Weather in Santaizi, Linghai

Overview of natural disasters (natural disasters/natural hazards)

"Natural disaster" is an abnormal phenomenon in the nature on which human beings depend, and the harm caused by natural disasters to human society is often shocking. Among them, there are earthquakes, volcanic eruptions, mudslides, tsunamis, typhoons, floods and other sudden disasters. There are also gradual disasters, such as land subsidence, land desertification, drought, coastline changes, etc., which can only gradually appear in a long time; There are also environmental disasters caused by human activities, such as ozone layer change, water pollution, soil erosion, acid rain and so on. These natural disasters and environmental damage are intertwined. It has become the common theme of the international community to scientifically understand the occurrence and development of these disasters and minimize their harm.

Natural variations on the earth, including those induced by human activities, occur all the time. When this mutation brings harm to human society, it constitutes a natural disaster, because it brings different degrees of damage to human production and life, including through labor and the relationship between people and nature. Disasters are negative or destructive. Therefore, natural disasters are a manifestation of the contradiction between man and nature, with

The main sudden natural disasters in the world are: drought, flood, typhoon, storm surge, freezing injury, hail, tsunami, earthquake, volcano, landslide, debris flow, forest fire, agricultural and forestry diseases and insect pests, etc.

There are many kinds of natural disasters in China. Earthquake, typhoon, rainstorm, flood, waterlogging, high temperature, lightning, fog, haze, debris flow, landslide, tsunami, road icing, tornado, hail, snowstorm, collapse, ground collapse, sandstorm, etc. It occurs in all parts of the country and local areas every year, causing extensive damage or devastating blows to local areas. China has suffered the most natural disasters in the world.

1, meteorological disaster

There are more than 20 kinds of meteorological disasters, mainly including the following types:

(1) rainstorm: mountain torrents, river flooding and urban water accumulation;

(2) Rain and waterlogging: waterlogging;

(3) Drought: drought in agriculture, forestry and grassland, and water shortage in industry, cities and rural areas;

(4) Dry-hot wind: dry-hot wind and foehn wind;

(5) High temperature heat wave: extreme heat and high temperature, human diseases, burns, and crop ripening;

(6) Tropical cyclones: gale, rainstorm and flood;

(7) Cold damage: crops, livestock and fruit trees are harmed by strong cooling and low temperature;

(8) Freezing injury: frost, crop and livestock freezing injury, water pipes and oil pipes freezing injury;

(9) Freezing rain: wires, branches and roads are frozen;

(10) Freezing: rivers, lakes and seas freeze, and roads freeze after rain and snow;

(1 1) Snow damage: snowstorm, snow;

(12) Hail disaster: destroying crops and houses;

(13) Wind disaster: falling trees, reversing houses, reversing cars and reversing boats;

(14) Tornado: local destructive disaster;

(15) Lightning: lightning casualties;

(16) Continuous rain (lewd rain): it is not conducive to crop growth and development, grain mildew, etc.

(17) dense fog: human diseases and traffic jams;

(18) low-altitude windshear: aviation accident;

(19) acid rain: crops are harmed.

2. Marine disasters

Marine disasters mainly include the following types:

(1) storm surge: including typhoon storm surge and temperate storm surge;

(2) Tsunami: There are two types: long-range tsunami and local tsunami;

(3) Waves: including wind waves, swells and nearshore waves, which are divided into typhoon waves and cyclone waves;

(4) seawater;

(5) red tide;

(6) Coastal disasters: such as coastal erosion, landslides, land salinization and seawater pollution.

(7) the harm of El Nino.

3. floods

(1) rainstorm disaster;

(2) mountain torrents;

(3) snowmelt flood;

(4) ice flood;

(5) dam-break flood;

(6) Debris flow and cement flood.

4. Earthquake disaster

(1) tectonic earthquake;

(2) Collapse earthquake;

(3) mine earthquake;

(4) Reservoir earthquake, etc.

5, crop biological disasters

(1) Crop diseases: There are mainly more than 240 kinds of rice diseases, 50 kinds of wheat diseases and 40 kinds of corn diseases.

There are more than 40 kinds of cotton diseases, such as soybean, peanut and hemp.

(2) crop pests; There are mainly 252 species of rice pests, more than 0/00 species of water wheat pests, 52 species of corn pests and cotton pests.

More than 300 kinds of flower pests, as well as a variety of pests of other crops;

(3) Crop weeds: about 8,000 species;

(4) rodents.

6. Forest biological disasters

(1) Forest diseases: 29 18 species;

(2) Forest pests: 5020 species;

(3) Forest rodents: 160 species.

