Geography questions. Analyze the reasons for Southwest Dahan from a geographical point of view

Geographical causes of the great drought in the southwest:

It is difficult for cold and warm air to meet, and the temperature is high – precipitation is persistently low, and water vapor evaporation is high.

Since autumn, the southwest of China has been controlled by dry and warm air, the temperature is abnormally high, the main weather system affecting the precipitation in southwest China - the southern branch trough activity is weak, the cold air in the north mainly from the easterly path southward, rarely can penetrate into the hinterland of the Yunnan Plateau, resulting in less precipitation in southwest China, and autumn and winter drought in Yunnan. Under the influence of El Niño, the convective activity from the South China Sea and the Indochina Peninsula to the western Indian Ocean was suppressed, which was not conducive to the warm and humid air mass activity in the Bay of Bengal, the Indochina Peninsula and Yunnan, resulting in less precipitation.

Recently, China's southwestern region is still in the midst of a drought that has not been seen in a century, and the continuous sunny, hot and rainy weather has led to the continuous aggravation of the drought situation in the five provinces, autonomous regions, and municipalities of Yunnan, Guizhou, Sichuan, Chongqing, and Guangxi.

The first is the influence of plateau thermal factors on the Qinghai-Tibet Plateau. Other provinces in southwest China are greatly affected by the "roof of the world", the Qinghai-Tibet Plateau last winter had less snow, the plateau thermal conditions are good, resulting in the weakening of the Indo-Myanmar trough, the weak South Asian monsoon, the water vapor transported to the southwest of China is not abundant, coupled with the cold air from the north to the south is easterly northerly, resulting in drought in the southwest region.

The second is the impact of El Niño. Under this influence, the sea surface temperature (SST) in the eastern equatorial Pacific Ocean is warmer, the subtropical high is stronger as a whole, and the water vapor carried by the East Asian monsoon meets the cold air from the north to the south, resulting in more precipitation in the eastern part of China and frequent snowfall in the north. On the contrary, the southwest region of China is dominated by downdrafts, and there are often sunny and sunny weather.

The third is that there is no cold air opportunity. Although there have been several cold air impacts on our country this winter, most of the cold air has started to move eastward in the north. With warm air forms the first conditions for rainfall:

Convective weather. However, if the second condition for the formation of rainfall, "water vapor", is not abundant, it still cannot form good precipitation.

The drought was caused by the El Niño phenomenon, which caused a decrease in precipitation in southwest China, resulting in a series of droughts in autumn, winter and summer.

1. The D area is a valley trending northwest-southeast, at the foot of the windward slope of the southeast monsoon, and there are three rivers flowing into it to provide water sources, and the water sources are abundant.

2. The land is on the shady slope of the sun, with less sunshine and less evaporation, so that there is more water than the land on the sunny slope.

c.Test question analysis: The terrain in the southern region is complex, and the difference between east and west is obvious. There are Yunnan-Guizhou Plateau and Sichuan Basin in the west, so the terrain is dominated by plateau flatland.

China's northwest region is deep inland, the temperature changes drastically, and the annual precipitation shows a gradual decrease from east to west The eastern and southern parts of Xinjiang have very little precipitation, and in general, drought is the main feature of the natural environment in this region Affected by precipitation, from east to west, the natural landscape of northwest China generally shows a change from grassland to desert grassland and desert

So the answer is: grassland;Desert steppe;Desert

1. The main manifestations of disasters are strong winds, precipitation (and some confusion in the magnetic field may also occur). Gale force winds here can be stronger than twelve, and precipitation causes flooding.

2 The entire city of New Orleans could not function normally, all supplies could not be transported to the city, there was a shortage of housing, and at the same time, the water supply, electricity, post and telecommunications, and other departments related to daily life could not operate normally.

3 The equatorial region is a warm and humid updraft, and there is no depression to collide with it, so it cannot form a typhoon or hurricane.

4 The reason for the weakening is very simple, because the warm and humid air mass is constantly being consumed after landfall, so the power will be weakened, which is actually the process of continuous reduction of energy in the process of strong winds and precipitation.

There should be a picture for this question, right?

1. Heavy rain, flooding, urban waterlogging, etc.

2. No picture will not.

3. There is no geostrophic deflection force on the equator, and the geostrophic deflection force near the equator is very small, so it will not form a typhoon eye.

4. First, there is more friction on land, which creates greater resistance to typhoons. Clause.

2. After the typhoon makes landfall, it cannot be supported by water vapor from the sea, and the energy is gradually reduced and depleted.

