1
Cloud
Types
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Be
a careful, knowledgeable observer of the atmosphere. Want
more info on clouds?
Cloud
Identification & the 27 States of the Sky
"Cloud Boutique" from
the Plymouth State College Meteorology Program
"Power
of Clouds" from the South Florida Sun-Sentinel
"Why
is the sky blue?" Now you can find out. |
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2
24
Hour Data Sources
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Rapid
communications and advances in computing technology allow
processing mind-boggling amounts of data for use in analyses
and forecasting. The
National Centers for Environmental Prediction (NCEP) carry
out these operations for the U.S.
National Weather Service (NWS). |
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3
Surface
Observations
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About
7,000 conventional surface stations report at each of the
primary analysis times (0000, 0600, 1200, and 1800 UTC).
Approximately 90% of these surface reports are from land
stations. |
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4
Radiosonde
Observations
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The
radiosonde network of over 700 stations reports upper air
data twice a day at 0000 and 1200 UTC. Approximately 90%
of the radiosondes report from the Northern Hemisphere.
About 80% of the soundings reach 100 mb. |
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5
METSAT
Observations
(c. 1992)
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As
satellite technology has improved during the past decade,
the number of meteorological satellite (METSAT) observations
has increased dramatically. So many satellite observations
are available that the analysis routines thin the METSAT
observations before they go into the meteorological models.
See the links at the end of the page for more information
on satellites |
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6
METSAT
Winds
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Since
1990, estimates of the surface wind speed over the oceans
have been made by the Special
Sensor Microwave/Imager (SSM/I), a passive microwave
radiometer flown aboard DMSP
polar orbiting satellites. These observations result
from the relationship between wind speed and the emissivity
of the ocean surface, which changes as the winds increase.
Remote sensing capabilities offer powerful tools for observing
the Earth System.This airborne
dust imagery is but one example. See the Satellite
Meteorology Links for more information. |
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7
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This
sequence of map images shows a cold front moving crossing
N.C. on February 12, 1999. Learning
to read the station model plots and to interpret the
imagery will help you understand what is happening in our
four dimensional (3-D plus time changes) atmosphere. |
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8
Wx
Data Time Series,2/12/99
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Upper
Image: As the front crossed central N.C. on February 12,
1999, one of the graphing calculators captured this time
series of three important weather parameters.
Lower Image: Actual National Weather Service Meteogram of passage
of cold front February 12, 1999. |
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9
The
Atmosphere
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Note
the logarithmic vertical pressure distribution on this
average temperature profile of the entire atmosphere. We
focus primarily on the conditions in the troposphere where
approximately 90% of the atmosphere's mass is located. |
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10
The
Solar Spectrum
|
 The
intensity of the sun's spectrum is strongest in the neighborhood
of Mr. Roy G. Biv, who is widely known for his artistic talents.
The solar electromagnetic spectrum has influences that extend
beyond sunburn. Can you recall radio, television or other
communications being disrupted by solar
flares? (Above solar flare image source
here)
For practical applications of radiation principles, go to "Wien's
Law in the news." |
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11
Reasons
for the Seasons
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Seasons
on Earth are caused by the tilt of the planet's rotational
axis. As Earth revolves around the sun, its orientation
with respect to the sun changes.
Another
explanation
Excellent graphic and explanation from USA Today depicting
the Reasons
for the Seasons. |
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12
Differential
Heating
of the Atmosphere
|
Here's
an activity that is an excellent model of differential heating
and can be used to explain the fundamentals of weather.
