AS Cambridge Geography: Core Knowledge Review | AS剑桥地理：核心知识点梳理

📚 AS Cambridge Geography: Core Knowledge Review | AS剑桥地理：核心知识点梳理

Welcome to this comprehensive review of AS Cambridge Geography. The syllabus is divided into core Physical and Human Geography topics, each demanding a clear grasp of processes, patterns, and case-study applications. This guide summarises the essential concepts you need to master for success in the examination.

欢迎阅读这篇AS剑桥地理全面梳理文章。大纲由核心自然地理和人文地理主题组成，每一个主题都要求清晰掌握过程、模式与案例运用。本指南总结了为在考试中取得成功你必须掌握的关键概念。

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1. The Global Hydrological Cycle | 全球水循环

The global hydrological cycle is a closed system: the total amount of water on Earth remains constant. Water is held in major stores – oceans, ice caps, groundwater, lakes, and the atmosphere – and moves between them through flows such as evaporation, transpiration, precipitation, runoff, and infiltration.

全球水循环是一个封闭系统：地球上的总水量保持不变。水被储存在海洋、冰盖、地下水、湖泊和大气等主要储存库中，并通过蒸发、蒸腾、降水、径流和下渗等流动过程在它们之间移动。

The cycle is driven by solar energy and gravitational potential energy. Within a drainage basin, the system becomes open: inputs (precipitation) enter, stores (interception, soil moisture, channel storage) hold water, and outputs (river discharge, evapotranspiration) leave the basin.

水循环由太阳能和重力势能驱动。在一个流域内部，系统变为开放：输入（降水）进入，储存（截留、土壤水分、河道储存）持水，输出（河流流量、蒸发蒸腾）离开流域。

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2. Drainage Basin Inputs, Stores and Flows | 流域输入、储存与流量

A drainage basin or catchment is the area that collects precipitation and feeds a river system. Precipitation is the primary input; vegetation intercepts some rainfall, reducing throughfall. Storage occurs in lakes, soil, groundwater aquifers, and as channel storage. Key flows include surface runoff, throughflow, percolation, and baseflow.

流域（或集水区）是收集降水并补给河网的区域。降水是主要输入；植被截留部分降雨，减少了穿透雨。储存发生在湖泊、土壤、地下含水层和河道储存中。关键流动包括地表径流、壤中流、渗透和基流。

The water balance is expressed as a simple equation that helps hydrologists assess water availability:

P = Q + E + ΔS

水平衡可通过一个简单方程表达，帮助水文学家评估可用水量：P = Q + E + ΔS，其中P为降水量，Q为径流量，E为蒸发蒸腾量，ΔS为储水量变化。当P > Q+E时储水增加，可能发生饱和与洪涝。

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3. Storm Hydrographs and Runoff Processes | 暴雨流量过程线与径流过程

A storm hydrograph plots river discharge against time during and after a rainfall event. The rising limb shows increasing discharge; the peak discharge is the highest flow; the recession limb shows falling discharge. Lag time is the delay between peak rainfall and peak discharge. Baseflow represents groundwater contribution.

暴雨流量过程线绘制了一次降雨事件期间及之后的流量随时间变化。上升段显示流量增加；洪峰流量为最高流量；退水段显示流量下降。滞时是降雨峰值与洪峰之间的延迟。基流代表地下水的贡献。

Hydrograph shape depends on basin characteristics: small, circular basins with steep slopes and impermeable surfaces produce a short lag time and high peak – a ‘flashy’ response. Vegetation, permeable soils, and gentle slopes increase infiltration and reduce peak discharge.

流量过程线的形状取决于流域特征：坡度陡、不透水面多的小型圆形流域产生短滞时和高洪峰——即“暴涨暴落”响应。植被、透水性土壤和平缓坡度增加下渗，降低洪峰流量。

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4. Fluvial Processes: Erosion, Transport and Deposition | 河流作用：侵蚀、搬运与沉积

River erosion shapes the channel through hydraulic action (force of water), abrasion (sediment scraping the bed), attrition (particle collisions causing breakage), and solution (chemical dissolution). These processes are most effective at high velocity and on less resistant rocks.

河流侵蚀通过水力作用（水流冲击力）、磨蚀（沉积物刮擦河床）、磨损（颗粒碰撞破碎）和溶蚀（化学溶解）塑造河道。这些作用在流速高、岩石抵抗性弱的条件下最为有效。

Transported sediment moves as traction (rolling), saltation (bouncing), suspension (carried within the flow), and solution (dissolved). The Hjulstrom curve illustrates the critical velocities needed for erosion, transportation, and deposition of different particle sizes. Deposition occurs when energy falls, especially at concave banks of meanders or when a river enters a lake or sea.

