Thunderstorm - what is it?Where are dissecting the sky and lightning ominous thunder?The storm - a natural phenomenon.Lightning-called electrical discharges can form inside clouds (cumulonimbus), or between the Earth's surface and clouds.They are usually accompanied by thunder.Lightning associated with torrential rains, heavy wind, and often with hail.
Thunderstorm activity - is one of the most dangerous natural phenomena.People struck by lightning survive only in isolated cases.
simultaneously acts on the planet about 1,500 thunderstorms.Intensity discharge estimated at hundreds of lightning strikes per second.
distribution of thunderstorms on Earth uneven.For example, over the continents of 10 times more than the ocean.Most (78%) of lightning discharges is concentrated in the equatorial and tropical zones.Very often fixed storm in Central Africa.But the polar regions (Antarctica, Arctic) and poles lightning almost can not see.The intensity of the storm turns out to be connected with the heavenly body.In the middle latitudes the peak of its accounts for the afternoon (afternoon) hours for the summer.But at least it registered before sunrise.And important geographical features.The most powerful storm centers are located in the Himalayas and the Cordillera (mountain areas).Various annual number of "storm days" in Russia.In Murmansk, for example, they are only four, Arkhangelsk - fifteen Kaliningrad - eighteen, Peter - 16, in Moscow - 24 Bryansk - 28 Voronezh - 26 Rostov - 31, Sochi - 50 Samara - 25, Kazan andYekaterinburg - 28, Ufa - 31, Novosibirsk - 20 Barnaul - 32, Chita - 27, Irkutsk and Yakutsk - 12 Blagoveshchensk - 28, Vladivostok - 13 Khabarovsk - 25, Yuzhno-Sakhalinsk - 7, Petropavlovsk-Kamchatsky - 1.
Development thunderstorms
How it goes?Storm cloud is formed only under certain conditions.Necessarily the presence of ascending currents of moisture, and the presence of a structure to be where one is the proportion of particles in the ice condition, the other - in the liquid.Convection, which will lead to the development of thunderstorms occur in some cases.
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Uneven heating of the surface layers.For example, the water with a substantial temperature difference.Above the big cities storm intensity will be slightly stronger than in the surrounding area.
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When displacing cold air warm.Front convention often develops simultaneously with Widespread and Nimbostratus clouds (clouds).
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When lifting the air in the mountain ranges.Even small elevations may lead to increased cloud formation.This forced convection.
Any storm cloud, regardless of its type, must pass through three stages: cumulus, maturity, stage of decay.
Classification
Thunderstorms some time been classified only in the place of observation.They share, such as spelling, local, frontal.Now the storm is classified by the performance, depending on the weather environments in which they develop.Updrafts are formed due to the instability of the atmosphere.To create thunderclouds it is a basic condition.A very important characteristic of such flows.Depending on their thickness and size are formed, respectively, different types of storm clouds.How are they divided?
1. Cumulonimbus odnoyacheykovye (local or vnutrimassovye).Have hail and thunderstorm activity.The transverse dimensions of 5 to 20 km, vertical - from 8 to 12 km."Lives" a cloud to an hour.After the storm the weather does not change.
2. Mnogoyacheykovye cluster.Here the magnitude more impressive - up to 1000 km.Mnogoyacheykovy cluster covers a group of storm cells at different stages of formation and development, and at the same time constituting a unit.How do they work?Mature storm cell located in the center of that decay - downwind.Transverse their size can reach 40 km.Clustered mnogoyacheykovye storm "give" wind (squall, but not strong), rain, hail.The existence of a mature cell is limited to half an hour, but the cluster itself can "live" for several hours.
3. squall lines.It also mnogoyacheykovye thunderstorms.They also called linear.They can be either solid or with a gap.Wind gusts are longer here (at the forefront).Mnogoyacheykovaya line at the approach seems to be a dark wall of clouds.The number of streams (both uplink and downlink) are quite large.That is why such a complex of thunderstorms are classified as multicell, although the structure of another storm.Squall line can give an intense rain and large hail, but often "limited" strong sniskhodyaschimi flows.Often it passes in front of the cold front.In the pictures, such a system has the form of a bent bow.
4. Superyacheykovye thunderstorms.There are such rare thunderstorm.They are particularly dangerous to human life and property.Cloud this system is similar to odnoyacheykovym because both are different one upflow zone.But they have different sizes.Superyacheykovoe cloud - a huge - nearly 50 km in radius, height - up to 15 km.Its boundaries may be in the stratosphere.The shape resembles a single semi-circular anvil.Upstream rate is much higher (up to 60 m / s).A characteristic feature - the presence of rotation.That it creates a dangerous extreme events (large hail (greater than 5 cm), the devastating tornadoes).The main factor for the formation of such clouds are surrounding conditions.It is a very strong convention with a temperature of 27 and winds with varying direction.Such conditions occur when wind shear in the troposphere.Formed in the thermals, precipitation transferred to the downstream area, which ensures a long life of the cloud.Precipitation is unevenly distributed.Livni go near the upstream and hail - closer to the northeast.The back of the storms could be displaced.Then the most dangerous area is next to the main riser.
There is the concept of "dry storm."It is a rare phenomenon, characteristic of the monsoon.With such a lack of rainfall storm (just does not get it evaporates as a result of exposure to high temperatures).
movement speed
in isolated thunderstorms it is approximately 20 km / h, sometimes faster.If the cold fronts are active, the rate may be 80 km / h.Many of the old thunder storms are replaced by new cells.Each of them is a relatively small distance (about two kilometers), but in aggregate distance increases.
mechanism electrifying
Where are themselves lightning?The electric charges around the cloud and within constantly moving.This process is quite complicated.The easiest way to submit a picture of the electric charges in clouds mature.They dominate the positive dipole structure.How is it distributed?The positive charge is placed at the top, and the negative - below it, inside the cloud.According to the basic hypothesis (this area of science can be regarded as yet little-investigated), heavier and larger particles are negatively charged, and small and light have a positive charge.The first fall faster than the latter.This causes the spatial separation of the space charge.This mechanism is supported by laboratory experiments.Has a strong charge transfer particles can ice pellets or hail.The magnitude and the sign will depend on the water content of clouds, temperature (ambient), the speed of collision (main factors).Not excluded the impact of other mechanisms.Discharge occurs between the ground and the cloud (or a neutral atmosphere, or ionosphere).It was at this point we have seen leaping through the sky flash.Or lightning.This process is accompanied by loud peals (thunder).
Thunderstorm - is a complex process.In his study may take many decades, perhaps even centuries.
