The review of geography system knowledge in senior high school has been summarized.

1. What are some examples to prove that the earth is spherical?

A: ① Sailing around the world, watching ships by the sea, Foucault pendulum experiment, solar eclipse, etc.

2. The shortest route of an airplane is a great circle and a bad arc passing through two points. What are great circles and bad arcs?

A: The center of the great circle on the earth's surface coincides with the center of the earth. The equator, the twilight aperture and the warp coil are all natural circles.

If the starting point and the ending point are on the equator, you can fly along the lower arc of the equator (the central angle is less than180); If the starting point and the ending point are located on the same warp, they also fly around the lower arc of the warp; If the starting point and the ending point are on the termination line, you can fly along the bad arc of the termination line. If two points have the same latitude but different longitudes, for example, the right picture flies from ② to ⑤, it must fly to the southeast first and then to the northeast.

Tip: first distinguish the northern and southern hemispheres, and then mark the rotation direction of the earth on the periphery. The top view looks just a straight line.

3. How many kinds of isolines are there? What information can the density of isoline reflect?

A: There are countless kinds. The density of contour lines reflects the rate of change of a certain geographical quantity. For example: ① The density of contour lines reflects the size of slope, and the denser contour lines, the steeper slope and the more rapid water flow; ② The density of isoline reflects the velocity of groundwater flow. The denser the contour line, the faster the groundwater flows. ③ The density of isobar reflects the pressure gradient force. The denser isobar, the greater the wind speed.

4. Why do two identical isolines sometimes appear in the isoline map?

Answer: When the isoline in the isoline map suddenly changes from increase (decrease) to decrease (increase), two identical isolines or a closed isoline will appear. For example, the abrupt change of contour line reflects the transformation and transition of terrain area.

How is the contour line of crater lake drawn?

A: See the right figure. The short line in the figure indicates the slope line, which always points to the side with low altitude, so the crater lake has the characteristic of decreasing from a certain contour line to the outside.

6. the problem of repairing water wells and sewers?

(as shown on the right) Why is 1, 3,5 reasonable and 2,4 unreasonable?

Answer: The reason for building the drainage ditch is that the drainage is not smooth, and the water can flow by itself in the direction perpendicular to the isobar (contour line), so there is no need to repair the drainage ditch. Therefore, "the drainage ditch should be parallel to the isobar to increase the catchment" is unreasonable; When repairing water wells, "multiple wells should not be arranged on a line perpendicular to the phreatic water level line", such as the existing wells at 1 and 2 1, the water sources of the two wells will be greatly reduced, and the catchment areas of the two wells are small, so 2 is unreasonable.

7. Does altitude affect the morning and evening of sunrise?

A: It does have an impact. Generally, the higher the altitude, the earlier the sunrise and the later the sunset. Days at the same latitude and high altitude are longer.

8. Why is 1 solar day on the plane shorter than one solar day on the earth when the plane flies from west to east? If you fly from east to west, it will be longer than the sun on the earth?

Answer: Let the angular velocity of the earth's rotation be φ 0, and the angular velocity of the plane relative to the center of the earth be φ 1. If the star is taken as the reference point, a solar day on the plane should be 360/(φ 0+φ 1), while the solar day on the earth should be 360/φ 0. So when the plane flies from west to east, the solar day on the plane is shorter than that on the earth, and vice versa.

9. Is the sunrise and sunset direction in the equatorial region due east and west all year round?

A: Obviously not. It can be analyzed by drawing a light map. The equatorial region is the same as other non-polar daytime regions. When the sun shines directly in the northern hemisphere, the global sunrise is northeast, the sunset is northwest, and when it shines directly in the southern hemisphere, the global sunset is northwest.

Tip: Analysis of the apparent motion diagram of the sun As for the extreme day, the sun shines directly in the northern hemisphere:

(1) Where extreme days occur, the sunrise is due north, the sunset is due north, and the sun is due south at noon.

