Weather Patterns and Severe Storms - Term Paper Example

1 Weather Patterns and Severe Storms Introduction The study of weather patterns has become more vital than ever before because of the advent of global warming. Weather patterns are more closely scrutinized than ever to detect the changes that global warming has brought to the global climate. On the other hand, severe storms in the form of thunderstorms, tornadoes, hailstorm and floods have wrought havoc in the lives of many people around the globe and thus, there is an ever-present interest in understanding as to how exactly they developed for the purpose of timely detection before they can actually do damage. Weather patterns appear evident by observing the weather for a number of years. Thus, in places in the middle latitude like the British Isles, northern Europe, and central North America, the summers are characterized by warm weather, the winters are cold accompanied by snow and ice, and the amount of rainfall in the months of June and November are quite the same. All these patterns of weather observable in a region for a number of years make up its climate. Weather has various elements but the most important are mean temperature and mean rainfall or precipitation. The others are wind, air pressure, humidity, cloud, and sunshine. The single source of power and energy that powers weather is the sun as it is provides the necessary heat to kick off the different elements of weather (Jennings & Rosewarne 6-7). Temperature. Temperature is the hotness or the coldness of the earth’s atmosphere and it is normally measured by degrees Celsius (Centigrade). This factor is important because it has a bearing on the other elements of weather. Temperature is affected by such factors as sunshine, time, geography and wind. Exposure to sunshine is determined by the length with which a 2 location is exposed to the sun’s intensity, and the presence or absence of clouds. Time also affects temperature as the earth has varied exposure to sun due to earth rotation and revolution. Areas found in or near the equator have the least variation in temperature and the farther one goes from the equator, the higher the variation of the temperature. Other vital geographical factors are: altitude, or the distance from the sea level with the higher the altitude goes, the lower the temperature is; proximity to the sea, where temperature slowly changes; sea temperature, which varies from each other; currents of oceans, as currents that move towards the poles are warm while those that move water towards the equator are cool (BBC 2). Humidity. Humidity is the amount of water vapor in the atmosphere, and a more humid atmosphere means the presence of a lot of water vapor and low humidity implies less. The air can hold only a certain amount of water vapor at once and once saturated, the water vapor condenses leading to precipitation in the form of dew or frost. However, the higher the temperature the more water vapor the air can hold which means that places along the equator area are capable of being more humid than those far from it. The saturation point of the atmosphere in holding water vapor is called dew point (BBC p. 3). Precipitation. Precipitation refers to the process when the atmosphere has reached its dew point and the water vapor that is being held by air starts to fall to the ground in the form of snow, drizzle, hail, sleet, fog, mist and rain. The kind of precipitation that a certain location gets is largely dependent on its temperature and atmospheric pressure (BBC 4). Clouds. Clouds are formed because when air rises it becomes cooler and therefore hold less water vapor. Once it reaches its dew point, the water vapor condenses and become water droplets, forming clouds. The kinds of clouds are: high-level clouds like cirrus, cirrocumulus, 3 and cirrostratus; medium-level clouds, like altrostratus, altocumulus, and nimbostratus, and; low-level clouds, which include stratocumulus, stratus, cumulus, and cumulonimbus (BBC 6). Fig. 1 A synoptic chart showing wind direction Atmospheric Pressure and Wind. Atmospheric pressure is the pressure of air on the earth’s surface. There is low pressure when the air molecules expand, becomes lighter and rises. This happens when the temperature is warmer. High pressure, on the other hand, occurs when the air is colder making the air molecules contract, become heavier and sink towards the earth. On the other hand, wind is the movement of air masses from one area to another dictated by pressure ratio; from high to low and the greater the difference between the two the faster the movement of the wind (see Fig. 1) (BBC 7). Fronts. When two different air masses meet, a front occurs. There are three kinds of fronts: warm fronts; cold fronts, and; occluded fronts. Warm fronts happen when warm air rises over cold air while cold fronts occur when cold air passes below warm air. Occluded fronts on the other hand, occur at transition stages when cold fronts slowly replace warm fronts or the other way around (BBC 8). 4 The earth has patterns of wind and pressure. Above the equatorial line, for example, is a band of low pressure at 0, and two low pressure bands can be found around the Arctic at 60 North and at the Antarctic at 60 South. Two high bands can be found in between them at 30 North and 30 South. Winds move from high to low pressure areas all the time and are most intense in the middle of the high and low bands and weakest around the band themselves. The movement of the winds from high to low bands is called prevailing winds (or trade winds because they helped trade ships in navigating and sailing) (BBC 9). The activities of the air in the equatorial line determine the wind patterns of the world. The hot weather in the equator causes hot air with water vapor to rise causing low pressure band in the area. This low pressure takes in air from both sides – north and south. The air from both sides also undergoes the same process of rising and as it rises, it pushes away the cooler air on top to both directions, that