Knowledge points of geography and physical geography in senior high school

Key points of knowledge memory in senior high school geography compulsory book

Unit 1 Cosmic Environment

1. 1 the known universe of mankind

1 hierarchy of celestial system: total galaxy-galaxy-solar system-earth-moon system.

anagalactic nebula

Solar system: The central celestial body is the sun.

The closest planet to the sun is Mercury, and the farthest planet is Pluto.

The closest planet to the earth is Venus, and it is Mars that humans are currently exploring and preparing to emigrate.

The asteroid belt lies between the orbits of Mars and Jupiter.

Total galaxy: the universe we observe is not the whole universe, its center is the observer.

The earth in the universe: The earth is an ordinary planet, and its characteristics are not special compared with other planets.

The earth is a special planet, because only life is found in the present universe.

Five conditions for the existence of life on earth:

(1) Stable solar illumination conditions

(2) A safer cosmic environment

(3) Due to the moderate distance between the sun and the earth, the surface temperature is suitable (average temperature 15 degrees).

(4) Because of the moderate mass and volume of the earth, before the formation of the atmosphere (mainly nitrogen and oxygen), the earth can attract the atmosphere.

(5) Formation and existence of liquid water

1.2 the relationship between the sun, the moon and the earth

1 Solar radiation is electromagnetic wave.

The source of solar energy is the nuclear fusion reaction of internal substances.

Only 2.2 billion solar radiation energy reaches the earth.

The solar radiation energy used by human beings includes: solar power generation, water heaters, and fossil fuels such as coal, oil and natural gas.

The solar atmosphere is divided into three layers: photosphere, chromosphere and corona.

6 the influence of solar activity on the earth

Photosphere-sunspot (because the ambient temperature is lower than 1500 degrees)-is the main sign of solar activity.

Chromosphere-flare-the strongest display of solar activity

Coronal solar wind

Impact on the Earth: (1) Changes that affect the Earth's climate.

(2) Flare will affect the ionosphere and interfere with short-wave radio communication.

(3) It affects the earth's magnetic field and produces the phenomenon of "magnetic storm".

1.3 new exploration of the universe by human beings

1 develop the universe

(1) Space resources: satellite communication, space experiments, etc. (vastness, high vacuum, strong radiation, weightlessness)

(2) Solar energy resources (space utilization)

(3) Mineral resources (found in moon rocks)

2. Protecting the cosmic environment: measures to deal with space junk (pushed to other orbits and brought back to Earth)

1.4 basic forms of earth motion-rotation and revolution

1 Earth rotation

(1) The direction is: from west to east (the top view of the north celestial pole is counterclockwise, and the top view of the south celestial pole is clockwise) (draw the top view of the north and south poles, the equatorial side view, etc.), and the northern end of the earth axis always points to the vicinity of Polaris (from the northern hemisphere, the height of Polaris on the ground is equal to the local geographical latitude).

(2) Period: sidereal day -360 degrees-real period -23 hours, 56 minutes and 4 seconds.

Solar Day -360 degrees 59 minutes-Human actual cycle -24 hours

(4) Speed: There is no speed at the north and south poles (the speed is 0).

Linear speed-decreasing from the equator to the poles (60 degrees latitude is half of the equator)

Angular velocity-everything is equal except the pole (15 degrees/hour, 1 degree /4 minutes).

2 the revolution of the earth

(1) Orbit of revolution: An elliptical orbit that approximates a perfect circle, in which the sun is at a focal point.

(2) Perihelion-65438+1early October-the linear speed and angular speed of revolution are faster.

Perihelion-early July-the linear and angular velocities of revolution are relatively slow.

(3) direction: from west to east (counterclockwise as viewed from the north celestial pole)

(4) Period: revolution 360 degrees-sidereal year -365 at 6: 09: 10 second.

3 the relationship between the earth's rotation and revolution-moving in the same direction at the same time

The intersection angle between the ecliptic plane and the equatorial plane (currently 23 degrees and 26 minutes)

The characteristics of the earth's revolution: the existence of ecliptic angle and the fact that the northern end of the earth's axis points near Polaris remain unchanged for a certain period of time.