(2) For the Arctic, the sun does not set all day, and the altitude angle of the sun remains the same all day. Seen from the North Pole, the sun should move clockwise in the sky, which is opposite to the rotation direction of the earth.

③ Other extreme solar regions: there is no sunrise or sunset, but there are the highest and lowest solar heights at most. The highest solar height still appears at 12 local time, and the lowest solar height is 0 local time.

10. What is the relationship between the direction of the rod shadow and the direction of the sun?

A: It depends on the relative position of the sun and the pole. For example, if the sun is in the northeast of the pole, the shadow will fall in the southwest. When the sun is due south of the South Pole, it sets due north (noon).

1 1. Why is the water in the south of Shannan Yang and the water in the north of Shannan Yin?

Answer: The reason is that the Central Plains is located in the north of the Tropic of Cancer, and there is no direct sunlight all the year round. At noon, the sun will only come from the south. Therefore, when the elevation angle of the sun is less than the slope of the north slope, the south side of the mountain can be illuminated by the sun, which is called "Yang", while the north side of the mountain cannot be illuminated, which is called "Yin". Suggestion: Drawing analysis

Why is Shuibei Yang? Mainly because the topography of our country is high in the west and low in the east, and the river flows eastward, the south bank of the river is easy to be eroded and wet due to geostrophic bias, which is called "Yin" and the north bank of the river is "Yang".

The above statement spread from the Central Plains, and later spread to all of China. People have extended this saying that the south of the mountain is yang and the north of the mountain is yin.

12. Why was Pluto, once one of the nine planets, downgraded to a dwarf planet in 2006?

A: A planet is a celestial body orbiting the sun. Its own gravity is enough to overcome its rigid physical force and make the celestial body spherical, and it can clear other objects near its orbit. Pluto's orbit crosses Neptune, and because of its small mass, it can't clear its orbital obstacles, so it is downgraded to a dwarf planet.

13. Why can't we see the chromosphere and corona layer of the solar atmospheric structure?

A: Because the brightness of the photosphere is much higher than that of the chromosphere and the corona, we usually see the photosphere of the sun. During the total solar eclipse, the chromosphere and corona can only be seen if the photosphere is blocked. Chromosphere and corona layer can only be observed by means of optical instruments, such as coronagraph.

14. When people observe the moon on the earth, they find that the moon is almost as big as the sun at the full moon. Why?

A: Around the fifteenth day of the lunar calendar, it coincides with the distance between the sun and the earth/the distance between the moon and the earth = the radius of the sun/the radius of the moon, giving people the visual impression that the moon is almost as big as the sun. The size of an object depends on the apparent radius. The apparent radius refers to the angle between the straight line from the observer's eyes to the center of the light arc and the straight line from the observer's eyes to any point on the light arc.

15. How to simply identify the moon phase? How to use the moon phase to identify the direction?

A: The first quarter moon is D-shaped, and the moon faces west. Some students questioned that since it is D-shaped, according to the principle of "going up north and down south, left west and right east", the moon should face east! However, most parts of China always face the southern sky to observe, so it becomes "south facing north, left east facing right facing west". The waning moon is C-shaped, and the surface of the moon faces east.

16. When is noon on the moon? What time is around 10 am?

A: The moon is just in the direction of due south or due north (local due south) of the observer, and then the moon goes to the midpoint of sunrise and sunset. For example, the first quarter moon rises later than the sun and then sets. The moon rises at about 12 and sets at about 24: 00, so the first quarter moon reaches the upper meridian at dusk.

Noon in the morning refers to noon, that is, local time 12, and the sun is located due south or north of the local area.

17. The moon goes around the earth. Why can you only see one side?

Answer: Because the revolution speed and rotation speed of the moon are the same, but the moon also revolves 1 when it rotates 1, and the effects of the two movements cancel each other out, so what we see is always the same side. Figure: The direction of rotation and revolution is counterclockwise.

