Meteorology and Climatology (Outline Edition)
a part
1. Weather : A synthesis of the atmospheric state (air temperature, air pressure, temperature) and atmospheric phenomena (wind, cloud, fog, precipitation, etc.) in the atmosphere in a certain area at a certain moment or within a certain period of time. It is transient, changeable, and unstable.
2. Saturated water vapor pressure ( E ) : The water vapor pressure in the air cannot increase without limit. At a certain temperature, if the water vapor pressure increases to a certain limit value, the water vapor in the air will reach saturation. When the air reaches this limit, it will be Saturated humid air, the part of the pressure generated by the water vapor in the saturated humid air is called the saturated water vapor pressure, that is, the maximum water vapor pressure.
3. Ground radiation : While the earth's surface absorbs solar radiation , it transmits most of the energy to the atmosphere in the form of radiation. The way that the surface of the earth radiates radiation is called ground radiation.
4. Dew : In the evening or at night, due to radiation cooling on the ground or objects, the air layer close to the surface of the ground also cools down. When the water vapor content in the air is supersaturated, there will be condensation of water vapor on the surface of the ground or objects , if the dew point temperature at this time is above 0 degrees, tiny water droplets will appear on the ground or features, called dew.
5. Local wind : The local airflow movement caused by uneven heating of the surface and terrain dynamics (local environmental differences) is called local circulation or local wind.
6. Typhoon : A tropical cyclone with a maximum wind speed greater than or equal to 32.6m/s near the center of the ground is called a typhoon. A tropical cyclone is formed on a tropical ocean with a warm center structure and a strong cyclonic vortex.
7. Climate : The synthesis of a large number of weather processes in a certain period of time under the long-term effects of solar radiation, underlying surface properties, atmospheric circulation, and human activities in a region is an atmospheric process with a long time scale.
8. Climate system : The climate system is a unified physical system including the atmosphere, hydrosphere, land surface, cryosphere and biosphere, which can determine the formation, distribution and change of climate.
9. Adiabatic process : Various processes in the atmosphere are usually accompanied by different forms of energy conversion. During energy conversion, the state of the air changes. In meteorology, the state change process when there is no heat exchange between any air block and the outside world is called an adiabatic process.
10. Air mass : Air mass refers to a large piece of air with relatively uniform meteorological elements in the horizontal direction within a certain range . In the same air mass, the key distribution of meteorological elements in various places is almost the same, and the weather phenomena are also roughly the same. The horizontal range of the air mass can reach several thousand kilometers, and the vertical height can reach several kilometers to more than ten kilometers, often extending from the ground to the tropopause.
11. Monsoon : On a yearly cycle, the prevailing wind in a large area changes significantly with the seasons. The wind direction not only changes seasonally, but also changes in direction by more than 120 degrees.
12. Urban heat island effect : The temperature in a city is often higher than that in the surrounding suburbs. In terms of the spatial distribution of temperature, the temperature in the city is high, like a "heat island" standing on top of the cooler "ocean" in the countryside. This phenomenon is called urban The heat island effect or urban heat island.
three parts
1. The relationship and difference between weather and climate
Connection: ① There is a statistical connection between the two.
②Climate includes not only the weather conditions that often occur over the years, but also the extreme weather conditions that occur occasionally in certain years.
Differences: ① Different concepts;
② Different time scales: the weather cycle is short and the climate cycle is long;
③The stability is different: the weather is unstable and the climate is more stable;
④ The weather system is simple (cyclone, anticyclone), and the climate system is huge (one energy source, five subsystems).
2. Variation characteristics of isotherms in the northern hemisphere in July
(1) The isotherm map in July decreases from low latitudes to the poles
(2) The isotherms are relatively sparse in July, indicating that the temperature difference between the north and the south in the northern hemisphere is small in summer.
(3) In July, the isotherms of the northern hemisphere are convex to high latitudes on the continent and convex to the equator in the ocean
(4) The position of the hot equator is at 20ºN in summer, and the Sahara is the hottest place in the world, forming a high temperature center.
3. What are the main conditions for the formation of clouds and rain, and why do different types of clouds and rain form?
