Tornado Trouble

What is a tornado?

Tornadoes are mobile, destructive vortexes of violently rotating winds. They have the appearance of a funnel-shaped cloud and advance beneath a large storm system. Tornadoes may only touch down for around 30 seconds, however they may do so several times as a storm moves across an area and generally track no more than 5km in length. They are also known as a whirlwind or twister. They are not also known as a hurricane or typhoon. Most tornadoes have wind speeds less than 110 miles per hour, are about 80m across, and travel a few miles before dissipating.

Where in the world is at risk from tornadoes and how about tornado alley, USA?

Tornadoes form all over the world, but some areas are more prone to tornadoes than others. The USA gets a lot of tornadoes, about 1,000 each year on average. Tornado Alley is an area in plains of the mid-USA that has a very high number of very destructive tornadoes. Tornadoes also occur on a yearly basis in Bangladesh. The UK also experiences smaller tornadoes occasionally.

Texas has more tornadoes than any other state in the USA, but Oklahoma has the most dangerous storms (F4 and F5 storms). Conditions in tornado alley are favourable for tornado formation, as during the summer, the plains of Middle America get very hot (creating updrafts) and there are many thunderstorms. Tornadoes form during thunderstorms, when unstable hot air near the ground rises and meets the cooler air above in the thunder clouds. Tornadoes can form at any time of the year, but most of them form from March to August (in the Northern Hemisphere).  In the US, intense thunderstorms often form when cold air from the north or west converges with moist tropical air from the south. A great number of the springtime tornadoes in ‘tornado alley’occur in this way.

In Bangladesh, tornadoes are formed from supercell thunderstorms, resulting from the complex mixing of different air masses (usually a hot and dry air mass from India and a moist air mass from the Bay or Bengal), as well as being associated with tropical cyclones.

In the UK, they are most commonly associated with intense, often small depressions (low atmospheric pressure) that move rapidly across the country.

Tornado Alley

 

Tornado World Risk Map

What atmospheric conditions give rise to a tornado developing and how do they form?

Tornadoes form when unstable hot air near the ground rises and meets the cooler air above in the thunder clouds. Very hot temperatures create updrafts from the ground. Hot air rises, cools and condenses forming thunderstorms. Tornadoes may during thunderstorms, when unstable hot air near the ground rises and meets the cooler air above in the thunder clouds. or because it is forced to rise by being undercut by cooler air. Intense convection (rising warm air) caused by the rapid warming of the ground surface during a summer’s day. Cumulonimbus (thunderstorm) clouds have very powerful updrafts. Most tornadoes in the US are spawned by intense thunderstorms known as ‘supercells’. When this vertical updraft interacts with the larger scale horizontal winds a strong vertical wind shear results. This in turnn causes the air to rotate to form a ‘tube’of spinning air – this is the familiar funnel-shape associated with a tornado.

After a tornado touches down, a downdraft develops near the rear of the supercell. This begins to wrap itself around the tornado and starts to cut off the inflow of the warm humid air that is sustaining it, causing the tornado to weaken and dissipate, accounting for the short lived nature of tornadoes.

How is the severity of Tornadoes measured?

Tornadoes are measured on the Fujita Scale. The scale was introduced in 1971 by Tetsuya Fujita of the University of Chicago. The scale was updated in 1973, taking into account path length and width. In 2007, the Fujita scale was updated, once again to the Enhanced Fujita Scale, which was introduced in the United States. The new scale more accurately matches wind speeds to the severity of damage caused by the tornado.

Fujita Scale Diagram

What are the key hazards caused by Tornadoes?

The main hazard of tornadoes is winds, often exceeding 400kph (250mph). One of the features of a tornado is its very narrow path of destruction, often only a matter of a few hundred metres. However, within this narrow belt, the destruction to property can be absolute. The winds and powerful updrafts are capable of lifting cars and mobile homes, uprooting trees and removing roofs from houses. Farm animals and people can be lifted off the ground. One of the greatest dangers associated with tornadoes is the frenzy of loose materials scything through the air, such as sheets of corrugated iron and pieces of wood picked up by the turbulent winds (as shown with the car debris in the video below).

 http://www.youtube.com/watch?v=oJlfAGC8G8w

In what key ways do Tornadoes differ from Hurricanes? 

	Hurricanes	Tornadoes
Width	150km+	1/2 km
Location	8º and 15º north and south of the equator	Most parts of the world
	Develop over warm seas	Develop over land and sea (they are known as water spouts over the sea)

NB: The Wizard of Oz features a tornado not a hurricane…

http://www.youtube.com/watch?v=WhQySxqSANU

Case Studies MEDC/ LEDC differences

MEDC: Oklahoma Tornado 2013

– 20^th May 2013

– 2:56-3:35 (long time!)

– EF5 tornado

– 24 deaths, 377 injured.

– Winds of up to 200mph caused damage to vehicles and property, total damage on $2bn.