18. What is the white night phenomenon?

A: There are no extreme days or non-extreme days in areas with latitudes higher than 49. The local summer has longer days and shorter nights. Due to scattering, it was still bright before dawn after sunset. This phenomenon is called white night. For example, this phenomenon occurred in Mohe, China, during the summer to the day before and after.

19. Why did the sky change from blue to gray when the solar eclipse occurred?

A: During the total solar eclipse, the white light of the main body of the sun was blocked by the moon and did not reach the earth's atmosphere, so the blue-violet light inside was greatly reduced. The outer circle of the sun is red, and the blue is less. If it is less, it will naturally spread out and become dark gray.

20. What time zones are used in the west and east of the United States?

A: The western time is: west eight District (LA time), and the eastern time is: West District 5 (new york time).

Chapter II Atmosphere

2 1. What's the point of sunbathing?

A: Sunlight contains various wavelengths of light: infrared, red, orange, yellow, green, cyan, blue, purple, ultraviolet and so on. Infrared rays in sunlight have strong thermal effect and are easily absorbed by objects, so they are usually used as heat sources. The ability to penetrate clouds is stronger than visible light.

It is best to get some sunshine from 6 am to 10. At this time, the infrared rays in the sun are strong and the ultraviolet rays are weak, which can play the role of promoting blood circulation and removing blood stasis; 4 pm to 5 pm is also the best time to bask in the sun, which can promote the absorption of calcium and phosphorus in the intestine, enhance physical fitness and promote normal calcification of bones. However, the sunshine time is longer in summer, and the heat wave is rolling at 4-5 pm, so the sunshine time can be slightly delayed.

22. What are the hazards of ultraviolet rays? What are the factors that affect the intensity of ultraviolet rays?

A: According to the research, the harm of ultraviolet rays to human body is mainly manifested as ① damage to the skin, which can slightly burn the skin. After sun exposure, the skin looks dry and rough, prone to wrinkles and aging, and may even induce skin cancer in severe cases.

Example: Regular exposure to the sun will increase melanin in the skin and make the skin black. If the skin is poor, after a few days of sun exposure, peeling and redness may occur.

② Ultraviolet rays are also very harmful to eyes, especially for the elderly, which will obviously increase the risk of cataract.

This is why the electric appliance emits infrared rays through the remote control instead of using ultraviolet rays to control the operation of the electric appliance.

Benefits of ultraviolet rays: disinfection and sterilization, help the human body to supplement vitamin D and promote the absorption of calcium.

The intensity of ultraviolet rays is mainly affected by the sun's height, altitude and weather.

For example, for Chongqing, ultraviolet rays are strongest in July and August in summer, especially around noon. Because the sun is high at this time, it is often dry and rainy under the control of subtropical high, and the weakening effect of clouds on ultraviolet rays is also quite weak.

23. Why does the Antarctic ozone hole appear in local spring instead of winter?

A: Although the Antarctic ozone layer is the lowest in winter, it is basically in a state of extreme night near the Antarctic in winter. The decomposition of ozone by HCFCs requires the irradiation of ultraviolet rays from the sun as an external condition. It's extremely daytime in the Antarctic when it comes to spring, and the ultraviolet rays are particularly strong.

24. Why is the highest temperature around 2 pm and the lowest temperature around sunrise in a day?

A: The weather is mainly determined by the temperature, and the fundamental factor affecting the temperature is the intensity of solar radiation. Solar photothermal is not the main reason for the direct temperature rise. The direct absorption of solar heat energy by air is only about 14%, while 43% of the energy in the visible region is absorbed by the ground. When the ground absorbs solar radiation heat, it is conducted into the air through radiation, convection and other forms, which is the main reason for the temperature rise.

After noon, solar radiation began to weaken, but the ground still absorbed more heat than it consumed. Until about 1 in the afternoon, the ground temperature reached the highest and the ground radiation reached the strongest. Because it takes a certain time for heat to transfer from the ground to the atmosphere, the temperature near the ground reaches the highest at about 2 pm, and the atmospheric reverse radiation also reaches the maximum in a day.