The main condition for the formation of cloud and rain is the existence of condensation nuclei, and the adiabatic cooling of the air vertically rising makes the air supersaturated. Large water droplets play an important role in the formation of rain. Due to the different forms and scales of the vertical upward movement of the air, the states, heights, and thicknesses of clouds are also different. Atmospheric uplift movement modes mainly include: thermal convection, dynamic uplift, atmospheric fluctuations, and terrain uplift. Different clouds have different horizontal ranges, cloud heights, cloud thicknesses, water content in clouds, temperature in clouds, and up-and-down airflow, so the shape, intensity, and nature of precipitation also vary accordingly.
4. The reason why air pressure changes with time
The change in air pressure is a reflection of the increase or decrease in the weight of the air column above the ground, and the weight of the air column is the product of its mass and the acceleration of gravity. The acceleration due to gravity can be regarded as a constant value. Changes in the mass of the air column are mainly caused by thermal and dynamic factors. The thermal factor refers to the volume expansion or contraction caused by the increase or decrease in temperature, the increase or decrease in density, and the increase or decrease in mass caused by the converging or diverging airflow. The dynamic factor refers to the change of air column mass caused by atmospheric movement, such as the convergence and divergence of horizontal airflow, the movement of air masses of different densities, and the vertical movement of air.
5. Temporal and spatial distribution characteristics of astronomical radiation
(1) The distribution of astronomical radiation energy varies completely with latitude
(2) The maximum astronomical radiation obtained in the summer half year is at the latitude zone of 20°-25°, and gradually decreases towards the two poles, and the minimum value is at the poles.
(3) The equator receives the most astronomical radiation in the northern hemisphere in the winter half of the year.
(4) The north-south difference of astronomical radiation is not only different with winter and summer, but also with latitude at the same time.
(5) The difference of astronomical radiation between summer half year and winter half year increases with the increase of latitude.
(6) Within the polar circle, there are polar day and polar night phenomena. During polar nights, astronomical radiation is zero.
6. Advantages and disadvantages of Köppen climate classification:
Advantages: ① The concept of climate type was proposed for the first time
②The method is simple and clear, and it is more consistent with the natural landscape.
Disadvantages: ① B belt and A, C, D, E belts juxtaposed improperly
② Neglecting the analysis of climate causes, it is easy to classify low-latitude highland climate and high-latitude climate into one category.
7. Differences in warming and cooling between land and sea and their causes
Differences: Continents heat up quickly and cool down quickly, and the temperature rises and falls greatly. Over the ocean, the temperature changes slowly. For example, in the ocean, the annual maximum and minimum temperatures appear one or two months later than that of the continent.
Reason :
①The two absorb and reflect solar radiation differently
Under the same solar radiation intensity, the solar energy absorbed by the ocean is more than that absorbed by the land, because the reflectivity of the land to sunlight is greater than that of the water surface. On average, the difference in reflectivity between land and water is about 10-20%. In other words, the solar energy absorbed by the water surface under the same conditions is 10-20% more than that absorbed by the land surface.
② The thickness of the energy distribution is different
Solar energy absorbed by land is distributed over very thin surfaces, while solar energy absorbed by seawater is distributed over thicker layers. This is because the rocks and soil on the land surface are opaque to solar radiation of various wavelengths, while water is opaque to ultraviolet rays and visible rays with shorter wavelengths, except for red rays and infrared rays. quite transparent.
③ The heat conduction methods of the two are different.
Solar energy obtained on land mainly relies on conduction to spread underground, while water has other more efficient methods, including waves, ocean currents and convection. These actions allow vertical and horizontal exchanges of thermal energy of the water. Therefore, the solar radiation received by the land surface is concentrated on the surface, a thin layer, so that the surface heats up sharply, and the sensible heat exchange between the land surface and the atmosphere is strengthened; on the contrary, the solar radiation received by the water surface is distributed in a thicker layer, As a result, the water temperature is not easy to increase, and the sensible heat exchange between the water surface and the atmosphere is relatively weakened. About half of the solar radiation obtained by sand is transmitted to the air, while the solar radiation obtained by water is only 0.5% transmitted to the air.
④Vapor content is different
There is sufficient water supply on the sea surface, so that the evaporation is relatively large, and the heat loss is large, which also makes the water temperature not easy to rise. Moreover, the air has more water vapor due to the evaporation of water, so that the air itself has a greater ability to absorb ground radiation, which makes it difficult for the temperature to drop. The opposite is true on land.