is, north and south. The air pushed away on both sides sink to the ground on the north and south, respectively, creating high pressure zones (BBC 9). Severe Storms Severe storms refer to “deep, moist convective events (usually thunderstorms) which produce damaging weather such as destructive winds, damaging hail, tornadoes, heavy rain conducive to flash-flooding, or a combination of these phenomena” (Zschau & Küppers 154). Thunderstorms. A thunderstorm is rainfall accompanied by thunder and lightning and classified as severe when it has three-quarter hail or more or winds gusting more than 50 knots (57.5 Mph) or tornado. A thunderstorm averages 15 miles in diameter and usually lasts for 30 minutes. The thunderstorm develops as follows: first, the sun heats the earth’s surface, warming 5 Fig. 2 The Development of Thunderstorms in Three Stages the air above it; second, if this warm air is forced to rise, and will continue to do so if it is warmer than its surroundings, transferring heat in the process to the upper levels of the atmosphere (convection); third, the water vapor in the rising air begins to cool and releases heat, condensing into a cloud; fourth, the cloud begins to grow in the upward direction in the area with a below freezing temperature; fifth, the water vapor turns to ice and some into water droplets, the ice having a positive charge and the water vapor negative; sixth, when the built-up charges are released, a bolt of lightning is released causing sound waves heard as thunder (NOAA 2006). Tornadoes. Tornadoes, also called twisters, are funnel-shaped, rotating columns of air that can spin at more than 300 miles per hour. It is one of the smallest storms yet also the most violent (Woods & Woods 2007 6). Although it is air, it is manifested sometimes by a condensation funnel made up of water goblet augmented by the dust and debris it carries with it. Scientists surmised that it develops from a rotating updraft, initiated by winds going in differentdirections forming a supercell thunderstorm which is a “long-lived (greater than 1 hour) and highly organized storm feeding off an updraft – as large as 10 miles in diameter and up to 50,000 feet tall – can be present as much as 20 to 60 minutes before a tornado forms” (NOAA 2006). A supercell thunderstorm can develop into a tornado but there are also tornadoes that do 6 not form out of the supercell thunderstorms. Fig. 2 Tornado Hail. Hail is a weather disturbance in which hailstones, which are made of ice, fall from the sky immediately after a thunderstorm (Burby 1999 p 6). This is because updrafts during thunderstorms carry “raindrops upwards into extremely cold areas of the atmosphere where they freeze into ice” (NOAA 2006). The usual time for hailstorm is in summertime. Hailstone diameter can range from 1/6 inch to 5 inches or from tiny pebbles to golf balls. The largest hailstone recorded is 1.67 pounds. They can also accompany tornadoes and winter storms (Liebsch & Liebsch 63). The latest theory on hailstone formation is that “supercooled water may accumulate on frozen particles near the back-side of the storm as they are pushed forward across and above the updraft by the prevailing winds near the top of the storms. Eventually, the hailstones encounter downdraft air and fall to the ground” (Liebsch & Liebsch 63). Conclusion/Reflection 7 It is evident from the study of weather patterns and severe storms that there is one single determining element that affects all other elements of the weather: temperature. This is because the degree of heat in the earth’s atmosphere determines, as discussed previously, precipitation, humidity, clouds and atmospheric pressure. Temperature therefore kicks off a chain of event and any change in the intensity of temperature can create an entirely different weather pattern or can impel even more severe storms than what the world has so far experienced. This is significant today because of the advent of global warming. Global warming, which is an aggravated condition of the greenhouse effect, is the continuous heating up of the earth’s atmosphere because of its inability to reflect back the sun’s heat outside. The abundant presence of gases like Co2, ozone and water vapor has trapped the heat in the earth’s atmosphere and is causing earth temperature to shoot up (Gonzales 374). This higher temperature that the earth is experiencing will eventually alter weather patterns and climates. As previously pointed out, a higher temperature allows the atmosphere to hold more water vapor which implies that more precipitation can also be produced in the form of rainfall, snow and ice. There will be extreme climates as the higher temperature will create a lower atmospheric pressure and the volume of precipitation a higher atmospheric pressure. And because of the degree of difference between the two pressures, there will be faster wind movement in between the pressure bands. In short, the higher temperature that global warming brings with it will play a havoc on weather patterns, climates and worse, on the lives of people around the globe who will be on the receiving end of an inclement and much more hazardous weather condition. Life on earth will never be the same. Works Cited Burby, Liza N. Hail. The Rosen Publishing Group: 1999. Elements of weather and climate. Geography. BBC. 2008. http://www.bbc.co.uk/schools/gcsebitesize/geography/weather/elementsofweatherrev Gonzalez, Joseph. The Complete Idiots Guide to Geography.   Alpha Books: 2004. Jennings, Terry & Rosewarne, Graham. Weather Patterns: Weather Patterns. Evans Brothers: 2005 Liebsch, Bill & Liebsch, Janet. (2007). Its a Disaster!: And What Are You Gonna Do About It? Fedhealth Severe Weather Primer. NOAA. 2006. http://www.nssl.noaa.gov/primer/ Woods, Michael & Woods, Mary B. Tornadoes. Lerner Publications: (2007). Zschau, Jochen & Küppers, Andreas. Early Warning Systems for Natural Disaster Reduction: EWC ’98 by International IDNDR-Conference on Early Warning Systems for the Reduction of natural Disaster. Springer: 2003. Read More