4 direct point of the sun: the only intersection of sunlight and light on the earth at an angle of 90 degrees.

5. The north-south movement of the direct point of the sun:

The northernmost part-the Tropic of Cancer-June 22nd-the summer solstice in the northern hemisphere.

The southernmost point-Tropic of Capricorn-65438+February 22nd-Northern Hemisphere Winter Solstice

On the equator-March 2 1 Sunday and September 23-the vernal equinox and autumnal equinox in the northern hemisphere.

Revolutionary period-the year of the return of the motherland-5: 48: 46 in 365.

1.5- 1.6 the geographical significance of the earth movement

Alternate day and night

1 the formation of day and night: the earth is not luminous and opaque.

Half of the earth is illuminated by the sun, that is, the hemisphere during the day, and the other half is facing away from the sun, that is, the hemisphere at night.

The dividing line between the solar hemisphere and the night hemisphere-the termination line (circle)-the height of the sun is 0 degrees.

From the perspective of solid geometry-the plane where the twilight aperture is located is perpendicular to the sunlight.

local time

The earlier time is in the east of 1 (draw a longitude diagram: longitude of east longitude, longitude of west longitude, longitude of east and west longitude of 0 degrees and around 180 degrees).

International standards for dividing two zones: 0 time zone, 12 east-west zone and 8 east zones.

Deviation of horizontal motion of an object along the surface: along the direction of motion, it is not biased on the equator, the northern hemisphere leans right, and the southern hemisphere leans left.

3 Variation of day and night length and noon sun height

The length of day and night reflects the length of sunshine.

The noon sun height is the maximum sun height in a day (not necessarily 90 degrees).

4 Changes in the length of day and night

In the summer half year in the northern hemisphere-from the vernal equinox to the autumnal equinox-the sun shines directly on the northern hemisphere-the days in all latitudes in the northern hemisphere are longer than the nights. The higher the latitude, the longer the day and the shorter the night. Summer Solstice-The day length at all latitudes in the northern hemisphere reaches the maximum in a year, and extreme days appear in the Arctic Circle and its northern region.

In the winter half year in the northern hemisphere-from the autumnal equinox to the vernal equinox of the following year-the sun shines directly in the southern hemisphere-the night at all latitudes in the northern hemisphere is longer than the day, and the higher the latitude, the longer the night and the shorter the day. Winter solstice-the length of each latitude in the northern hemisphere reaches the minimum in a year, and the Arctic Circle and its northern region are extremely night.

At the vernal equinox and the autumnal equinox, the sun shines directly on the equator, and the length of day and night is equal all over the world, each being 12 hour.

5 changes in the height of the sun at noon

At the same time, the height of the sun decreases from the direct point of the sun to the north and south sides at noon (finding the position of the direct point is the key)

From summer solstice, the sun shines directly on the Tropic of Cancer, and the height of the sun decreases from the Tropic of Cancer to the north and south at noon. At this time, the noon sun height reaches the maximum in a year in the tropic of cancer and its northern latitude (there are two maxima in the south of the tropic of cancer) and the minimum in the southern hemisphere latitude (there is only one minimum in all regions of the world, that is, the local winter to the sun).

In winter solstice, the sun shines directly on the tropic of Capricorn, and the height of the sun decreases from the tropic of Capricorn to the north and south sides at noon. At this time, the noon sun height in the tropic of Capricorn and its southern latitude reaches the maximum in a year, and the noon sun height in the northern hemisphere reaches the minimum.

At the vernal equinox and autumnal equinox, the sun shines directly at the equator, and the height of the sun decreases from the equator to the poles at noon.

Summary: At the same latitude except the equator, the length of day and night and the height of the noon sun change with the seasons, which makes the solar radiation have the law of seasonal change and form four seasons. In the same season, the length of day and night and the height of the sun at noon change with latitude, which makes the solar radiation have the law of latitude differentiation and form five zones.

6 Division of four seasons

The traditional four seasons in China: starting from beginning of spring, Changchun, beginning of autumn and beginning of winter.

It is mainly suitable for life and agricultural production in the Yellow River valley of China.

Summer is the season with the longest day and the highest sun in a year.

