Hello steemians, how are we doing and hope our day is going fine as well. Today I will be enlightening us about a serious type of synoptic disturbance called THUNDERSTORMS as regards our geographic environment.
I remember as a child growing up, I used to be very afraid of heavy rainfall (although I’m a bit afraid of it now lol) then because of the heavy sound of thunder that comes with the rain .sometimes I would have to hide under my parents bed though. My grandfather would always say that thunder is the voice of God hmmm, although I didn’t believe. Sometimes I ask myself why can’t it just rain without the sound of thunder little did I know that lightening is even worse because of the electric charge that comes with it.
Image source Pixabay. CC0 creative commons license. Contributed by Artem_Apukhtinv
Thunderstorms are the most frequent form of synoptic atmospheric disturbances. It has been estimated that at any moment in time, there are about 3000 thunderstorms which are occurring over different points or part of the earth. Thunderstorm occurrences are not uniformly distributed around the globe. The occurrence of thunderstorms are more in some regions and less in other regions. If we take a look at the tropical regions of the world, we would see that thunderstorms are more in those areas
The majority occur over the tropics while very few occur over the polar regions of the earth. This is because thunderstorms are unstable phenomenon which require rising cells of heated moist air which have been triggered off by an uplift over an obstacle. Since they require a warm moist air mass to help them develop fast. Thunderstorms are very rare in dry season because of the low atmospheric moisture content in the air during the season or in areas where cold and dry air mass prevail.
Thunderstorms are of different sizes which can be very large and also small too, shapes as regards it can take any form because it has no defined pattern and structures but they may be considered to fall into two broad categories which are the local or air mass thunderstorms and organized thunderstorms
Thunderstorms were studied extensively by two American scientists H.R BYEAS and R. BRAHIM under the American thunderstorm projects.
There are three distinct stages in the development of thunderstorms, and these are;
- The cumulus stage ( development stage)
- Mature stage
- Dissipating stage
Each of these stages can last for about 20 to 40 minutes approximately. So let’s talk about the various stages.
The cumulus or development stage
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Image source credit: wikimedia. Creative commons license. Contributed by NOAA
The initial stage of thunderstorm is known as the developing stage also popularly known as the cumulus stage. This initial stage is characterized by the upward movement of heated air. Naturally, moist air with higher temperature tends to have lower mass and hence, they are lighter than the cooler air. This is as a result of the absorbed heat by the earth surface which is released later in the day into the air nearest to the surface, hence, the hotter air displaces the cooler higher in the atmosphere. The movement of this hot air can also be aided by wind movement.
This heated air gets cooled on its way up but since it is moisturized, the water molecules begins to condense. At a very high altitude, complete condensation of this hot air occurs as it meets even cooler atmospheric region thereby forming what is known as cumulus cloud, named after this phenomenon.
The heat which was latent in the air is then released and this causes the air initially existing at that atmospheric region to absorb more heat making them loose moisture and gets drier. This drier air also moves even higher into the atmosphere. This movement leaves a pressure imbalance which paves way for the formation of the thunderstorm.
The mature stage
The continuous release of latent heat of vaporization continually injects fresh supplies of energy from the atmosphere which accelerate the up drought thus expands the cloud to several kilometers so that the initial cumulus cloud now develops into cumulonimbus cloud (which has a great vertical extent) because of its height, the top of the cumulonimbus cloud may reach temperatures below freezing point thus allowing the wegner Bergeron ice-crystal process to begin operating.
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[klinefelter’s syndrome credit: wikimedia CC3.0 license. Author: unknown]
However, areas where the top of the cloud is still above freezing levels may still initiate the droplet coalescence process on account of great vertical extent (up to 10-12km) and huge volumes (up to 100 -150km cube) of the cloud.
The velocity of the up graph (up to 30m/s) means that the growth of the rain drops either by freezing or by coalescence will be very rapid. The falling rain drops and ice pellets within the cloud sets off an active down drought within one half of the cloud.
This down drought is accelerated by frictional drag as the raindrops reach their thermal velocities and chill the air within the lower cloud. The horizontal temperature contrast between the up draft in one part of the cloud and down draft in the other part of the cloud may reach 4-5 degree Celsius. This accelerate the clouds to another 2-3km so that its upper levels now reach beyond 12km
In the region of down drafts, very heavy rain occurs followed by lightning and thunder. The down draft hits to ground surface and spreads outwards forming a micro cold front dust of violent gushing wind with speeds outward up to 100km per hour. This winds are often destructive to the environment. It may also scoop up violently the warm surface air to generate a thunderstorm cell.
The dissipating stage
In this stage, the cumulonimbus cloud expands and reaches its greatest vertical extent. Its top extends beyond about 12km where it is caught up by the upper westerly. These strong winds elongate the top of the cloud to give it its characteristic anvil shape.
Gradually as the supply of moist air within the cloud cell is expended (used up) ,the supply of latent heat energy diminishes and then the up draft diminishes as well to also be replaced by down draft throughout the cloud.
The rainfall in this stage thus gets lighter and lighter as the cloud diminishes in size until after about 30 minutes, the former cumulonimbus cloud degenerates into thin layers of strato cumulus.
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Image source credit: wikimedia. Creative commons license. Contributed by NOAA
This strato cumulus gradually disperse and the thunderstorm event is over. Apart from the often destructive guts of winds from the down drafts and the very heavy rainfall, the most spectacular feature of the thunder storm is their lightening and associated thunder. Three are two general classes of lightening which are the cloud to ground and cloud to cloud lightening.
Lightening is a tremendous bolt of extremely high voltage electric current. It is caused by an increase in the electrical field strength between the negatively charged earth and the positively charged clouds (lower clouds). When the field strength reaches the breakdown potential, an electric current is initiated which can produce electricity. Thunder is therefore the sound we hear that is caused by this super-heated air. This phenomenon is referred to as thunderstorm electricity.
There are a lot of effects (hazards) related to thunderstorms because of its dangerous nature. When thunderstorms occur, there is what we call the cloud to ground effect. The lightening strikes from the cloud strait to the ground thereby releasing electric charge to the ground. And we all know that electricity and water are friends(water conducts electricity) in the sense that anything that has blood flowing in them can be electrocuted when this happens. Thunderstorms cause about 90 to 100 deaths yearly and over 80 injuries yearly as well which might equally lead to death also.
Thunderstorms can also cause flash floods which are very disastrous to our immediate environment. Flash floods comes with heavy speed flow of water that can destroy anything in its path and before you know it it's all over. Flash floods don't last especially if the area affected is an upland(a little higher than sea level). It can also cause down burst of rain, hail and water sprout.
Conclusion
There are alot of synoptic environmental disturbances but thunderstorms are one of the most dangerous amongst them because of the electric charge that comes with the lightening from it. They are natural phenomenals which we do not have the power to control or change as human beings but we can reduce it's effects on us by preparing for them (precautionary measures)We can shield ourselves from them by staying indoors whenever it rains and there is a sign of lightening (since lightening causes thunder sounds) .
Its your girl 
References
- Dangerous Weather ~ucar
- thunderstorm formation ~windows2univers
- cumulus cloud ~wikipedia
- What is a thunderstorm? ~eartheclipse
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