– Due to warm moist air from the Gulf of Mexico interacting with cool, dry air from Canada. Lead to instability of warm air that was forced to rise rapidly leading to thunderstorms. Wind shear at different altitudes caused spinning updrafts leading to tornadoes.

– Oklahoma state population density of 21 people/km^2.

Responces:

The National Oceanic and Atmospheric Administration (NOAA) Storm Prediction Center (SPC) provided predicts hazardous weather events over the USA and coordinates warnings with the National Weather Service (NWS). Prediction includes the use of observations, numerical forecast models, Doppler Radar and satellites to generate forecasts. Warning is given out and there is a set procedure for events. The public is advised to take all necessary safety precautions. People in the USA are very much aware if they live in a tornado prone area. Advice includes taking shelter in tornado cellars, basements or small rooms in the centre and base floor of houses. People should lie flat and protect their head from falling or flying debris, stay away from windows and outside walls. If in the open, lie flat in a ditch or lower bit of land.

President Barack Obama has declared a major disaster in Oklahoma, ordering federal aid to the affected areas.

LEDC: Tangail, Bangladesh

– 13^th May 1996

– 500-1000 deaths, 30000+ injured, 100000+ homeless, 80 villages destroyed.

– Telephone lines destroyed, crops destroyed.

– At least two separate tracks: Northern track very long- 50 miles + in length!

– Prosperity of textile industry in the region meant economic success of region and building of sheet metal structures (better than mud houses). Air filled with loose sheet metal was fatal and main cause of injuries (99% of injuries).

– Population density of 1,100 people/km² in Tangail District.

Responses:

– Hundreds of paramedics and volunteers rushed to area, but poor weather meant it was hard to reach/ work in area.

– Poor quality and inadequate number of aid meant hospitals turned people away and 7% of hospital deaths were due to sepsis after-wound infections.

– Poor warning system: only 28 weather stations, without Doppler radar or forecasters. Organisations such as the World Meteorological Organisation should donate equipment and training. Tornado warning sirens and shelters are needed. Education of hazards and adequate responses should be increased.

– Studies show that for every $1 invested in storm, cyclone and flood warning prediction systems in Bangladesh, the estimated return is between $8 and $500 for a 10-year period.  Economic and Social Commission for Asia and the Pacific (ESCAP) has help set up the Regional Integrated Early Warning System for Africa and Asia (RIMES) with the collaboration of the Asia Disaster Preparedness Centre, by international donations. RIMES has supported Bangladesh in developing long-lead flood forecasting and in concurrent monitoring of depressions and cyclone formation in the Bay of Bengal. The Government of Bangladesh has mobilized US$ 28 million from the Climate Resilient Fund for a comprehensive early warning system improvement project, of which US$4 million is budgeted for technical inputs for RIMES.

Tangail District Location

Evaluation:

– Undoubtedly greater economic loss in USA, due to more high-tech/ valuable possessions damaged. However, relative loss in Bangladesh perhaps greater in terms of essentials to life lost. Then again, destruction was absolute in both areas affected and responses are more important.

– Greater warning, housing quality, preparedness/ education (people and shelter) in USA meant far lower social loss (loss of life, etc.). Better (quicker and more skilled) emergency services/ government response and lower number of people affected meant lower social losses. Population density important here also as more people at risk/ to provide aid to after event.

Credit to:

http://www.enchantedlearning.com

http://www.google.co.uk/maps

http://www.islandnet.com

wxbrad.com

en.wikipedia.org

http://www.unescap.org/

i2.cdn.turner.com/

mierdenblog.files.wordpress.com/

upload.wikimedia.org/

Geo factsheet 192 Tornado.pdf

 

Desertification

Desertification is defined as “land degradation in arid, semi-arid and dry sub-humid areas” by the United Nations Convention to Combat Desertification. It poses many risks and the livelihoods of more than one billion people are threatened. A third of all crops are cultivated on land affected by desertification. 100% of Senegal and Jordan is desert and dryland areas. Europe is not exempt; up to 35% of Spain is at risk. Globally the cost of desertification is estimated to be around €100b per year.

The four main causes of desertification are as follows. Overgrazing and overbrowsing of plants happens when animals cover a small patch of land. It removes the vegetation cover that protects the soil from erosion. Secondly, when faced with the need for production of food, farmers can exploit natural resources to the point that soil nutrients and organic matter diminish greater than the soil’s natural regeneration capacities. Deforestation means that the soil is no longer bound to the land by the roots of the tress and can be washed away. Poorly drained irrigation systems turn crop lands salty. Other factors which can enhance desertification include drought, flooding, fires, climate change and natural weather trends.

The effects of desertification are the destruction of livelihoods, starvation, emigration, human health problems due to dust and a lower quality of life, income and a higher infant mortality rate. Future farming cannot take place on the land for a very long time with denuded landscapes taking an average of 125 years to recover with the correct soil compaction.