⑤ The specific heat of rock and soil is less than that of water.
8. The distribution and function of water vapor in the atmosphere
Distribution of water vapor:
(1) Vertical distribution - the water vapor content decreases with the increase of altitude, and the water vapor below the height of ten kilometers accounts for about 99% of the total water vapor.
(2) Horizontal distribution - the higher the latitude, the less content; the higher the terrain, the less content; more in the ocean, less on land.
The role of water vapor in the atmosphere:
(1) It is the main factor of weather changes - weather phenomena such as clouds, rain, snow, frost, dew, etc., are formed by the phase transition of water vapor under certain conditions.
(2) Affecting the temperature of the atmosphere and the ground - water vapor can strongly absorb ground radiation and also absorb a small part of solar radiation, thereby making the atmosphere gain heat; at the same time, it emits long-wave radiation to the ground, making the ground gain heat.
9. The factors affecting the effective radiation on the ground are:
(1) Clouds, mist, water vapor and wind: they can strongly absorb and reflect the long-wave radiation emitted by the ground, increasing the atmospheric inverse radiation, thus reducing the effective radiation on the ground;
(2) Altitude: Air density, water vapor, and dust decrease with the increase of altitude, the atmospheric inverse radiation decreases correspondingly, and the effective radiation increases;
(3) Surface characteristics: the undulating and rough surface has a larger radiation surface than a smooth surface, and the effective radiation is also larger;
(4) Ground cover: When objects with poor thermal conductivity such as straw, turf, and fallen leaves cover the ground, the effective radiation of the ground can be reduced.
10. Why is there more frost and fog on a clear and windless night than on a rainy night?
(1) The ground is strongly radiated and cooled, and the temperature drops rapidly;
(2) When the thin layer of air near the ground contacts the cold ground, the air will gradually cool down and reach the dew point temperature, and the water vapor in the air will condense on the contacted ground surface or objects on the ground surface;
(3) If the dew point temperature is below 0°C, the water vapor directly condenses on the contact surface into white ice crystals called frost;
(4) When there is a lot of water vapor in the air, many tiny water droplets or ice crystals suspended in the air will form in the air due to strong radiation cooling, and this phenomenon is called fog.
11. The concept and characteristics of Foehn
Concept: unsaturated moist air, after being blocked by mountains and forced to lift by power, it is dry and hot wind formed by sliding down the leeward slope.
Features: (1) The air mass (cluster) below the condensation height on the windward slope is cooled by rd (unsaturated), and the air mass above is by rm
Cooling (saturated - supersaturated), and a lot of precipitation.
(2) The air mass (cluster) on the leeward slope heats up according to rd, the evaporation is vigorous, and the rain shadow area appears. Dry and hot winds appear at the foot of the leeward slope.
12. Are the air masses affecting my country primary or denatured?
Most of the air masses active in China are denatured air masses moved from abroad, among which the most important ones are denatured polar continental air masses and denatured tropical oceanic air masses .
Why? ① my country's terrain is complex, with mountains accounting for 2/3, and there is a lack of large-scale and uniform underlying surfaces;
②Most parts of my country are located in mid-latitudes, and mid-latitudes are areas where cold and warm air frequently meet, lacking circulation conditions conducive to air stagnation or slow movement.
13. In a day, the solar radiation is the strongest at noon, but why does the highest temperature appear around 2 o'clock in the afternoon?
① The heat of the atmosphere mainly comes from the long-wave radiation of the ground;
②The level of ground temperature is not directly determined by the amount of solar radiation absorbed by the ground at that time, but by the amount of heat stored on the ground;
③ At noon, the solar radiation is the strongest, and the temperature of the ground keeps rising. In the afternoon, although the sun's radiation begins to weaken, the heat gained by the ground is still more than the heat lost, and the long-wave radiation on the ground continues to strengthen, and the temperature continues to rise;
④At a certain time in the afternoon, the heat obtained by the ground is less than the heat lost due to the further weakening of solar radiation. At this time, the ground temperature begins to drop, and the highest value of the ground temperature appears on the ground. The moment of descent, this moment is usually around 1 o'clock in the afternoon;
⑤Because it takes a certain amount of time for the heat from the ground to be transferred to the air, the highest temperature appears around 2 o'clock in the afternoon.
