Jenny Grandjean
Hurricanes Assignment – MET 1010 / Summer 2012
Hurricanes are giant, spiraling tropical storms that can pack wind speeds of
over 160 miles (257 kilometers) an hour and unleash more than 2.4 trillion gallons (9
trillion liters) of rain a day. These same tropical storms are known as cyclones in the
northern Indian Ocean and Bay of Bengal, and as typhoons in the western Pacific
Ocean.
Hurricanes begin as tropical disturbances in warm ocean waters with surface
temperatures of at least 80 degrees Fahrenheit (26.5 degrees Celsius). These lowpressure systems are fed by energy from the warm seas. If a storm achieves wind
speeds of 38 miles (61 kilometers) an hour, it becomes known as a tropical
depression. A tropical depression becomes a tropical storm, and is given a name,
when its sustained wind speeds top 39 miles (63 kilometers) an hour. When a storm’s
sustained wind speeds reach 74 miles (119 kilometers) an hour it becomes a hurricane
and earns a category rating of 1 to 5 on the Saffir-Simpson scale.Hurricanes are
enormous heat engines that generate energy on a staggering scale. They draw heat
from warm, moist ocean air and release it through condensation of water vapor in
thunderstorms.
A typhoon is a mature tropical cyclone that develops in the northwestern part
of the Pacific Ocean between 180° and 100°E. This region is referred to as the
northwest Pacific basin. In an average season, tropical cyclones are mostly
experienced in northwest Australia between Exmouth and Broome in Western
Australia and in northeast Queensland between Port Douglas and Maryborough. In
the Australian region, the official tropical cyclone season runs from 1 November to
30 April with most occurring between December and April. On average, about 10
cyclones develop over Australian waters each year and around six of these cross the
coast. There is some correlation between cyclone frequency and the El-Nino
Southern Oscillation status, with activity subdued in El-Nino events and enhanced
during La-Nina events, especially in the Coral Sea.
Interesting fact: The greatest number of tropical cyclones in the Australian region in
any one-year was 20 in 1983. Since 1950, the lowest number of tropical cyclones in
any season was just five in 1987.
Most hurricanes that hit the United States begin either in the Caribbean or the
Atlantic. Many of the worst start as seedlings coming off the coast of Africa. Like all
tropical cyclones, a hurricane needs the warm water of the tropics, which feeds a
storm with energy, in order to form. The atmosphere must be laden with moisture.
The tropics as part of the water cycle in the current climate system. By covering.
The eye is a region of mostly calm weather at the center of strong tropical cyclones.
The eye of a storm is a roughly circular area, typically 30–65 km (20–40 miles)
in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where
Jenny Grandjean
the second most severe weather occurs. Since the strongest winds are located in a
cyclone's eyewall, the tropical cyclone usually weakens during this phase, as the inner
wall is "choked" by the outer wall. Eventually the outer eyewall replaces the inner one
completely, and the storm can re-intensify.
TRMM is a research satellite designed to improve our understanding of the
distribution and variability of precipitationwithin the tropical and sub-tropical regions
of the Earth, TRMM provides much needed information on rainfall and its associated
heat release that helps to power the global atmospheric circulation that shapes both
weather and climate. In coordination with other satellites in NASA's Earth Observing
System, TRMM provides important precipitation information using several spaceborne instruments to increase our understanding of the interactions between water
vapor, clouds, and precipitation, that are central to regulating Earth's climate.
In a developing hurricane, heat pushes up rainclouds around the eye of the
storm, forming high-altitude clouds called "hot towers." Using NASA's Tropical
Rainfall Measuring Mission scientists can now get an X-ray peek into the tower. A
quick look at the height can tell them whether the storm is likely to intensify into a
dangerous hurricane.
Feeder bands of clouds streaking out from the extreme edges of a hurricane
are not to be ignored. We call them "feeder bands" because they are pulling moisture
up from the ocean "feeding" the clouds of the storm. Typically a day or two after the
hurricane has passed the remainder of the feeder bands will come ashore, dropping
incredible amounts of rain. Often the flooding caused by these rains causes more
damage than the actual hurricane. One of the dangerous features of a hurricane is the
sea swell that it lifts through its powerful suction. When this swell comes to shallower
off-shore waters, it becomes a huge surf surge, reaching up to 25 feet height, like a
tsunami that, aided by the rain deluge, can flood and inundate everything far inland.
This watch should trigger your family's disaster plan, and proactive measures should
be initiated especially those actions that require extra time such as securing a boat,
leaving a barrier island, etc. Scientists use statistics from previous years to help predict
how many hurricanes there will be. After a hurricane has been begun, the
meteorologists will use a model to track the hurricane's path within 3 to 5 days ahead.
The Hurricane Hunters are aircraft that fly into tropical cyclones in the
North Atlantic Ocean and Northeastern Pacific Ocean for the specific purpose of
directly measuring weather data in and around those storms. A dropwindsonde is a
packet of instruments used to obtain data on the atmosphere over the ocean,
notes NASA's website. Dropwindsondes are attached to parachutes and then
dropped from an airplane. As they float down toward the ocean, they radio
atmospheric information back to the airplane.
Jenny Grandjean
When a HURRICANE WATCH is issued for your part of the coast this indicates the
possibility that you could experience hurricane conditions within 36 hours. This
watch should trigger your family's disaster plan, and proactive measures should be
initiated especially those actions that require extra time such as securing a boat,
leaving a barrier island, etc.
When a HURRICANE WARNING is issued for your part of the coast this indicates
that sustained winds of at least 74 mph are expected within 24 hours. Once this
warning has been issued, your family should be in the process of completing
proactive actions and deciding the safest location to be during the storm.