Discuss the relative importance of physical and human factors in accounting for changes to vegetation over time within ecosystems in the British Isles
Discuss the relative importance of physical and human factors in accounting for changes to vegetation over time within ecosystems in the British Isles The British Isles is an example of a Lithosere succession, in that it began as bare rock from glacial retreat. The plant succession started with the pioneer species which were algae and bacteria. Both began to broke down rock surface through weathering. Then lichens and mosses began growing in the area which helps with water retention and provides a base for soil. The next stage of primary succession is herbs/grasses/flowering plants/ferns. These add nutrients and organic matter to the ground which provided soil. Next, shrubs invaded and colonised the area. Shrubs dominate and shade out the sere below them. Small trees such as birch and willow were the following sere which invaded and colonised the area. They produced humus from leaf fall which provided nutrients for the soil through nutrient recycling and encouraged new growth of the sere. The last sere is the larger trees which are oak and ash which dominate the area and shade out smaller trees. This sere is the climax community in that it is stable and no further succession happens after. The climax community is the deciduous woodland biome we know today. The main characteristics include the location in which they are found, which is in temperate maritime climate such as
Temperature Inversions.
Temperature Inversions Normally, the air near the ground is warmer than the air at higher altitude. An inversion is the reverse situation--colder air at ground level than higher up. Cold air is heavier than warm air. Thus once an inversion forms, the air is very stable. Mixing that would normally occur by the rising of warm air is inhibited. Consequently pollutants such as carbon monoxide, sulphur compounds and ice fog remain trapped near the ground when there is an inversion. Types of Inversions The stability and mixing of air near the surface is controlled to a great degree by the presence of temperature inversions in the lower atmosphere. These inversions typically are very extensive, blanketing entire cities or regions. In each case, warm air is produced over a layer of cooler air in contact with the surface. There are basically four types of temperature inversions, each are explained below. Marine Inversions If you live near a coastline, you have probably experienced a marine inversion layer. Near cool oceans, such as in the western U.S. and Western Europe, a marine inversion can turn a hot summer day at the beach into a cool, foggy, overcast shiver. The ocean is typically quite cool compared with the land, particularly at middle latitudes where the heating by sunlight is not strong. Air sitting over cold water also tends to be cool. Moreover, a great deal of
Urban Areas have a significant impact on climatic characteristics Discuss.
Katie-Jane Sullivan "Urban Areas have a significant impact on climatic characteristics" Discuss. An urban area is characterised by a high population density and vast human features in comparison to areas surrounding it. Urban areas are created and further developed by the process of urbanisation. Other characteristics of urban areas include high rise buildings, good transport links and large amounts of vehicles. These characteristics, together with the high population density, means they have a significant impact on climatic characteristics. One climatic characteristic that urban areas affect is the cloud cover. Urban areas generally have 5-10% more close cover due to the greater concentration of condensation nuclei. This encourages the cloud formation due to the heating which increases the uplift of air. Similarly urban areas also have a significant impact on the precipitation levels. For example, urban areas are more prone to thunderstorms due to the enhanced convectional uplift. Another climatic characteristic that is affected is the wind. Urban areas have lower wind speeds due to the roughness of land surfaces. This is due to the varying height of buildings which exerts a fractional drag on the air moving over and around these buildings. This creates turbulence, giving rapid and abrupt changes in the wind speed and direction. Usually the greater area of buildings
B)Explain why the amount of solar radiation absorbed by the earth's surface varies from place to place and from time to time.
A)Define the terms insolation and albedo. Insolation is a combination of the phrase 'Incoming Solar Radiation'. It is the name for all energy which comes from the sun to the earth. The sun does not give out heat, but energy which is converted to heat when it reaches the earth. The albedo of an object is the measurement of how reflective it is against the sun. Snow will have a high albedo as is it is white and therefore a colour which reflects the sun's rays. Dark coloured surfaces such as a freshly ploughed field or rock will have a low albedo as it cannot reflect heat and will instead absorb it. It is also energy which goes straight back into space without having been converted into heat. B)Explain why the amount of solar radiation absorbed by the earth's surface varies from place to place and from time to time. The sun radiates solar energy which reaches the earth and is converted to heat. The location and time of this reaction, however, is variable due to the shape and tilt of the earth and the fact that it turns. This means that the energy reaches different places at different intensities at different times of day and different times of the year. This is dependent on many factors, not just those to do with the physical state of the earth. The shape, tilt and spin of the earth is the first factor which effects how much energy is absorbed by an area of earth. Due to the
Explain how atmospheric circulation gives rise to the formation of low and high pressure areas in your chosen climatic region
Explain how atmospheric circulation gives rise to the formation of low and high pressure areas in your chosen climatic region. Illustrate and explain the seasonal changes in the distribution of these pressure systems. The circulation of the atmosphere in Tropical regions is described by Hadley's cell. This is affected by two main processes, and pressure gradient force is the first of these. This says that air will move from the area of higher pressure to an area of lower pressure. The greater the difference in pressure, the stronger the airflow will be. The second main process is Coriollis' force. The rotation of the Earth deflects the air moving across the Earth's surface. The rotation deflects air to the right in the Northern Hemisphere and the left in the Southern Hemisphere. These two forces play a major part in the Global Circulation that is the key to the World's climates. Hadley's Cell explains the Tropical circulation; this is a direct cell, as it is a result of direct heating from the sun. It begins at the Equator, where the most intense solar radiation is found, making it the hottest place on Earth. The warm air rises from the Equator causing low pressure. This area of low pressure is often called the Doldrums, and is an area of heavy convectional rainfall. The rising air now spreads out pole wards and cools. The cooling air sinks over the tropics, creating high
Rain by Somerset Maugham - Comment on the significance of the recurrent image of rain in this short story.
