GEOG 203 Exam #3

Topics 8-12

Evaporation and precipitation

Constantly circulates water through: atmosphere, hydrosphere, lithosphere, and biosphere

More than ___ of water is found in the ocean

97%

More than ____ of the world is the ocean

70%

Hydrologic Cycle:

• Over land

Precipitation > evaporation + transpiration

Hydrologic Cycle:

• Over water

Evaporation > precipitation

Hydrologic Cycle:

• Advection

• Each year land gains 8% of water while oceans lose 8% of water

Evaporation

• Open water

• Soil 

• Plant Surfaces 

Transpiration 

• Plants release water 

  • Evaporates

• Cooling Mechanism

ACTET

Actual Evapotranspiration

POTET

Potential Evapotranspiration

Potential Evapotranspiration

“Amount of water that would evaporate/transpire under optimum moisture conditions when there is adequate precipitation and soul moisture supply”

• Maximum amount of water that could potentially evaporate/transpire under optimum conditions

POTET is determined by 

Atmospheric energy: 

• Latitude

• Temperature

= DEMAND

Precipitation (PRECIP) = ?

Supply

Water Budget Inputs

Precipitation

Water Budget Expenditures

• Evaporation from land and water

• Runoff to streams

• Transpiration from plants 

Infiltration & Percolation

     H2O is available in the middle

← Field Capacity — Wilting Point →

PRECIP >

Surplus

ACTET > PRECIP

Soil-Moisture Utilization

PRECIP > POTET

Soil-Moisture Recharge

POTET > ACTET

Deficit

Drought

Less precipitation than expected or needed

• Compared to climate normals 

• demand exceeds supply

Naturally recurring feature of the global climate system

4 Main Types of Drought

• Meteorological

• Agricultural

• Hydrological

• Socioeconomic

Groundwater

• Largest potential water source

• found in aquifers

• linked to surface supplies → recharge

Weather

Short-term conditions

Climate

refers to the average weather conditions over a long period of time

Principle Temperature Controls

• Latitude

• altitude

• cloud cover

• land/water

4 Precipitation mechanisms

• Convergent lifting 

• Convectional Lifting 

• Orographic Lifting 

• Frontal Lifting 

Equatorial region

• Convergence of the trade winds 

• Lots of convection 

• Ample moisture available

Subtropics

• sinking air 

• Hadley cells produce high pressure

Mountain Regions

• Wet climate on the windward side 

• Dry climate on the leeward side

Continental interiors 

• far away from moisture sources 

Types if temporal precipitation patterns

• Uniform → all months get approximately equal amounts

• Summer max 

• Winter max 

• Double maxima 

Climate Classifications:

1. Genetic Classifications

• Based on forcing factors: 

  • Net Radiation

  • Thermal Regime

  • Air masses 

Climate Classifications:

2. Empirical Classifications

• Based on actual data

  • temperature

  • precipitation

Climate Regions of the world

1. Tropical 

2. Mesothermal (Mild winter) 

3. Microthermal (Cold winter) 

4. Polar & Highland 

5. Desert

Tropical Climates

• Between the tropic of Cancer and tropic of Capricorn

• Consistent insolation and daylength

• Rainfall determined by ICTZ

• Warm oceans, unstable atmosphere

Tropical Climate Subtypes

1. Tropical Rainforest

2. Tropical Monsoon

3. Tropical Savanna

Mesothermal Climates

• Midlatitude mild winter 

  • Warm & temperate 

  • True seasonality

• Regions Dominated by: 

  • Changing air masses (mT, cP) 

  • Midlatitude wave cyclones 

  • West Coast/East Coast differences 

  • Decreasing temperatures (Poleward) 

Mesothermal Climate subtypes

• Humid-subtropical 

• Marine west coast 

• Mediterranean

Microthermal Climates

• In middle and high latitudes

• General Characteristics

  • Temperatures: 

    • Winters: Cold and long 

    • Summers: Hot (south) to cool (north) 

  • Moisture: 

    • Year-round 

    • Small monsoon region in Asia = dry winters

• No Microthermal climates in the Southern Hemisphere

Microthermal Climate Subtypes

Humid Continental

• Hot Summer (U.S. Midwest and Northeast) 

• Mild Summer 

Subarctic 

• Cool summer (boreal forest) 

• Very cold winter (Siberia) 

Polar and highland climates

General Characteristics

• no true summer 

• Temperature

  • Even during 24 hours of daylight, T < 10 C (50 F)

  • Too cold for trees 

• Moisture: 

  • Extremely dry —”Frozen deserts” 

Polar and highland subtypes

• Tundra

  • Summers barely above freezing 

  • permafrost 

• Ice Cap 

  • Below freezing year-round 

  • Greenland & Antarctica 

Desert (Arid and Semiarid) Climates

• Most extensive climate region

• moisture demand (POTET) > supply (PRECIP) 

