"Sandstorm" Changes in Ground Forms PPT Courseware

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"Sandstorm" Changes in Ground Forms PPT Courseware

Based on the above pictures, what are the main phenomena that you find when sandstorms occur?

1. Strong winds stir up dust and sand on the ground;

2. There is a lot of sand in the air;

3. The air is quite turbid;

4. The weather is gray, no sunlight can be seen, and visibility is extremely low;

5. There is sand everywhere on cars, buildings and people, making it difficult for people to walk;

What is a sandstorm?

Sandstorms, also known as sandstorms or dust storms, refer to severe weather phenomena in which strong winds blow up dust and sand on the ground, making the air very turbid and with horizontal visibility less than 1,000 meters.

Sandstorm is a general term for both sandstorms and dust storms. It refers to a serious sandstorm weather phenomenon in which strong winds blow up a large amount of sand and dust material from the ground and roll it into the air, making the air extremely turbid and the horizontal visibility is less than 100 meters. A sandstorm refers to a sandstorm caused by strong winds blowing a large amount of sand into the near-surface layer; a dust storm is a storm caused by strong winds carrying a large amount of dust and other fine-grained materials into high altitudes.

Sandstorm intensity is divided into 4 levels:

1. Level 4 ≤ wind speed ≤ level 6, 500 meters ≤ visibility ≤ 1000 meters, it is called a weak sandstorm;

2. Level 6 ≤ wind speed ≤ level 8, 200 meters ≤ visibility ≤ 500 meters, it is called a moderate intensity sandstorm;

3. Wind speed ≥ Level 9, 50 meters ≤ visibility ≤ 200 meters, is called a strong sandstorm;

4. When it reaches its maximum intensity (instantaneous maximum wind speed ≥25 meters/second, visibility ≤50 meters, or even reduced to 0 meters), it is called an extremely strong sandstorm (or black storm, commonly known as "black wind").

How do sandstorms form?

Sandstorms mostly occur in deserts, sandy areas and dry sandy exposed surfaces. The air here is easily heated, while the air above is relatively cold, causing warm air to rise and cold air to sink, forming air convection. When strong winds occur for a long time, it is easy to carry dust from the ground to high altitudes and be blown to other places by strong winds, forming sandstorms.

What causes sandstorms?

The causes are diverse, both natural and man-made, such as the global greenhouse effect, forest decline, vegetation destruction, climate anomalies and other factors.

Which conditions for the formation of sandstorms are related to human activities?

Over-exploitation of natural resources, excessive deforestation, and over-cultivation of land due to population expansion are the main causes of sandstorms, and have increased their intensity and frequency.

Dangers caused by sandstorms

1. Deaths of humans and animals, collapse of buildings, and reduction in agricultural production.

Sandstorms are no less harmful to people, animals and buildings than typhoons and tornadoes. In the past five years, my country's northwest region has been hit by sandstorms more than 20 times, causing economic losses of more than 1.2 billion yuan and more than 200 people dead and missing...

2. Air pollution and topsoil loss.

There are at least 38 chemical elements in sandstorm dust. Its occurrence greatly increases the concentration of atmospheric solid pollutants, causing long-term and potential harm to the atmospheric environment, soil, and agricultural production in the origin and surrounding areas. Especially after the meager topsoil on which crops depend is scraped away, the barren land will seriously affect crop yields.

Sandstorm Disaster Prevention and Emergency Response

Emergency points

●Close doors and windows promptly and seal them with tape if necessary.

●Wear a mask when going out and cover your head with a gauze scarf to prevent dust from invading your eyes and respiratory tract and causing damage. Special attention should be paid to traffic safety.

●Motor vehicles and non-motor vehicles should slow down, pay close attention to road conditions, and drive with caution.

●Properly place outdoor items that are easily damaged by sandstorms.

Expert Tips

●It is not advisable to go out when a strong sandstorm occurs, especially the elderly, children and people with respiratory allergies.

●Be prepared to protect yourself from wind and sand.

How to prevent sandstorms

Experts point out that at present, human beings' ability to control weather is still very limited. The key to mitigating the frequency and intensity of sandstorm disasters lies in the ecological protection and construction of the ground, especially the protection of surface vegetation. It is necessary to adhere to the ecological protection and construction policy of "prevention first, protection first, and prevention and control equal emphasis", establish and improve the laws and policies for ecological protection, and stop production activities that cause the ecological environment to continue to deteriorate.

Based on the results of the discussion, think about it, what should humans do to prevent sandstorms?

1. Plant trees to form an ecological barrier; plant flowers and grass in the city to increase the green area.

By planting trees, we can reduce wind speed and sand erosion. In addition, forests are also known to have functions such as soil and water conservation, water storage, wind protection and sand fixation, and climate regulation. The adoption has strong ecological benefits.

2. Promote ecological restoration and protection zones centered on returning farmland to forests and grasslands.

Increase vegetation coverage and rainfall, thereby regulating the water cycle in arid areas and ultimately improving the climate environment;

3. In areas with serious water and soil erosion such as the Hetao area and sandy land, focus on protecting water resources and natural oases, control desertified land, preserve natural oases, and gradually expand artificial forests;

4. The desert areas of Mongolia are the main source of sandstorms that will affect the climate of my country and Southeast Asia for a long time now and in the future. Therefore, cooperation with surrounding areas should be strengthened to jointly prevent and control sandstorms.

5. Establish awareness of environmental protection, increase publicity efforts, and improve people's environmental quality;

People should use less or refuse to use disposable wooden chopsticks, save paper, and vigorously promote the reuse of paper and other recyclable resources.

Achievements and goals achieved

In 1978, the country implemented the "Three North" protective forest system construction project. In 1991, it launched the national desertification prevention and control project, putting China's desertification prevention and control on the track of engineering and large-scale development. After long-term and hard work, China's desertification prevention and control work has made remarkable achievements.

State Forestry Director Zhou Shengxian pointed out that China’s goals for desertification control are: striving to basically curb the spread of desertification in about 10 years, that is, by 2010; and by 2030, on the basis of consolidating the results of previous governance, to achieve the goal of human advancement and desertification retreat. ; By 2050, strive to basically control all the desertified land that can be controlled.

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For more information about the "Changes in Ground Forms and Sandstorms" PPT courseware, please click on the "Changes in Ground Forms ppt Sandstorms" ppt tag.

"Sandstorm" Changes in Ground Forms PPT Courseware 2:

"Sandstorm" Changes in Ground Form PPT Courseware 2 Read the small information and discuss: Among the basic conditions for the formation of sandstorm weather, which conditions are related to human activities? Small information Sandstorm weather is when strong winds raise sand and dust, making the air turbid, and the horizontal visibility is less than 1,000 meters..

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Update Time: 2024-11-20

This template belongs to science courseware E-education edition sixth grade science volume 1 industry PPT template

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