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7.
What Causes Thunderstorms and Tornadoes? |
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2005
23 June 2005. RELEASE: 05-159
NASA
RESEARCHERS STUDYING TROPICAL CYCLONES
NASA hurricane
researchers are deploying to Costa
Rica next month to investigate the
birthplace of eastern Pacific tropical
cyclones. They will be searching
for clues that could lead to a greater
understanding and better predictability
of one of the world's most significant
weather events -the hurricane...As
scientists and coastal residents
brace for another potentially challenging
hurricane season, NASA is launching
the Tropical Cloud Systems and Processes
(TCSP) mission. TCSP is a month-long
research effort primarily intended
to document "cyclogenesis,"
the birth of tropical storms, hurricanes
and related phenomena...Researchers
will monitor oceanic thunderstorms
to study why some systems develop
into tropical cyclones and some do
not. Researchers feel the data is
vital to understanding how such weather
systems evolve and travel. The data
also could support development of
a more accurate and timely warning
system to help safeguard property
and lives..."This experiment
is significant for two reasons," said
Robbie Hood, an atmospheric scientist
at the Marshall Space Flight Center,
Huntsville, Ala. She is one of three
lead scientists for the project in
Costa Rica. "We will have an
opportunity to take a closer look
at the factors contributing to the
initiation and intensification of
tropical cyclones which are still
somewhat mysterious processes for
researchers and operational forecasters.
We will also be examining what are
the best combinations of satellite
and aircraft technologies to improve
how hurricanes are monitored and
predicted,"
she said.
11 January 2005. NASA RELEASE:
05-015. Saharan
Dust Affects Thunderstorm Behavior in Florida. Scientists
using NASA satellite data have discovered tiny
particles of dust blowing across the Atlantic
Ocean from the Sahara Desert can affect Florida
thunderstorms. Dust affects the size of the
top or "anvil" of a thunderstorm,
the strength and number of updrafts of warm
winds. It also affects the strength of convective
(heat generated) thunderstorms by influencing
the amount of rain that builds up and falls.
... The researchers found when saharan dust
is in the air, the anvils produced by Florida's
convective thunderstorms tend to be a little
smaller in area, but better organized and thicker.
This affects the amount of incoming sunlight
and warmth reaching the ground, potentially
affecting long-term climate. If occurring over
time, more sunlight and warmer temperatures
would mean a warmer climate. The researchers
also noticed the updrafts of warm moist air,
which build into thunderstorms were stronger,
and there were more updrafts produced in the
presence of the dust.... Saharan dust can act
as cloud condensation nuclei, giant cloud condensation
nuclei and ice nuclei. Van den Heever ran two
types of computer model simulations, one that
included saharan dust and another without the
desert dust. She then compared the results and
found something unusual. The increased concentrations
of cloud condensation nuclei due to the dust
decreased the amount of rainfall at the Earth's
surface. ...For more information and images
about this research on the Web, visit Looking
At Earth from NASA.
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Causes Thunderstorms and Tornadoes:
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2004
21 June 2004. NASA
RESEARCH HELPS HIGHLIGHT LIGHTNING SAFETY
AWARENESS WEEK --
NASA will mark National Lightning Safety Awareness
Week, June 20-26, through unique contributions
its lightning research makes to climate studies,
and severe storm detection and prediction.
NASA research is striving to improve our understanding
of lightning and its role in weather and climate.
14 January 2004. NASA RELEASE : 04-017. A
'Hot Tower' Above The Eye Can Make Hurricanes
Stronger -- They
are called hurricanes in the Atlantic, typhoons
in the West Pacific, and tropical cyclones
worldwide; but wherever these storms roam,
the forces that determine their severity
now are a little less mysterious. NASA scientists,
using data from the Tropical Rainfall Measuring
Mission (TRMM) satellite, have found "hot
tower" clouds are associated with tropical
cyclone intensification. ... a "hot
tower" [is] a rain cloud that reaches
at least to the top of the troposphere,
the lowest layer of the atmosphere. It extends
approximately nine miles (14.5 km) high
in the tropics. These towers are called "hot" because
they rise to such altitude due to the large
amount of latent heat. ... A particularly
tall hot tower rose above Hurricane Bonnie
in August 1998, as the storm intensified
a few days before striking North Carolina...
more than $1 billion damage and three deaths....
