Introduction about physical geography, concepts, and theories

1. Introduction to
Physical Geography,
Earth System and
Processes
RalphC. Navelino

2. Objectives:
At the end of this module, you should be able to:
1. Identify the different definitions of
physical geography;
2. examine the relationship between
geography, earth, and sun; and
3. create a Venn diagram showing the
interaction between geography, earth, and
sun.

3. BREAKOUT ROOM:
1. Each student will be divided into groups
2. During discussion, each student should open
their cameras
3. Choose one reporter that will represent each
groups.
4. The duration of the breakout room will be 15
minutes.

4. BREAKOUT QUESTION:
Group 1: What is Physical Geography?
Group 2: Identify and define the four spheres.
Group 3: What is the history of Physical Geography?
Group 4: What are the relationships between earth
and sun?

5. Introduction
The vast discipline of geography is divided into two major
branches: 1) physical geography and 2) cultural or human geography.
Physical geography encompasses the geographic tradition known as the
Earth sciences tradition. Physical geographers look at the landscapes,
surface processes, and climate of the earth—all of the activity found in
the four spheres (the atmosphere, hydrosphere, biosphere, and
lithosphere) of our planet. In contrast, cultural or human geography
spends time studying why people locate where they do (including
demographics) and how they adapt to and change the landscape in
which they live. Someone studying cultural geography might also
research how languages, religion, and other aspects of culture develop
where people live; how those aspects are transmitted to others as
people move; or how cultures change because of where they move.

6. History of Physical Geography
Some of the first truly geographical studies occurred
more than four thousand years ago. The main purpose of
these early investigations was to map features and places
observed as explorers traveled to new lands. At this time,
Chinese, Egyptian, and Phoenician civilizations were
beginning to explore the places and spaces within and outside
their homelands. The earliest evidence of such explorations
comes from the archaeological discovery of a Babylonian clay
tablet map that dates back to 2300 BCE.

7. History of Physical Geography
The early Greeks were the first civilization to
practice a form of geography that was more than
mere map making or cartography. Greek
philosophers and scientist were also interested in
learning about spatial nature of human and physical
features found on the Earth. One of the first Greek
geographers was Herodotus (circa 484 - 425 BCE).
Herodotus wrote a number of volumes that
described the human and physical geography of the
various regions of the Persian Empire.

8. History of Physical Geography
The ancient Greeks were also interested in the
form, size, and geometry of the
Earth. Aristotle (circa 384 - 322 BCE)
hypothesized and scientifically demonstrated
that the Earth had a spherical shape. Evidence
for this idea came from observations of lunar
eclipses. Lunar eclipses occur when the Earth
casts its circular shadow on to the moon's
surface. The first individual to accurately
calculate the circumference of the Earth was the
Greek geographer Eratosthenes (circa 276 - 194
BCE). Eratosthenes calculated the equatorial
circumference to be 40,233 kilometers using
simple geometric relationships. This primitive
calculation was unusually accurate.
Measurements of the Earth using modern
satellite technology have computed the
circumference to be 40,072 kilometers.

9. This early map of the world was constructed using map making techniques
developed by Ptolemy. Note that the map is organized with crisscrossing
lines of latitude and longitude.

10. History of Physical Geography
During the Renaissance (1400 to 1600 CE) numerous journeys of
geographical exploration were commissioned by a variety of nation states in
Europe. Most of these voyages were financed because of the potential
commercial returns from resource exploitation. The voyages also provided an
opportunity for scientific investigation and discovery. These voyages also
added many significant contributions to geographic knowledge. Important
explorers of this period include Christopher Columbus, Vasco da
Gama, Ferdinand Magellan, Jacques Cartier, Sir Martin Frobisher, Sir Francis
Drake, John and Sebastian Cabot, and John Davis. Also during the
Renaissance, Martin Behaim created a spherical globe depicting the Earth in
its true three-dimensional form in 1492. Behaim's invention was a significant
advance over two-dimensional maps because it created a more realistic
depiction of the Earth's shape and surface configuration.

11. This map was constructed by Oliva in 1560. It describes the known world at this time and
suggests that North America is part of Asia. Further exploration of the world would soon
reject this idea.

12. History of Physical Geography
Today, the academic traditions described by Pattison are still dominant
fields of geographical investigation. However, the frequency and magnitude of
human mediated environmental problems has been on a steady increase since
the publication of this notion. These increases are the result of a growing
human population and the consequent increase in the consumption of natural
resources. As a result, an increasing number of researchers in geography are
studying how humans modify the environment. A significant number of these
projects also develop strategies to reduce the negative impact of human
activities on nature. Some of the dominant themes in these studies include:
environmental degradation of the hydrosphere, atmosphere, lithosphere,
and biosphere; resource use issues; natural hazards; environmental impact
assessment; and the effect of urbanization and land-use change on natural
environments.

13. Definition of Physical Geography
Physical geography consists of many diverse elements.
These include: the study of the earth's interaction with the
sun, seasons, the composition of the atmosphere,
atmospheric pressure and wind, storms and climatic
disturbances, climate zones, microclimates, the hydrologic
cycle, soils, rivers and streams, flora and fauna,
weathering, erosion, natural hazards, deserts, glaciers and ice
sheets, coastal terrain, ecosystems, geologic systems, and so
much more.

14. The Four Spheres
1. The atmosphere itself has several layers to study, but the atmosphere as a
topic under the lens of physical geography also includes research areas
such as the ozone layer, the greenhouse effect, wind, jet streams, and
weather.
2. The hydrosphere encompasses everything having to do with water, from
the water cycle to acid rain, groundwater, runoff, currents, tides, and
oceans.
3. The biosphere concerns living things on the planet and why they live
where they do, with topics from ecosystems and biomes to food webs and
the carbon and nitrogen cycles.
4. The study of the lithosphere includes geological processes, such as the
formation of rocks, plate tectonics, earthquakes, volcanoes, soil, glaciers,
and erosion.