Ways to combat desertification include reforestation, managing livestock correctly to reverse desertification, not burning grasslands, restoring water sources and using new fertilisers and soil amendments. Leaving the landscapes to recover fertility themselves is also an option. In Africa, a project is taking place to plant an 8,000km wall of tress (15km wide), to slow down wind erosion and improve river infiltration, protecting the area in the continent between the Sahara in the north and the savannahs of the south.

A major issue is that projects like the Great Green Wall in Africa do not receive enough global attention or funding, with the example project receiving less than half of its required funding (total estimated at €2.4b). The responses to combating desertification have been limited as it is not integrated into wider policies such as climate change, which it is very relevant to. Finally, people must make a living from their land, therefore the suggested schemes must benefit the farmers in order for them to adopt them.

Peak Oil

Peak oil is the point in time when the maximum rate of petroleum extraction worldwide is reached, after which the rate of production is expected to enter terminal decline.

The Problem

There will come a time when worldwide oil reserves will completely dry out, but the more pressing matter in respect to peak oil is the extraction of crude oil is becoming limited. Limiting factors are the cost of exploration and production, along with physical boundaries of accessibility.

It is inevitable that the global demand will move to a point where it consistently exceeds supply, especially with the increased use in developing countries. Over 100 countries have already passed the point of peak production; oil production in USA peaked in 1970.

The problem is that oil is becoming unaffordable, not that oil is running out. Oil companies admit that it is getting more difficult and more expensive to extract.

What Problem?

Since the 1970s prediction have been made that oil is about to dry up and have been proven wrong.

BP does not see peak oil being a problem of the next few years. They state that more than 40 years of oil and 60 years of gas are available at today’s consumption rates. They say that many of the hydrocarbons in the ground are yet to be discovered and utilised and it is thought by many that the world’s oil supply will remain high due to better techniques of extraction and mapping. However, surely the seismic remapping of old oil fields and the  investments in technology aimed to squeeze every last drop of oil out of them shows that the oil companies have run out of new sites and have instead resorted to “scraping the bottom of the barrel.” In this case the date for peak oil is surely approaching quickly.

The Effects

Peak oil will cause a sharp and permanent rise in oil prices, having many effects.

Higher and more volatile oil prices will mean that they have more potential to destabilise economic, political and social activity in the future. Wars and conflict could occur due to political tension of the trading of oil.

Not only will the oil industry be affected, the global manufacturing industry will suffer, as plastics and some fabrics are made of oil- based ingredients.

It could be argued that a lack of oil will be a bonus for the environment, with a shift to renewable energy. It could also symbolise the collapse of capitalism and unsustainable globalisation.

Postponement

New discoveries of oil reserves, methods of extraction and the efficient use of oil will postpone the peak oil date, as the supply will not have to be as big for a smaller demand. “A priority is to develop technology to take oil out of cars,” says Birol (Chief Economist and Director of Global Energy Economics at the International Energy Agency in Paris). “In 20 years’ time I would like to see a system where oil still has an important role, but where alternative technologies are picking up and there has been a substantial growth in renewable energy.”

Geographical Accuracy of “The Core” (Film)

In the film “The Core” the Earth’s core has been caused to stop spinning. This leads to worldwide problems such as deaths due to pacemakers failing, powerful thunderstorms and birds losing their sense of direction. Within a year, the Earth’s electromagnetic field will collapse, irradiating the planet. The only way to get the core spinning again and to save mankind, is to go down to the centre of the Earth and set off a chain of nuclear explosions. How accurate is the film though?

The Earth’s interior was described and explained accurately in the film with the crust, the mantle, the outer core and the inner core being described correctly. The mantle is also subdivided into the upper mantle, asthenosphere and the lower mantle as stated in the film. We know the structure of the Earth’s interior from observing the behaviour of seismic waves generated during earthquake activity. The description of the rotating outer core due to massive convection currents is also correct and it is thought that this circulating magma generates a weak magnetic field, which in turn drives the inner core’s rotation, thereby creating the Earth’s relatively strong magnetic field, as described in the film.

However in the “The Core” the outer core ceases to rotate due to “Project DESTINI.” This project was designed as a weapon to propagate earthquakes through the Earth’s core, but it unintentionally stopped the core’s rotation instead. With today’s technology controlling a giant mass of hot fluid 2,900km below the surface of the Earth is impossible. It is possible that the film is accurate with the idea that the Earth’s magnetic field would stop due to the outer core’s rotation ceasing, as this rotation in turn causes the magnetic field.

One impossible concept in the film is the empty caverns in the mantle. The pressure is 3.5 million times that of the Earth’s surface so these cavities are not possible and not geographically accurate.

One amusing part of the film is when hundreds of birds fall out of the sky due to their navigational systems, which rely on the Earth’s magnetic field, failing to work. Scientists have no significant data to show exactly how birds would be effected in this scenario, but surely their eyes would come in useful when preventing them from flying into the ground!