Winter is the season with the shortest day and the lowest sun height in a year.

Spring and autumn are the transitional seasons of winter and summer.

The division of four seasons in European and American countries: starting from vernal equinox, summer solstice, autumn equinox and winter solstice.

In fact, the division of the four seasons in the northern temperate zone is combined with the climate:

Spring: March, April and May Summer: June, July and August.

Autumn: September, 10, 1 65438+1October Winter: 12,1,February 7.

Borders: South, Tropic of Cancer, South and Arctic Circle.

Name: Tropical-Direct sunlight.

North temperate zone, south temperate zone-no direct sunlight, no extreme day and night.

The northern cold zone and the southern cold zone-there are extreme days and nights.

The five zones reflect the law that the annual total solar radiation decreases from low latitude to high latitude. Unit 2 Atmospheric Environment

The atmosphere is the most active part of the earth's natural environment.

2. 1 composition and vertical distribution of the atmosphere

1 Composition of the lower atmosphere: mainly dry and clean air, water vapor and solid impurities.

2 the role of each component

Nitrogen and oxygen (accounting for 99% of the air volume), nitrogen is the basic component of life on earth, and oxygen is the necessary substance for human beings and all living things to maintain life activities.

Carbon dioxide is the basic raw material for photosynthesis of green plants, which plays a role in keeping the ground warm.

Ozone can absorb a lot of ultraviolet rays from the sun and protect life on earth from excessive ultraviolet rays, and is known as the "umbrella of life on earth". A small amount of ultraviolet rays that penetrate the atmosphere and hit the ground play a role in sterilization and treatment.

Water vapor and solid impurities (condensation nuclei) are necessary conditions for cloud formation and rainfall.

Impact of human activities on atmospheric composition: too much carbon dioxide is emitted, and HCFCs are emitted.

4 vertical distribution of the atmosphere

Fundamentals: temperature, density and atmospheric movement.

(1) Troposphere: the lowest layer of the atmosphere near the ground. 3/4 of the whole atmospheric mass and almost all water vapor and solid impurities are concentrated in this layer. It is most closely related to humans living at the bottom of the troposphere.

Features: (1) The temperature decreases with the elevation. Reason: The heat source in the troposphere is the ground.

(2) The convection movement is remarkable. Reason: the upper part is cold and the lower part is hot.

Tropospheric thickness: low latitude 17- 18km.

Mid-latitude area 10- 12km.

8-9 kilometers in high latitudes.

(On the three-circle circulation diagram of the pressure belt and the wind belt, the heights of the three circles are different. )

(3) The weather phenomenon is complex and changeable (convection rises, temperature drops, and cooling into clouds leads to rainfall)

(2) Stratosphere: from the tropopause to the height of 50-55km.

Features: (1) The temperature is distributed vertically, with little change with height in the lower layer, and the temperature rises rapidly with the increase of height over 30 kilometers. Reason: The heat source in the stratosphere is ozone absorbing solar ultraviolet rays.

The ozone layer is at a height of 22-27 kilometers.

(2) The airflow is mainly advection. Reason: The upper part is hot and the lower part is cold.

Relationship with human beings: the ozone layer is the sky barrier, and the atmosphere is stable, which is conducive to high-altitude flight.

(3) Upper atmosphere: the air pressure is very low and the density is very low.

Upper limit of atmosphere: the altitude is 2000-3000 kilometers, and the air pressure here is 0.

At an altitude of 80-500 kilometers, there is an ionosphere that can reflect radio waves. 2.2 Thermal state of the atmosphere.

1 Weakening effect of atmosphere on solar radiation

Solar spectrum: visible region (0. 4 - 0。 76 microns) accounts for 50% of the total radiation energy of the sun, and is the least weakened by the atmosphere. Therefore, the solar radiation energy directly absorbed by the atmosphere is very small.

The ultraviolet region is mainly absorbed by ozone.

The infrared region is mainly absorbed by water vapor and carbon dioxide.

(1) absorption: selectivity, ozone absorbs ultraviolet rays, and water vapor and carbon dioxide absorb infrared rays. It hardly absorbs visible light, which is also called selectivity.