English Rain: Somerset Maugham. Task: Comment on the significance of the recurrent image of rain in this short story. Rain, by Somerset Maugham seems to have a rather irrelevant title when first looked at. The first part of the story that introduces us to the story have no relevance to rain, or any other weather feature for that matter. However, as the story progresses, rain, and metaphors about the weather play a very important part in the story, and it sets the mood of the story. We do not get an image of the weather until page 8 (page numbers from collected short stories vol.1). However when the rain is introduced it happens very quickly and it moves the story on. 'But Mrs Davidson had given two or three of her birdlike glances at heavy grey clouds that came floating over the mouth of the harbour. A few drops began to fall. "We'd better take shelter," she said. They made their way with all the crowd to a great shed of corrugated iron, and the rain began to fall in torrents.' This quote shows how immediate the rain came. It seems to the reader that as soon as they have shelter, the rain falls intensely. It is also interesting here, because it seems that they have only been on the island for a few minutes, but yet then, the rain starts. The reader gets an impression of nature versus the English-men. We get the impression that nature is fighting the white men and
Energy tranfers within the atmosphere
Energy transfers in the atmosphere The source of energy for our planet is the sun. The sun's energy moves through space, and then through the earth's atmosphere and then finally reaches the earth's surface. This energy is then absorbed by the earth's surface and is then re-radiated as heat energy. There are three ways that heat energy is transferred through the atmosphere, radiation, conduction and convection. Conduction happens near the ground as heat energy is passed on through the movement of heat particles. All heat energy travels from a warmer region to a cold region, therefore the rate of conduction depends on factors such as temperature, surface area and the given levels of conductivity for various substances. The conduction of heat energy through the atmosphere is intensified by the amount of heat energy, which is radiated by the sun to be absorbed by the earth's surface. The transaction of heat energy from the sun to the earth is known as radiation. This is how the earth receives the heat energy emitted from the sun. This radiant heat energy is also absorbed by the earth's surface, this is what provides us with an average surface temperature of 14/15 degrees C. The heat energy absorbed by the earth's surface fluctuates in certain regions of the atmosphere due to various factors i.e. clouds absorbing heat, the sun's orbital path and the
Climatic Hazards (Atmospheric Circulation)
Climatic Hazards (Atmospheric Circulation) Our planet is made up of many different climate zones that are located in different parts of the world and climate is the main reason why we have different areas such as rainforests and desserts. The main major climate zones are 'tropical' where rainforests are located at tropical latitudes on the equator with some exceptions, e.g. Indonesia. Australia and Northern Brazil are good examples of large rainforests. The sun is high up in the sky and these areas gain a lot of sunlight throughout the year averaging temperatures of approximately 34°c. Polar is a major climate zone and is of course mainly around the Poles b between 60-90°c North and South. These climates are very dry and freezing cold with fairly mountainous terrains e.g. Antarctica. Arid is a very important world climate and consist mostly of our very dry and warm areas e.g. our desserts. They are located around the tropic of cancer and tropic of Capricorn in countries such as North Africa where we have the Sahara dessert. These are very dry because prevailing winds come over the land and land masses are very large. Finally we 'temperate' climates such as in the UK which are located 40-60°c North and are fairly dry but can also be very wet and are also very cold with a lot of vegetation growth. I have stated that major climate zones are clearly caused by our climate but
The Sahel and the ITCZ
The Sahel and the ITCZ Air masses moving over Africa have different characteristics depending on their areas of origin. Air originating over the tropical oceans, known as maritime tropical air, is warm, moist, and unstable. When this moisture-laden air is forced to rise and become cooler, condensation and precipitation often occur. Conversely, the hot, dry air that originates over the African continent (continental tropical air) is incapable of producing rain, even if it is forced to rise. Over most of Africa, air moves toward the equator. Northern Hemisphere winds from the northeast and Southern Hemisphere winds from the southeast converge at the intertropical convergence zone (ITCZ), a low-pressure zone centred on the equator. Air rises at the ITCZ, spreads out, and descends in the north and south, in subtropical high-pressure zones centred on the Tropic of Cancer and Tropic of Capricorn. After descending, the air flows outward, either pole ward into temperate regions or back toward the equator. The ITCZ constantly shifts its position, moving north of the equator during the Northern Hemisphere's summer, and south of the equator during the Northern Hemisphere's winter (see below diagram). This shift brings about seasonal changes, notably in the tropical summer rainfall zone. During the summer season (July to September in the Northern Hemisphere and December to February in
The aim of this project was to investigate what differences exist in temperatures in the local area, and to consider the effects of certain geographical aspects on these.
Introduction The aim of this project was to investigate what differences exist in temperatures in the local area, and to consider the effects of certain geographical aspects on these. This is in relation to the unit of work on Climate, Environment and People contained in the GCSE Geography syllabus, and this project uses principle ideas from this unit of study. There are many factors that affect the temperature of a region, be they on a grand scale, such as across a country or continent, or in a very small area, where a few environmental differences, such as the shelter of a building or tree, can cause a difference in temperature of one or two degrees Celsius. On a national scale, the latitude of the location will obviously have an effect, a fact clearly illustrated by the e difference in temperature between a temperate region, such as London, and a tropical rainforest town, such as Manaus in Brazil. This effect can also make a difference on a smaller scale; there is a one or two degree temperature variation between the cities of Portsmouth and London in the UK, which are only 120 km apart. Altitude is another major factor, as it is generally cooler at higher altitudes than it is at sea level, hence the appearance of snow at the top of mountains at even the warmest of latitudes. This is due to the density of the air, which decreases as the altitude increases. It is