Please enable JavaScript.
Coggle requires JavaScript to display documents.
What effects the climate in the UK (Structure of the Atmosphere…
What effects the climate in the UK
Air masses effecting the UK
Arctic Maritime - Cold, moist air that brings snow and blizzards to Scottish Highlands.
Polar continental - Cold dry air (Siberia and Northern Scandinavia_ winter cyclone. High pressure cyclone - effects the East
Polar Maritime - Cold, moist air, travelling from Greenland and North America
Tropical Maritime - Warm, moist air from central America and Caribbean
Tropical Continental - Hot dry air from North Africa and Western Europe. Summer anticyclone. High pressure system.
Depressions - Areas of low atmospheric pressure which produce cloudy, rainy and windy weather. these low pressure systems often begin over the Atlantic. Moving eastwards towards the UK. They are responsible for the UK's changeable weather.
In a depression the air is rising. As it rises it cools, the water vapour condenses to form clouds and perhaps precipitation, hence why it rainy and windy.
Anticyclones are opposite in winter and summer
In Winter, Polar continental, travelling from Siberia, Northern Scandinavia. The weather is colder than normal, the sun generates some heat but cold in the shade. The days are short with sun from 8-4. Little to no cloud cover. No rain because of absent clouds. Little to no wind as pressure gradient is small. Freezing temperatures at night, frost from the falling cold air. This system can last for 3-5 days.
In summer. Tropical continental, Northern Africa / Sahara / West Europe. The temperature is higher than average which can result in heatstroke. Longer hours of daylight - 18 hours, 4 - 10. Little to no cloud cover. No precipitation, intense heating over a long period of time, can result in convectional heating. Little to no wind, gentle pressure gradient. Warmer than average for several days. Can last for 3-5 days
Structure of the Atmosphere
Troposphere - Temperatures decrease by 6.[4 degrees within every 100 metres. This because the earths surface is washed with solar radiation. The layer is unstable and contains most of the atmospheres water vapour, clouds, dust and pollution.
The Tropopause - Forms in the upper unit of the earths climate layer where temperature remain constant despite any increase in height.
Stratosphere - It is characterised by a steady increase in temperature. This gas absorbs incoming ultra violet radiation. Winds are light in the lower parts bu increase with height; pressure continues to fall and the air is dry. It acts as a protective shield against meteorites which usually burns out as they enter gravitation field. It is an isothermal layer where temperatures do not change with increasing height.
Mesosphere - The temperature falls rapidly as there is no water, clouds, dust or ozone. The layer experiences the atmosphere's lowest temperatures. the strongest winds.
Stratopause The strongest winds - has no change in temperature
Thermosphere - Temperature rise rapidly with height, perhaps to reach 1500 degrees Celsius. This is due to an increasing proportion of atomic oxygen in the atmosphere which, like ozone, absorbs incoming ultra violet radiation.
Factors effecting the daytime energy budget
Radiation - the transfer of heat from one body to another by electro-magnetic waves
Due to the tilt of the earth and it's rotation over 24 hours, at any one time half of the earth in daylight as it is facing the sun while the other half is facing away and is in darkness.
Not all of the sun's energy reaches the earth's surface as much is lost as passes through the atmosphere. 5% is scattered straight back to space by dust and smoke particles. 24% is reflected back to space, 18% by the white upper surface of clouds and water droplets within them and 6% by the earth's surface, mainly by snow, ice and water surfaces. 23% is absorbed by atmospheric gases, mainly by ozone and oxygen at high levels, with small amounts by carbon dioxide and water vapour near the earth's surface.
Reflected Solar Radiation
Albedo - The percentage of solar radiation that is reflected back to space by the Earth's surface
The Albedo varies on the surface e.g. snow has an average albedo of 80% whereas dark soil has an albedo of 7%. Also, according to the time of the day; when the sun is at a high angle near midday it has a low albedo but reflection can reach 80% when the evening when the sun is low
Some urban areas because of their surfaces have higher albedo averages. For example white buildings reflect more sunlight compared to black buildings and tarmac which absorbs more sunlight. Material of the buildings e.g. glass allows for absorption compared to solid surfaces.
What is conduction and how does it vary?
Sensible heat transfer - Occurs when heat energy is transferred by direct conduction or convection
Air is a poor conductor of heat, so only a thin layer next to the surface is wamed by conduction
Warming causes the air molecules to expand, become lighter and rise through air that is cooler and denser. This process of convection transfers heat to higher altitudes and, on very hot summer days, strongly rising air current can reach the tropopause. Cooler air moves down to replace the rising air and is, in turn heated.
Warm winds near the surface can be deflected upwards by an obstacle and can reach 600 metres above the surface is the wind turbulence is very strong.
How do clouds influence the daytime energy budget?
High, thin clouds such as cirrus, allow incoming solar radiation to pass through but absorb some long wave radiation, so warming the earth's surface
Deep convective clouds, especially collombulus, neither heat nor cool overall
An overcast sky with complete cloud cover of low, thick clouds, such as stratus and stratcumbulus, can reflect 80% of solar radiation and cool the earth's surface
Latent heat transfer - Occurs when water on the earth's surface evaporates to water vapour or ice melts to water vapour. The heat needed to make these changes is absorbed from the air, leaving less energy for heating at the surface. This latent heat is stored in the water vapour and may be carried upwards in the convection currents untill it cools sufficiently for the water vapour to condense into water droplets or change into ice crystals. During this change the stored heat is released into the air, increases the speed and content of convection. Much solar radiation is lost by latent heat transfer being used to convert snow and ice back to water in high latitudes in spring and early summer.
Influence of latitude on temperature
At the equator the sun's rays are vertical at noon, all year round. Insolation is intense because a given amount of solar radiation heats a relatively small part of the earth's surface. Towards the poles the sun's rays strike the surface at increasingly low angles reducing the intensity of the insolation and therefore the temperatures.
The higher the latitude (i.e. close to the poles) the greater the thickness of the atmosphere through which the sun's rays have to pass. This means there is greater absorption, scattering and reflection of solar radiation (except in the polar region where the air is clean and contains little water vapour)
Length of daylight and darkness
Latitude influences the length of daylight and darkness which alters the temperatures in mid latitudes but has little effect on the equatorial regions.