What is the temperature of the place?
The air temperature measured in a place with open air circulation and no direct sunlight.
In meteorology, the physical quantity that expresses the degree of hotness and coldness of the air is called air temperature, or air temperature for short. The international standard unit of temperature measurement is degrees Celsius (℃).
The temperature mentioned in the weather forecast refers to the air temperature measured in the open air without direct sunlight (usually measured in a blind box). The maximum temperature is the highest value of the temperature in a day, which usually occurs between 14 and 15 o'clock; the minimum temperature is the lowest value of the temperature in a day, which usually occurs before sunrise.
Extended information
Influencing factors:
1. Natural factors
In addition to the cycle caused by changes in solar radiation, the temperature of a certain place In addition to the periodic changes, there are also non-periodic changes caused by the movement of the atmosphere. The change in actual temperature is the result of the simultaneous effects of these two aspects. If the former has a large effect, the temperature will show periodic changes; on the contrary, it will show non-periodic changes.
However, judging from the general trend and most situations, the periodicity of diurnal and annual changes in temperature is still dominant. Each component of the heat balance, such as radiation difference, latent heat and sensible heat exchange, is affected by different control factors. These factors such as latitude, season and other astronomical factors have obvious zonal and periodic characteristics.
The nature of the underlying surface, the height of the terrain, and weather conditions, such as cloud cover, atmospheric dryness and humidity, etc., all have non-zonal characteristics. At the same time, the influence of these factors is also different in different locations, so the temperature distribution caused by changes in the heat budget is also uneven.
2. Human influence
(1) Influence of the characteristics of the urban underlying surface (the contact surface between the bottom of the atmosphere and the earth's surface).
A large number of artificial structures in the city, such as paved floors and various building walls, change the thermal properties of the underlying surfaces. The urban surface contains less water, and more heat enters the air in the form of sensible heat, causing the air to heat up. At the same time, the urban surface has a higher absorption rate of sunlight than the natural surface and can absorb more solar radiation, which in turn causes the air to gain more heat and increase the temperature.
(2) Urban air pollution.
Motor vehicles, industrial production and a large number of crowd activities in cities produce a large amount of nitrogen oxides, carbon dioxide, dust, etc. These substances can absorb a large amount of thermal radiation energy in the environment, producing well-known The greenhouse effect causes further warming of the atmosphere.
(3) Influence of artificial heat source.
Factories, motor vehicles, residents' lives, etc. burn various fuels and consume a lot of energy. Countless furnaces are burning and emitting heat.
(4). The natural underlying surface in cities is reduced.
The number of buildings, squares, roads, etc. in the city has increased significantly, and natural factors such as green spaces and water bodies have decreased accordingly. More heat is emitted and less heat is absorbed, and the ability to alleviate the heat island effect has been weakened.
Baidu Encyclopedia-Temperature