British weather, climate and cloud types.

-British Climate and weather-

• Britain has a mild climate. It is in the
• temperate climatic zone and the sea affects the weather. In general, this means
• that Britain gets cool, wet winters and warm, wet summers. The weather
• conditions are also very changeable.
• Prevailing winds are the dominant wind
• direction in an area. The temperature of the wind and the amount of rainfall
• partly depend on where the air has come from. Looking at where the air has come
• from helps to explain the characteristics of the weather. A large body of air
• with similar characteristics is called an air mass.
• Locations that are further
• north receive less concentrated energy from the Sun. The equator lies directly
• underneath the Sun and so countries that fall on the equator receive the
• strongest solar energy. This means that in the Northern Hemisphere, the Sun's
• energy becomes less concentrated and therefore the temperatures become cooler
• as you travel north. Temperatures decrease with altitude. There is a 1°C drop
• in temperature for every increase of 100 m in height. This is because the air
• is less dense in higher altitudes. Distance from the sea. Coastal areas are
• most affected by the sea. The sea takes longer to heat up and cool down than
• land. So in the winter the sea keeps coastal areas warm and in summer, it cools
• them down. The effect that ocean currents have on the temperature depends on
• whether the ocean current is hot or cold. Britain is on the same latitude as
• Siberia and parts of Russia, yet it does not suffer the same long, harsh
• winters. Britain's mild climate is partly due to the Gulf Stream, a large
• Atlantic Ocean current of warm water from the Gulf of Mexico. When the land
• warms up, it heats the air above it. This causes the air to expand and rise. As
• the air rises it cools and condenses. If this process continues then rain will
• fall. This type of rainfall is very common in tropical areas but also in areas
• such as South East England during warm sunny spells. The British Isles are
• affected by a number of different air masses. When warm and cold air meet, a
• depression forms.

-Climate and Weather-

• Weather describes the day-to-day
• conditions of the atmosphere. Weather can change quickly - one day it can be
• dry and sunny and the next day it may rain. Climate describes average weather
• conditions over longer periods and over large areas. The table below shows the world climatic
• zones.
• Weather affects us in many ways. It
• affects what we do and what we wear, how we travel and even our moods.
• Meteorologists measure weather conditions in different places and use this
• information to report and make forecasts about future weather conditions. This
• is useful because people can be warned about hazardous weather conditions such
• as storms and floods. Temperature is measured in Celsius (°C) using a
• thermometer. The thermometer must be shaded from direct sunlight and should
• have air circulating around it. The thermometers can be placed in a Stevenson
• Screen. This is a wooden box with slatted sides, a sloping roof and legs to
• keep the screen off the ground. It is painted white to reflect the sun.
• Precipitation is measured using a rain
• gauge. This is a funnel inside a graduated container. The depth of the rain in
• millimeters can be read from the side of the container. Wind direction is
• reported by the direction it is blowing from, according to the compass. Wind
• blowing from the west is travelling eastwards so is called a westerly wind, not
• an easterly wind. Wind speed can be measured using an anemometer. The strength
• of the wind is measured on the Beaufort scale.

-Type of Clouds-

• Cloud cover is measured in units called oktas.
• Each okta
• represents one eighth of the sky covered by cloud.
• Air pressure. Air is light but because
• there is so much of it above us, it exerts a pressure on us. Air pressure is
• measured by a barometer. The units used are millibars. The greater the reading, the higher the
• pressure.
• A high-pressure system is called an
• anticyclone. Air falls in an anticyclone so no clouds are formed. In summer,
• high pressure usually results in clear skies, gentle breezes and fine weather.
• In winter high pressure leads to clear skies and colder conditions.
• An area of low pressure is called a
• depression. Air rises in a depression so clouds and rainfall are formed.
• Depressions therefore bring unsettled weather and rain. Winds are normally
• stronger. They usually form over the Atlantic Ocean and are carried across
• Britain by westerly winds. A synoptic chart is any map that summarize
• atmospheric conditions over a wide area at a given time. It displays
• information on temperature, precipitation, wind speed and direction,
• atmospheric pressure and cloud coverage, all observed from many different
• weather stations, aeroplanes, balloons and satellites. Clouds are categorised according to
• height and shape. The different categories of clouds are then given names based
• on Latin words, eg
• nimbus clouds bring rain, stratus clouds appear as layers.