Seeking geographical knowledge: weather and climate.

The ever-changing atmospheric state is not only the atmospheric state in a certain time and space, but also the continuous change of atmospheric state in a certain time interval. So it can be understood as a general term for weather phenomena and weather processes. Weather phenomenon refers to various natural phenomena in the atmosphere, that is, the comprehensive expression of the spatial distribution of various meteorological elements in the atmosphere (such as wind, clouds, fog, rain, snow, frost, thunder, hail, etc.). ) in an instant. Weather process is the process of weather phenomena changing with time in a certain area.

Weather is the general name of atmospheric conditions (such as cold and warm, wind and rain, dry and wet, sunny and so on). ) and its changes in a short time in a certain area. Weather system usually refers to the atmospheric motion system with typical characteristics, such as high pressure, low pressure, high pressure ridge and low pressure trough, which cause the change and distribution of weather. All kinds of weather systems have certain time and space scales, and they are intertwined and influence each other. The combination of many weather systems constitutes a large-scale weather situation and hemispheric and even global atmospheric circulation.

The weather system is always in the process of rebirth, development and extinction, and there are corresponding weather phenomena in different development stages. Therefore, the weather and weather changes in a region are related to the weather system and its development stage, and are the comprehensive results of atmospheric dynamic and thermal processes.

All kinds of weather systems are formed, developed and evolved in a certain atmospheric circulation and geographical environment, and all reflect the environmental characteristics of a certain region. For example, the polar regions and their surroundings are covered with ice and snow all year round, and the air is cold and dry. This unique geographical environment has become the background condition for the formation and development of polar low-altitude cold high pressure and high-altitude polar vortex and low trough. It is a necessary condition for the emergence and development of convective weather system that the equatorial and low latitudes are hot and humid all the year round and the atmosphere is unstable. Mid-high latitudes are areas where cold and warm air currents often cross. Cold and warm air masses not only come and go frequently, but also have unstable baroclinic, which is an important basis for the formation and development of frontal and cyclone systems. The formation and activities of weather system will in turn have a profound impact on the structure and evolution of geographical environment. Therefore, understanding the formation, structure, movement and change of weather system and its relationship with geographical environment is of great significance for understanding the formation, characteristics and change of weather and climate and predicting the evolution of geographical environment.

Weather forecast is a science that human beings predict the weather development.

From proverbs to the calculation of Naville-Stokes equation by computer, numerical prediction has a long history.

Today's weather forecast can make a more accurate forecast of the weather in a week.

At present, most weather forecasts broadcast the maximum and minimum temperature, rainfall probability, sunny and cloudy days, and ultraviolet index.

1. Weather conditions: On the special map, fill in the factors such as air pressure, wind power, temperature, humidity, clouds, weather phenomena observed by meteorological stations all over the world at the same time. After drawing and analyzing, we can see the air movement state and weather distribution of the whole earth or a certain area at a certain time on a certain day, just like taking a big picture of air and weather on the ground. This picture contains a map of the weather situation. What will the weather be like in the future? There may be some other weather conditions. This analysis and judgment is called weather situation forecast.

2. High pressure ridge: On the same plane at the same height, the area where the central air pressure is higher than the adjacent surrounding air pressure is called high pressure. The air flow in the high-pressure area spreads from the center to all directions, and due to the influence of the earth's rotation bias force, it shifts to the right in the northern hemisphere and flows clockwise. If the air pressure in an area is higher than the adjacent three sides and lower than the other side, then this area is called a high-pressure ridge, which is often a prominent part of high pressure, just like a ridge extending from a mountain. Under the control of high pressure and high pressure ridge, the air sinks, the weather is fine, and there are few clouds, rain and strong winds.

3. Low pressure and low pressure tank: the antonym of high pressure is called low pressure. That is, in the area where the central air pressure is lower than the adjacent air pressure, air flows from the periphery to the low-pressure center, and flows counterclockwise due to the influence of geostrophic deflection force. If the air pressure in a certain area is lower than the adjacent three sides and higher than the other side, then this area is called a low-pressure trough, just like a one-year river ditch extending from the Great Lakes. Under the control of low pressure and trough, the air moves upward, and the weather is complex, with clouds, rain and strong winds.