The higher the temperature, the stronger the atmospheric inverse radiation.

The atmosphere mainly loses heat in the form of inverse radiation and atmospheric radiation, and there is no solar radiation to supplement heat until sunrise the next day, so the temperature reaches the lowest value around sunrise the next day.

25. Why is the monthly average minimum temperature in the northern hemisphere mainland not on the winter solstice but on "March 9"?

A: The winter solstice is the southernmost limit of the direct point of the sun, and the solar radiation in the northern hemisphere reaches the minimum, but the heat in the atmosphere mainly comes from the ground radiation, and it will take some time for the atmospheric temperature to reach the minimum. So their minimum values are not synchronized.

26. How high is the altitude in the thermal cycle?

Answer: The minimum height of thermal circulation refers to the area with an average height of 500 hectopascals and above, that is, about.

The area above 3000-5000 meters and within the troposphere is called high altitude.

27. How wide is the influence of land-sea breeze?

Answer: Because the sea-land wind is only affected by the difference of thermal properties in one day, the energy is weak, the wind force is not strong, and the range is small. Generally only 20-50 kilometers deep into the land, also known as coastal wind. The land-sea wind is strongest at 2-3 pm, because the temperature difference between land and sea is the largest at this time.

There is a similar wind near the reservoir.

28. Put a cup of freshly boiled water and a glass of ice water together. Why does the fog on hot water float to the ice water?

Answer: According to the analysis of thermodynamic cycle, the air above the ice water cools, contracts and sinks, and the air above the hot water supplements horizontally, forming a thermodynamic cycle.

29. How is the night rain in Bashan area formed?

A: In areas similar to valleys or basins, the valleys flow downward during the day, and the hillsides are heated quickly, and the airflow rises; At night, the hillside cools down quickly, and the airflow sinks, while the valley bottom is warmer, and the airflow rises relatively, and it condenses when it meets cold at high altitude, forming night rain.

Note: Compared with the atmospheric temperature at the same height, the temperature changes at different speeds with different distances from the ground.

30. Why are the subtropical high and subtropical high not caused by thermal factors?

A: When we analyze the three-circle circulation, we first assume that the earth does not rotate, a cold high pressure will form near the extreme low, a hot low pressure will form near the equator, and a single-circle circulation will eventually form between the high pressure and the low pressure. But in fact, subtropical high and sub-extreme low are produced in rotation, so equatorial low and polar high are formed by thermal factors, while subtropical high and sub-polar low are formed by dynamic factors.

Students naughty three thousand questions series 2

Continue with the second chapter

3 1. How many windless areas are there on the earth?

A: Two, between 5 degrees north and south latitude in the equatorial windless area and about 30 degrees south and north latitude in the subtropical windless area. Due to the small air pressure difference in the nearby area, the wind is quite small. Note: Malacca Strait is located in the equatorial windless zone, and it is the strait with the least wind and waves.

32. What's the difference between the East Asian monsoon and the South Asian and Southeast Asian monsoon?

A: The East Asian monsoon is mainly affected by the difference in thermal properties between land and sea. The monsoon in South Asia and Southeast Asia is mainly formed by the seasonal movement of wind pressure belts, but it is also affected by the differences in land and sea properties.

33. Why is the winter monsoon in East Asia stronger than the summer monsoon?

A: The magnitude of wind power depends on the air pressure difference, which in turn depends on the temperature difference. In winter, the temperature difference between north and south is large, and the air pressure difference is large.

It's windy. The source of winter wind is Siberia, Mongolia, which belongs to temperate continental climate. It is called the cold pole in the northern hemisphere, and its intensity is relatively strong.

34. Which parts of China are affected by the southwest monsoon?

A: The southwest monsoon can affect Yunnan, Guizhou, Sichuan, Chongqing, Tibet, Guangxi and Qionglai in China, but it mainly affects the southwest. The areas most affected by the southwest monsoon are South Asia and Southeast Asia. The southwest monsoon in South Asia generally prevails from June to September, and the southwest monsoon in Southeast Asia generally prevails at 5- 10. The midsummer mainly affects southwest China.

