How to distinguish "cloudy" from "cloudy"?

Hehe, in order to avoid asking anything else next time, it's free.

Terminology of weather forecast

(1) Classification of weather forecast

Weather forecast can be divided into short-term, medium-term and long-term types. Short-term within 48h, medium-term after 48h, and long-term after half a month. Short-term weather forecasts are usually broadcast on radio and TV.

Before the occurrence of severe weather system, meteorological stations at all levels should issue "news", "report", "alarm" and "emergency alarm" in time.

"News"-It is expected that a disastrous weather system will affect the area in two days, or it is difficult to determine whether it has a significant impact, but it is a threat to the area, so you can release "news" first, such as "Typhoon News".

"Report"-It is expected that there will be some disastrous weather in two days, which will have a certain impact on the region. Reports can be issued, such as "gale report" and "high temperature report".

"Early warning"-It is expected that a disastrous weather system will affect the local area within two days and cause great harm, that is, an "alert" will be issued, such as "typhoon warning", "rainstorm warning" and "gale warning".

"Emergency Alert"-If it is predicted that the typhoon will affect it within 24 hours and the maximum wind force near the center reaches 12 or above, a "Typhoon Emergency Alert" will be issued. For the impact of tropical depression, tropical storm and strong tropical storm within 24 hours, corresponding emergency warnings are also issued.

(2) the sky condition

The sky condition is determined by the amount of clouds in the sky and the intensity of sunshine, which can be divided into four situations: sunny, partly cloudy, cloudy and cloudy.

Sunny days: the sky is cloudless, or the medium and low clouds are less than 1%, and the high clouds are below 40%.

Partly cloudy: there are 1% ~ 30% medium-low clouds or 40% ~ 50% high clouds in the sky.

Cloudy: There are 40% ~ 70% medium-low clouds or 60% ~ 10% high clouds in the sky.

Cloudy day: It is dark, covered with clouds, or slightly cloudy, but it still feels dark.

(3) Precipitation intensity

The classification of precipitation intensity is shown in the following table.

Equal grade

12h total precipitation (mm) 24h total precipitation (mm)

Xiaoyu

0.0~5.0 0.0~ 10.0

Zhongyu

1. 1~ 15.0 10. 1~25.0

torrential rain

15. 1~30.0 25. 1~50.0

torrential rain

30. 1~70.0 50. 1~ 100.0

heavy downpour

70. 1~ 140.0 100. 1~200.0

Heavy rain; rainstorm

〉 140.0 〉200.0

Intensity of snowfall

The intensity classification of snowfall is shown in the following table.

Equal grade

12h snowfall (mm) 24h snowfall (mm)

Minor Snow

0.0~ 1.0 0.0~2.5

middle school

1. 1~3.0 2.6~5.0

Major Snow

〉3.0 〉5.0

Note: Conversion between snowfall and precipitation: 1 0mm thick snow equals1mm precipitation.

(5) Wind power generation

The classification of wind power levels is shown in the following table.

Wind power level (km/h)

Equivalent wind speed of surface objects (m/s)

Quiet, straight.

0~0.2

1

Smoke can indicate the wind direction, and the leaves tremble slightly.

0.3~ 1.5

2

The face felt the wind, the leaves sounded slightly, the flag began to move, and the tall grass began to shake 1.6 ~ 3.3.

three

Leaves and twigs are shaking, flags are fluttering in the wind, and tall grass is shaking 3.4 ~ 5.4.

four

It can blow up dust and paper on the ground, and the branches shake. The tall grass undulates.

5.5~7.9

five

Small trees with swaying leaves make small waves on the inland water surface. The high grass wave fluctuates obviously by 8.0 ~ 10.7.

six

The branches are shaking, the wires are whirring, and it is difficult to lift the umbrella. Tall grass fell to the ground from time to time.

10.8~ 13.8

seven

The whole tree shakes to bend its branches, making it inconvenient to walk in the wind ~ 13.9 ~ 17.38+0.

eight

When twigs break, people will feel great resistance to progress. 1.72 ~ 20.7.

nine

The straw house was damaged, the roof tiles were lifted, and the branches could be broken by 20.8 ~ 24.4.

10

Trees can be blown down, and general buildings are damaged by 24.5 ~ 28.4.

1 1

Rare on land, trees can be blown down, and general buildings are seriously damaged by 28.5 ~ 32.6.

12

Very few on land, with a destructive power of 32.7 ~ 36.96.

(VI) Judgment method of precipitation intensity (for reference)

(l) Yu Hui: A few drops of precipitation have no effect on field work.

(2) Light rain: Raindrops are clearly identifiable and do not splash on the floor or roof tiles. Shallow mud pits form slowly on the ground, and at least two minutes after the rain begins, the slate or roof tile can be completely wet. The sound of rain hitting the house is relaxed, and there is only the sound of dripping under the eaves.

(3) moderate rain: rain falls like a line, and raindrops are not easy to distinguish. When they land on hard ground or roof tiles, they will splash, puddles and mires will soon form, and there will be rustling rain on the house.

(4) Heavy rain and rainstorm: the rain is like a downpour, and the head-up space is blurred into pieces. When it lands on a roof tile or hard ground, it will splash several inches. The pool was quickly formed, the visibility was greatly reduced, and there was noise on the roof.

(7) Continuous rainy weather and main continuous rainy weather in China.