The Northern Hemisphere is a counterclockwise cyclone, so the landfall will initially be southeasterly, with no wind at the eye of the storm, then southwesterly.

High winds are disasters in themselves, such as heavy rains or thunderstorms, and landslides or mudslides can occur in mountainous areas. The horizontal flow of air forms the wind, and the airflow rises vertically in the equatorial region. Say there is no typhoon. When the air flow is blocked, the wind weakens.

There are only answers, and explanations are too cumbersome.

1, A 150 degrees east longitude B:AC C:AO d:ab2, March 21 September 23.

3,180 large.

4, propylene buty. 5. 4:00 on March 22 and 15:00 on June 22

Answer: (1) 150 degrees east longitude, ac, ao, ab

2) The day of the spring equinox and the day of the autumn equinox are the same.

3,180 large.

Explanation: (1) In Figure A, the date dividing line has a 180-degree meridian and a 0-hour line, and it can be judged that the 60-degree meridian on the way is 60 degrees east longitude, and the 60-degree east longitude is also a 0-hour line; Therefore, the morning line should move eastward for 6 hours on the basis of 60 degrees east longitude, that is, move 90 degrees, and the morning line in Figure A is 60 + 90 = 150 degrees east longitude.

In Figure B, the line that follows the direction of the Earth's rotation from day to night is the dusk line, and the line from night to day is the morning line, so the ac arc in Figure B is the morning line.

In Figure C, according to the explanation in Figure B above, ao is the morning line, and it can be seen that the direct point of the sun is at 75 degrees east longitude, that is to say, 75 degrees east longitude, the current time is 12 o'clock, and it moves west from 75 degrees east longitude for 6 hours, which is the meridian where 90 degrees is located, and 15 degrees west longitude, which is our morning line.

In Figure D, ab can be obtained as the morning line according to the explanation in Figure B above.

2) The date of the coincidences between the morning and dusk lines and the meridian is when the direct point of the sun is on the equator, and the date is spring (autumnal equinox), the morning and dusk line is moving eastward from self-study, and the direction of rotation of the earth is also from west to east, so the direction is the same.

3) The difference between the morning and dusk lines at the equator is 180 degrees, and due to the scattering of the atmosphere, the sky is also bright when the sun is not visible (before the sun rises and after the sun sets), so the range of brightness is greater.

4) The date of Figure A is the day of the vernal equinox, the sun is directly at the equator, and the global day and night are equinoxes, and the other three figures are all the sun in the northern hemisphere, so the day in the northern hemisphere is greater than the night.

5) Figure A shows that 60 degrees east longitude is 0 o'clock from question (1), so when the time of Beijing (120 degrees east longitude) is 0 + (60 15) = 4, the time marked on the map is March 21;;; In Figure C, the sun shines directly in the Northern Hemisphere, and there is a polar night in the Antarctic Circle, and the date is judged to be June 22, and the sun is directly exposed to 75e (time at 12 o'clock), and the time of Beijing 120e is 12+(120-75) 15=15.

Answer: (1) 105w

2) (160e, 0) or (160e, 46 degrees 52 minutes n) (3) a

Explanation: (1) From Beijing time (120e) to 9 o'clock, we can find that the longitude where 0 point is located is 120e and moves to the left (that is, 135 degrees) for 9 hours (that is, to the west), and it is obtained that the time of 15 degrees west longitude is 0 o'clock, that is, the meridian in the middle of the shaded part in Figure A is 15 degrees west longitude, so it can be seen that the longitude of place A continues to move 90 degrees from 15 degrees west longitude to the west, which is 105 degrees w

2) From (1), it can be seen that the middle meridian of the shaded part of Figure A is 15 degrees west longitude, the corresponding daytime middle meridian is 180-15=165 degrees east longitude (time is 12 o'clock), and the local time in the question is 11:40, and the longitude position can be calculated as 165-5=160 degrees east longitude;; At this time, the polar day occurs in the Arctic Circle and its north, indicating that the next day is the summer solstice, and the direct sunlight is at 23 degrees 26 minutes N, and the latitude position is found to be the equator or 46 degrees 52 minutes N

3) At this time, only day and night are bisected at the equator, and the latitude mentioned in the title is the equator. From question (1), it can be seen that the longitude where A is located is 105W, and the longitude corresponding to A is 75E, and the range of day is 75e-180-105W, and the range of the Eastern Hemisphere is 60W-0-120E, and the common part of the two is 75E-120e, a total of 45 degrees, and the range is less than 90 degrees.