Deutsch: Troposphäre / Español: Troposfera / Português: Troposfera / Français: Troposphère / Italiano: Troposfera
The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and 99% of its water vapour and aerosols.

In the context of the environment, the troposphere refers to the lowest layer of the Earth's atmosphere, extending from the surface up to an average altitude of about 10 to 15 kilometers (6 to 9 miles). It is the layer where weather events occur and where we live and breathe. The troposphere plays a crucial role in regulating the Earth's climate, air quality, and weather patterns.

Here are some examples and key characteristics of the troposphere:

1. Weather Systems: The troposphere is where weather phenomena take place. It is the layer where clouds form, precipitation occurs, and temperature and humidity variations shape weather patterns. Examples include the formation of thunderstorms, hurricanes, and atmospheric fronts that lead to changes in temperature and air pressure.

2. Air Circulation: The troposphere is characterized by vertical and horizontal air circulation patterns. Warm air near the Earth's surface rises, cools, and then descends, creating convection currents. These currents are responsible for the movement of air masses, the distribution of heat, and the transportation of moisture throughout the atmosphere.

3. Temperature Gradient: Generally, as altitude increases within the troposphere, temperature decreases. This temperature gradient is known as the lapse rate and is influenced by factors such as solar radiation, cloud cover, and air pollution. The decrease in temperature with altitude is due to the diminishing effect of heat absorption from the Earth's surface.

4. Composition: The troposphere is composed mostly of nitrogen (about 78%) and oxygen (about 21%) along with trace amounts of other gases, such as carbon dioxide, water vapor, methane, and ozone. The presence of these gases in the troposphere influences climate, air quality, and the greenhouse effect.

5. Air Quality: The troposphere is the layer directly involved in human and animal respiration. It is where pollutants emitted from various sources, such as industrial activities, transportation, and biomass burning, accumulate. Poor air quality in the troposphere can lead to respiratory illnesses, cardiovascular problems, and other health issues.

6. Greenhouse Effect: The troposphere is essential for the greenhouse effect, which helps regulate the Earth's temperature. Greenhouse gases, such as carbon dioxide and methane, trap heat radiating from the Earth's surface, preventing it from escaping directly into space. This natural phenomenon is vital for maintaining a habitable temperature range on Earth, but human activities have enhanced the greenhouse effect, leading to global warming and climate change.

Similar concepts and layers related to the troposphere include:

1. Stratosphere: The stratosphere is the layer above the troposphere, extending from about 10 to 50 kilometers (6 to 31 miles) above the Earth's surface. It is characterized by the presence of the ozone layer, which absorbs harmful ultraviolet radiation from the sun. The stratosphere plays a crucial role in protecting life on Earth from excessive UV radiation.

2. Mesosphere: The mesosphere is the layer above the stratosphere, extending from about 50 to 85 kilometers (31 to 53 miles) above the Earth's surface. In this layer, temperatures decrease with increasing altitude, reaching extremely low temperatures. Meteors that enter the Earth's atmosphere often burn up in the mesosphere due to the high temperatures generated by friction.

3. Thermosphere: The thermosphere is the layer above the mesosphere, extending from about 85 kilometers (53 miles) and beyond. It is characterized by high temperatures, primarily due to the absorption of intense solar radiation. The International Space Station and many satellites orbit within the thermosphere.

4. Ozone Layer: While the troposphere contains only a small amount of ozone, the majority of the Earth's ozone is found in the stratosphere. The ozone layer plays a crucial role in absorbing and filtering out harmful ultraviolet (UV) radiation from the sun, protecting life on Earth from its damaging effects.

Understanding the structure and functions of the troposphere and its interactions with other atmospheric layers is essential for studying weather patterns, climate change, air quality, and the overall dynamics of the Earth's atmosphere. It helps scientists and researchers make predictions, develop climate models, and implement strategies for environmental protection and sustainable development.