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
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
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