Earth’s Movements, Relief, and Climate

Posted on Nov 6, 2024 in Geology

Movement of the Earth

The Earth is a planet in constant motion as it travels through space. Two of its most important movements are rotation and translation.

Rotation Movement

Rotation is the movement where the Earth spins counterclockwise on an imaginary line called the axis of rotation, which passes through the poles. This rotation takes 24 hours and results in the sequence of days and nights. When the sun’s rays hit a part of the Earth’s surface, that area is illuminated, and the temperature increases, resulting in daytime. Conversely, the area not receiving sunlight experiences night, and the temperature decreases. The Earth takes one full rotation about its axis in 24 hours, but time zones vary across the globe. We can use the cardinal points for orientation, as the sun always rises in the east and sets in the west.

Translation Motion

The Earth not only rotates on its axis but also revolves around the sun. This movement is called translation and takes approximately 365 days, 5 hours, and 48 minutes. The Earth’s orbit is an ellipse. The consequences of this motion are the seasons. The tilt of the Earth’s axis causes the sun’s rays to hit the Earth with varying intensity, resulting in the changing seasons. The arrival of the seasons is determined by solstices and equinoxes. The time it takes for the Earth to complete one orbit around the sun is called a year. Every four years, an extra day is added to February, making it a leap year.

Formation of Relief

In 1912, German geophysicist Alfred Wegener attempted to explain the formation of relief by developing the theory of continental drift. He proposed that the Earth’s continents were once joined together in a supercontinent called Pangea. By 1966, Wegener’s attempts to prove his theory led to the development of the theory of plate tectonics, which states that the Earth’s crust is made up of fragments in the form of plates of different sizes.

Movements of the Earth’s Crust

The movements, collisions, and separations of tectonic plates have allowed geologists to explain many phenomena that were previously thought to be unrelated. A tsunami, or big wave in Japanese, is a wave formed by a shock wave or series of waves generated by earthquakes or volcanic activity on the seabed. The Pacific Ocean, the most active area on the planet, is the most affected area and is called the “Ring of Fire.”

Forms of Relief

• Water: One of the most powerful erosive agents. It can be found in solid form, like snow or ice, breaking rocks due to temperature changes, or in liquid form.
• Wind: Particularly important in areas with low vegetation, usually carrying particles in suspension, which increases weathering.
• Ice: Glaciers are large masses of ice that move by gravity.
• Human Beings: Capable of significantly altering the landscape. Human intervention has led to the humanization of much of the planet.

Specific Landforms:

• Mountains: The highest landforms, with elevations greater than 1000 m.
• Mountain Ranges: Large sets of mountains.
• Plateaus: Flat and elevated areas.
• Hills: Similar to mountains but less steep.
• Plains: Have an almost horizontal relief, with gentle slopes.
• Volcanoes: Landforms resulting from the accumulation of lava and other volcanic products.
• Continental Shelves: The area between the coast and a depth of 200 m.
• Continental Slopes: The slopes that separate the edge of the continental shelf from the abyssal plain.
• Abyssal Plains: Located at depths between 4000 and 6000 m.

Peninsular Relief Features

The high altitude of the Iberian Peninsula makes it the second-highest region in Europe after Switzerland. The coastal plains are low, except in the east, and the coasts are slightly indented, with the exception of Galicia. The Balearic Islands are a continuation of the mainland, while the Canary Islands are volcanic in origin. The highest point in Spain is Mount Teide in Tenerife, which is almost 4000 meters high.

The Plateau

The Iberian Plateau is surrounded by mountains: the Cantabrian Mountains to the north, the Iberian System to the east, and the Sierra Morena to the south.

Temperature

Temperature is a weather element that tells us the degree of heat and is measured by a thermometer. Temperatures are expressed as averages for a day, month, or year. Several factors influence temperature:

• Latitude: The angle at which sunlight hits the Earth’s surface is not the same everywhere. The farther we move away from the equator, the lower the temperature, as the sun’s rays hit the surface at an oblique angle and have to cover a larger area.
• Altitude: The atmosphere’s ability to retain heat decreases as we ascend. Higher altitudes have less water vapor and other gases, leading to lower temperatures.
• Continentality: Large bodies of water have a moderating effect on temperature. Coastal areas tend to have milder temperatures than inland areas.

Three Major Climate Zones

• Hot Zone: Located between the tropics, this zone receives the most direct sunlight. It is always summer in the hot zone.
• Temperate Zones: Located between the tropics and the polar circles, these zones experience four seasons a year.
• Cold Zones: Characterized by a significant lack of solar radiation, it is always winter in the cold zones.

Precipitation (Water Cycle)

Water on the Earth’s surface is heated by the sun, evaporates, and rises. As it reaches higher altitudes where the temperature is lower, it begins to condense. Earth’s gravity then pulls the water droplets down as rain. Rainfall is measured using a rain gauge. Three factors determine precipitation:

• Latitude
• Continentality
• Relief

Warm Climates

Found between the tropics, these climates have very high temperatures, averaging above 22°C annually.

• Equatorial Climate: Rainfall throughout the year, exceeding 1500 to 2000 mm. Temperatures are uniform, averaging above 20°C. There is only one season, which is warm and humid.
• Tropical Climate: Warm all year round. The temperature range increases as we move away from the equator. Rainfall ranges between 400 and 1000 mm.
• Desert Climate: Defined by aridity, with rainfall below 100 mm.

Temperate Climates

Found between 40 and 60 degrees latitude, these climates experience four seasons a year.

• Mediterranean Climate: Mild winters, dry and warm summers. Rainfall occurs during the intermediate seasons, spring and fall, ranging between 250 and 800 mm.
• China Climate (Humid Subtropical): Rainfall exceeds 1000 mm, concentrated during the summer season, with dry winters.
• Oceanic Climate: Proximity to the sea results in a small annual temperature range and significant precipitation (1000-2000 mm). Temperatures are moderate in winter.
• Continental Climate: Typical of the interior of continents, with cold winters and hot summers. Rainfall varies between 300 and 700 mm, with heavy snowfalls.
• Temperate Desert: Differs from the warm desert not by rainfall but by temperature, which is cold in winter.

Cold Climates

• Polar Climate: Characteristic of regions with average monthly and annual temperatures below 0°C. Precipitation is limited and falls as snow.
• High Mountain Climate: Cold winters with temperatures below zero and short, cool summers. Rainfall exceeds 1000 mm annually, usually in the form of snow.