Absorption & Radiation Lab (Word
.doc format)
Absorption & Radiation
Lab (Acrobat .pdf format) |
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13
Seabreeze
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The
differential heating of land and adjacent waters bodies
help set up land-sea
(lake) breezes. In the absence of background synoptic
flow, a sea -breeze, a mesoscale thermal circulation, can
reach 50 km inland. Some sea-breezes have been reported
to reach as far as 400 km inland in Australia. |
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14
Landbreeze
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The
land breeze, a nighttime feature, is essentially the reverse
of the sea breeze. It is not as strong and does not move
as far from the coast. |
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15
Lakebreeze
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The
clouds lined up on the west side of Lake Michigan are the
result of a lake breeze. |
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16
Effect
of Prevailing Wind
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Enhancing
the lake breeze, the prevailing north-northeasterly wind
moves cool lake air far inland over northeast Illinois
before it warms enough to be lifted and form cumulus clouds. |
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17
Sinking
Air
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The
clear zone along the coast is a result of the sea breeze
circulation. As the return flow sinks offshore, the air
is warmed through an adiabatic
process and skies remain clear. |
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18
Terrestrial
Effects: Rivers
|
Observe
the sea breeze cloudiness and the cumulus cloud field over
Georgia and South Carolina. Can you identify the rivers
in the southeast U.S.? A sound knowledge of geography and
terrain features is important to understanding what happens
in the atmosphere. |
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19
Coast
Shape
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Observed
from the ocean, concave coastlines weaken sea breeze cloud
systems because the winds experience directional difluence.
What do you think happens with a convex or peninsular coastal
shape? |
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20
Terrestrial:
Valleys
|
Under
clear skies and with this visible imagery, the dendritic
pattern of fog in valleys identifies the orientation of
mountain-valley landforms. Compare this image to the same
geography's cloud pattern later
the same day. |
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21
Terrestrial
Effects:
Ridge Cumulus
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By
mid-day, clouds on the ridges have replaced the valley
fog of earlier in the morning. Mountain-top cumulus
can develop into thunderstorms, partly as a result of upslope
flow as the sun heats the mountain tops early in the day
before the valleys have been heated. The warm peaks and
cool lower slopes cause a differential heating-driven valley
breeze and convergence on the ridges. The converging air
rises and forms clouds. |
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22
Cloud
Interactions
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You
can observe many cloud interactions in satellite imagery.
Some web sites have "looped" (animated) imagery. (In the
early days of satellite imagery analysis, a length of 16mm
movie film -- in which successive individual frames depicted
sequential METSAT images -- was taped end-to-end to form
a loop and was run continuously through a projector to
observe animation, which we take for granted today.) Using
a time sequence and knowledge of the underlying surface
features, an analyst can determine the velocity of cloud
features and weather systems. |
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23
Downdraft
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As
a thunderstorm dissipates ("rains out"), the rain-cooled
air spreads out forming a circular area of clearing, here
approaching 100 miles diameter. In this image, there is
a new thunderstorm on the outflow boundary. |
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24
Boundary
Intersections
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Interactions
between convective storms can be the catalyst for strong
or severe storms. Satellite and radar images allow monitoring
of such interactions. Watch for these interactions when
thunderstorms are occurring. Try to identify where intersecting
outflow boundaries or merging clusters of showers or merging
lines of showers will enhance convection. |
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25 |
Cloud
In A Jar Using CBL
More
ideas |
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26 |
Merry-go-round (Coriolis)
Spinning
Blackboard |
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27
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Mid-latitude
and Severe Storms - (tornadoes, severe thunderstorms
and winter storms)
The
Carolina snowstorm of January 24-25, 2000 - A case study |
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28
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Tropical
Systems
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29
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Evaporative
Cooling Lab-
MS Word .doc file
format
Adobe
Acrobat .pdf file format
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30
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More
Links
and References
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DataStreme
Links & References Page
Weather
Channel Glossary
USA
Today Glossary |
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Precip
Types
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Precipitation
Type: http://www.nws.noaa.gov/er/rah/research/ptype.html
Archived Maps: http://www.weather.unisys.com/archive/index.html
METSAT Imagery: http://www.rap.ucar.edu/weather/satellite.html
Partial Thickness
Nomogram
Critical Thickness
Values
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| Please
send any comments concerning the information, references
and data on this page to John
White |
