Understanding Earth’s Climate: Zones, Energy, and Weather
Understanding Earth’s Climate
An elliptical orbit means that the solar energy received will be lower at the moments of greatest distance from the Sun than in closer proximity.
Geoastronomic Zones
Tropical Zone: Located within the tropics and divided in half by the Equator.
Temperate Zone: Located to the north, between the Tropic of Cancer and the Arctic Circle, and to the south, between the Tropic of Capricorn and the Antarctic Circle.
Polar Zone: Located between the Arctic Circle and the North Pole, and the Antarctic Circle and the South Pole. (Approximately 23°27′)
Heat Transfer Mechanisms
Conduction involves the direct heating of a colder material by a warmer material when they are in contact.
Radiation occurs when radiant energy is transmitted through space, such as when an electric lamp illuminates a room.
The denser, colder air is drawn down by gravity, forcing it into the less dense, warm air. This process is called convection, and the movements that occur in materials are called convection currents.
The effect of convection is always to move cooler air to hot spots and transfer heat from hot spots to colder areas.
Different Forms of Energy
- A rock rolling downhill demonstrates mechanical energy.
- An ocean current represents both thermal and mechanical energy.
- Fuels like oil and coal possess chemical energy.
- Lava from a volcano heats the ground and causes burning through conduction.
- Landslides on a mountain are examples of potential energy converting to kinetic energy.
Main Types of Wind
Planetary winds affect large areas of the planet and blow with interruptions and diversions throughout the year.
Continental winds are caused by the marked differences in pressure between the continents and oceans, according to the seasons.
Cyclonic winds blow circularly around low-pressure areas and are considered disturbances.
Local winds blow only in some regions due to particular characteristics.
The movement of air masses from their place of origin, when they lose their inertia, will meet other discontinuities or masses called fronts.
Types of Fronts
Cold Front: When a cold air mass moves under a warm air mass at rest or in motion. Characteristics: low thermometer readings, increased pressure, sudden squalls, and abrupt changes.
Warm Front: When a warm air mass is moving faster and behind a cold air mass. Characteristics: gradual temperature decrease, possible fog formation, rainfall of several hours, and continuous drizzle.
Occluded Front: Occurs when there are three air masses, two of which are cold and one warm. This type of front occurs at the final stage of a cyclone.
The Hydrosphere
The hydrosphere is the liquid layer that surrounds our planet, covering almost three-quarters of the surface.
Causes of Currents
Internal causes: Currents produced depend greatly on temperature and salinity. Tsunamis originating from ocean floor earthquakes are caused by huge masses of water projecting violently upwards.
External causes: Drift currents are caused by local winds; these currents are superficial and do not extend to significant depths. Wave motions are surface waves that are movements of seawater.
The Water Cycle
Evaporation depends mainly on the provision of energy from the sun, atmospheric pressure, temperature, and air currents.
Condensation is caused by cooling air saturated with water vapor.
Precipitation is the falling of water from condensation in the clouds, rushing over seas and continents due to gravity.
This process is a continuous cycle with no beginning or end.
Forms of Water Vapor
Dew: Formed by the condensation of water vapor on the Earth’s surface.
Frost: Formed when water vapor condenses into thin ice needles that cover the soil and plants.
Fog: When condensation occurs at ground level or low altitude.