(2) Reflection: Clouds and dust with larger particles. The reflection of clouds is the most important.

For example, in summer, when it is cloudy, the temperature will not be too high.

(3) Scattering: air molecules or tiny dust prevent some solar radiation from reaching the ground. (Note that some of them can reach the ground. )

The clear sky is blue.

The red ones at the traffic lights are hard to disperse, and you can see them in the distance.

The attenuation of solar radiation by the atmosphere is inversely proportional to the solar altitude angle: the higher the sun altitude, the less attenuation. At the same time, remember that the higher the sun is, the stronger its radiation is. Therefore, although the northern hemisphere is far from the sun in summer, the higher the height of the sun, the longer the day and the higher the temperature. )

The ground is the direct heat source of the troposphere (the long wave of the ground is absorbed by the water vapor and carbon dioxide in the troposphere).

4. Heat insulation effect of the atmosphere on the ground: atmospheric inverse radiation (atmospheric radiation to the ground)

Solar radiation (short wave), ground warming, ground radiation (long wave), atmospheric warming, atmospheric radiation (long wave), atmospheric reverse radiation (heat insulation)

The sky is cloudy and the temperature is high at night.

The weakening of the atmosphere and heat preservation have narrowed the daily temperature difference. Thermal insulation increases the average surface temperature to 15 degrees, forming an environment suitable for human survival.

Global heat balance: the average annual heat budget of the whole earth is balanced.

Problems at present: Excessive emission of carbon dioxide leads to global temperature rise and a series of ecological changes, thus affecting the global economic structure. 2.3 the movement of the atmosphere

1 Heat source of atmospheric movement: solar radiation.

The root cause of atmospheric movement: the heat difference between high and low latitudes.

Vertical movement of the atmosphere: the rise or fall of airflow is caused by uneven cold and heat.

The horizontal movement of the atmosphere is called wind, which is caused by the pressure difference on the same plane.

Thermal cycle: it is the simplest form of atmospheric movement because of the uneven heat and cold on the ground.

On the same plane, the cold place on the ground is high pressure and the hot place is low pressure, which corresponds to the sky above the ground. On the same plane above the ground, the density above the cold ground decreases due to the air sinking to the ground, forming a low pressure above the hot ground, and the air above the ground is rising, forming a high pressure above the ground (again, the plane ratio of the sky and the sky is the same, and the plane ratio of the ground and the ground is the same)

Pay attention to remember: on the same plane, the density is high, the density is low and the air pressure is low at atmospheric pressure.

Example: Urban Wind-heat Island Effect

5 horizontal movement of the atmosphere-wind

Pressure gradient: the pressure difference per unit distance

Horizontal pressure gradient: the pressure gradient on the same horizontal plane

Horizontal pressure gradient force: the force that urges the atmosphere to flow from high pressure area to low pressure area is the direct cause of wind formation. If the density of the atmosphere is uniform on the same plane, there will be no airflow without the pressure gradient, that is, there will be no wind. The direction of this force is perpendicular to the isobar and points to the low pressure (vector). The magnitude of this force is related to the density of isobar. In the same picture, the wind speed is high where the isobars are dense and low where the isobars are sparse.

6 the relationship between wind direction and stress:

(1) is subjected to a force: the horizontal pressure gradient force, and the wind direction is perpendicular to the isobar and points to the low pressure.

(2) There are two forces: plus a geostrophic deflection, the wind is finally parallel to the isobar (note that the deflections in the northern and southern hemispheres are different).

(3) There are three forces: plus the ground friction, the isobar of the friction wind direction has an intersection angle (acute angle).

Note: There are only two effects of high altitude on the atmosphere.

Friendly reminder: can you draw the wind direction according to the isobar? (Cyclone and anticyclone map) 2.4 Global atmospheric circulation

1 atmospheric circulation: a global regular atmospheric movement. (Three-circle circulation, monsoon circulation)

2 Low latitude circulation: (The pressure zone and wind zone mentioned below refer to the names near the ground)

(1) equatorial low-pressure area: due to the formation of thermal action, the airflow converges and rises, which is easy to form clouds and cause rainfall, forming a rain area. Controlled all the year round, forming a tropical rainforest climate (Amazon Plain, Congo Basin, Malaysia Islands in Southeast Asia).

