Cyclones can be identified and monitored constantly as soon as they originate over the ocean using sophisticated technology such as weather satellites and weather radar. These instruments detect various factors associated with the cyclone's formation and subsequent evolution including its intensity, extent of wind damage, and loss of life.
In addition to these observations from space, ships at sea often report signs of a developing storm that may indicate the presence of a cyclone off the coast. For example, sailors will often notice that the wind is blowing from one direction offshore but then changes direction abruptly near land. This is known as a "landfall" and usually indicates that a cyclone is approaching or has recently passed by the coastline. If there are no warnings issued for the affected area, it is useful to know that it can take days or even weeks before the effects of a cyclone reach land.
When a cyclone reaches land, it can have devastating consequences for people who lack proper protection from the elements. In addition, cyclones can cause enormous damage to property and disrupt transportation networks; thus, they are capable of causing death, injury, or loss of business during their passage across land.
Scientists use statistical methods to analyze the characteristics of cyclones so that future predictions can be made about where and when they might form.
Infrared satellites track cyclones based on their surface temperatures, allowing forecasters to watch a cyclone's path and pace throughout the night. A satellite image of a storm at 11:30 p.m. Eastern Time on March 6, for example, showed that Cyclone Ida had slowed down as it moved over India.
Satellites take infrared images of Earth's surface every few hours. When clouds or other atmospheric conditions block some of this light from reaching the ground, scientists can tell by looking at these images whether there is still a cold spot under the blocking body. If there is, then this cold spot must be coming from outside the cloud cover, which means that it comes from below the cloud layer and is therefore a sign that an air mass is moving away from its origin location.
Cyclones form when air flows rapidly in parallel layers called cells. The cells may be as small as the diameter of a human hair but they can also be as large as several hundred miles across. As the cells converge they begin to rotate around a central point, forming a spiral motion that can only end when the wind reaches 360 degrees around the cell, thus creating a complete circle or loop. At this point, the cells will split apart again, continuing their circular motion until they dissipate or merge with another system.
Cyclones are cyclones. Tropical cyclones are meteorological phenomena that arise over the ocean as a result of the release of energy from evaporation and saturation of water on the ocean's surface. They consist of a rotating vortex of air surrounded by a mass of unstable water vapor called the cyclonic circulation or gyre. The rotation of the vortex creates a wind known as the cyclone wind speed, which can reach 70 miles per hour (110 km/hour) or more near the center of the storm.
Tropical cyclones form when an area of high atmospheric pressure develops into a depression, which becomes more widespread as it gains strength from its interaction with the surrounding atmosphere. Once sustained winds reach 34 mph (55 kph), it is classified as a tropical depression. A tropical depression can last for several days before it weakens into a tropical storm, which can last even longer. A tropical storm becomes a hurricane when winds exceed 74 mph (119 kph). A hurricane lasts three to five days before weakening to a typhoon. A typhoon lasts one to four days before dissipating.
Tropical cyclones form where there is sufficient moisture in the atmosphere. If you travel west across the Atlantic Ocean from Europe, for example, you will arrive in North America where there is enough moisture in the atmosphere for tropical cyclones to form.
Every year, there are 10–14 cyclones. Hurricanes strike the Atlantic Ocean roughly five or six times every year. Pulse-Doppler radar, photogrametry, and ground swirl patterns are used to identify cyclones and hurricanes. Not all storms that reach hurricane strength qualify as cyclones.
The number of hurricanes has increased in recent years. There were only four hurricanes in 1980. In 2004, there were 9 hurricanes, including 3 major hurricanes (Category 3 or greater). In 2005, there were 12 hurricanes, including 4 major hurricanes.
Scientists are concerned that overdevelopment of coastal areas could increase the frequency of strong storms. Also, global warming could change the path of hurricanes, make them stronger, or cause them to stay in one place for longer periods of time.
Cyclones can cause extensive damage when they hit land. Hurricane Floyd killed 56 people in 1999 after it struck parts of Virginia and North Carolina. The damage totaled more than $40 billion.
In addition to killing people, cyclones can destroy buildings, vehicles, and entire villages. They can also leave millions of people without food or clean water. After Hurricane Katrina, many people didn't know how to protect themselves from future storms. They lost their homes, their jobs, and almost everything else they owned.
Natural Disasters, Cyclones, and Earth Observation Cyclones, hurricanes, and typhoons are all extremely violent storms with winds exceeding 119 kilometers per hour (74 MPH). There are between 80 and 100 of these storms on average each year, and while only a portion of them make landfall, they may bring damage when they do.
What is the difference between a hurricane, a typhoon, and an cyclone? They are all large-scale atmospheric disturbances that can cause widespread damage when they move over land. However, not all large-scale atmospheric disturbances that affect land are called "storms". For example, high pressure systems can also influence weather by preventing moisture from reaching portions of the globe. Such areas are often referred to as "dry holes" because there is no moisture present to support precipitation.
Why do some years produce many disasters, while other years don't? Unpredictability of severe weather causes this problem. Severe weather events are rarely repeated identically next time around. The frequency, intensity, and location of disaster events are influenced by many factors beyond human control. For example, the interplay between oceans, continents, and atmosphere determines where and when tropical storms will form. Also important are internal dynamics within individual storms. Factors such as wind speed and direction, amount of water vapor in the air, size of clouds, and temperature differences across surfaces of rotating storms parts play a role in how strong they will be. No two storms are exactly alike!
To detect and track tropical cyclones, the center use satellite imagery, numerous meteorological instrumentation, and computer-based prediction modeling. When tropical cyclones threaten inhabited coastal regions, the center offers warnings. This information may be used to track and forecast the path of a tropical storm. Should a storm's intensity increase, weather stations across its path will report new data that help predict how strong it will become as it moves over land.
Scientists use several methods to detect tropical cyclones. Satellite images are taken from space and can reveal important information about tropical storms that could not be obtained otherwise. Instrumental observations are made at ground level using weather stations. They provide data on wind speed and direction, pressure, temperature, humidity, and other factors. Computer models based on these observations and other inputs such as sea surface temperatures are also used for tracking and predicting tropical cyclones.
Tropical cyclones are classified by strength into three categories: depression, storm, and hurricane. Scientists use various criteria to make this determination including barometric pressure, wind speed, satellite intensity estimates, and proximity to land. A depression has sustained winds of 39 mph or less while a storm has winds of 40-73 mph. A hurricane is defined as a storm with winds greater than 74 mph.
Cyclone detection devices measure fluctuations in solar radiation, which is affected by clouds and aerosols inside the troposphere, the lowest layer of the atmosphere.