7. Forest fire

The National Science and Technology Commission, the State Planning Commission and the Natural Disaster Comprehensive Research Group of the State Economic and Trade Commission classify natural disasters into seven categories: meteorological disasters, marine disasters, flood disasters, geological disasters, earthquake disasters, crop biological disasters, forest biological disasters and forest fires. However, disasters closely related to our daily life mainly include:

I. Geological disasters

Both natural changes and human activities may lead to changes in geological environment or geological body. When this change reaches a certain level, landslides, mudslides, land subsidence, ground collapse, rock swelling, sand liquefaction, land freezing and thawing, soil salinization, land desertification, earthquakes, volcanoes, geothermal disasters and other consequences will do harm to human beings and society. This phenomenon is called geological disaster. Geological disasters also include derivative disasters.

(1) Debris flow. Debris flow is a special torrent containing a lot of sediment and stones, which is stimulated by heavy rain, melting snow and ice in mountain valleys.

The formation of debris flow: the following three conditions must be met at the same time: steep terrain is convenient for water collection and water collection; Abundant loose matter; There is a lot of water in a short time.

The material composition of debris flow can be divided into three categories: debris flow consists of a large number of cohesive soil, sand particles and stones with different particle sizes; Mainly cohesive soil, containing a small amount of clay particles and stones, with high viscosity, which is called debris flow when it becomes thick mud; Water-rock flow is composed of water, sand and stones of different sizes.

Hazard of debris flow: hazard to residential areas; Harm to roads and railways; Harm to water conservancy and hydropower projects; Damage to mines;

(2) landslides. The phenomenon that the rocky mountain on the landslide slides down a weak surface (or weak zone) under the action of gravity for various reasons is called landslide, which is commonly called "mountain walking", "mountain crossing" and "soil sliding".

Conditions of landslide: Only when the slope rock mass is cut and divided into continuous states by various structural planes can it slide downward.

The active intensity of landslide is mainly related to the scale, speed, distance, accumulated potential energy and generated kinetic energy of landslide.

Activity time of landslide: It is mainly related to various external factors, such as earthquake, rainfall, freezing and thawing, tsunami, storm surge and human activities.

(3) collapse. Collapse, also known as caving, collapse or collapse, is a geological phenomenon that the rock mass on the steep slope suddenly breaks away from the parent body under the action of gravity and rolls and accumulates at the foot of the slope (or gully rock).

According to the composition of collapse materials, collapse can be divided into two categories: soil and falling rocks.

Activity time of collapse: collapse generally occurs during or after heavy rain and long-term continuous rainfall; In the fierce process; During or after the excavation of slope toe; The initial stage of reservoir impoundment and the peak period of rivers; After strong mechanical vibration and big blasting.

Regionality of collapse: Southwest China is the main area of collapse distribution in China.

(4) Land subsidence. Land subsidence is a phenomenon of crustal deformation caused by long-term drought, which reduces the groundwater level and over-exploits groundwater.

(5) earthquake. Earthquake is a devastating natural disaster. Earthquakes not only directly cause landslides, ground fissures and house collapses, but also cause secondary disasters such as fires, floods, explosions, landslides, mudslides, toxic gas diffusion and plagues.

The second is floods and other disasters.

(1) waterlogging. Waterlogging refers to flash floods caused by large-scale rainstorms or extremely heavy rains, floods caused by the steep rise of river water levels, waterlogging disasters that inundate farmland, houses, people, livestock and transportation facilities, and waterlogging disasters that lead to crop failure due to the difficulty in draining accumulated water in low-lying areas.

(2) floods. Flood disaster refers to the phenomenon that water flows out from waterways or artificially restricted places, endangering people's lives and property.

(3) Ice flood disaster. Ice flood disaster is a phenomenon that the water level of the river rises obviously due to the resistance of ice to the water flow, which leads to disasters.

(4) Earthquake disaster. Earthquake flood refers to the flood disaster caused by landslides caused by earthquakes blocking rivers or shaking dams.

3. Gale disaster. The wind is strong enough to endanger people's production activities, economic construction and daily life.

Hazards of gale: harmful gale mainly refers to typhoon, cold wave gale, thunderstorm gale and tornado.

According to the influence of strong wind on agricultural production, it can be summarized as mechanical injury, wind erosion, physiological injury, affecting agricultural production activities and so on. Typhoon is the most destructive of strong winds.

Tropical cyclone disaster. Tropical cyclone is a kind of cyclone vortex that occurs in tropical or subtropical oceans.