搬运的泥沙以推移质（滚动）、跃移质（跳跃）、悬移质（在水流中携带）和溶解质的形式运动。Hjulstrom曲线展示了不同粒径颗粒侵蚀、搬运和沉积所需的临界流速。当能量下降时发生沉积，尤其在曲流的凹岸或河流汇入湖泊、海洋处。

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5. Resulting Fluvial Landforms | 河流地貌

In upland valleys, vertical erosion dominates, producing V-shaped valleys, interlocking spurs, waterfalls, and gorges. A waterfall forms where hard rock overlies softer rock; undercutting causes collapse and retreat, leaving a steep-sided gorge downstream.

在上游山谷中，下蚀占主导，形成V形谷、交错山嘴、瀑布和峡谷。瀑布形成于硬岩覆盖软岩之处；淘蚀导致崩塌和后退，在下游留下陡峭的峡谷。

In lowland areas, lateral erosion and deposition create meanders, oxbow lakes, floodplains, and levees. Meanders develop as the thalweg of maximum velocity swings to the outside bend, eroding the bank and depositing on the inside as a point bar. An oxbow lake forms when a meander neck is cut off during a flood.

在下游低地，侧蚀和沉积形成曲流、牛轭湖、泛滥平原和天然堤。曲流的形成是因为最大流速的流谷线偏向凹岸，侵蚀河岸并在凸岸沉积形成点坝。当曲流颈在洪水中被截断时，就形成了牛轭湖。

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6. The Atmospheric Energy Budget and Transfers | 大气能量收支与传递

The Earth’s energy balance involves incoming shortwave solar radiation (insolation) and outgoing longwave terrestrial radiation. The global heat budget is balanced, but at the poles there is a deficit and at the equator a surplus. Ocean currents and atmospheric circulation redistribute heat.

地球的能量平衡涉及入射的短波太阳辐射（日照）和射出的长波地球辐射。全球热量收支是平衡的，但极地存在亏损，赤道存在盈余。洋流和大气环流重新分配热量。

Albedo – the reflectivity of a surface – affects energy absorption. Snow and ice have a high albedo, reflecting much radiation; forests and oceans have a low albedo. The natural greenhouse effect, caused by gases such as CO₂ and water vapour, traps outgoing longwave radiation and warms the lower atmosphere.

反照率——表面的反射能力——影响能量吸收。冰雪具有高反照率，反射大量辐射；森林和海洋反照率低。由CO₂和水蒸气等气体造成的自然温室效应捕获射出的长波辐射，使低层大气变暖。

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7. Global Weather Systems and Climate Types | 全球天气系统与气候类型

The global atmospheric circulation consists of the Hadley, Ferrel, and Polar cells. Ascending air at the Equator creates a low-pressure belt (ITCZ) with heavy rainfall; descending air around 30°N and 30°S forms subtropical high-pressure zones associated with hot deserts.

全球大气环流由哈得莱环流、费雷尔环流和极地环流组成。赤道上升气流形成低压带（热带辐合带），带来大量降水；南北纬30°附近的下沉气流形成副热带高压带，与热荒漠相关。

Mid-latitude depressions develop where warm tropical air meets cold polar air along the polar front. These rotating low-pressure systems bring frontal rainfall and changeable weather. Anticyclones are high-pressure systems with stable, dry conditions. Tropical cyclones are intense low-pressure storms that require sea temperatures above 27°C and form within 5°–20° latitude.

中纬度气旋在暖热带气团与寒冷极地气团沿极锋相遇处发展。这些旋转的低压系统带来锋面雨和多变天气。反气旋是高压系统，带来稳定、干燥的天气。热带气旋是强烈的低压风暴，需要海温高于27°C并形成于纬度5°至20°之间。

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8. Weathering Processes and Types | 风化作用与类型

Weathering is the breakdown of rocks in situ. Physical weathering includes freeze-thaw where water in cracks freezes, expands, and shatters rock, and exfoliation where rocks peel in layers due to pressure release or temperature changes. Chemical weathering involves reactions such as carbonation (acidic rainwater dissolving limestone) and hydrolysis (where feldspar turns into clay).

风化是岩石在原地的分解。物理风化包括冻融作用（裂缝中的水冻结膨胀，使岩石破碎）和剥离作用（因压力释放或温度变化岩石呈层状剥落）。化学风化涉及诸如碳酸化（酸性雨水溶解石灰岩）和水解（长石转变为黏土）等反应。

Biological weathering is caused by plant roots growing into cracks, or by organic acids from decaying vegetation. Climate strongly controls the dominant type: in hot, humid regions chemical weathering is intense; in cold, wet climates freeze-thaw prevails; in arid areas salt weathering can be significant.

