Atmospheric humidity. Saturated vapor and psychrometer – hygrometer

Atmospheric humidity is the amount of water vapor present in the air. It is an essential component of the atmosphere and plays a critical role in climate, meteorology and human well-being. Atmospheric humidity is commonly measured using two main concepts: relative humidity and absolute humidity.

Relative humidity is a measure of how much moisture is in the air compared to the maximum amount the air can hold at a specific temperature and pressure. It is expressed as a percentage and is calculated by dividing the current vapor pressure by the maximum vapor pressure at that temperature. A relative humidity of 100% means that the air is saturated and can hold no more water vapor.

Absolute humidity, on the other hand, is a direct measure of the actual amount of water vapor in the air, usually expressed in grams per cubic meter or grams per kilogram. It can be determined using instruments such as hygrometers or using equations that consider air temperature and pressure.

Atmospheric humidity has several effects on the climate and the environment. For example, high humidity can make the air feel heavier and warmer, as water vapor retains and transfers heat more efficiently than dry air. In addition, high humidity can influence cloud formation and precipitation, as water vapor condenses to form water droplets or ice crystals.

Atmospheric humidity affects our perception of temperature through the heat index. Atmospheric humidity is also important for agriculture, as it affects the ability of the air to support plant life and crop growth.