35. Why didn't the east coast of North America at the same latitude form a large-scale monsoon climate compared with Asia?

A: The North American continent is much smaller than Eurasia, and the difference in thermal properties between the land and the ocean is relatively small, which is greatly influenced by the ocean.

36. How is the plateau monsoon formed on the Qinghai-Tibet Plateau?

A: The opposite wind direction prevails in the Qinghai-Tibet Plateau in winter and summer. It is an independent wind system formed by the thermal action of the Qinghai-Tibet Plateau. Compared with the surrounding free atmosphere with the same height, the plateau is a heat source in summer, forming a thermal depression near the plateau; Winter is a cold source, forming a cold high pressure. Refer to the right picture

37. How is the crisp autumn weather formed?

A: Autumn height refers to sunny weather controlled by high pressure in autumn. Air is low in water content and high in oxygen content, which makes people feel smooth in breathing, so it is called "refreshing".

38. Is it true that low pressure is a cyclone?

A: 99% of the time, it is correct. Generally speaking, low pressure is a cyclone, but it is not absolute. If there is a low pressure center near the equator, because the geostrophic deflection force near the equator is zero, the airflow cannot rotate and a cyclone cannot be formed.

39. How are the cold and warm front positions of frontal cyclones distributed?

Answer: As shown on the right, it is a cyclone in the northern hemisphere. Both A and B have low pressure troughs (isobars protrude to high values). The cold air mass driven by high latitude wind is a cold front, and the warm air mass driven by low latitude wind is a warm front. It can also be simply written as: "The trough of low pressure on the left side of the cyclone is a cold front", which holds true in both the northern and southern hemispheres. Remember the name "Left Chill" of a character in the legendary swordsman?

40. In what season and latitude did frontal cyclones occur in China?

A: The spring rebound in the mid-latitude area is most likely to form a cyclone, and the cold and warm air currents in the north and south of the mid-latitude meet to form a front. In autumn, sunny weather is more likely to form in northern China.

4 1. Also affected by the quasi-static front of Kunming, why is it rainy in Guiyang and sunny in Kunming in winter?

A: As shown on the right, the precipitation can be mainly behind the front with the help of the cold front, and the precipitation of the warm front is mainly in the rain area before the front, and the Guiyang side is in the rain area.

The actual rain area is on the side of the cold air mass, and the right picture depicts the moving direction of the cold and warm air mass.

42. Why is the dividing line between subtropical monsoon climate and temperate monsoon climate in Japan roughly at 40ON?

A: Because Japan is an archipelagic country in the ocean, its climate is obviously maritime, and it is influenced by Japanese warm current, so the dividing line can be pushed northward to about 40ON, while the monsoon climate in China is continental, and this dividing line is about 35ON along the Qinling-Huaihe River.

43. Why does precipitation increase first and then decrease from the foot of the mountain with higher altitude, and generally it is the most on the mountainside?

A: Precipitation in mountainous areas is generally on windward slopes. In the process of water vapor climbing along the terrain, the temperature drops and the water vapor condenses to form precipitation. There is not a lot of water vapor condensation at the foot of the mountain, and there is less precipitation. The farther the water vapor condenses to the mountainside, the air is supersaturated to form precipitation, and when the water vapor content decreases at a certain height, the precipitation decreases again. Therefore, the windward hillside area has the most abundant precipitation.

44. What's the difference between rain shadow effect and wind-burning effect?

A: Both of them are basically the same. They both talk about the situation that the temperature of the leeward slope of the mountain rises and there is little precipitation after the airflow passes through the mountain.

Rain shadow effect emphasizes that precipitation is scarce, and foehn usually reminds people of high temperature, but both exist at the same time.

