1.0 Introduction
1.1 Origin of Heat Waves
Heat waves form when high pressure a lift (from 10,000 - 25,000 feet (3000 - 7600metres) strengthens and remains over a region for several days up to several weeks. This is common in summer (in both Northern and Southern hemispheres) as the jet stream “follows the sun”. on the equator side of side of the jet stream, in the middle layer of the atmosphere is the high pressure area. Summer time weather patterns are generally slower to change than in winter as a result, this mid level high pressure also moves slowly. Under high pressure, the air acts as a dome capping the atmosphere, this cap helps to trap heat instead of allowing it to lift. Without the lift there is little or no convection and therefore little or no convective clouds (cumules clouds) with minimal chance for rain. The end result is a continual build up of heat at the surface that people experience as heat waves.
In the Eastern United States, a heat wave can occur when a high pressure system originating from the Gulf of Mexico and the Caribbean sea while hot dry air masses form over the desert Southwest and North Mexico.
The SW winds on the backside of the high continue to pump hot, humid gulfair northwestward resulting in a spell of hot and humid weather for much of the Eastern states.
In the western cape province of south Africa, a heat wave can occur when a low pressure offshore and high pressure inland combine to form a Bergwind. The air warms as it descends from the Karoo interior, and the temperature will about 10oc from the interior to the costs. Humidities are usually very low and the temperature can be over 40oc in summer south (51.5°c) was recorded one summer during a Bergwind occurring along the Eastern cape coastline.
1.2 Objectives of the Study
The general objectives of this projects to undertake a study on theories, origin and effect of heat waves. Increased human morbidity and mortality, particularly among the elderly and infirm:
- To know the stress for out door workers
- To increased bush fire risk
- To know the in animals
- To know the damage to crops and vegetation
- To increased energy demand, e.g greater demand for air conditioning
- To know the stress on energy supply infrastructure,
- To increase demand for water e.g human consumption, cooling in power stations
- To shifts in tourism preferences due to higher temperatures
1.3 Aim / Purpose of the Study
- To understand the health impact of heat waves and its effects
- To assess the state of and gaps in current knowledge
- To comment on current research methodology
- To make evidence-based recommendation for public health intervention programmes
- To highlight or pinpoint the direction of further research
1.4 Scope of the Study
The scope of the research is focused analyzing the theories, origin and effect of heat waves and how heat waves is measured to become widely accepted. Also, it will analyze how it is easily understood and how people associate extreme values with their experience.
1.5 Definition of Terms
The theories, origin and effect of heat waves can also be ascribe to the following:
Heat Stress:
This arises from a period where temperature is warmer, on average, than the recent past. Maximum and subsequent minimum temperature averaged over a have-day period and the previous 30 days are compared to characterize this heat stress in a second index.
Severe Heat Wave:
An event where EHF values exceed a threshold for severity that is specific to the climatology of each location.
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