Our natural world (OCR)

Global Circulation System

A complex pattern of atmospheric movements that distribute heat and moisture around the Earth, significantly influencing the planet's climate and weather patterns.

Hadley Cell

(Largest cell) the low-latitude overturning circulations that have air rising at the equator and air sinking at roughly 30° latitude.

Ferrel Cell

(Middle cells) its circulation are complicated by a return flow of air at high altitudes towards the tropics, where it joins sinking air from the Hadley cell.

Polar Cell

(Smallest and weakest cell) which extends from between 60 and 70 degrees north and south.

High Pressure

A condition of the atmosphere in which the pressure is above average.

Low Pressure

Characterized by or exhibiting atmospheric pressure that is below average.

Tropical Storms

Distribution: These storms thrive in warm ocean waters (typically above 26°C or 80°F) near the equator.

Frequency:  The global number of tropical storms formed each year varies, but averages around 80-100. 

Droughts

Distribution: Can occur anywhere globally.

Frequency: Can last weeks, months, or even years. Their frequency varies depending on the region's climate. 

Causes of Extreme Weather Conditions Associated with Tropical Storm

1. Warm Ocean Temperatures

2. Low Atmospheric Pressure

3. Coriolis Effect

4. Minimal Wind Shear

5. Moisture Availability

Warm Ocean Temperatures

Fuels tropical storms as warm, moist air rises from the ocean surface, it cools and condenses, releasing energy that powers the storm.

Low Atmospheric Pressure

A key ingredient to tropical storms as air naturally flows from high pressure to low pressure.

Coriolis Effect

Deflects winds circulating in the storm system.

Minimal Wind Shear

Allows the storm to develop a more organized structure, concentrating its energy and strengthening it.

Moisture Availability

More available moisture adds more energy to release when it condense which fuels the storm intensity.

El Niño

The above-average sea-surface temperatures that periodically develop across the east-central equatorial Pacific.

Triggers: Shifted Jet Stream, Suppressed Convection, and Reduced Rainfall

La Niña

The periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific.

Triggers: Intensified Trade Winds, Altered Atmospheric Circulation, and Disrupted Precipitation Patterns

Layers of the Earth

Crust, Mantle, Inner Core, and Outer Core

Crust

The outermost, thin, solid layer (around 30-70 km thick). It is the earth’s skin with two main types;

Continental Crust

Thicker and less dense, made up mostly of granite and other rocks. (Continents)

Oceanic Crust

Thinner and denser, composed mainly of basalt. (Ocean Floors)

Mantle

The thickest layer, made up of hot, solid rock (about 2800 km thick).

Upper Mantle

More rigid due to cooler temperatures in which its solid portion, along with the crust, forms the lithosphere, which is broken into tectonic plates.

Outer Core

Liquid layer made of super hot molten iron and nickel (about 2200 km thick) where movement within this layer is crucial to plate tectonics.

Inner Core

Solid sphere of iron and nickel at the Earth's center (about 1200 km radius).

Plate Tectonics

A theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates which move slowly over the underlying mantle.

Convection Currents

A process that involves the movement of energy from one place to another

Earthquakes

Occurs when sudden movement or stress release happens along plate boundaries.

Shallow-Focus Earthquakes

The most common and destructive earthquakes where the movement of tectonic plates creates stress and strain on the rocks along plate boundaries.

Deep-Focus Earthquakes

Less frequent but can be powerful when the immense pressure and heat at these depths cause the rock to deform in a ductile (bendable) way, leading to sudden breaks and deeper earthquakes.

Volcanoes

Form at plate boundaries where molten rock (magma) from the mantle erupts onto the surface.

Shield Volcanoes

Broad, gently sloping volcanoes with a dome-like shape.

Composite Volcanoes

( or stratovolcanoes) are steep-sided, conical mountains with alternating layers of ash, lava, and rock debris that erupts with a more explosive style/

Mountain ranges

Created when plates collide and push against each other, forcing rock layers to buckle and rise.

Constructive Plate Boundaries (Divergent Boundaries)

Plates that diverge or pull away from each other.

Destructive Plate Boundaries (Convergent Boundaries)

One plate dives (subducts) beneath another.

Oceanic-Continental Convergence

Creates mountain ranges on the continent and volcanic arcs offshore.

Oceanic-Oceanic Convergence

Forms deep ocean trenches and volcanic island arcs.

Conservative Plate Boundaries (Transform Boundaries)

Plates that slide horizontally in opposite directions.

Collision Zone Boundaries

A special case of convergent boundaries occurs when two continental plates collide head-on.

Hotspots

Stationary plumes of hot molten rock rising from deep within the mantle, typically not located at plate boundaries.

Seismic-Resistant Construction

Advancements in engineering allow for buildings designed to withstand strong shaking. 

Smart Building Materials

Emerging materials like self-healing concrete that can repair cracks or shape-memory alloys that return to their original form after deformation offer promising possibilities for earthquake-resistant infrastructure.

Earthquake Monitoring Networks

Densely distributed seismic sensor networks can detect subtle changes in ground movement that might precede earthquakes. 

AI-Powered Prediction Models

Artificial intelligence can analyze vast amounts of seismic data to identify patterns and correlations that might lead to improved earthquake prediction capabilities.

Early Warning Systems for Public Alerts

Advanced communication technologies can be used to disseminate real-time earthquake alerts to the public via smartphones, loudspeakers, and other channels.