45. What are the factors that affect the daily temperature range and annual range?

A: Diurnal temperature range: ① The lower the latitude, the greater the diurnal temperature range, because the higher the noon sun height in low latitudes, the greater the diurnal variation of the sun height. ② Coastal areas are regulated by the ocean, and the daily temperature difference is smaller than that in inland areas.

③ The higher the altitude, the greater the daily temperature difference in large-scale terrain area. The daily temperature difference in Qinghai-Tibet Plateau is larger than that in Sichuan Basin.

(4) Small-scale topographic area: The daily temperature difference in concave land is greater than that in convex land, because the contact area between concave land and ground is greatly affected by ground radiation. For example, Xinxian County is located in the Yangtze River valley and Feng Ming is located in the mountainous area, so the temperature difference in Xinxian County is greater than that in Feng Ming.

Temperature annual range: ① The higher the latitude, the longer the daytime in summer, the smaller the height of the sun at noon in winter and the shorter the daytime, so the higher the latitude, the greater the temperature annual range. (2) The specific heat of the land is smaller than that of the ocean, and the temperature rises rapidly in summer, and the temperature is higher than that of the ocean; In winter, the temperature drops rapidly, and the temperature is lower than that in the ocean, so the temperature in the inland area is higher than that in the ocean. ③ At the same latitude, the lower the altitude, the greater the annual temperature difference.

(4) The concave annual range is large and the convex annual range is small. Concave land > plain land > convex land

46. Is the daily temperature difference large at high altitude?

A: Large-scale terrain area: The higher the altitude, the greater the daily temperature difference. Eg 1: The daily temperature difference in Qinghai-Tibet Plateau is greater than that in Yunyang.

Small-scale topographic area: eg2: Mount Tai is higher than Jinan, but the daily range is smaller than Jinan in plain area.

The main reason is that the size of the ground area affects the intensity of ground radiation, thus affecting the temperature difference.

47. Why is the temperate continental climate the largest in the whole year?

A: First of all, the temperate climate has the most distinct four seasons and the largest annual temperature difference. Compared with temperate monsoon climate and temperate maritime climate, temperate continental climate is less affected by the ocean, and its annual temperature can reach 62.3℃.

48. What are the characteristics of the daily temperature difference between Qinghai-Tibet Plateau and Daxinganling and annual range?

A: ① The daily temperature difference in Qinghai-Tibet Plateau is greater than that in Daxing 'anling. In large-scale terrain area, the higher the altitude, the greater the daily temperature difference.

② The Qinghai-Tibet Plateau is extremely cold all year round. Because of the high altitude, it is not affected by the winter wind, and the temperature is relatively small throughout the year.

49. Why does global warming make middle latitudes drier and high latitudes wetter?

A: With global warming, mid-latitude evaporation will be more intense, mountain glaciers will gradually retreat and eventually melt without ice, rivers in arid areas will gradually disappear, land desertification will intensify, and oases in the lower reaches of rivers will gradually disappear. Global warming may lead to the accelerated melting of snow and ice in high latitudes, and the rising of water vapor is easy to condense into clouds and lead to rainfall, but the precipitation will increase, which is suitable for farming.

Chapter III Land and Sea

50. How is the saltwater lake formed?

A: The lagoon was originally a freshwater lake, but because the inflow of water is less than the outflow of water, the lake surface will gradually shrink and the evaporation will gradually decrease, and finally the balance between the inflow and outflow of water will be achieved, and the lake surface area will not change. The river water flowing into the lake must contain a little mineral, which is gradually precipitated. With the shrinking of the lake area, the salinity gradually increased, and eventually it became a saltwater lake.

5 1. Why should the tunnel be excavated at the anticline? Not syncline?

A: Because syncline is conducive to collecting groundwater and easy to collapse. However, the arching of anticline strata conforms to the mechanical principle, and groundwater collection is not easy to occur.

52. The Andes were formed by the collision and extrusion of two plates?

A: The Andes were formed by the extrusion of the Antarctic plate and the American plate, while the Rocky Mountains in North America were formed by the collision and extrusion of the Pacific plate and the American plate. Reference plate tectonic map

53. Is the extension of natural belt the same as the density of vegetation?

Answer: No, the extension of the natural belt mainly depends on the heat. Usually, the natural zone of Shanyang slope is higher.