(2) Subtropical high pressure area: It is formed due to the dynamic action, and the airflow accumulates and sinks above 30 degrees latitude, forming a rainless area (except the East Asian monsoon area), and the areas under its control all the year round form a tropical desert climate (Sahara Water Desert in North Africa, West Asia Desert, West North America Desert, South America Chile, West Peru Desert, Australia Desert).

(3) Trade winds: The airflow blowing from subtropical high to equatorial low changes from north wind to northeast trade winds in the northern hemisphere and southeast trade winds in the southern hemisphere.

3 Mid-latitude circulation:

(1) Sub-extreme low pressure area: It is formed by the rising of warm air flow at low latitudes and cold air flow at high latitudes. Form a temperate and rainy zone.

(2) Mid-latitude westerly belt: The airflow blowing from the subtropical high to the subtropical low belt turns into a southwesterly wind to the right in the northern hemisphere and a northwesterly wind to the left in the southern hemisphere, which is customarily called westerly wind. Its perennial controlled area forms a temperate maritime climate on the west coast of the mainland. (Western Europe, western North America, such as Vancouver, Canada, the west side of the Andes at the southern tip of South America, the southern tip of Australia, Tasmania, New Zealand, etc. )

4 high latitude circulation:

(1) Polar high pressure area: Due to thermal action, cold air sinks, resulting in less rain area. However, due to the low temperature and low evaporation in the polar region, the polar region belongs to the region where precipitation is greater than evaporation and belongs to the humid region.

(2) Polar easterly wind: Under the action of geostrophic bias (in polar regions, the geostrophic bias is greater), the northern hemisphere turns to the northeast wind to the right, and the southern hemisphere turns to the southeast wind to the left. In order to distinguish it from the trade winds, the polar winds are called polar easterlies.

Summary: There are 7 pressure zones and 6 wind zones near the earth's surface. (Learn to draw)

5. Movement of pressure belt and wind belt

(1) Motion reason: Motion with the motion of the direct point of the sun.

(2) Movement direction: As far as the northern hemisphere is concerned, it generally moves northward in summer and southward in winter.

Note: according to the position of the sun, the schematic diagram in the textbook can judge whether the bisector of the sun is bisected or not, and know which direction the pressure belt and the wind belt have moved south or north. This will be related to the Mediterranean climate.

6 Influence of land and sea distribution on atmospheric circulation

(1) It can be seen from the distribution map of the global sea level isobar that, except near Antarctica (especially in the area south of 30 north latitude), the pressure zones are basically banded (because the oceans in the southern hemisphere are absolutely dominant, and the zonal pressure zones are more obvious than those in the northern hemisphere), and the pressure zones near the ground are all cut into blocks, which are not banded.

(2) Take the Asia-Pacific region as an example.

In summer, the Indian depression (Asian depression) on the Eurasian continent cut off the subtropical high belt that moved northward with the direct point of the sun, and the rest of the subtropical high retreated into the ocean. The one in the Pacific Ocean is called the North Pacific High (Hawaii High).

In winter, the Mongolian-Siberian high (Asian high) on Eurasia cuts off the sub-polar low belt that moves southward with the direct point of the sun, and makes the rest of the sub-polar low belt retreat to the ocean, which is the Aleutian low in the Pacific Ocean.

Atmospheric activity centers, these high and low pressure centers on land and sea in winter and summer, are called atmospheric activity centers because of their strong strength and wide range. They move north and south with the seasons and have a great influence on the weather and climate of the world.

8 monsoon circulation

(1) Definition: The prevailing wind in a large area changes significantly with the seasons.

(2) Monsoon circulation is also a part of atmospheric circulation. East Asia is the most typical region in the world, and other regions (southeastern United States and southeastern Australia) also have monsoon.

(3) The reasons for the formation of monsoon: First, the difference of thermal properties between land and sea.

The second is the seasonal movement of pressure belt and wind belt.

For example, the monsoon formed by the different nature of land and sea forces: the winter and summer monsoon in East Asia and the winter monsoon in South Asia.