14. The influence of topography on the formation of precipitation:
(1) After passing through the obstacles of mountains, the uplift movement of the air flow is caused, and the clouds condense to cause rain
(2) The low-pressure system and the front meet the obstacles of the mountains, making the system move sluggishly and prolong the rainy time
(3) When the airflow enters the valley, due to the trumpet effect, the airflow converges and rises. If the air is humid, precipitation will occur
(4) In summer, in the continental climate zone, the temperature increases on the south and north slopes of the mountains are different or the temperature on the slopes at the bottom of the valley increases quickly, and the temperature on the top of the mountain increases slowly, which will produce local thermal convection and form convective rain or thunderstorm
(5) When the airflow passes through the rough and uneven terrain area, due to the influence of friction, it produces turbulent upward movement. Under the condition of sufficient water vapor, it often forms low stratus clouds or stratocumulus clouds, and produces a small amount of precipitation, such as drizzle, light rain, etc.
15. Factors affecting climate formation and change
reference:
(1) The uneven distribution of solar radiation on the earth's surface;
(2) The existence of the earth's rotation forms three circles of circulation;
(3) The existence of thermal differences between land and sea makes the belt-shaped pressure belts separated into isolated high and low pressure centers;
(4) The effects of warm and cold ocean currents make the climate more complicated.
two parts
1. Atmospheric structure : refers to the layering of the atmosphere in the vertical direction and the inhomogeneity of the distribution of meteorological elements in the horizontal direction.
Including: troposphere, stratosphere, mesosphere, thermosphere, exosphere.
2. Ground effective radiation : Ground radiation and atmospheric inverse radiation often exist. The difference between the radiation emitted by the ground and the atmospheric inverse radiation absorbed by the ground is called the effective ground radiation.
The changing law of ground effective radiation:
Diurnal variation: reaching the maximum around noon, then gradually decreasing, and reaching the minimum in the morning
Annual variation: large in summer and small in winter, but due to the influence of water vapor and clouds, the maximum value appears in spring.
The factors that affect the effective radiation on the ground are:
(1) Clouds, mist, water vapor and wind: they can strongly absorb and reflect the long-wave radiation emitted by the ground, increasing the atmospheric inverse radiation, thus reducing the effective radiation on the ground;
(2) Altitude: Air density, water vapor, and dust decrease with the increase of altitude, the atmospheric inverse radiation decreases correspondingly, and the effective radiation increases;
(3) Surface characteristics: the undulating and rough surface has a larger radiation surface than a smooth surface, and the effective radiation is also larger;
(4) Ground cover: When objects with poor thermal conductivity such as straw, turf, and fallen leaves cover the ground, the effective radiation of the ground can be reduced.
3. Non-adiabatic temperature change
(1) The non-adiabatic change of air temperature
(1). Conduction: It is to rely on the thermal movement of molecules to transfer heat energy from one molecule to another, and the molecules themselves do not change their positions. When there is a temperature difference between the air and the ground, or between an air mass and an air mass, heat will be exchanged due to conduction.
(2). Radiation: Objects are constantly exchanging heat by radiation. The atmosphere heats up mainly by absorbing the long-wave radiation from the ground, and at the same time, the ground also absorbs the long-wave radiation emitted by the atmosphere, so that heat is constantly exchanged between them through long-wave radiation. Air masses can also exchange heat through long-wave radiation.
(3). Convection: When the warm and light air rises, the surrounding cold and heavy air descends to supplement it. This lifting motion is called convection. Through convection, the upper and lower layers of air mix with each other, and heat is exchanged accordingly.
(4). Turbulent flow: The irregular movement of air is called turbulent flow, also known as turbulent flow. Turbulence is created when air layers rub against each other or when air flows over rough and uneven ground. When there is turbulence, mixing occurs between adjacent air masses and heat is exchanged. Turbulent flow is an important mode of heat exchange in the friction layer.
4. Adiabatic change of air temperature
Adiabatic Processes: Processes that take place in the atmosphere, usually with different forms of energy conversion. During energy conversion, the state of the air changes. In meteorology, the state change process when there is no heat exchange between any air block and the outside world is called an adiabatic process.
