Solar Energy: Impact on Earth, Meteorology & Uses
Solar Energy and Earth’s Processes
The Sun emits energy created by nuclear reactions. Geological agents are natural systems that produce erosion, mass movement, and sedimentation. Hot water moves due to temperature differences.
When land and water absorb sunlight, they warm up. Some areas of the Earth receive more solar energy than others. Around the Equator, the rays are perpendicular to the ground. At the poles, the rays are oblique.
Atmospheric and Oceanic Currents
Air (ocean) currents are movements of air (water) created because of the unequal heating of the Earth’s surface. Warm air (ocean currents) from the Equator moves towards the poles. Cold air (ocean currents) from the poles moves towards the Equator.
Local Atmospheric Phenomena
Sea breezes and storms are local atmospheric phenomena. The main atmospheric phenomena are:
- Thermals: Columns of hot air that rise from the warm surface heated by the Sun.
- Storms: Occur when temperature differences between warm air on the ground and cold air at higher altitudes are significant. They cause thermals, which can become violent.
- Coastal breezes: The movement of air in coastal areas with warm climates. The Sun warms the land and the sea, but not equally.
- Valley breezes: The movement of air that develops when warm air descends. This ascent creates winds that blow toward the upper valley.
- Thermal inversion: Occurs when the air at higher altitudes is warmer than air near the ground. As a result, pollution from industries and traffic is trapped near the ground.
Meteorology: Understanding Weather and Climate
Meteorology is the science that studies the atmosphere and its phenomena, including weather and climate.
Meteorologists use weather satellites and weather stations to produce weather maps. They draw isobars.
Isobars are lines that connect points of equal atmospheric pressure, measured in millibars.
Weather Map Predictions
Weather maps help to make predictions about:
- Winds: Movements of large masses of air produced by differences in atmospheric pressure. There are anticyclones (areas with high pressure) and depressions (areas with low pressure). Air rises and forms clouds.
- Clouds: A mass of water made of tiny water droplets.
- Rain: Forms when water droplets expand and become heavy.
- Snow: Forms when water vapor freezes.
- Hail: Falls from cumulonimbus clouds.
Living Beings and Solar Energy
All living beings use solar energy in different ways:
- Plants use it during photosynthesis.
- Animals use it to warm their bodies.
- Birds use it to fly.
Industrial Uses of Solar Energy
- Heat: Solar water heaters are simple devices that produce hot water.
- Electricity: A solar cell is a device that converts sunlight into electricity. Parts include: hot water out, cold water in, hot water deposit, black panel, metal coil.
Risks from Solar Energy
The atmosphere filters solar radiation, but some risks remain:
- Damage to the ozonosphere: CFC gases can react chemically with oxygen, allowing more UV light to reach the surface.
- The greenhouse effect and global warming: The greenhouse effect traps water vapor, methane, and other gases in the atmosphere. Without these gases, heat would escape back into space, and the Earth would freeze. However, an increase of these gases causes global warming.
Additional Notes (Demonstrations)
- Chimney effect: Air is heated by the fire and ascends.
- Hot and cold water: Form a current.
- Spirals: The rotational movement of the Earth causes air and ocean currents to form spirals.
- Accumulating heat near forests: Best observed near a rocky coast *without* vegetation.
- Hot air balloon: The difference in temperature is greater in the morning because the air is colder, and the balloon rises more easily.