A tropical cyclone is a storm system characterized by a low pressure center and numerous thunderstorms that produce strong winds and flooding rain. Tropical cyclones feed on heat released when moist air rises, resulting in condensation of water vapour contained in the moist air.
Overview EditWhile tropical cyclones can produce extremely powerful winds and torrential rain, they are also able to produce high waves and thus damaging storm surge. They develop over large bodies of warm water, and lose their strength if they move over land. This is the reason coastal regions can receive significant damage from a tropical cyclone, while inland regions are relatively safe from receiving strong winds. Heavy rains, however, can produce significant flooding inland, and storm surges can produce extensive coastal flooding up to 40 kilometres (25 mi) from the coastline.
Although their effects on human populations can be devastating, tropical cyclones can also relieve drought conditions. They also carry heat and energy away from the tropics and transport it toward temperate latitudes, which makes them an important part of the global atmospheric circulation mechanism. As a result, tropical cyclones help to maintain equilibrium in the Earth's troposphere, and to maintain a relatively stable and warm temperature worldwide.
Many tropical cyclones develop when the atmospheric conditions around a weak disturbance in the atmosphere are favorable. Others form when other types of cyclones acquire tropical characteristics. Tropical systems are then moved by steering winds in the troposphere; if the conditions remain favorable, the tropical disturbance intensifies, and can even develop an eye. On the other end of the spectrum, if the conditions around the system deteriorate or the tropical cyclone makes landfall, the system weakens and eventually dissipates.
The term "tropical" refers to both the geographic origin of these systems, which form almost exclusively in tropical regions of Vexillium, and their formation in Maritime Tropical air masses.
The term "cyclone" refers to such storms' cyclonic nature, with counterclockwise rotation in the Northern Hemisphere and clockwise rotation in the Southern Hemisphere.
Depending on their location and strength, tropical cyclones are referred to by other names, such as hurricane, typhoon, sirayai, tropical storm, cyclonic storm, tropical depression and simply cyclone.
The term Sirayai is derived from the pre-Cruisian Utameyas name for the wind god, which was adopted by the Guwimithian Empire and Utania's HuMOC thereafter. However, HuMOC uses the term Tropical Cyclone officially, uses "Sirayai" increasingly as the colloquial term to replace "Hurricane", while "Hurricane" is used popularly by the media.
Vexwide, tropical cyclone activity peaks in late summer, when the difference between atmospheric and sea surface temperatures is the greatest. However, each particular basin has its own seasonal patterns.In the southern Cisgronkian Ocean, the Cyclone season begins late October and ends in May. Southern Hemisphere activity peaks in mid-February to early March.
In the Northern Cisgronkian and Cislendian Oceans, a distinct tropical cyclone season occurs from June 1 to November 30, sharply peaking from late August through September.
Observation and Forecasting Edit
Intense tropical cyclones pose a particular observation challenge, as they are a dangerous oceanic phenomenon, and weather stations, being relatively sparse, are rarely available on the site of the storm itself. Surface observations are generally available only if the storm is passing over an island or a coastal area, or if there is a nearby ship. Usually, real-time measurements are taken in the periphery of the cyclone, where conditions are less catastrophic and its true strength cannot be evaluated.
Tropical cyclones far from land are tracked by weather satellites capturing visible and infrared images from space, usually at half-hour to quarter-hour intervals. As a storm approaches land, it can be observed by land-based Doppler radar. Radar plays a crucial role around landfall by showing a storm's location and intensity every several minutes.
Several agencies worldwide track and monitor the growth, development and paths of tropical cyclones.
In Ishrakan, the Utanian Hurricane and Meteorological Observation Centre (HuMOC), founded by President Okarvits in 301ap, monitors all South-western Cisgronkian cyclone activity. Working with the Utanian Coast Guard, and commercial and other military shipping in the ocean, and having two satellites at its disposal, HuMOC monitors activity in the region and provides weather warnings to shipping and regional government agencies.
Presently, most tropical cyclones are given a name using one of several lists of tropical cyclone names. Storms of tropical storm strength are given names to allow the public to easily distinguish between systems when there are multiple systems in an individual basin at the same time.
These names are taken from lists which vary from region to region and are drafted a few years ahead of time. While, at present, there is no Vexwide co-ordination on the naming of tropical cyclones leading to the possibility that a storm may be named twice, there is a general rule that the national agency that first identifies the tropical storm and is closest to it will name it.
Names usually follow an pre-assigned alphabetical list that changes from year-to-year, and the names of tropical cyclones that cause devastation are usually stricken from those lists after the season has ended and new names are chosen to take their place. In Utania, TCs Gordon and Hirana have been removed from the HuMOC list for just this reason.
HuMOC uses personal names and follows the Ingallish alphabet for ordering. The names are a mixture of Utani, Westrian, Phenixien, Ingallish, Guwimithian and Tarqviti names to reflect the regions of persons affected.
Notable Tropical Cyclones Edit