When an air mass moves upward without any heat exchange with the outside world, if the volume of the air mass rises to a certain place, the internal pressure will be higher than that of the surrounding atmosphere. Equilibrium, the volume of the gas block needs to expand, in the process of expansion, it overcomes the external pressure and does work, the energy consumed by the air mass to do work is taken from the inside of the air mass, so the temperature of the gas block is lowered, the above process is called adiabatic cooling of air temperature.
Conversely, when the air mass is sinking, if there is no heat exchange with the outside world, since the external air pressure is higher than the internal pressure of the air mass, the air mass will be compressed to reduce the volume of the air mass. The temperature rise is called adiabatic heating.
5. Cloud drop growth and condensation process.
6. Common cooling processes in the atmosphere :
① Radiative cooling ② Contact cooling ③ Mixed cooling ④ Adiabatic cooling
7. Forces acting on air
(1) Pressure gradient and pressure gradient force
(2) Geostrophic deflection force (Fc )
(3) Inertial centrifugal force (C)
(4) Friction (R)
8. Geographic classification (geographic location of air mass source and nature of underlying surface): Northern Hemisphere
air mass
Arctic air mass (oceanic air mass): Polar regions north of 65°N
polar air mass
Polar Continental Air Masses: Siberia and Mongolia, Canada and Alaska
Polar marine air masses: over the mid-latitude oceans of the North Pacific and North Atlantic
tropical air mass
Tropical Continental Air Masses: Subtropical Deserts in North Africa and Southwest Asia
Tropical Maritime Air Masses: Over Oceans Controlled by Subtropical High
Equatorial air mass (equatorial oceanic air mass): Equatorial regions
9. The concept of air masses
The horizontal distribution of meteorological elements in a large-scale air mass is relatively uniform, and the vertical distribution is basically the same. In the area controlled by it, the weather and climate characteristics are also roughly the same.
10. convection:
11. The concept of hot and dry wind : hot and dry wind formed by sliding down the leeward slope after the unsaturated humid air is blocked by the mountain and forced to lift by power.
12. Factors affecting the saturated water vapor pressure of the solution surface:
13. The five subsystems of the climate system : atmosphere, hydrosphere, land surface, cryosphere and biosphere.
14. Atmosphere according to the extension height of the front: ground front, high altitude front, convective front
15. In addition to the change of the sun itself, the energy of astronomical radiation is mainly determined by the distance between the sun and the earth, the height of the sun and the length of the day.
16. Division of climate zones and climate types
Köppen climate classification - experimental classification
Schaller's Climate Classification - Genetic Classification
Zhou Shuzhen's Climate Classification
17. Causes of urban heat island effect
1. The influence of the characteristics of the underlying surface of the city (the contact surface between the bottom of the atmosphere and the surface).
2. The main reason is urban air pollution
3. The main reason is the influence of artificial heat source.
4. The natural underlying surface in the city is reduced.
18. Tropospheric characteristics
① The temperature decreases with altitude
②The air has strong convection and turbulent movement
③ The horizontal distribution of meteorological elements is uneven:
19. Solar constant : The solar radiation energy obtained within one minute for an area of one square centimeter perpendicular to the sun's rays at the upper boundary of the atmosphere.
20.
21. Factors Affecting Evaporation Rate of Water Surface
Temperature Humidity Air Pressure Wind Evaporation Surface Properties Evaporation Surface Shape Salinity
22. Gradient Wind
When the air particle moves in a curve, it is not only affected by the pressure gradient force and the geostrophic deflection force, but also by the inertial centrifugal force. When these three forces reach a balance, the wind is called gradient wind.
23. Air mass in winter in my country
Siberian air mass (most of the area)
Tropical Pacific Air Mass (Southeast Coast)
South China Sea air mass (Yunnan)
24. Divide according to moving speed and weather characteristics
Type 1 cold front (slow moving cold front)
Type II cold front (rapid cold front)
25. Typhoon Formation Conditions
initial disturbance
warm ocean
Earth's rotation deflection force
Tropospheric wind vertical shear is small
26. Köppen climate classification
Advantages: 1. For the first time, the concept of climate type was proposed
2. The method is simple, the boundaries are clear, and it is more in line with the natural landscape.
Disadvantages: 1. It is not appropriate to juxtapose the B belt with the A, C, D, and E belts
2. Neglecting the analysis of climate causes, it is easy to classify low-latitude highland climate and high-latitude climate into one category.