Monsoon formed by seasonal movement of pressure belt and wind belt: South Asian summer monsoon (southwest monsoon), which means that the direct point of the sun moves northward, and the southeast trade wind in the southern hemisphere crosses the equator, and the geostrophic deflection force turns right to form southwest wind.

(4) Why East Asia is the most typical monsoon region in the world: East Asia is located between Asia-Europe continent, the largest continent in the world, and the largest ocean Pacific Ocean, and the thermal difference between land and sea is more significant than other parts of the world.

(5) East Asian monsoon: (temperate monsoon, subtropical monsoon)

Winter wind: a northerly wind with high pressure, low temperature and dry wind from Mongolia and Siberia.

Summer monsoon: the southerly wind from the northwest of Hawaii High in the North Pacific Ocean, with high temperature, high humidity and rainy weather.

(6) South Asian monsoon: (tropical monsoon)

Winter wind: the northeast wind from Mongolia-Siberia (the sea water in North India flows counterclockwise).

Summer monsoon: a southwest wind from the southern hemisphere (the sea water in the northern Indian Ocean flows clockwise)

9 Subtropical High and the Movement of Precipitation, Drought and Flood-Rain Belt in China

The rain belt in late spring (May) is in South China (Pearl River Basin).

In early summer (June-July), the rain belt moved to the middle and lower reaches of the Yangtze River until southern Japan, forming a month-long plum rain.

From July to August, the rain belt moves to the northeast and north China.

In September, the subtropical high retreated to the south, the rainy season in the north ended, and the south entered the second rainy season.

Summary: the rainy season in the north starts late, ends early and is short; The rainy season in South China starts early, ends late and is long.

The subtropical high moves northward faster (the summer monsoon is strong), resulting in waterlogging in the north and drought in the south.

The subtropical high moves slowly northward (the summer monsoon is weak), which causes drought in the north and waterlogging in the south.

1 Common weather systems: frontal system (cold front, warm front), cyclone and anticyclone, frontal cyclone.

Front system: (cold and warm air mass refers to relative temperature)

Similarities between cold and warm fronts: cold air mass is under the front and warm air mass is on the front.

It rains on one side of the cold air mass (the cold front is called the back of the front and the warm front is called the front).

(1) cold front and weather: the cold air mass moves to the front of the warm air mass actively (extremely cold wave).

Weather changes: it is often cloudy, windy, rainy, and cooling. There is strong wind, bringing rain and snow, etc. ); After crossing the border, the air pressure rose, the temperature and humidity plummeted and the weather turned fine.

(2) Warm front and weather: The warm air mass moves to the front of the cold air mass.

Weather change: there will be continuous precipitation when crossing the border; After crossing the border, the temperature rose, the air pressure dropped and the weather turned fine.

Cold front is the main factor affecting the weather in China. Rainstorms in summer and cold waves in winter are cold front weather.

4 Low pressure (also called cyclone) and high pressure (also called anticyclone)

(1) Cyclone: The central airflow rises and it is easy to form rainy weather.

The horizontal airflow converges counterclockwise in the northern hemisphere (the four fingers of the right hand hold the horizontal airflow to converge, and the thumb up indicates that the vertical airflow rises), while the horizontal airflow converges clockwise in the southern hemisphere (the left hand).

(2) Anti-cyclone: the central airflow sinks and the weather is fine. (For example, dry weather in summer and crisp autumn in the Yangtze River valley)

The horizontal airflow diverges clockwise in the northern hemisphere (the four fingers of the right hand are slightly open, which means the horizontal airflow diverges, and the thumb is downward, which means the central airflow sinks), and diverges counterclockwise in the southern hemisphere (the left hand).

Frontal cyclone: Cyclone is low pressure. In the actual atmosphere, the low-pressure system often has a low-pressure trough extending in a certain direction along the center (just like the plastic circular washbasin we are using now is squashed), and a frontal system is formed on the low-pressure trough. Frontal and cyclone are a whole (no high pressure system)

Note: In the low-pressure system in the northern and southern hemispheres, learn to judge that the cold front is the initiative of the cold air mass and the warm front is the initiative of the warm air mass according to the direction of air convergence movement in the cyclone. 2.6 Formation and change of climate

1 Climate elements: temperature and precipitation (the average or statistics of these two elements should be used to describe the climate of a place).