4. Slot line: In the low-pressure slot, the points with the lowest air pressure are connected into a line, which is called "slot line". There are obvious differences in temperature and humidity and sudden changes in wind direction on both sides of the slot line. Under normal circumstances, there is a southerly warm and humid airflow in front of the trough, and there is more upward movement. If there is enough water vapor, it is easy to produce precipitation. Behind the trough, it is mostly dry cold air with northerly wind, which flows downwards, with clouds and rain but little wind. Although sometimes a small number of cloud systems are generated, they will also dissipate. The trough line moves from west to east, which is called "west trough".

5. Shear line: In a certain area, due to the obvious difference of airflow direction and speed, there is a big discontinuity or sudden change. For example, in summer near Jinan and Shandong Peninsula, there is often shear of southeast wind and southwest wind at the back of subtropical high. This lateral change from east to west will affect the thunderstorm weather in Hebei Province from south to north. Sometimes, in the area slightly north of Beijing, it is easy to produce lateral deformation, which in turn produces south pressure, which affects the local precipitation weather in Hebei.

6. Vortex: Vortex is an air vortex with a low center height on the high-altitude isobaric surface. The airflow in the vortex flows counterclockwise and moves upward, such as abundant water vapor, which often causes rainy weather. The vortex generated in Sichuan, Gansu and Qinghai in the southwest of North China is called southwest vortex. When it moves to the northeast of our province, it will produce strong thunderstorm weather, sometimes accompanied by hail and strong wind. The masses say that "three days after a thunderstorm" is often caused by this cold vortex.

7. Cold front: Because the earth's surface is uneven, the distribution of land and sea is uneven, and the absorption of solar heat energy is very different, so the low-level air is divided into cold and warm. The intersection of cold and warm air is the front. When cold air pushes warm air forward, it is called cold front, which is a normal wind in North China. The weather before the cold front is warm and humid, and there are many cloud systems. The cold front is out of date, often with bad weather, sometimes thunderstorms, accompanied by hail and strong winds. After the cold front, generally speaking, the north wind roared, the temperature dropped and the weather gradually cleared up. When the cold front moves from the northwest, it is called the northwest cold front, the west cold front moves from west to east, and the north cold front presses from north to south. A cold front is sometimes generated behind the main cold front, which is called a secondary cold front.

8. Typhoon: Typhoon is a "tropical cyclone" that occurs in the western part of the North Pacific Ocean, and it is a very violent storm. When the typhoon first formed, it was just a tropical depression. As it moves westward, it gradually deepens, causing the local moist and hot air on the ocean surface to rise to high altitude in a large range, and the surrounding low-level air flows to the low-pressure center, forming a large vortex rotating counterclockwise, with a diameter of 200- 1000km, a "typhoon eye" at the center, a radius of 5-30km, extremely low air pressure and high wind waves. Typhoon has little influence on North China. In July and August, it is sometimes affected by typhoon trough or edge, which can produce heavy rain and strong northeast wind.

9. Squall line: a weather change zone with strong convection and rapid change of wind direction and speed, which often appears in front of the fast moving cold front and typhoon edge in spring and summer. When the squall line crosses the border, the air pressure rises sharply, the wind direction turns sharply and the wind speed rises sharply. There are usually thunderstorms and sometimes hail. Hail line has a short time and life history, but it has a great influence on production and people's life.

10, meteorological elements: various elements representing the physical state and phenomena of the atmosphere. Mainly includes: temperature, air pressure, wind, humidity, clouds, precipitation and various weather phenomena. The data of meteorological elements and their changes are often used in weather forecast, climate analysis and related scientific research.

1 1. Weather phenomena: various physical phenomena in the atmosphere. Such as clouds, precipitation thunderstorms, rainbows in the atmosphere and other light phenomena. Its comprehensive changes can often show the characteristics of atmospheric changes.

12, millibar: atmospheric pressure unit commonly used in meteorology. Millibar is the unit of pressure, which is one thousandth of bar. One millibar is equal to 3/4 mm, and a standard atmospheric pressure is 760 mm, which is also equal to 10 13.3 millibar.

13, Isobar: the connecting line of points with the same air pressure value. It can show the distribution of air pressure in space, and clearly see the position, range and intensity of high pressure and low pressure.

14, potential meter: one of the units with high potential. At the sea level of 45 degrees latitude, one potential meter is equal to one meter, but it is slightly different with the change of latitude, but the difference is not more than 0.02 meters.