Strong tropical cyclone, accompanied by strong wind, heavy rain, huge waves and storm surges, has a wide range of activities and strong destructive power, and is an important disastrous weather system. China is one of the few countries in the world seriously affected by tropical cyclones.

Hail disaster. Hail is ice or hockey that falls to the ground from strong cumulonimbus clouds. According to the size and damage degree of hail, Kejiangbao is divided into three grades: light hail disaster, medium hail disaster and heavy hail disaster. China is one of the countries suffering from hail disasters in the world.

The intransitive verb marine disaster

(1) storm surge. The interaction between cold air from high latitudes and tropical cyclones from the sea leads to the occurrence of strong winds and huge waves along the coast, thus forming storm surges. The western Pacific is the area that produces the most storm surges.

Storm surge type: typhoon type; Cold high pressure combined with cyclone type in the Yellow Sea and Bohai Sea; Transverse cold and high pressure type; Strongly isolated yellow sea and Bohai sea cyclone type; Strong Mongolian low pressure type;

Spatial distribution of storm surge disasters. Storm surges in China are all over the coast, but the main concentrated areas from north to south are: Laizhou Bay; Jiangsu Xiaoyanghekou to Zhejiang Dehaimen; Wenzhou, Taizhou, Shacheng to Minjiang Estuary; Shantou, Guangdong to the Pearl River Estuary; The east coast of Leizhou Peninsula and the northeast coast of Hainan Island.

(2) catastrophic waves. Waves that cause disasters at sea are called catastrophic waves.

Formation of disastrous waves: caused by typhoon, temperate cyclone, cold wave and other weather systems and formed by strong winds.

According to the type of weather system, disastrous waves are cold and high pressure (also called cold wave type); Typhoon type; Cyclone type; Cold high pressure and cyclone cooperate.

(3) sea ice. Sea ice is frozen by harmful water, including river ice and icebergs flowing into the ocean. Sea ice is one of the outstanding marine disasters in polar oceans and some high latitudes.

Disaster caused by sea ice. Pushing down offshore oil platforms, damaging offshore engineering facilities and waterway facilities, or colliding with ships, causing major shipwrecks; Obstruct the navigation of the ship, damage the propeller or hull, and make it lose its navigation ability. Sea ice blocks the harbor, making it unable to operate normally or greatly increasing the cost of using icebreakers to break ice and pilot; It is the aquaculture facilities and places that destroy the fishing moratorium for too long and cause economic losses.

The main characteristics of sea ice disasters are the Bohai Sea, the northern Yellow Sea and the coastal waters of Liaodong Peninsula, as well as some bays of Shandong Peninsula, which are easy to freeze in winter in China.

(4) Tsunami. Tsunamis are mainly marine disasters caused by severe earthquakes in countries along the Pacific Ocean.

Conditions for tsunami formation: the focal point of the submarine earthquake that caused the tsunami is shallow, generally less than 20 km to 50 km; The magnitude is generally above 6.5 on the Richter scale; There must be a large-scale vertical movement on the seabed; The sea area where submarine earthquakes occur must have a certain water depth, especially the transoceanic tsunami, which is generally above 1000 meters.

Hazards of Tsunami: The form of tsunami in coastal areas is the sudden rise of sea water, which suddenly forms a "water wall" marching towards the shore. With the rumbling noise, it instantly invaded the coastal land, engulfing fertile fields, towns and villages, and then the sea water suddenly receded, or rose first, sometimes repeatedly, causing huge losses to human life and property.

(5) Red tides. Concept of red tide: Red tide refers to the sudden increase in the number of some tiny phytoplankton, protozoa or bacteria in seawater under certain environmental conditions, which makes the color of seawater change within a certain range and last for a period of time.

Harm of red tide: causing marine variation, partially interrupting the marine food chain and threatening the survival of marine life; Some red tide organisms excrete or decompose mucus in vitro after death, which makes marine animals filter and breathe, thus leading to suffocation and death. Or the toxins contained in red tide organisms are ingested by marine animals, resulting in poisoning death of fish, shrimp and shellfish. Some of them can also cause vertebrates and humans to die after eating. In the following sections, we will introduce several common natural disasters with large destruction areas, and also introduce some measures for disaster prevention and relief.

