What are the basic elements of climate?

Air pressure: the pressure of the atmosphere is the pressure generated by the movement of air molecules on any surface unit area.

Temperature: the temperature of the atmosphere, indicating the degree of heat and cold of the atmosphere. It is the average kinetic energy of air molecular motion. The general unit is celsius, or thermodynamic temperature K.

Atmospheric humidity (humidity for short): indicates the water vapor content or humidity degree in the air, which can be expressed by physical quantities such as specific humidity (G), absolute humidity (pv), water pressure (E), dew point and relative humidity.

Wind: the movement of air relative to the ground. Meteorology often refers to the horizontal movement of air, expressed by wind direction and wind speed. Wind is a vector with magnitude and direction. Wind direction refers to the direction of the wind. Wind speed refers to the distance that air moves in the horizontal direction in unit time, and the unit is meter/second or kilometer/hour. (0- 12)

Cloud: a visible polymer consisting of a large number of water droplets and ice crystals suspended in the air. In routine meteorological observation, the shape, height and amount of clouds should be determined.

Precipitation: refers to liquid water and solid water falling from the clouds, such as rain, snow and hail.

Evaporation: evaporation on the surface of a liquid. Meteorology refers to the process of water changing from liquid to gas.

Radiation: the process of sending energy or material particles from a radiator to all directions in space. In meteorology, solar radiation is usually called short-wave radiation, while earth surface radiation and atmospheric radiation are long-wave radiation.

Sunshine: the time when the sun shines. Meteorology usually provides the observed actual light time.

Visibility: refers to the lowest horizontal distance, in meters or kilometers, that a person with normal vision can see or identify the target (black, high humidity and low humidity) from the sky background at that time. Visibility indicates the cleanliness and transparency of the atmosphere. Observed values are usually divided into 10 levels.

Air humidity: the humidity of the air is referred to as air humidity for short, which reflects the amount of water vapor in the atmosphere and the humidity of the air.

Commonly used expressions are: absolute humidity, water vapor pressure, relative humidity, saturated air pressure, dew point, etc.

(1) Absolute humidity: the mass of water vapor per unit volume (1m3) (kg). From the ideal gas state equation, we can get:

(2) Relative humidity: the ratio of absolute humidity ρw of air to absolute humidity ρv of saturated air at the same temperature. It is equal to the percentage of water vapor partial pressure Pw of air and water vapor partial pressure Pv of saturated air at the same temperature.

(3) Water content: The water vapor mass (kg) contained in wet air 1kg dry air also becomes the specific humidity in meteorology. It is equal to the water vapor mass (kg) divided by the dry air mass kg.

Dew point or frost point cools the air near the plane of pure water (or pure ice) to saturation temperature without changing the air pressure and mixing ratio.

The difference between the saturated vapor pressure of undersaturated air at a certain temperature and the actual vapor pressure at that time. Its unit is the same as that of air pressure.