The density of vegetation mainly depends on water. Only when this kind of vegetation is distributed on the shady and sunny slopes of the mountain can we analyze the density of a certain plant on the sunny and shady slopes of the mountain, so it can already be used for heat. So we mainly analyze its water, such as the Qinling Mountains. The same vegetation may be distributed on the south slope, but the water on the south slope is richer, so the vegetation on the south slope should grow more densely.

54. Why is the natural belt on the western slope of Taihang Mountain higher than that on the eastern slope?

A: As I mentioned in my last question, the extension of the natural belt mainly depends on the heat. The precipitation on the eastern slope and the western slope of Taihang Mountain exceeds 400 mm, but the precipitation on the eastern slope is slightly higher than that on the western slope, which leads to the fact that the light and heat on the eastern slope are not as good as those on the western slope, so the natural belt on the western slope extends higher.

55. Why is the south slope of Kilimanjaro natural belt higher than the north slope? Why is the snow line lower than the north slope?

A: Kilimanjaro is located about 5 degrees south of the equator, and there are no obvious shady and sunny slopes near the equator, so the difference of natural zones mainly depends on precipitation. The south slope is located in the windward slope of the southeast trade wind, with more precipitation, and the snow line should be lower than the north slope.

56. What are the factors that affect the snow line? Why is the snow line on the south slope of Mount Everest lower than that on the north slope?

A: For the snow line, it must be (snowfall = melting snow), so the level of the snow line is affected by precipitation and temperature. Although the south slope of Mount Everest has a large amount of snow melting due to strong sunlight, its snowfall is also large, so it is not surprising that the snow line on the south slope is 500 meters lower than that on the north slope. Please analyze for yourself, is the snow line lower on the southern slope or the northern slope of Tianshan Mountain?

57. Is the snow line in the Alps low on the south slope or low on the north slope?

A: The snow line is determined by both precipitation and heat. The southern slope has a Mediterranean climate, with hot and dry summers and mild and rainy winters. The northern slope has a temperate maritime climate, with more rainfall and lower temperature than the Mediterranean climate zone, so the snow line on the northern slope is lower.

58. What is the connection between alpine desert belt and alpine ice and snow?

A: If there is an alpine snow belt on a mountain, there must be an alpine desert belt, but if there is an alpine desert belt, there is not necessarily an alpine snow belt, because the temperature of the alpine snow belt is much lower than that of the alpine desert belt.

59. How to judge whether a natural belt is distributed according to non-zonality?

A: Non-zonality, that is, it does not follow the general law, neither latitude and longitude zonality nor vertical zonality. For example, the Patagonian desert in South America is not zonal because it is located on the leeward slope of the west wind. Other places on the earth with the same latitude and land and sea position belong to temperate maritime climate.

60. Why is the salinity of the warm current flowing through the ocean at the same latitude higher than that of the cold current flowing through the ocean?

A: Warm current flows through areas with high water temperature, strong evaporation and much dissolved salt, so the salinity of warm current at the same latitude is higher than that of cold current.

6 1. Why is the salinity of seawater in the northern hemisphere at the same latitude generally lower than that in the southern hemisphere?

A: This is determined by the land and sea distribution in the northern and southern hemispheres. The northern hemisphere has a large land area, and the southern hemisphere, especially south of 30oS, is basically ocean. Land runoff can dilute seawater and reduce its salinity.

62. Why is the Somali cold current in summer and the Somali warm current in winter in the waters near Somalia?

A: First of all, the reasons are different. Somali waters are affected by southwest monsoon in summer, and the surface seawater is blown away, and the bottom cold seawater comes up, which belongs to compensation current. Although these seawater flows from low latitude to high latitude, the temperature is low, so it is a cold current; In winter, the northeast monsoon prevails in the North Indian Ocean, which is a wind current that blows the seawater near Somalia. Although this wind flow comes from high latitudes, it is supplemented by the equatorial countercurrent on the southeast ocean surface, and the water temperature is high, so it is a warm current. See ocean current chart.