Seven. Other disasters

In addition to earthquakes, floods, typhoons, plagues and other disasters that seriously affect our lives and even threaten our lives, we must constantly raise our awareness and strengthen our ability to prevent other disasters such as lightning, fog and hail.

thunder and lightning

(A) the formation of lightning

Weather accompanied by thunder and lightning becomes a thunderstorm in meteorology. In thunderstorm weather, when the potential difference between the cloud and the ground reaches a certain intensity, discharge imagination will occur, and lightning strikes the ground or some objects, which will cause lightning strikes. According to research, the lightning current intensity can usually reach tens of thousands of amperes and the temperature can reach 20000 degrees Celsius. The harm degree of such a strong current and high temperature can be imagined.

(2) Measures to prevent lightning strike

1, in thunderstorm weather, people try to stay indoors, don't go out, close doors and windows to prevent lightning from entering the room.

2. Try not to get close to doors and windows, stoves, heaters and other metal parts, and don't stand barefoot in mud or concrete. It's best to sit in a chair with a non-conductive object under your feet.

Don't swim or row in the river, because Israeli lightning will attack people through the water.

4. When there is a thunderstorm outside, look for low-lying places or ditches as soon as possible, and don't shelter from the rain under isolated trees, towers and telephone poles.

5, once someone was struck by lightning, should be timely rescue, rescue method is the same as the electric shock first aid, timely artificial respiration and extracorporeal heart massage, etc. And rushed to the hospital at the same time.

Dense fog prevention

A large number of small water droplets or ice crystal particles are suspended in the air near the lower level, which makes people's vision blurred. When the horizontal energy distance of relevant personnel drops below 1000m, it is called fog. Fog is graded. When the energy distance is less than 1000m and more than 500m, it is called light fog. When the visible distance is less than 500 meters, it is called fog; When the visible distance is less than 200 meters, it is called dense fog.

Fog disaster protection measures:

1. Try not to go out. When you have to go out, wear a mask to prevent inhalation of toxic gases.

2. Try to exercise as little as possible in foggy days, and don't exercise in foggy days.

Pedestrians should be careful when crossing the road, and see the passing vehicles clearly.

4. Vehicles and cars should drive slowly, obey the instructions of the traffic police, don't catch cars (boats), and don't crowd on the ferry when it stops.

hail

(A) the concept of hail

Hail is ice or hockey that falls to the ground from strong cumulonimbus clouds.

(B) the harm of hail

According to the size and degree of hail, hail hazards can be divided into three levels: light hail hazard, medium hail hazard and heavy hail hazard. Hail is very harmful to crops, and China is one of the countries suffering from hail disasters in the world.

(3) The geographical distribution characteristics of hail in China.

1, hail area:

Hail areas in Qinghai-Tibet Plateau, hail areas in the north and hail areas in the south.

2. Areas with less hail:

Hail-free areas in China are mainly distributed in the great plains, deserts and great basin.

3. Temporal distribution characteristics of hail;

The hail season in China is mainly in spring, summer and early autumn.

According to the change characteristics of hail season in various places, it can be divided into the following four types:

Hail in spring, hail in summer, hail in late spring and early summer, double peaks.

There are several types of daily variation of hail: afternoon hail type; Night hail type; Noon hail type; Multimodal, etc.

(D) the intensity characteristics of hail

Hail range, hail size and weight, hail duration and cumulative thickness.

(5) Forecast and defense of hail

1. Hail is an unpredictable and disastrous weather. The meteorological station uses a large number of real-time meteorological information such as weather radar, meteorological satellite monitoring and weather map to track and extrapolate the hail weather. People also have a lot of forecasting experience, such as "more hail in dry years", "more steep winds in spring and more hail in summer" and "pagoda-shaped dark clouds with red clouds below and hail in front". To sum up, there are six forecasting methods:

(1) Feel hot and cold; (2) Identify the wind direction as "no east wind, no tide, no south wind and no hail"; (3) Look at the cloud color; (4) listen to thunder; (5) Know lightning; (6) observation object.

2, hail defense:

(1) hail avoidance; (2) hail suppression; (3) hail resistance; (4) hail suppression

Most people can do hail avoidance, and the last three items need special departments and personnel. Now with the progress of technology, artificial hail suppression has achieved good results.

3. When the hail comes:

(1) Understand the weather forecast of hail, and move people, animals and outdoor articles to safety.

(2) Try not to go out when the hail comes, and pay attention to protect your head and face when you have to go out.

(3) If you are outdoors when the hail comes, you should immediately find a place to hide, preferably a solid building.

(4) If you are driving or in a car, you should immediately park your car in a place where you can avoid it, and you must not rush forward to avoid unnecessary injuries.

(5) Sometimes hail will be accompanied by storms, so special attention should be paid to prevention and avoidance.