Kelley said, "The motivation for this
new research is that it is not enough to
predict the birth of a tropical cyclone.
We also want to improve our ability to predict
the intensity of the storm and the damage
it would cause if it struck the coast."
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2003
17 December 2003. NASA
STUDIES SHOW GLOBAL WARMING IS LIKELY TO DRIVE
BIG CHANGES IN CALIFORNIA'S COASTAL WATERS -- Global
warming could have profound effects on the
intensity and seasonal timing of wind-driven
upwelling of deep ocean water along the California
coast, impacting many coastal ecosystems,
according to recent studies by researchers
at the University of California, Santa Cruz.
30
September 2003. Observations
of a "weekend effect" in diurnal
temperature range, Piers M. de F. Forster and
Susan Solomon , National Oceanic
and Atmospheric Administration Aeronomy Laboratory,
Boulder, CO 80305; and Department of Meteorology,
University of Reading, Reading RG6 6AH, United
Kingdom. Using surface
measurements of maximum and minimum temperatures
from the Global Daily Climatological Network
data set, we find evidence of a weekly cycle
in diurnal temperature range (DTR) for many
stations in the United States, Mexico, Japan,
and China....We conclude that the weekend
effect is a real short time scale and large
spatial scale geophysical phenomenon, which
is necessarily human in origin. We thus provide
strong evidence of an anthropogenic link to
DTR, an important climate indicator. Several
possible anthropogenic mechanisms are discussed;
we speculate that aerosol-cloud interactions
are the most likely cause of this weekend
effect, but we do not rule out others. PNAS
| vol. 100 | no. 20 | 11225-11230.
18
September 2003. Hurricane
Isabel's landfall. If
you happened to be in North Carolina, the
sight of advancing Hurricane Isabel was surely
unwelcome. From space, though, it was a thing
of beauty. High above Earth, NASA satellites
took some remarkable pictures of Hurricane
Isabel's landfall. See also: Recipe
for a Hurricane -- NASA satellites improve
hurricane forecasts using space-based observations,
data assimilation, and computer climate modeling.
3
June 2003. Lightning
Spies. In
late April 2002, a cold front pushed eastward
across the midwestern United States. Ahead
of the cold front, a powerful thunderstorm
formed over Maryland, spawning what was perhaps
the state’s worst tornado. With winds
estimated at over 260 miles per hour, the
tornado touched down and traveled a path of
destruction for 24 miles (39 kilometers),
claiming several lives and injuring more than
100 people. The thunderstorm associated with
this tornado persisted from the Appalachian
Mountains to the Atlantic Ocean, causing an
estimated $120 million in damages.
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2001
18
October 2001. WEATHER
FORECASTERS MAY LOOK SKY-HIGH FOR ANSWERS -- These
days, weather forecasters are lucky if they
can accurately predict the weather a week
into the future. But a new study, funded in
part by NASA, says shifting wind patterns
inthe stratosphere during the winter may help
forecasters predict weather on the surface
two months ahead of time, because they have
an affect on where storms track in the northern
hemisphere.
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2000
March 2000. Flood
in Mozambique [1.1MB PDF NASA Lithograph] Floods
are one of the most common and widespread
of all natural disasters. These images from
the Enhanced Thematic Mapper Plus (ETM+) onboard
the Landsat 7 satellite, illustrate the severity
of the floods experienced in Mozambique, Africa
in March 2000.
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Table of Contents |
1998
August 1998. Hurricane
Bonnie [1.2MB PDF NASA Lithograph] Few
things in nature can compare to the destructive
force of a hurricane. Called the greatest
storm on Earth, a hurricane is capable of
destroying coastal areas with sustained winds
in excess of 155 mph, intense rainfall and
a storm surge.
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