Geography Lecture Notes PDF

Lecture Notes Energy and Radiation: Energy: ○ Definition: A measure of the ability or capacity of a system to do work. ○ Key Concepts Energy cannot be created or destroyed (Conservation of Energy). It can change form and be transfer...

Lecture Notes Energy and Radiation: Energy: ○ Definition: A measure of the ability or capacity of a system to do work. ○ Key Concepts Energy cannot be created or destroyed (Conservation of Energy). It can change form and be transferred from one location to another. Forms: The focus is on Radiant Energy—energy that travels in the form of electromagnetic waves. Solar Output: ○ Solar Wind: Clouds of charged (ionized) gases emitted from the sun’s surface. Auroras: Light displays near the poles (e.g., Northern Lights). Communications Disruptions: Interference with satellite signals and radio communication. Possible links to weather patterns. ○ Electromagnetic Radiation Energy that travels through space or material as a disturbance in electric and magnetic fields. Can be modeled using waveforms. Electromagnetic Radiation: ○ Electromagnetic Spectrum Ranges from Gamma Rays (shortest wavelength) to Radio Waves (longest wavelength). The important measurement here is wavelength, typically measured in microns (µm). Figure 2.5 in your text visualizes the spectrum. ○ Types of Electromagnetic Radiation Gamma Rays X-Rays Ultraviolet (UV) Infrared (IR) Microwaves Radio Waves ○ Wavelength & Frequency These properties are key to understanding the nature of electromagnetic radiation. Longer wavelengths have lower frequencies and vice versa.  Radiation Principles: ○ Stefan-Boltzmann Law All objects above absolute zero (0 K = -273.15°C) emit radiation. Key Principle: The higher an object's temperature, the more radiation it emits per unit of surface area. ○ Net Radiation The balance between incoming and outgoing radiation at Earth's surface is critical in determining the climate and temperature. Atmospheric Processes: Lapse Rates: ○ SALR (Saturated Adiabatic Lapse Rates) ○ MAR (Moist Adiabatic Lapse) Rate varies with temp. and moisture content (RH = 100%) parcel of air cools with heat. Typical range 2 degrees Celsius to 9 degrees Celsius per KM. Rate at which a dry (RH < 100%) parcel of air cools with height. DAR (or DALR) is 10 degrees Celsius per KM. DAR (Dry Adiabatic Lapse Rate) Stability Conditions: Conditions can become stable, unstable, or conditionally unstable which is specific. Stable is Unstable is Conditionally unstable Air Masses and Fronts: ○ Air masses are defined as a large body of air with relatively uniform temperature and humidity characteristics. They are classified based on their source region: Polar (P): Cold air masses Tropical (T): Warm air masses Maritime (m): Moist air masses Continental (c): Dry air masses ○ A front is the boundary of two different air masses. They are split into two different types of fronts: Cold Front: A cold air mass advances and replaces a warm air mass. Characteristics: Steep slope, rapid movement, cumulonimbus clouds, thunderstorms, heavy rain or snow. Warm Front: A warm air mass advances and replaces a cold air mass. Characteristics: Gentle slope, slow movement, stratiform clouds, steady rain or drizzle. Stationary Front: Two air masses meet but neither advances.  Characteristics: Little movement, persistent cloudiness and precipitation. Weather Elements: ○ Temperature: Measures the degree of hotness or coldness of an object or substance. ○ Humidity: The amount of water vapor in the air. Relative Humidity: The ratio of the actual amount of water vapor in the air to the maximum amount of water vapor the air can hold at a given temperature. ○ Pressure: The force exerted by the atmosphere on a unit area of Earth's surface. ○ Clouds: Visible masses of condensed water vapor floating in the atmosphere. Types: Cirrus, cumulus, stratus, and their combinations. ○ Precipitation: Any form of water that falls from the atmosphere to Earth's surface, such as rain, snow, sleet, or hail. ○ Wind: The horizontal movement of air from high-pressure to low-pressure areas. Climate and Climate Change: Climate Systems and Processes: ○ Climate is the long-term average weather conditions of a particular region. It's influenced by various factors, including solar radiation, atmospheric composition, ocean currents, and topography. ○ Greenhouse Effect: Natural Greenhouse Effect: A natural process that warms the Earth's surface. Enhanced Greenhouse Effect: Human activities, such as burning fossil fuels, release greenhouse gases into the atmosphere, trapping more heat and leading to global warming. ○ Greenhouse Gases: Carbon Dioxide (CO2): The primary greenhouse gas, primarily from burning fossil fuels. Methane (CH4): A potent greenhouse gas emitted from agriculture, waste decomposition, and fossil fuel production. Nitrous Oxide (N2O): A greenhouse gas emitted from agricultural activities and industrial processes. Fluorinated Gases: Human-made gases used in various industries, including refrigerants and aerosols. Climate Change Impacts: ○ Rising Global Temperatures: Leading to heatwaves, altered precipitation patterns, and more extreme weather events. ○ Sea-Level Rise: Caused by thermal expansion of water and melting glaciers and ice sheets, leading to coastal flooding and erosion.  ○ Ocean Acidification: Increased CO2 absorption by oceans, impacting marine ecosystems and biodiversity. ○ Extreme Weather Events: More frequent and intense hurricanes, droughts, floods, and wildfires. Climate Change Mitigation and Adaptation: Mitigation: Reducing greenhouse gas emissions to limit climate change. ○ Transitioning to Renewable Energy: Solar, wind, hydro, and geothermal power. ○ Improving Energy Efficiency: Reducing energy consumption in buildings and transportation. ○ Carbon Capture and Storage (CCS): Capturing CO2 emissions and storing them underground. ○ Afforestation and Reforestation: Planting trees to absorb CO2. Adaptation: Adjusting to the impacts of climate change. ○ Infrastructure Development: Building resilient infrastructure to withstand extreme weather events. ○ Coastal Protection: Implementing measures to protect coastal communities from sea-level rise. ○ Water Resource Management: Efficient water use and drought management. ○ Agricultural Adaptation: Developing climate-resilient crops and farming practices. International Agreements: ○ Paris Agreement: A global agreement to limit global warming to well below 2 degrees Celsius above pre-industrial levels. ○ Kyoto Protocol: An international treaty that commits countries to reduce greenhouse gas emissions. Geomorphology: Fluvial Processes: involve the work of running water, shaping the Earth's surface through erosion, transportation, and deposition. Key concepts include: ○ Stream Channel Forms: The shape of a stream channel can vary, influenced by factors like slope, discharge, and sediment load. Common forms include straight, meandering, and braided channels. ○ River Systems: A network of interconnected streams and rivers, including tributaries and main channels. ○ Fluvial Landforms: Meanders: Curved channels formed by lateral erosion and deposition. Meandering landorms consist of the following: Floodplains: a flat area of land adjacent to a stream or river that is subject to periodic flooding. formed by the deposition of sediments, when the river overflows its banks during high flow  events. Characterized as broad, flat land that's often rich in nutrients which is good for farming. Oxbow Lakes: Defined as a crescent-shaped body of water that forms when a meander of a river is cut off from the main channel by either erosion or sediment deposition. Happens when a meandering river creates a shark curve which then gets cut off as the two high flow points on each bend merge. Cut Off Channels: Defined as a new, straighter river path formed when a meandering river erodes through a narrow neck of land, bypassing the curve. can lead to the abandonment of the meandering loop and leaving an oxbow lake behind. Levees: Defined as a naturel or artificial embarkments that run parallels to a river or stream, formed by sediment from floodwaters. Provides protection from overflowing onto surfaces. Meander Scars: Defined as remnants of old meanders that have been abandoned by a river. They appear as crescent shaped depressions or basins in the landscape where a former river channel one was. Backswamps: Backswamps are low-lying, wet areas that are typically found behind levees or floodplains. These areas are subject to periodic flooding and are often poorly drained. They can be rich in organic material and support swamp vegetation. Scroll bars: Scroll bars are a series of ridge-like landforms found on the inside curves of meandering rivers. These are formed by sediment deposition, typically in a series of alternating light and dark bands, as the river meanders and deposits sediment on the inner bends. Terraces: Terraces are step-like landforms that represent former riverbeds or floodplains. They are created when a river cuts down into its own floodplain, often due to changes in climate or tectonic uplift, leaving behind a series of flat or gently sloping surfaces at different elevations. Braided Streams: a stream of a braided style of flow with pockets of sediments everywhere. consists of the following: multiple channels numerous bars and islands steep valley gradient coarse sediments high width to depth ratio These streams occur with these conditions: Stream banks are erodible & non-cohesive Bedload comprises a relatively high % of total sediment load  Discharge is flashy (variable) they'll often conclude into floodplains, bars and channels, and terraces. Weathering Processes: ○ Geomorphology is defined as the study of landforms and landscapes. ○ The two different types of process are the following: Endogenic Process: within the earth like a volcano or earthquake. Exogenic Process: on earths surface including weathering, mass wasting, fluvial, and glacial. ○ weathering process includes: physical changes chemical changes biological changes ex. a rock heating and exanding ○ Chemical Weathering Process: defined as a chemical decomposition of mineral materials. Can be a solution to it is dissassociation of a mineral into its constituet ions in the prescence of water ex. dissolving salt Hydrolysis: defined as a chemical reaction of a mineral with water to form new minerals and dissolved components. Oxidation: defined as a reaction between dissolved oxygen in water and a mineral forming oxides (i.e. iron oxide) In general, chemical weathering process is most affective when: high temp low pH under moist conditions Materials will form stronger than the origional substance. Mass Movement: defined as mass moving down a slope, being rock or sand down a mountainside ○ what influences the slope's stability is: material gradiant moisture content ○ It will slide as one unit down the slope given lower moisture content. ○ The flow will be more oriented towards higher moisture content. Glacial Processes: defined as massive bodies of ice, are powerful agents of erosion and deposition, shaping the Earth's landscape over millennia. ○ Glacial Formation Accumulation Zone: The upper part of a glacier where snow accumulates and compacts over time. Ablation Zone: The lower part of a glacier where ice melts or sublimates, leading to mass loss.  Equilibrium Line: The boundary between the accumulation and ablation zones. ○ Glacial Erosion Plucking: As glaciers move, they freeze onto rock fragments and lift them out of the bedrock. Abrasion: Rock fragments embedded in the ice scour the bedrock, creating striations and polishing the surface. ○ Depositional Landforms Moraines: Ridges of till (unsorted glacial sediment) deposited by glaciers. Terminal Moraine: A ridge of till marking the farthest advance of a glacier. Lateral Moraine: A ridge of till deposited along the sides of a glacier. Medial Moraine: A ridge of till formed by the merging of two lateral moraines. Outwash Plains: Flat, often sandy plains formed by meltwater streams flowing from the glacier's edge. Kettle Lakes: Depressions formed by the melting of buried blocks of ice. Drumlins: Smooth, elongated hills formed by glacial till. Eskers: Long, winding ridges of sand and gravel deposited by meltwater streams flowing within or beneath the glacier.