2 climate forming factors (causes of different climate types)

(1) solar radiation-the most basic reason, leading to the temperature difference of different climate types.

(2) the underlying surface-the direct heat source and water source of the atmosphere (the difference between marine climate and continental climate, and the difference between plain and mountainous climate)

For example, annual range with a maritime climate is smaller, and annual range with a mountainous climate is smaller than the nearby plain areas.

(3) Atmospheric circulation-dual nature, on the one hand, it regulates the global distribution of heat and moisture, on the other hand, atmospheric circulation itself is also a climate phenomenon.

For example, there are two kinds of subtropical climate: Mediterranean climate and subtropical monsoon climate, with the same latitude, but different atmospheric circulation and different climate characteristics.

(4) Human activities have an increasing impact on the climate (changing the atmospheric composition and water vapor content, releasing heat to the atmosphere, and changing the physical and biological characteristics of the earth's surface).

Summary: The basic characteristics of climate are formed by the long-term interaction of the above climatic factors.

2 climate type (remember the characteristics of temperature and precipitation: monthly change of temperature, annual change of precipitation, monthly change of precipitation)

There are four types of tropical climate: the monthly average temperature is above 20 degrees, and the precipitation varies greatly from climate type to climate type.

(1) Tropical rain forest climate (affected by equatorial low pressure all year round, with high temperature and rainy all year round)

(2) Tropical desert climate (affected by subtropical high or land trade winds all year round, with high temperature and little rain all year round)

(3) Tropical monsoon climate (the northeast wind prevailing in South Asia in winter due to the influence of Mongolia-Siberia high is a dry season, the southwest monsoon blows in summer, and the rainy season is from June to September).

(4) Tropical grassland climate (this climate type is located between the equatorial low pressure zone and the trade wind zone, and is affected by the movement of the direct solar point. When the equatorial low pressure moves, it is wet season, rainy, and when the trade winds move, it is dry season, with little rain. Agricultural activities are sown in the rainy season and harvested in the dry season)

Subtropical climate type: the average temperature in Leng Yue in winter is above 0 degrees, and the average temperature in the hottest month in summer is above 20 degrees. There are only two types of climate in the world:

(1) Mediterranean climate: distributed in all continents except Antarctica, at 30? 0? 2——40? 0? The west coast of the mainland lies between the westerlies and the subtropical high. When the west wind moves in winter, it comes from the ocean and is mild and rainy. When the subtropical high moves in summer, downdraft prevails, which is hot and dry.

(2) Subtropical monsoon climate (outside Asia, the difference in thermal properties between land and sea is not as big as that between Eurasia and the Pacific Ocean, so it is called subtropical monsoon humid climate): in winter, it is influenced by Mongolia-Siberia high, and northerly winds prevail, with low temperature and little rain, while in summer, it is influenced by summer monsoon from the ocean, with high temperature and rainy.

Temperate climate type: Except maritime climate, the average temperature in Leng Yue in winter is below 0℃, and the average temperature in the hottest month in summer is above 20℃.

Temperate maritime climate, temperate continental climate and temperate monsoon climate.

(1) temperate maritime climate: 40? 0? 2 - 60? 0? The west coast of the mainland (the high latitude side of the Mediterranean climate) is controlled by the west wind all the year round, and it is mild and rainy all year round.

(2) Temperate monsoon climate: It is distributed on the high latitude side of subtropical monsoon, affected by winter monsoon, cold and dry, affected by summer monsoon, with high temperature and rainy (its winter is lower than tropical climate).

(3) Temperate continental climate: controlled by continental air mass all year round, with large diurnal range, large annual range and scarce precipitation, mainly in summer.

Polar climate: the annual average temperature is below 0℃. Downward flow prevails, precipitation is scarce, and it is a humid area due to less evaporation.

Climate change: For more than two billion years, the earth's climate has changed alternately between cold, warm, dry and wet, with different change cycles. Since the end of 19, the world temperature has fluctuated obviously.