Understanding Climate and its Controls

• Climate refers to long-term atmospheric changes.
• These changes occur over extended periods.
• Natural patterns influence climate.
• Climate involves temperature and precipitation frequency.
• Weather is the short-term atmospheric condition, including temperature and rainfall patterns, which changes daily.

Climate Controls

• These are conditions that affect temperature and rainfall patterns in an area:
• Latitude: distance in degrees from the equator
• Altitude: height above sea level
• Global Wind Circulation: system of winds transporting heat
• Topography: surface features
• Bodies of Water: significant water accumulation areas
• Vegetation: plants in a particular area

Latitude

• Latitude measures the distance in degrees from the equator.
• The equator is an imaginary horizontal line dividing the earth.
• Increasing distance from the equator (higher latitude) correlates with decreasing temperature, and vice versa.
• Equatorial regions receive the greatest annual precipitation.
• Tropical Zones: 23.5 degrees north and south
• Temperate Zones: 23.5 to 66.5 degrees, experience four seasons
• Polar Zones: 66.5 to 90 degrees north and south

Altitude

• Altitude is the height of a place above sea level.
• Higher altitude means lower average yearly temperature due to less gas to absorb heat.

Global Wind Circulation

• This is a worldwide system of winds transporting heat from tropical latitudes
• Polar Cell: colder wind temperature, in the polar zone
• Ferrel Cell: moderate wind temperature, in temperate zones
• Hadley Cell: hotter wind temperature, in the tropical zone
• Wind cells balance temperature differences through convection patterns.
• Warm air rises, and cold air sinks.
• Amihan carries cold air from the northern Philippines.
• Habagat carries air from the southwest, bringing moisture.

Topography

• Topography refers to the features on the Earth's surface.
• Windward sides of mountains are rainy, while leeward sides are dry.
• Wet/Windward sides receive high precipitation.
• Dry sides tend to become deserts due to low precipitation.
• The Sierra Madre exemplifies this effect in the Philippines.

Bodies of Water

• Bodies of water significantly accumulate water on the Earth's surface
• Warm air holds more moisture.
• Rainfall is heavier near warmer parts of the ocean.

Vegetation

• Vegetation includes the plants in a particular area
• Plants absorb and release energy from the sun
• Vegetation affects temperature and precipitation through transpiration.
• Lack of vegetation results in higher temperatures due to unabsorbed heat, contributing to greenhouse gases.

Global Warming and Climate Change

• Global Warming is a marked increase in ambient temperature due to the release of greenhouse gases.
• Climate Change is a long-range change in temperature, wind, and precipitation patterns.

Volcanoes

• Volcanoes are weak spots in the Earth's crust where magma moves onto the surface.
• They release temperature/pressure from inside the earth.
• Earth has four layers: inner core (solid, highest temperature), outer core (liquid), mantle, and crust.
• Temperature decreases from the inner core to the crust.
• The mantle is the thickest layer and the origin of magma.
• Formation occurs in the asthenosphere, a layer in the mantle with high temperature and pressure, melting rocks.
• Convection balances temperature differences.
• Earthquakes & Volcanic Eruptions are signs of movement in the mantle -> convection movement.
• They are formed at the Pacific Ring of Fire (plate boundaries) or hot spots.
• Hot spot: an area under the mantle plume where magma is hotter.
• Volcanoes farther from a hotspot are older, with fewer eruptions.
• Active volcanoes are directly over hotspots.
• Volcanoes exist on land and in water.

Main Features of a Volcano

• Magma is molten material inside the volcano.
• Lava is molten material that has reached the Earth’s surface.
• Magma Chamber is a reservoir of magma inside the earth.
• Crater is a bowl-shaped basin on top of a volcano.
• Main Vent is the main outlet for magma.
• Secondary Vent is a smaller outlet for magma.

Classification of Volcanoes by Activity

• Active volcanoes have erupted within the last 10,000 years.
• Potentially Active (Dormant) volcanoes have no eruption record in 10,000 years but could erupt.
• Inactive (Extinct) volcanoes have not erupted in 10,000 years and are not expected to erupt again.

Types of Volcanic Eruptions

• Effusive Eruption: Lava flows out without much airborne volcanic material.
• Explosive Eruption: Magma and materials are expelled with gaseous substances.

Types of Lava Flow

• Aa flow is blocky, rough, and viscous, moving slower.
• Pahoehoe flow is fluid, smooth, and thin, flowing in broad sheets at higher temperatures.

Natures of Volcanic Eruption

• Dissolved gases in magma form bubbles that can cause explosive eruptions.
• Gases include water vapor, carbon dioxide, and sulfur.
• Viscosity is a liquid's resistance to flow.
• Temperature inversely affects viscosity.
• Higher temperature leads to lower viscosity (easier flow).
• Lower temperature leads to higher viscosity.
• Basaltic/Mafic magma has the lowest silica content, is thin and fluid, and forms flat, broad volcanoes.
• Rhyolitic/Felsic magma has 70% silica content, is thick and stiff, and forms tall volcanoes.
• Andesitic magma is intermediate in composition and properties.

Classification of Volcanoes by Structure

• Shield Volcanoes: broad dome structure, not high, but cover large areas, formed from fluid basaltic magma (e.g., Mauna Loa).
• Cinder Cones: smallest, steep slope, cone-shaped, built from lava fragments (e.g., Taal Volcano).
• Composite Volcanoes: tall, symmetrical, cone-shaped with multiple layers (stratovolcanoes).

Benefits of Volcanoes

• Volcanoes create fertile land and raw materials.
• They provide renewable energy from geothermal power plants.