63. How is the density current in the Strait of Gibraltar formed?

A: Due to the density difference between the two sides of the Gibraltar Strait, the salinity of seawater on the Mediterranean side is relatively high, while that on the Atlantic side is relatively low. When two kinds of seawater with different densities meet in the Strait of Gibraltar, the seawater on the Atlantic side must be higher than that on the Mediterranean side, and the surface ocean current flows from the Atlantic to the Mediterranean.

64. What is the density flow direction of the Turkish Strait?

A: First of all, there is more precipitation in the Black Sea than in the Mediterranean, and the Black Sea joins some big rivers including the Danube. Furthermore, the latitude of the Black Sea is relatively high and the evaporation is relatively small, which makes the sea surface of the Black Sea higher than that of the Mediterranean Sea. Surface seawater flows from the Black Sea to the Mediterranean Sea through the Strait, while the bottom ocean current flows in the opposite direction. However, due to the shallow strait, the amount of water flowing into the Black Sea is hindered, which makes the amount of water flowing into the Black Sea less than that flowing out of the Black Sea, maintaining the dynamic balance of water in the Black Sea.

65. Why can the Peruvian cold current form a large fishing ground, but the California cold current does not form a large fishing ground?

A: Five cold currents in the middle and low latitudes:

Peru cold current, California cold current, Benguela cold current, Canary cold current and Western Australia cold current all meet the conditions for forming fishing grounds. But among the five cold currents, only Peru has the strongest cold current and the largest fishing ground.

66. What are the causes of the warm current in Guinea?

A: The reason is the same as equatorial countercurrent.

67. Why does the equatorial countercurrent in the northern Indian Ocean only exist in winter?

A: The equatorial countercurrent is the backflow in the equatorial region when the north-south equatorial warm current meets the west coast of the ocean (compensation current).

In summer, the prevailing wind direction in the North Indian Ocean is the southwest monsoon, which can't form the north equatorial warm current, so it can't form the equatorial countercurrent. The equatorial countercurrent in the Pacific Ocean exists all the year round; Although the equatorial countercurrent in the Atlantic Ocean exists all the year round, it is not obvious because of the topography of the west coast of South America. So when there is equatorial countercurrent in the northern Indian Ocean, it must be winter in the northern hemisphere.

68. How to distinguish weathering from erosion?

A: Weathering is an external force that breaks the rock surface (but still adheres to the matrix), erosion is an external force that peels off the fragments formed on it, and handling is an external force that moves these peeled fragments to other places.

69. What's the difference between the Three Gorges of the Yangtze River and Norwegian fjords?

A: The scenery of Norwegian fjords is similar to that of the Three Gorges in China, but the causes are different. Norwegian fjords are many U-shaped valleys and V-shaped valleys excavated due to the erosion of glaciers, and later formed with the rise of sea level. The Three Gorges of the Yangtze River was formed due to the uplift of the Sichuan Basin, the leakage of lake water and the downward cut of depth, mainly due to the erosion of running water.

Analyze the causes of the valley in the lower reaches of Congo River by yourself.

70. What is the difference between U-shaped valley and V-shaped valley in origin and shape?

A: The U-shaped valley is formed by glacier erosion, and the shape of the valley is U-shaped, while the V-shaped valley is formed by flowing water eroding the river bank. Because the surface velocity of the river is faster than that of the bottom and banks, and the erosion effect on the lower part of the valley is weak, it is V-shaped with "upper width and lower width".

7 1. Are the causes of the ups and downs in Eastern Europe Plain and Inner Mongolia Plateau the same?

A: The ups and downs of the eastern European plain are the result of glaciation, while the ups and downs of the eastern Inner Mongolia Plateau are due to the wind.