15. Sub-branches of Physical Geography
 Geomorphology: the study of Earth's landforms and its surface's
processes—and how these processes change and have changed
Earth's surface—such as erosion, landslides, volcanic activity,
earthquakes, and floods
 Hydrology: the study of the water cycle, including water distribution
across the planet in lakes, rivers, aquifers, and groundwater; water
quality; drought effects; and the probability of flooding in a region.
Potamology is the study of rivers.
 Glaciology: the study of glaciers and ice sheets, including their
formation, cycles, and effect on Earth's climate.

16. Sub-branches of Physical Geography
 Biogeography: the study of the distribution of life forms across the planet,
relating to their environments; this field of study is related to ecology, but it
also looks into the past distribution of life forms as well, as found in the
fossil record.
 Meteorology: the study of Earth's weather, such as fronts, precipitation,
wind, storms, and the like, as well as forecasting short-term weather based
on available data.
 Climatology: the study of Earth's atmosphere and climate, how it has
changed over time, and how humans have affected it.
 Pedology: the study of soil, including types, formation, and regional
distribution over Earth.
 Paleogeography: the study of historical geographies, such as the location of
the continents over time, through looking at geological evidence, such as
the fossil record.

17. Sub-branches of Physical Geography
 Coastal geography: the study of the coasts, specifically concerning what
happens where land and water meet.
 Oceanography: the study of the world's oceans and seas, including aspects
such as floor depths, tides, coral reefs, underwater eruptions, and currents.
Exploration and mapping are a part of oceanography, as is research into the
effects of water pollution.
 Quaternary science: the study of the previous 2.6 million years on Earth,
such as the most recent ice age and Holocene period, including what it can
tell us about the change in Earth's environment and climate
 Landscape ecology: the study of how ecosystems interact with and affect
each other in an area, especially looking at the effects of the uneven
distribution of landforms and species in these ecosystems (spatial
heterogeneity).

18. Sub-branches of Physical Geography
 Geomatics: the field that gathers and analyzes geographic data,
including the gravitational force of Earth, the motion of the poles and
Earth's crust, and ocean tides (geodesy). In geomatics, researchers
use the Geographic Information System (GIS), which is a
computerized system for working with map-based data.
 Environmental geography: the study of the interactions between
people and their environment and the resulting effects, both on the
environment and on the people; this field bridges physical geography
and human geography.
 Astronomical geography or astronography: the study of how the sun
and moon affect the Earth as well as our planet's relationship to
other celestial bodies.

19. Relationship between Earth and Sun
The earth receives almost all its energy from the Sun’s radiation. Sun also has
the most dominating influence on the changing climate of various locations on
Earth at different times of the year. The Earth rotates about on a fixed plane
that is tilted 23.5° with respect to its vertical axis around the sun. The Earth
needs 23hrs 56mins to complete one true rotation, or one sidereal period,
around the sun. The solar day, on the other hand, is the time needed for a
point on earth pointing towards a particular point on the sun to complete one
rotation and return to the same point. It is defined as the time taken for the
sun to move from the zenith on one day to the zenith of the next day, or from
noon today to noon tomorrow. The length of a solar day varies, and thus on
the average is calculated to be 24hrs. In the course of the year, a solar day may
differ to as much as 15mins. There are three reasons for this time difference.

20. Relationship between Earth and Sun
Change of Seasons
Seasons are caused by the Earth axis which is tilted by 23.5° with
respect to the ecliptic and due to the fact that the axis is always pointed
to the same direction. When the northern axis is pointing to the
direction of the Sun, it will be winter in the southern hemisphere and
summer in the northern hemisphere. Northern hemisphere will
experience summer because the Sun’s ray reached that part of the
surface directly and more concentrated hence enabling that area to heat
up more quickly. The southern hemisphere will receive the same
amount of light ray at a more glancing angle, hence spreading out the
light ray therefore is less concentrated and colder. The converse holds
true when the Earth southern axis is pointing towards the Sun.

21. Figure 1 below shows that the orbit of the Earth about the sun is not circular. The path is
elongated or elliptical. This means that the distance from the Earth to the sun varies
through the year. Two special events are depicted in the diagram. Aphelion (July 4) is
when the Earth is as far away from the sun as it ever gets. Perihelion (Jan. 3) is when the
Earth is as close to the sun as it ever gets. Note that these events do not correspond to
the coldest and hottest months for us in the Northern Hemisphere. The purpose of this
is to show that distance from the sun has nothing to do with seasons.

22. Figure 2 looks rather complicated. It does, however,
reveal some very important facts about the Earth and its
orbit around the sun. First note the purplish
rectangle. This represents the plane of the Earth's orbit
about the sun or the Plane of the Ecliptic. We now want
to measure the orientation of the Earth with respect to
the plane of its orbit, the plane of the ecliptic. Now note
the orange rectangle which represents the plane of the
equator. We can clearly see that the two planes do not
coincide. That is to say, the Earth is tilted with respect to
the plane of the ecliptic. Figure 2 also shows the Earth's
axis of rotation. If the Earth were not tilted with respect
to the plane of the ecliptic, then there would be a right
angle (90°) between the axis and the plane of the
ecliptic. Note that the axis is shy of 90° by 23°30'. This
deviation, or tilt, is called Inclination.

23. Any questions?
THANKS!