Download What is Weather?

Meteorology,
Weather, Climate
So, what’s meteorology?
No, it’s not the study of objects
from space that strike Earth.
Meteorology
• The study of the atmosphere and the
phenomena usually referred to as weather.
• One of the Earth sciences
– Sciences that seek to understand our planet
– In the study of meteorology, these sciences
often overlap and include aspects of
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Astronomy
Biology
Chemistry
Physics
Why is the study of the atmosphere
called “meteorology”?
• The origin of the word "meteorology" dates back to
ancient Greece.
• In 340 B.C., Aristotle, a philosopher of the day, wrote a
treatise called "Meteorologica" about “meteors,” then
defined as any object in the sky.
• These airborne items included clouds, snow, and rain-aspects of the atmosphere that fascinated him.
• Add “ology” for “ study of” and you get “meteorology.”
What is the difference between
climate and weather?
Climate
A composite of a region’s average conditions
Climate
• Applies to long-term changes
• Measured in terms of:
– Temperature
– Precipitation
– Snow and ice cover
– Winds
• Can refer to
– The entire planet
– Specific regions (continents or oceans)
What is Weather?
Weather
• Weather is the state of the atmosphere at
a given time and place.
• Shorter fluctuations atmospheric
conditions lasting
– Hours
– Days
– Weeks
Typical Newspaper Weather Map
Synoptic Weather Map
Studying the Atmosphere –
The Scientific Method
• Hypothesis
– An informal idea that has not been widely
tested by the scientific community
– Most are discarded.
• Theory
– When a hypothesis is capable of explaining a
wide array of observations.
– Additional observations support the theory
• New techniques for data analysis
• Devise models
Theories can be discarded
Ongoing work may disprove the
predictions of a current theory
An Historical Example . . .
The Geocentric Model of the Solar System
• Devised by Ptolemy (Claudius Ptolemaeus) in the
second century AD
• Accepted until 1543
The Heliocentric Model
replaced the Geocentric Model
Pluto is no longer considered a planet!
Pluto’s Been Demoted!
• On August 24, 2006 the International
Astronomical Union redefined the definition
of a planet as:
– “a celestial body that is in orbit around the sun
– has sufficient mass for its self-gravity to
overcome rigid body forces so that it assumes a
nearly round shape,
– and has cleared the neighborhood around its
orbit.”
Pluto is now considered
a “Dwarf Planet”
• Pluto lost its status as a planet because
it’s highly eccentric orbit crosses over the
orbit of Neptune.
– As such it hasn’t “cleared the
neighborhood around its orbit.
• A dwarf planet like Pluto is
– Any other round object that
• Has not “cleared the neighborhood around its orbit
• Is not a satellite
A Law or Unifying Theory
• If a theory has survived the test of time
– Years or decades
• It’s the closest approximation to “the truth”
as possible.
• It’s impossible to prove a theory as being
true.
• We can only prove it’s untrue.
A View of Earth
• Earth is a “water
planet.”
• The most
conspicuous features
seen from space are
– Oceans
– Clouds
A closer view shows . . .
• The three major parts
of Earth’s physical
environment
– The solid Earth (land)
– The water portion
– Atmosphere
Interfaces
• Our environment is
highly integrated
– It’s not dominated by
land, water, or air alone.
• It’s characterized by
continuous interactions
as
– Air comes in contact
with rock
– Rock comes in contact
with water
– Water comes in contact
with air.
Earth’s Four Spheres
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Earth is divided into four independent parts
Each loosely occupies a shell around Earth
– This why they’re called spheres
The Geosphere
• The solid Earth
• The largest sphere
– Extends from the
surface to the center of
the planet
• Three principle regions
based on
compositional
differences
– Crust
– Mantle
– Core
The Atmosphere
• A very shallow layer of
gases
• 99% is within 30 km (20
mi) of Earth’s surface
• An integral part of our
planet
– Provides the air we breath
– Protects us from harmful
short-wave solar radiation
• Energy exchanges
between Earth’s surface
and the atmosphere and
space produce weather.
The Hydrosphere
• The collective mass of water found on, under, and above
Earth’s surface
• The hydrosphere includes . . .
Oceans
• Cover nearly 71% of Earth’s surface
• Average depth is 3,800 meters (12,500 ft.)
• Accounts for 97% of Earth’s water
Streams
Lakes
Glaciers
Ground Water
Clouds
Volume Comparisons
Volume of the
Entire Hydrosphere
Volume of the
Entire Atmosphere
The Biosphere
• Includes all life on Earth
• Most is concentrated near
Earth’s surface
Distribution of Earth’s Water
Earth System Science
• The four spheres can be studied
separately
• However . . .
– The parts are not isolated.
– Each is related in some way to the others
– A complex and interacting whole results that
is called
• The Earth System
An Interdisciplinary Approach to
Studying Earth
• The way in which individual components of
land, water, air, and life forms are
connected must be understood.
• A system is
– Any size group of interacting parts that form a
complex whole to serve a function
– Most natural systems are driven by sources of
energy that move mater and/or energy from
one place to another.
Open Systems
• In most natural systems energy flows into
and out of the system.
• Weather systems are open systems.
– In storms the amount of water vapor available
changes, flow of air into and out changes, etc.
Course Outcomes
• Understand how various types of energy transfer
affect the atmosphere and weather
Course Outcomes
•
Understand weather variables
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Temperature
Air pressure
Wind
Moisture
In terms of
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Causes
How they’re measured and recorded
Patterns associated with various types of weather
How they’re used in weather prediction
Course Outcomes
• Understand how the
interaction of air masses
produces a storm
– Cyclogenesis
– Types of fronts
• The role of upper air
conditions
Course Outcomes
Surface Synoptic Map
Upper air map
• Plot and interpret weather maps
– Surface maps
– Upper air maps
Course Outcomes
• Identify Types of Severe Weather
Know what precautions to take . . .
Course Outcomes
• Forecast weather
using
– Synoptic maps
– Weather data trends
– Numerical Data