Transcript Document 7263170

MADISON’S CURRENT WEATHER
Madison Weather at
1000 AM CDT 24 JUL 2002
Updated twice an hour at :05 and :25
Sky/Weather: MOSUNNY
Temperature: 71 F (21 C)
Dew Point: 56 F (13 C)
Relative Humidity: 58%
Wind: SE10 MPH
Barometer: 30.27S (1025.0 mb)
Last 24 hrs in Madison
FOG
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CURRENT
VISIBLE
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Current Surface Weather Map
with Isobars (“iso” = equal & “bar” = weight), Fronts and Radar
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Current Surface Winds
with Streamlines & Isotachs (“iso” = equal & “tach” = speed)
L
H
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L L LL
L
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H
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Current Temperatures (°F) & Isotherms
(“iso” = equal +”therm” = temperature)
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Current Dewpoints (oF)
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Tomorrow AM Forecast Map
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Typhoon
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Announcements

Homework #3 Answer Key is posted at
http://www.aos.wisc.edu/~hopkins/aos100/homework



Homework #4 is due tomorrow
2nd Hour Exam is scheduled for tomorrow.
Study sheet is posted at:
http://www.aos.wisc.edu/~hopkins/aos100/exams

If you have ??, please see me.
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ATM OCN 100 - Summer 2002
LECTURE 17 (con’t.)
THE THEORY OF WINDS:
PART I - OBSERVATIONS & SCALES
A.
Introduction
– Nature of winds (and scalar quantities)
– Importance of Winds
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Current Midwest Winds & Isobars
H
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Modern Wind Energy Conversion System
(NE Wisconsin)
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Wind Power Potential
National Wind Technology Center, U.S DOE
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B. WIND OBSERVATIONS & ANEMOMETRY

Requirements
– Representative & away from obstacles

Historical Wind Observations
– Tower of Winds in Greece
(1st Century BC)
(Boreas - the north wind, etc.)
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B. WIND OBSERVATIONS & ANEMOMETRY

Requirements
– Representative & away from obstacles

Historical Wind Observations
– Tower of Winds in Greece
(1st Century BC)
(Boreas - the north wind, etc.)
– Maritime experiences
(Doldrums, trade winds, etc.)
– Beaufort Wind Force Scale
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BEAUFORT WIND FORCE SCALE
[Modern version, Source: Federal Meteorological Handbook I]
Scale Description
0
1
2
3
4
5
Calm
Land & Sea Observations
Smoke rises vertically.
Sea surface is like mirror.
Light air
Smoke, but not wind vane, shows direction of
wind.
Slight ripples on sea.
Light breeze Wind felt on face, leaves rustle, wind vanes
move.
Small, short wavelets.
Gentle breeze Leaves and small twigs moving constantly,
small flags extended.
Large wavelets, scattered whitecaps.
Moderate
Dust and loose paper raised, small branches
breeze
moved.
Small waves, frequent whitecaps.
Fresh breeze Small leafy trees swayed.
Moderate waves.
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Knots
<1
1-3
4-6
7-10
11-16
17-21
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BEAUFORT WIND FORCE SCALE (con’t.)
Scale Description
Land & Sea Observations
6
Strong
Large branches in motion, whistling heard in
utility wires. Large waves, some spray.
breeze
Knots
22-27
7
Near gale
Whole trees in motion.
White foam from breaking waves.
28-33
8
Gale
Twigs break off trees.
Moderately high waves of great length.
34-40
9
Strong gale Slight structural damage occurs. Crests of
waves begin to roll over. Spray may impede
visibility.
Storm
Trees uprooted, considerable structural
damage.
Sea white with foam, heavy tumbling of sea.
Violent
Very rare; widespread damage.
Unusually high waves.
storm
Hurricane
Very rare; much foam and spray greatly reduce
visibility.
10
11
12
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48-55
56-63
>63
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SEA STATE For Calm Conditions (Force 0)
Source: NWSFO Milwaukee
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SEA STATE For Strong Breeze Conditions (Force 6)
Source: NWSFO Milwaukee
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SEA STATE For Hurricane Conditions (Force 12)
Source: NWSFO Milwaukee
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Windsock
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B. ANEMOMETRY (con’t.)
Modern Wind Observation Techniques
– Surface (within 10 meters of surface)
– Aloft (altitudes above 10 meters)
 Modern Wind Instruments
– For Direct Surface Observations

 Anemometer
 Wind
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Vane
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ASOS Wind Instruments
Wind Vane (left) & Cup Anemometer (right)
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Aerovane
Measures wind speed & direction
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B. ANEMOMETRY (con’t.)

Modern Wind Instruments
– For Direct Surface Observations
 Anemometer
 Wind
Vane
– For Indirect wind measurements aloft
to include…
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Kites
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Pilot Balloons
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Radiosonde
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Green Bay Radiosonde Sounding – Tues. PM.
Tropopause
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Jet Stream
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Upper Tropospheric Jet Stream – Tues. PM
300 mb Level or 9500 m altitude
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Doppler Weather Radar
See Pg. 344-351 Moran & Morgan (1997)
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Example of Doppler Radar Displays during Tornado Event
Oklahoma City 3 May 1999
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Wind Profiler (FSL)
See Pg. 352 Moran & Morgan (1997)
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Recent 24-hr Wind Profiler Data: Blue River, WI
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Satellite Derived Winds Aloft [SSEC]
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C. CHARACTERISTIC SCALES of
ATMOSPHERIC MOTION


Importance of Scale
The Scales (from Table 9.2, Moran & Morgan):
Circulation
Planetary
Synoptic
MesoMicro
Space scale
[km]
10,000-40,000
100-10,000
1-100
0.001-1
Time scale
weeks-months
days-weeks
hours-days
seconds-hours
Scale Interaction
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Atmospheric Scales
(from the Weather Doctor)
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