ATMS-100 (GEOG-100)
Introduction to Meteorology
Fall 2013
ATMS-100 (GEOG-100): INTRODUCTION TO METEOROLOGY
Instructor:
Office:
Phone:
Email:
Office Hours:
Dr. Jeff Frame
111 Atmospheric Sciences
244-9575
[email protected]
M, W 1:30-2:30; T, Th 3:30-4:30
ATMS 100 / GEOG 100
Introduction to Meteorology
TA: Jeffrey Thayer
Office: ATMS 219
Email: [email protected]
Office Hours: Tues 1-2pm, Fri 2-3pm,
or by appointment!
Do not log into your computers yet!
About Your TA
B.S. in Atmospheric Science from Uni
LECTURE #17:
What is the Gulf Stream?
a warm ocean current that flows from the Gulf of Mexico northward through the Atlantic
Ocean
What is the thermocline?
Rapid temp. decrease with depth of few hundred meters below surface
How does oceanic temperature va
Energy, Temperature, and
Heat
ATMS-100
Fall 2013
Big Points for Today
1)
Phase changes and latent heat
2)
air
Warmer air is less dense than cooler
3) How does the sun heat the
atmosphere?
Conservation of Energy
Energy can be neither created
nor destroyed
Clouds and Precipitation
ATMS-100
Fall 2013
Cloud Formation
Most clouds form in RISING air
Why is rising air important?
As air rises, it expands and cools
Amount of water vapor in air
does not change as air rises
Cloud Formation
As temperature decreases,
Upper-Level and Surface
Winds
ATMS-100
Fall 2013
Upper-Level Winds: Review
Pressure gradient force
(PGF) acts perpendicular to
height lines toward low
heights (or low pressure)
Magnitude of PGF determined
by spacing of height lines (or
isobars)
Coriolis f
Radiation and the
Greenhouse Effect
ATMS-100
Fall 2013
Atmospheric Heating (Review)
From Monday, recall that
the atmosphere is heated
from below
Conduction heats thin
layer of air
Sun heats ground
Convection transports heat
upward
Atmosphere largely
The E
Atmospheric Moisture
ATMS-100
Fall 2013
Water Vapor in the Atmosphere
Review: Water vapor
is the most important
atmospheric gas to
weather changes
Rain, snow, and
clouds are all forms of
water in the
atmosphere
Concentration
variable, between 0
Humidity
H
Seasonal and Daily
Temperatures
ATMS-100
Fall 2013
Earths Orbit
Earth orbits
the sun
Orbit is an
ellipse (slightly
egg shaped)
Closest to sun
on January 3
(perihelion)
Farthest from
sun on July 4
Earths Axis
Earth orbits the
sun while tilted
on its axis
T
Vertical Structure of the
Atmosphere and Pressure
ATMS-100
Fall 2013
Everything is made of molecules!
The ground
Clouds
Your chairs
Your cars
You and me
The atmosphere (air)
See video: http:/
www.youtube.com/watch?v=AR0RfoWzQD0
Magnify one billion times
A
Air Masses and Fronts
ATMS-100
Fall 2013
What Is an Air Mass?
An air mass is a large body of air with similar
temperature and moisture concentrations in
the horizontal
Air masses form over flat, homogeneous
regions of the earths surface
The air acquires t
Mid-Latitude Cyclones:
Development
ATMS-100
Fall 2013
What Is the Jet Stream?
The jet stream is a
river of fast moving air
in the upper
atmosphere
Exists near tropopause
level
About 10 km (6 miles)
above sea level
300-200 mb
Upper-Level TroughJet stream a
General Circulation and the Jet
Stream
ATMS-100
Fall 2013
The General Circulation
Think of the atmosphere as a river
Individual weather systems in the
atmosphere are like turbulent eddies in a
river
Average these out and you will see the
general flow o
Atmospheric Stability and
Thunderstorm Development
ATMS-100
Fall 2013
Review
Clouds form in RISING AIR
As air rises, it reaches lower
pressures and expands
As air expands, it cools
Temperature drops but moisture
content remains the same, so RH
increases
P
Hurricanes: Intensification,
Structure, and Winds
ATMS-100
Fall 2013
Review: Hurricane Ingredients
Sea-surface temperatures
(SSTs) greater than 26.5C
Deep layer of warm water in
upper ocean
Cluster of thunderstorms
Usually in the form of a tropical
distur
Hurricanes: Introduction and
Formation
ATMS-100
Fall 2013
What Is a Tropical Cyclone?
A tropical cyclone is a low
pressure system that
develops over the tropical
oceans of the world
Tropical cyclones often move
into the middle latitudes or
over land are
Thunderstorm Complexes
ATMS-100
Fall 2013
What Is a Downburst?
A downburst is a strong
downdraft that comes in
contact with the ground
Sinking air must be colder
than the air around it
Microbursts are smaller
(and often more intense)
downbursts
Downbur
Supercell Thunderstorms
ATMS-100
Fall 2013
What Is a Supercell?
Supercell
thunderstorms are longlived, rotating
thunderstorm cells
Often isolated
Can last for hours
Always rotate
Supercells are the
strongest (and most
Hook Echo
Left/right side
nomenclatur
Hurricanes: Devastation and
Forecasting
ATMS-100
Fall 2013
1
Destructive Forces in a Hurricane
Strong winds
Storm surge
Inland flooding
Tornadoes
Saffir-Simpson Scale
Determined by maximum sustained wind speed
Dont memorize wind speeds, etc. for exam!
H
Thunderstorm Hazards
ATMS-100
Fall 2013
Thunderstorm
Hazards
Lightning
Produced by every thunderstorm
Hail
Flooding
Strong winds
Already discussed
Tornadoes
Next week
What Is Lightning?
Lightning is an electrical discharge in the
atmosphere
There are abou
Ordinary Thunderstorms
ATMS-100
Fall 2013
Thunderstorms
A thunderstorm is a tall,
vertically developed cloud that
produces lightning and thunder
Cant have thunder without
lightning!
Usually produce heavy
precipitation
Thunderstorm clouds are called
cu
Weather Forecasting
ATMS-100
Fall 2013
Scales and Life Span
The larger an atmospheric
phenomenon is, the longer it lasts,
and the more predictable it is.
How Is a Forecast Made?
Gather data
Satellites, radar, station data,
soundings, etc
Analyze data
Why
Mid-Latitude Cyclones: Life
Cycle
ATMS-100
Fall 2013
Review
At the surface, air spirals
CCW and inward toward
the center of a low
Surface convergence
Causes column to gain
air molecules
There must be net loss
of air molecules to
reduce pressure
Convergenc
El Nino, La Nina, and the Southern Oscillation
Polar Jet Stream
Strongest temperature gradient typically found on cold side of polar
front
Yields strong height (pressure) gradients aloft, especially near
tropopause
o Temperature gradient strongest in wint
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