生物风化由植物根系生长进入裂缝或腐烂植物释放的有机酸引起。气候强烈控制着主导的风化类型：在湿热地区化学风化强烈；在寒冷湿润气候下冻融作用占主导；在干旱地区盐类风化可能很重要。

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9. Mass Movement and Slope Stability | 块体运动与边坡稳定性

Mass movement is the downslope transfer of soil and rock under gravity. It is classified by speed and water content: rockfalls are rapid, dry movements on steep cliffs; landslides and rotational slumps occur along failure planes; mudflows and earthflows involve saturated, fast-moving material; soil creep is the slow, imperceptible movement of soil particles.

块体运动是土壤和岩石在重力作用下的下坡移动。根据速度与含水量分类：岩崩是陡崖上快速、干燥的运动；滑坡和旋转滑塌沿破坏面发生；泥流和土流涉及饱和快速运动的物质；土壤蠕动是土壤颗粒缓慢、难以察觉的运动。

Slope failure is triggered by factors such as heavy or prolonged rainfall, undercutting by streams or human activity, removal of vegetation, and loading of the slope. Slope angle and geology (e.g., layers of permeable rock over impermeable beds) increase the risk of mass movement.

边坡失稳由以下因素触发：长时间或高强度降雨、河流或人类活动的掏蚀、植被清除以及边坡加载。边坡角度和地质条件（例如透水岩层覆盖在不透水层之上）增加块体运动的风险。

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10. Population Dynamics and the DTM | 人口动态与人口转变模型

Population change depends on crude birth rate (CBR), crude death rate (CDR), and net migration. Natural increase = CBR − CDR. The Demographic Transition Model (DTM) describes how birth and death rates change as countries develop. Stage 1 has high fluctuating rates; Stage 2 sees falling death rates; Stage 3 shows falling birth rates; Stage 4 has low, stable rates; some models add Stage 5 with declining population.

人口变化取决于粗出生率（CBR）、粗死亡率（CDR）和净迁移量。自然增长 = CBR − CDR。人口转变模型（DTM）描述了出生率和死亡率如何随着国家发展而变化。第一阶段为高位波动；第二阶段死亡率下降；第三阶段出生率下降；第四阶段低位稳定；有些模型增加了人口下降的第五阶段。

Population pyramids illustrate age–sex structure. A wide base with a narrow top indicates high fertility and youthful population (Stage 1-2). A more rectangular shape reflects a balanced age structure with low fertility and low mortality (Stage 4). Dependency ratios measure the proportion of young and old dependents relative to the working-age population.

人口金字塔展示年龄—性别结构。底部宽、顶部窄表明高生育率和年轻人口（阶段1-2）。更接近矩形形状反映低生育率和低死亡率下平衡的年龄结构（阶段4）。抚养比衡量受抚养的年轻人和老年人与劳动年龄人口的比例。

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11. Migration: Causes and Consequences | 迁移：原因与后果

Migration is the permanent or semi-permanent movement of people across a boundary. Push factors are negative conditions in the origin (unemployment, war, famine, natural disasters), while pull factors are perceived advantages in the destination (job opportunities, safety, better services). Lee’s model of migration emphasises intervening obstacles, such as distance, cost, and immigration policies.

迁移是人口跨越边界的永久性或半永久性移动。推动因素是来源地的负面条件（失业、战争、饥荒、自然灾害），拉动因素是目的地的感知优势（就业机会、安全、更优质服务）。Lee的迁移模型强调中间障碍，如距离、成本和移民政策。

Migration has significant consequences: for origin areas, remittances can boost household income but brain drain may hamper development. For destinations, migration can fill labour shortages and create cultural diversity, but it may also strain housing and public services. Forced migration, such as refugees fleeing conflict, raises complex humanitarian issues.

迁移具有重大后果：对来源地而言，汇款可提高家庭收入但人才流失可能阻碍发展。对目的地来说，迁移能填补劳动力短缺并创造文化多样性，但也可能给住房和公共服务带来压力。被迫迁移，如逃离冲突的难民，则引发复杂的人道主义问题。

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12. Settlement Patterns and Urban Morphology | 聚落模式与城市形态

Rural settlement patterns are influenced by relief, water supply, and farming systems. Dispersed settlements occur where farmland is scattered; nucleated settlements form at crossroads or defensive sites; linear settlements develop along rivers, roads, or coastlines. The settlement hierarchy ranks settlements from isolated dwellings to conurbations based on population size and service range. Threshold population is the minimum number of people needed to support a service; high-order services require a larger threshold and wider sphere of influence.

乡村聚落模式受地形、水源和农耕系统影响。分散型聚落出现在农田分散的地区；聚集型聚落形成于十字路口或防御性位置；线型聚落沿河流、道路或海岸线发展。聚落等级体系按照人口规模和服务范围将聚落从孤立住宅排列到集合城市。门槛人口是支撑一项服务所需的最低人数；高阶服务需要更大的门槛和更广的影响范围。

Urban land-use

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