15, Meteorological Proverbs: Working people have accumulated rich experience in observing the sky in their long-term life and production practice, and summarized it into meteorological proverbs, which have been passed down to this day. China's weather proverbs are extremely rich and extensive, including explaining weather phenomena, weather changes and reflecting climate characteristics, such as "don't go out in the morning, travel thousands of miles at night", "the northeast is too stormy", "spring breeze is called autumn rain", "nine miles of wind, rain in the rain" and so on. Weather proverbs are often restricted by regional and seasonal factors, and need to be carefully studied and analyzed, so as to eliminate the false and retain the true, and to eliminate the rough and extract the essence. In use, it should be used flexibly after repeated verification according to local specific conditions.

Climate—

Climate is the average or statistical state of meteorological elements and weather phenomena for a long time, and the time scale is months, seasons, years, years to hundreds of years. Climate is measured by the characteristics of cold, warm, dry and wet, and is usually characterized by the average value and deviation value of a certain period.

Climate is the general state of the atmosphere in a certain region of the earth for many years, and it is the comprehensive expression of various weather processes in this period. Various statistics (mean, extreme, probability, etc. Meteorological elements (temperature, precipitation, wind, etc.). ) is the basic basis for expressing climate. Climate is closely related to human society, and many countries have recorded climate phenomena for a long time. During the Spring and Autumn Period in China, the sun shadow was measured by a standard table to determine the seasons. During the Qin and Han Dynasties, there were 24 solar terms and 72 climaxes. The word climate comes from ancient Greek, which means inclination, meaning that the climate in different places is related to the inclination of the sun's rays.

Due to the different distribution of solar radiation on the earth's surface and the different physical processes of different underlying surfaces such as ocean, land, mountains and forests under the action of solar radiation reaching the surface, the climate has obvious regional characteristics besides the temperature distribution in latitude. According to the horizontal scale, climate can be divided into macroclimate, mesoclimate and microclimate. Macroclimate refers to global and regional climate, such as tropical rain forest climate, Mediterranean climate, polar climate and plateau climate. Moderate climate refers to the climate of smaller natural areas, such as forest climate, urban climate, mountain climate and lake climate; Microclimate refers to a small range of climate, such as the atmosphere close to the ground and the climate under a small range of special terrain (such as mountains or valleys).

Under the influence of latitude, land and sea distribution, atmospheric circulation, topography, ocean currents and other factors, the world climate can be roughly divided into the following types:

Tropical rain forest climate: high temperature and rainy all year round;

Tropical grassland climate: high temperature all year round, divided into dry and wet seasons;

Tropical desert climate: high temperature and little rain;

Tropical monsoon climate: the annual high temperature is divided into three seasons: cool, hot and rainy;

Subtropical monsoon climate and monsoon humid climate: high temperature and rainy in summer, low temperature and little rain in winter;

Subtropical desert climate: basically similar to the tropical desert climate, but the winter temperature is slightly lower than the tropical desert climate;

Subtropical grassland climate: basically similar to tropical grassland climate, but distributed in subtropical zone;

Mediterranean climate: mild and rainy in winter and hot and rainy in summer;

Temperate maritime climate: warm in winter and cool in summer, with small annual temperature difference and even seasonal distribution of annual precipitation;

Temperate continental climate: scarce precipitation, severe cold in winter, extremely hot in summer and large annual temperature difference;

Temperate monsoon climate: hot and rainy in summer and cold and dry in winter;

Temperate broad-leaved forest climate: hot and rainy in summer and cold and dry in winter.

Temperate grassland climate: hot in summer and cold in winter;

Temperate desert climate: extreme drought, large temperature difference;

Coniferous forest climate in sub-frigid zone: mild in summer and cold in winter;

Mountain climate: vertical change from the foot of the mountain to the top of the mountain;

Polar tundra climate: winter is long and cold, and summer is short and cool;

Climate of polar ice sheet: it is cold all year round.

What's the difference between weather and climate-

Weather refers to a relatively rapid change of heat and cold or a temporary state of heat and cold. Climate refers to general weather conditions or major weather conditions that exist for a long time. It is very important to distinguish the differences between them, because they have different effects on human behavior. Secondly, it is more difficult to control some cultural and social factors by studying the influence of weather on people than by studying the influence of climate on people.

I hope it helps you!

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