101. What is cyclone?In Greek, the term cyclone mean spin. It is an atmospheric large-scale vortex with low pressure in the center.
The air rotates in the northern hemisphere in a counterclockwise direction, and in the southern hemisphere it is clockwise. Cyclones as a rule, brings with them difficult weather conditions, cloudiness, precipitation, wind strengthening, often seasonal phenomena: thunderstorms, fogs snowstorms, ice. It is characterized by the distribution of pressure and the nature of the air circulation under the influence of friction in the lower layers of the atmosphere In their origin the vortexes are divided into two main groups: tropical hurricanes typhoons and cyclones of temperate latitudes.A tropical cyclone is one of the most dangerous vortexes. It is thanks to the low pressure in the center that it moves with a huge speed that grows due to the planet’s rotations. Depending on the speed of these cyclones, they were divided into several types. Here are some of them:depression at a speed of up to 17 meters per second;Hurricanes – speed exceeds the mark of 39 meters per second;storms – up to 38 meters per second.The homeland of tropical vortices are oceanic expanses in the equatorial region between about 10-15 north and south latitudes.
the diameters of these giant vortices are several hundred kilometers and the height is from 5 to 15 km. in temperate latitudes tropical cyclones come from late june to early october and are most active in august-october. a distinctive feature of the cyclones of this group is that they are thermally homogeneous i.e. there are no temperature contrasts in different parts of the vortex they contain a colossal amount of energy. moving towards temperate latitudes tropical cyclones gradually lose their strength and decay.
if their paths ran only over the water areas of the oceans and their coastal seas only sea and ocean vessels caught in the path would be attacked by hurricanes. however some of the hurricanes hit the coastal areas of the continents and the islands causing great destruction. storm winds and heavy rainfall thats what typhoons bring to the inhabitants of the areas where they make their long journeys. cyclones of temperate latitudes are less dangerous. they occur primarily in the zones of the atmospheric fronts where two different air masses meet. in the northern hemisphere the most extensive cyclones are usually observed over the waters of the atlantic and pacific oceans. their repeatability depends on the time of year andthe geographical area.
on average in the northern hemisphere cyclones over the european part of the continent are more frequent in winter over the asian one in summer. cyclones have a diameter of the order of 2-3 thousand km or more. the weather in the cyclone of the extratropical latitudes is inhomogeneous: the front and rear parts of the cyclone are distinguished the left and right parts arein relation to the direction of its motion. in the anterior part of the cyclone continuous layered cloud cover of the warm front prevails complex sediments with winds of the southern quarter of the horizon. in the rear of the cyclone behind the cold front the weather is unstable with rainfall precipitation a gusty wind of the north-western and northern quarters; cloudiness can be with breaks and even with short-term clearings and in summer it will be of a convective type. the left most often northern part of the cyclone is characterized by weather conditions which can be called intermediate between the front and rear parts of the cyclone; the winds ofthe eastern and north-eastern quarters predominate the clouds are solid precipitation is complex falling with interruptions and gradually turning into a short-term shower type.
the right southern part of the cyclone for some period of his life is a warm sector it is filled with a warm air mass which eventually pushes up. here depending on the season and type of air mass the weather can be very different but it is mostly without significant precipitation with fog or low thin layered clouds often cloudless and always warm with winds of the southern and south-western quarter