (change of day and night).

The amplitude of temperature fluctuation is the difference between the highest and lowest air temperatures.

QUESTIONS AND TASKS

1. The air temperature at the earth's surface is +17 °C. Determine the temperature outside an aircraft flying at an altitude of 10 km.

2. Why is a thermometer installed in a special booth at meteorological stations?

3. Tell us how the air temperature changes during the day.

4. Calculate the daily amplitude of air fluctuations according to the following data (in ° C): -1.0, + 4, +5, +3, -2.

5. Think about why the highest daily air temperature is not observed at noon, when the Sun is high above the horizon.

PRACTICE 5 (Beginning. See pp. 133, 141.)

Topic: Solving problems on the change in air temperature with height.

1. The air temperature at the earth's surface is +25 °C. Determine the air temperature at the top of a mountain whose height is 1500 m.

2. The thermometer on the meteorological station, located on the top of the mountain, shows 16 ° C above zero. At the same time, the air temperature at its foot is +23.2 °C. Calculate the relative height of the mountain.

Reasons for changes in air temperature.

The temperature of the air varies daily following the temperature of the earth's surface. Since the air is heated and cooled from the earth's surface, the amplitude of the daily temperature variation in the meteorological booth is less than on the soil surface, on average by about one third.

The rise in air temperature begins with the rise in soil temperature (15 minutes later) in the morning, after sunrise. At 13-14 hours, the temperature of the soil, as we know, begins to drop. At 14-15 hours it equalizes with the air temperature; from that time on, with a further drop in soil temperature, the air temperature also begins to fall.

The diurnal variation of air temperature is quite correctly manifested only in conditions of stable clear weather.

But on some days, the daily course of air temperature can be very wrong. It depends on changes in cloudiness as well as advection.

The daily amplitude of air temperature also varies by season, by latitude, and also depending on the nature of the soil and terrain. In winter it is less than in summer. With increasing latitude, the daily amplitude of air temperature decreases, as the midday height of the sun above the horizon decreases. Under latitudes of 20-30° on land, the average daily temperature amplitude for the year is about 12°, under latitude 60° about 6°, under latitude 70° only 3°. At the highest latitudes, where the sun does not rise or set for many days in a row, there is no regular diurnal temperature variation at all.

The temperature of the soil surface also changes during the year. In tropical latitudes, its annual amplitude, i.e., the difference in long-term average temperatures of the warmest and coldest months of the year, is small and increases with latitude. In the northern hemisphere at a latitude of 10° it is about 3°, at a latitude of 30° about 10°, and at a latitude of 50° it averages about 25°.

Reasons for changes in air temperature

Air in direct contact with the earth's surface exchanges heat with it due to molecular heat conduction. But inside the atmosphere there is another, more efficient heat transfer - by turbulent heat conduction. The mixing of air during turbulence contributes to the very rapid transfer of heat from one layer of the atmosphere to another. Turbulent thermal conductivity also increases the transfer of heat from the earth's surface to the air or vice versa. If, for example, air is cooled from the earth's surface, then by means of turbulence, warmer air from the overlying layers is continuously delivered to the place of the cooled air. This maintains a temperature difference between the air and the surface and therefore supports the transfer of heat from the air to the surface. temperature changes associated with advection - the influx of new air masses into a given place from other parts of the globe, are called advective. If air with a higher temperature flows into a given place, they speak of heat advection, if from a lower one, they speak of cold advection.

The general change in temperature at a fixed geographical point, which depends both on individual changes in the state of the air and on advection, is called a local (local) change.

The daily and annual course of air temperature depends on the influx of solar heat and the nature of the underlying surface. In accordance with the daily course of the intensity of solar radiation, the maximum air temperature during the day between the sea or ocean occurs at about 12:30, and over land - about 14-15. The minimum air temperature occurs shortly before sunrise or at the time of sunrise, t i.e. during the period of the greatest cooling of the earth's surface. The difference between the maximum and minimum air temperature per day is called the daily temperature amplitude.

The value of the daily amplitude of air temperature is far from constant and depends on the nature of the underlying surface, cloudiness, air humidity, season and, finally, on the latitude and height of the place.

The greatest daily amplitude of air temperature occurs in the southern latitudes, above the sandy surface, in the warm season, in the absence of clouds and with low air humidity, that is, in the dry southern steppes or in deserts. Under these conditions, the difference between the maximum and minimum temperature per day can reach 25-30 and even 40°.

The presence of low cloudiness, fog, precipitation greatly smoothes the daily temperature variation. The temperature amplitude in these cases is insignificant.

The daily amplitude of air temperature over the oceans and large seas at a great distance from the coast is small and amounts to only 2-3°. In other words, as a rule, there are no significant changes in air temperature in the open sea (ocean) during the day. Such a relatively even daily course over the seas is explained by the thermal properties of water, which consist in its small and slow heating and cooling, which in the same way affects the temperature of the air adjacent to the water surface.

As for the annual course of air temperature, it depends on the same reasons as the daily course. On the continents, the maximum usually occurs in July, the minimum - in January, which coincides with the periods of the highest and lowest solstices. On the oceans and coasts, there is a delay in extreme temperatures: the maximum is observed in August, the minimum in February or early March.

In the equatorial zone, two temperature maxima are observed - after the spring and autumn equinoxes, when the height of the Sun is greatest, and two minimums after the winter and summer solstices, at the lowest Sun height in the year.

The difference between the maximum and minimum average monthly temperature during the year is called the annual temperature amplitude. Its value depends mainly on the nature of the underlying surface and the latitude of the place.

The smallest annual amplitude occurs over the oceans, especially between the tropics, where it is only 1-3 °; in temperate latitudes it increases to 5-10°, and in polar regions even more.

The greatest annual amplitude is observed over land, in the depths of the continents in temperate and high latitudes, where it can reach 40-50°, and in some places even 65°. For example, in Verkhoyansk (Yakutia) the average temperature in July is plus 15°, and in January minus 50°. In low latitudes over land, the annual amplitude of air temperature is relatively small, which is explained by a more uniform influx of solar heat.