  • Always deficit 

• Caused by: 

  • Subtropical highs 

  • stabilizing ocean currents 

  • rain shadow effects 

  • great distance to water 

____ → warmest year (since 1880)

2024

Average global temperatures have increased by about ___ since 1880

1.3 degrees C or (2.3 F) 

Natural Mechanisms

• Solar output

• Earth-sun relationships

• Movement of continents 

• Atmospheric variability 

• Volcanic activity 

Human mechanisms

• Land use/ land cover charge 

• Atmospheric chemistry 

Earth’s orbit

eccentricity

Axial parallelism

Precession

Fixed tilt

obliquity

Temperature change is caused by

Both natural and human-caused

Earth’s 4 sphere’s

Atmosphere

Hydrosphere

Lithosphere

Biosphere

Food Chain 

• Producers 

• Consumers 

  • Primary 

  • Secondary

  • Tertiary

• Decomposers

Biomes are mainly determined by

Temperature and precipitation and their seasonal distribution

Limiting Factors

Environmental characteristics that determine species distribution and size

• Microclimatic

  • Temp, precipitation, wind, sunlight, etc.

• Geomorphic 

  • slope, aspect

• Edaphic

  • soil type

• Element Cycling

  • Availability of carbon, nitrogen, etc.

Microclimatic Controls

determined by site-specific factors

Geomorphic controls

Slope = steepness

Aspect = orientation (N, S, E, W)

Important controls of temperature and moisture 

Ecosystem

a self-sustaining association of plants and animals and their physical environment 

Dynamic equilibrium 

Not Static

Succession

older, more simple communities are replaced by newer, more complex communities → Terrestrial & Aquatic

Terrestrial Succession

Competition for sunlight

Terrestrial Primary Succession

Beginning of a new ecosystem

Terrestrial Secondary Succession

Starts from the remains of previous ecosystem

Aquatic Succession

Competition

Aquatic Succession Stages

1. Oligotrophic

• Low nutrients 

2. Mesotrophic

• Medium nutrients 

3. Eutrophic 

• High nutrients

(as it goes through the stages, sediments and organics increase) 

Earth congealed from a 

Nebula

• dust, gas, (icy) comets 

Concentric circles 

• Core = ?

• Crust = ? 

Heaviest, Lightest

Layers of the Core

1/6 of the volume, 1/3 of mass

• Inner Core 

  • most dense 

  • solid iron

• Outer Core 

Layers of the earth

1. inner core 

2. outer core 

3. lower mantle 

4. upper mantle 

5. asthenosphere

6. lithosphere

7. Crust 

Lithosphere =

Upper mantle + crust

Crust:

• Composition, texture, density differences 

• Continental 

  • granite 

  • low density 

• Oceanic 

  • basalt

  • high density

Radius of Earth

6370 km

Geologic Cycle

Crust is in a constant state of change

• being formed by endogenic (internal) processes

• worn down by exogenic (external) processes

Mineral 

inorganic, non-living, natural compound 

• has chemical formula & crystalline

Rock 

Assemblage of minerals, mass of a single mineral, or a solid organic material 

Igneous rocks

(Fire formed) — Solidifies from cooling magma or lava

= products of crystallization of magma and lava

Sedimentary

(Sediments) — Sediments worn from other rocks

Metamorphic

(Change form) — Changing the chemistry, mineralogy, or texture of rocks formed by extreme pressure and heat

Plate Tectonics 

Changes in the configuration of the Earth’s crust due to internal forces 

• Upwelling of magma

• Sea-floor spreading and subduction

• plate movements

Magma is molten rock beneath the surface, slower cooling → larger crystals =

Intrusive

Lava is molten rock at the surface, faster cooling → smaller crystals =

Extrusive

Lithification

Acted upon by cementation, compaction, and hardening of sediments

Earth’s crust is composed of ___ plates

14

Plate boundaries 

1. Divergent = plates move apart, and new oceanic crust forms

2. Convergent = Continental and/or oceanic crust collides

3. Transform = Plates slide past one another 

Orogenesis

Mountain building 

1. Oceanic → Continental

2. Oceanic → Oceanic

3. Continental → Continental 

Crustal deformation processes

when pressure is exerted on the crust it either bends (Creating folds) or breaks (Creating faults)

Earthquakes → Focus

sub-surface area along a fault plane where motion is initiated

Earthquakes → Epicenter

area at the surface directly above the focus

Earthquakes → Aftershock

shocks that occur after and before the and shock

Types of volcanic activity

• Intrusive

• Extrusive

Types of volcanoes

• Shield

• Composite 

Shield Volcanoes

• Shield-like shape = no steep slopes 

• Lots of lava, but little pyroclastic

• Lava: low viscosity (=thin and runny)  

Composite

• Steep slopes

• formed by explosive eruptions 

• lots of pyroclastic, but little lava

• Lava: high viscosity (thick)