1. Persistent rainy weather

Continuous rainy weather refers to the rainy phenomenon for more than 3 consecutive days. Precipitation intensity can be light rain, moderate rain, heavy rain or rainstorm.

The continuous rainy weather process is caused by the stagnation or continuous recurrence of the weather system that produces precipitation in a certain area under the condition of stable weather situation and sufficient water vapor sources in a large area. It mainly occurs in the area where the warm and humid air on the north side of the subtropical high meets the cold air in the westerly belt.

2. The main continuous rainy weather in China

(l) Continuous rainy weather in spring: When blocking high occurs near Urals, there is a flat westerly circulation downstream, and the trough moves eastward from the plateau, bringing cold air to the south of the Yangtze River, while the western Pacific high or the South China Sea high is stable at sea, and the southwest warm and humid airflow is maintained in South China. In this circulation situation, there is a continuous low temperature and rainy weather process in spring.

(2) Meiyu in the Jianghuai Basin in early summer: Meiyu is a continuous rainy weather in the Jianghuai Basin in early summer with a long rainy period. Meiyu is caused by the frequent activities of fronts or cyclones caused by the long-term intersection of cold and warm air in this area.

(3) Continuous rainy weather in the middle and lower reaches of the Yangtze River in autumn: From September to June165438+1October every year, the westerly belt begins to move southward, and the subtropical high gradually recedes southward. At the same time, there is continuous rainy weather in the middle and lower reaches of the Yangtze River.

(4) Continuous rainy weather in Southwest China in autumn: In autumn, while continuous rainy weather occurs in the middle and lower reaches of the Yangtze River, it generally occurs in Sichuan, Guizhou and eastern Yunnan in Southwest China, starting in mid-September and ending in late l0.

(5) Continuous rainy weather in the southeast of Northwest China in autumn: September and 10 in the southeast of Northwest China are also rainy seasons, with continuous rainy weather, mainly light rain, and sometimes heavy rain or rainstorm.

(VIII) Rainfall types

According to the influence of airflow and convection on rainfall, rainfall can be divided into four types: cyclone rain, topographic precipitation, convective rain and typhoon rain.

(1) Cyclonic rainfall: The rainfall accompanied by cyclone or low-pressure transit is called cyclone rainfall, which is one of the important weather systems of four seasons rainfall in China. Cyclone rain can be divided into non-frontal rain and frontal rain. Non-frontal cyclone rain is caused by the rise of air flow caused by the convergence of air flow to low pressure, while frontal cyclone rain is caused by cyclone waves on the front. Cyclone wave is a frontal wave in the lower atmosphere. Cyclone wave occurs in temperate zone, so it is called temperate cyclone wave. When the cyclone wave develops to a certain depth, a cyclone is formed. Jianghuai cyclone is a frontal cyclone that occurs in Jianghuai basin and Hunan and Jiangxi areas. It occurs frequently in spring and summer, especially in June and July during the Meiyu period, which is one of the important weather systems that cause heavy rain in Jianghuai area.

Most of our country is temperate zone, which belongs to the intersection of north and south airflow, and cyclone rain is extremely developed. The proportion of cyclone rain is above 60% everywhere, over 80% in Central China and North China, and even 70% in the northwest inland. Most cyclones in China occur in the eastern plateau. Mongolia cyclone, northeast depression and Yellow River cyclone formed in the north. After the cyclone is generated in China, it generally moves to the northeast and goes to sea. The famous plum rain in the south of the Yangtze River was caused by the intersection of polar air mass and tropical ocean air mass in the south of the Yangtze River in June and July.

(2) Topographic precipitation: When the moist air mass moves forward, it is blocked by high mountains, and the airflow is forced to rise slowly, resulting in adiabatic cooling and condensation. The rainfall thus formed is called topographic precipitation. Topographic precipitation mostly falls on windward slopes, and leeward slopes are adiabatic heated due to air subsidence, which reduces cloud cover and rainfall.

Topographic precipitation often increases with the increase of topographic height. If topographic precipitation is not combined with convective rain or cyclone rain, the rain will not be very strong.

(3) Convective rain: When the ground is heated, the temperature of the air near the ground rises and the density decreases, so convection occurs. If the air is humid, the rising airflow will produce heavy rain or lightning, which is called convective rain. Convective rain mostly occurs in summer, with rapid development and short duration, accounting for a small proportion of annual precipitation.

(4) Typhoon storm: Typhoon storm is rain brought by storms in tropical oceans. This kind of storm is composed of an unusually strong hot and humid air mass in the ocean. Where the typhoon passes, the rainstorm is fierce, which can reach hundreds of millimeters at a time, and sometimes it can reach more than l000mm, which is very easy to cause disasters.

(9) Weather forecast

Radio and TV stations have weather forecast programs every day. Here is a little common sense: "Today's daytime" means 12h from 8 am to 2O pm; "Tonight" means 12h from 2O:00 to 8:00 the next morning. "Cloudy" means that the amount of clouds accounts for 40% ~ 70%; "Yin" means that the cloud cover accounts for 80% ~100%; "Clear" means that the cloud cover accounts for 10% ~ 30%.

The forecast time shall not exceed 12h, and refer to the precipitation level standard of 12h. For example, it is predicted that there will be thunderstorms at noon or at night today, which means the precipitation within 12h. If it is predicted that there will be moderate to heavy rain from day to night today, it refers to the precipitation within 24 hours.