Pattern of Climate Change

Glacial Period, Interglacial Period, and the Current Interglacial

Glacial Periods (Ice Ages)

Lasted for much longer durations, typically tens of thousands of years where colder global temperatures prevailed with drier conditions in many regions.

Interglacial Periods

Relatively warm intervals lasting several thousand years where global temperatures were warmer, with increased precipitation and vegetation growth in many areas.

The Current Interglacial

known as the Holocene epoch, which began about 11,700 years ago.

High Reliability Evidence

Global Temperature Data and Ice Cores

Moderate Reliability Evidence

Sea Ice Positions

Low Reliability Evidence 

Paintings and Diaries

Sunspots and Solar Activity

Suggests that variations in sunspot activity might influence Earth's climate.

 Volcanic Eruptions

Can inject large amounts of ash, dust, and sulfur dioxide aerosols into the stratosphere which impact global temperatures for a few years.

Milankovitch Cycles

Describe variations in Earth's orbit around the Sun and the tilt of its axis where orbital changes influence the amount of solar radiation reaching different parts of Earth at different times, impacting global temperatures over long timescales.

The Greenhouse Effect

A natural process that warms the Earth’s surface and acts like a giant blanket which traps some of the Sun's heat and preventing Earth from becoming a cold, desolate rock.

Human Activities that Influence The Greenhouse Effect

Burning Fossil Fuels, Deforestation, Industrial Processes, and Agricultural Practices

Consequences of the Enhanced Greenhouse Effect

Rising Global Temperatures, Increased Extreme Weather Events, Sea Level Rise, Ocean Acidification, and Disruptions to Ecosystems

Landscape

All the visible features of an area of countryside or land, often considered in terms of their aesthetic appeal.

Natural Landscapes

Primarily shaped by natural processes over long timescales.

Built Landscapes

Dominated by human-made features.

Uplands

Characterized by higher elevations, steeper slopes, and harsher weather conditions compared to lowlands.

Lowlands

Characterized by fertile soils, making them ideal for agriculture and supporting a higher population density.

Glaciated Landscapes

Recognizable by features like U-shaped valleys carved by glaciers, corries (circular hollows), and pyramidal peaks.

Weathering

The breakdown and alteration of rocks and minerals at the Earth's surface, preparing them for erosion.

Mechanical Weathering

Physical processes break down rocks into smaller fragments without altering their chemical composition.

Chemical Weathering

Chemical reactions transform rocks and minerals, changing their composition.

Biological Weathering

Plants, animals, and microorganisms contribute to rock breakdown.

Mass Movement

Downslope movement of rock, soil, and other debris under the influence of gravity.

Slides

Rapid movement of large masses of rock or debris down a slope.

Slumps

Downward and rotational movement of a block of rock or soil along a curved surface.

Earthflows

Slow, continuous movement of saturated soil down a slope.

Abrasion

Rocks and particles grind against each other, causing wear and tear.

Hydraulic Action

Moving water (waves, rivers) exerts force, breaking off rock fragments.

Attrition

Particles collide and break into smaller pieces as they are transported.

Solution

Water dissolves some minerals, carrying them away in solution.

Transport

The movement of eroded particles by wind, water, glaciers, or gravity.

Traction

Particles are dragged or rolled along the ground by wind or water.

Saltation

Particles bounce and skip along the surface, propelled by wind or water.

Suspension

Fine particles are carried within a fluid (air or water) for extended periods.

Deposition

The accumulation of transported sediment in new locations which occurs when the agent carrying the particles loses energy and can no longer transport them.

Sedimentary rocks

Layers of deposited sediments get compacted and cemented over time, forming sedimentary rocks like sandstone and shale.

Alluvial plains

Floodplains formed by the deposition of sediments by rivers.

Windblown deposits

It is when sand dunes are formed by the accumulation of wind-blown sand.

Glacial deposits

Till (unsorted glacial debris) and moraines (deposits left by glaciers) are formed by the deposition of material transported by glaciers.

Erosion by Waves

The erosive power of waves depends on factors like wave height, wave frequency, and the type of rock the waves are hitting.

Erosion

The geological process in which earthen materials are worn away and transported by natural forces such as wind or water.

Headlands

Areas of high land that jut out into the sea.

Bays

Curved indentations in the coastline between headlands.

Differential Erosion

A geological process in which different rock layers or materials are eroded at varying rates due to differences in their resistance to weathering and erosion.

Caves

Waves constantly batter the coast, and over time, cracks and weaknesses in the rock are exploited.

Arches

As caves grow deeper, the roof thins and weakens. Eventually, the roof collapses, leaving behind a natural arch.  

Stack

A tall, isolated pillar of rock standing offshore.

Beach

An accumulation of loose sediment (sand, pebbles, or cobbles) deposited by waves along the coast.

Spit

Are elongated narrow strips of land that project out from the coast at an angle.

Waterfall 

Occurs where the river encounters a sudden drop in elevation, often due to differences in rock hardness.

Gorge

Typically deep and narrow, with exposed rock faces showcasing the power of erosion.

V-shaped Valleys

Deep, narrow valleys with steep sides that form in the upper course of a river.

Floodplain

A flat, low-lying area bordering the river channel.

Meander

As a river flows across a floodplain, it may develop bends or curves called meanders.