Understanding the Atmosphere: Composition, Layers, and Weather
Weather Elements
Atmospheric Temperature: The degree of heat that the air has at a specific time and place.
Atmospheric Pressure: The pressure exerted by the air at any point in the atmosphere.
Humidity: The presence of water in the air.
Condensation: The transition of water from its gaseous state to its liquid or solid state. This varies depending on the degree of heat in the atmosphere.
Formation of Clouds: A cloud is composed of millions of droplets (or ice crystals when temperatures are very low) suspended in the air. A cloud can form when water vapor becomes liquid, for example, when moist air is cooled and condenses on small particles.
Precipitation: The way water flows by gravity from the condensation product of water vapor.
Air Mass
An air mass is a large volume of air whose physical properties, particularly temperature, moisture content, and vertical temperature gradient, are more or less uniform over an area of hundreds of kilometers. In addition to its homogeneity, the air mass is mobile and transformed during displacement. To characterize an air mass, it is necessary to differentiate the conditions of the origin or source where it originated and the subsequent transformations it may experience. In its origin, it had to be in contact with a surface of stable and homogeneous temperature and humidity.
Atmospheric General Circulation
A mechanism that redistributes water vapor and heat in the atmosphere and provides a balance of thermal and pressure differences on Earth.
Causes of Differences in Air Pressure
They can be thermal or dynamic. Thermal causes are related to the expansion and densification properties of hot or cold air masses, which change their temperature by contact with the Earth’s surface. Dynamic causes are related to atmospheric general circulation (low equatorial pressure, subtropical high pressure, low pressure associated with polar fronts, high polar pressure).
Movements of Convergence and Divergence
Convergence indicates an accumulation of air in a limited area of space. Cyclones or low-pressure areas act as centers of accumulation in the atmosphere, which must be offset by rising atmospheric motion. Divergence indicates a loss of air. Anticyclones are areas of decreased air (subsidence), resulting in the atmospheric stability that characterizes them.
The Atmosphere
The atmosphere is the gaseous layer that surrounds the Earth and is formed by the mixture of gases we call air. It protects us from X-rays and ultraviolet (UV) radiation and regulates temperature and climate. If there were an escape of infrared rays emitted by the Earth, it would lead to severe cold at night and excessive heat during the day. At an altitude of 1000 km, it is formed by five layers:
- Troposphere: The layer in contact with the ground, with a height of 13 km. This is where the air we breathe and atmospheric phenomena like wind and rain occur. When in contact with oceans, seas, and rivers, it contains 90% of the Earth’s water and much of its carbon dioxide. Its temperature decreases with height, reaching up to -70°C.
- Stratosphere: Extends from the boundary of the troposphere up to 50 km. At its top is the ozone layer, which absorbs ultraviolet radiation from the sun.
- Mesosphere: Between 50 and 80 km high. The majority of chemical radiation in the air is reached here. Temperatures drop to -90°C.
- Ionosphere: Reaches up to 500 km high and is made up of electrically charged gases due to UV and cosmic X-rays from the sun. Temperatures can reach 1500°C.
- Exosphere: The outer zone of the atmosphere, reaching temperatures of 2400°C.