Earth's Atmosphere and Global Climate Zones

The Earth's Atmosphere and Its Composition

The Earth is enveloped by a layer of gases known as the atmosphere. The atmosphere is composed primarily of two gases, nitrogen and oxygen, and is divided into five distinct layers.

Key Layers of the Atmosphere

The Troposphere

The two nearest layers to the land include the troposphere, which is the bottom layer of the atmosphere and is in direct contact with the surface of our planet. It contains water vapor, and the temperature drops with the increase of altitude in the troposphere. This layer is the site of most meteorological phenomena.

The Stratosphere and the Ozone Layer

The stratosphere is the layer located above the troposphere. It is very important because it abounds with a gas called ozone. The ozone prevents harmful solar ultraviolet radiation from reaching the terrestrial surface.

Distinguishing Weather and Climate

Weather refers to the state of the atmosphere in a specific place and at a determined time. In contrast, climate is the characteristic state of the atmosphere that is repeated in a particular place over a long period of time.

Meteorological Analysis

To understand the weather and climate, scientists analyze temperatures, precipitation, wind, and pressure collected at meteorological stations.

Temperature Factors

Temperature represents the amount of heat in the air and is measured with a thermometer in degrees Celsius. Several factors modify temperatures: they change with latitude, altitude, and distance to the sea.

Humidity and Precipitation

The amount of moisture or water vapor in the air originates from the evaporation of water from seas, oceans, rivers, lakes, wet lands, and plains. When the water vapor cools, it condenses and becomes liquid droplets formed in the clouds.

Precipitation is the water that falls from the atmosphere onto a site. It can fall as rain, sleet, or snow.

Global Climate Zones and Landscapes

Equatorial and Tropical Climates

Equatorial Climate: In the jungle around the equator, conditions are always very warm with abundant rainfall. Equatorial rivers are very regular in their flow, and the vegetation is staggered at different heights.

Tropical Climate: In the savanna, temperatures are always high. Rainfall is abundant but alternates between dry and wet seasons. This region includes rivers like the Podoko and is home to groups such as the Serer and Kikuyu. The savanna presents a distinct agricultural landscape.

Desert and Mediterranean Climates

Desert Climate: This is characterized by scarce rains. There are both hot and cold deserts; these landscapes are largely uninhabited due to extreme seasonal conditions.

Mediterranean Climate: Located around the Mediterranean Sea, this zone experiences high temperatures and irregular rainfall. The landscape features Mediterranean forests and scrub bushes with aromatics such as rosemary, thyme, and lavender (espigol). The environment has been shaped by fields of corn, vineyards, olive orchards, and cultivated vegetables. Furthermore, tourism has transformed the Mediterranean environment like no other.