Geography 155-08

Dr. Susan W.S. Millarswmillar@maxwell.syr.edu

Class meets: M&W 10:35 am – 11:30 am

The Natural

Environment

Flooding along Ohio River last week.

Images from NASA EOS.

1. What is the natural environment?

• The four spheres of Earth

– Atmosphere

– Hydrosphere

– Lithosphere

– Biosphere

• Structure of the course

Part 1

The Energy-A

tmosp

here

Syste

m

Part 2

The Water, Weather

and Climate Systems

Part 4The Earth-Atmosphere

Interface

Part 3Ecosystems and Biomes

Why Geography?

•Definition: Earth’s description

• Understanding spatial relationships

2. Association of American Geographers:

5 Themes•Location

• Region

• Human-earth relationships

• Place

• Movement

Location•Absolute location

– latitude and longitude•Syracuse, NY: 43°N, 76°W

•Relative location– relative to some other place or

feature•Syracuse, NY: south of Lake Ontario•Syracuse, NY: half way between NYC and Buffalo

Association of American Geographers:

5 Themes• Location

•Region

• Human-earth relationships

• Place

• Movement

Region

• Areas delineated based on commonalities

– Appalachia

– Rust belt

– America’s food basket

Folded mountain belt of Appalachians

Rust Belt

From: Rubenstein, 1994

Sun Belt

Based on a survey of geographers. From Rubenstein, 1994

Association of American Geographers:

5 Themes• Location

• Region

•Human-earth relationships

• Place

• Movement

Human-Earth Relationships

• Hazard perception

• Resource exploitation

• Environmental modification

Hazard Perception

•Fort Worth Tornado, 1999

Resource Exploitation

Bingham canyon copper mine, Utah

Environmental Modification

• City of Venice, Italy

Association of American Geographers:

5 Themes• Location

• Region

• Human-earth relationships

•Place

• Movement

Place• What makes a place unique.

• Mt. St. Helens, Washington

Association of American Geographers:

5 Themes• Location• Region• Human-earth relationships• Place•Movement

Movement

• Communication• Movement•Circulation

Circulation

The Gulf Stream

Palm trees in Scotland!

. . . At a latitude equivalent to Alaska. . .

3. Physical Geography

• Uses the scientific method

• In the framework of systems theory

General theory, governing laws

Hypothesis

RealWorld

Scientific method begins here

Predictions

Inductive reasoning

Observations, measurements

Theory formulation

Experiment and testing

Search for patterns and order

Explanation

Data collection

Perception

Real world understood

General statement

What data?

Model building

Refining of hypothesis

What’s known, what do we want to know?

Posi

tive

feedback

Negativ

e

feedback

Geosystems, p 7

Observation of the real world

• Lots of heavy rain makes rivers muddy.

Hypothesis• Greatest sediment loss with

highest annual precipitation

Data Collection

Rainfall dataSediment loss (yield) from land

Testing Predictions• Measure precipitation and sediment yield in

as many places as possible• Expected results:

0

200

400

600

800

1000

1200

1400

0 500 1000 1500

Rainfall

Sedim

ent

Yie

ld (

t m

-2 y

r-1)

Actual Results

0

200

400

600

800

1000

1200

0 500 1000 1500 2000

Precipitation (mm)

Sed

imen

t Y

ield

(t

m-2 y

r-1)

Refine Hypothesis

• Observations of real world• Are other factor(s) important?• Vegetation!

Relationship between vegetation and sediment

yield

0 10 20 30 40 50

Percent vegetation cover

Sed

imen

t Yie

ld

Interaction of different factors

0

200

400

600

800

1000

1200

0 500 1000 1500 2000 0 10 20 30 40 50

Percent vegetation cover

Sed

imen

t Yie

ld

4. Systems Theory

• A set of ordered, inter-related things and their attributes, linked by flows of energy and matter.

• System Feedbacks– Positive feedback: change leads to

growth.– Negative feedback: change leads

to reduction in growth.

Positive Feedback

• Growth continues in same direction

• Runaway system

0

4

8

12

16

20

0 1 2 3 4 5

Time Step

• Compound interest• Greenhouse

warming and evaporation

Negative Feedback

• Limits growth• System control

66

68

70

72

74

0 2 4 6 8 10

Time Step

Tem

p (

oF)

-ve feedback 1

-ve feedback 2

• Human sweating• Greenhouse warming

and increased cloud cover

Feedbacks lead to system stability

• Earth-system tends to remain in equilibrium (balance).

• But is it a steady-state equilibrium, dynamic equilibrium? Or metastable?

Steady-State Equilibrium

• Fluctuates around a mean value

Figure in Geosystems, p10

Dynamic Equilibrium and Metastable

Systems• Trend of operation varies – dynamic• Jumps to a new level of operation - metastable

Steady-state

Relaxation

Steady-state

Perturbation

A Geomorphic System

A metastable system

Global System

Summary

• Physical geographers study the natural environment.

• Use the scientific method to understand earth systems

• Focus on spatial relationships that help explain aspects of the system.