PRECIPITATION & CLOUDS Flashcards
What is meant by precipitation?
It is the movement of water from the atmosphere to the earth surface, e.g. rain, sleet or snow.
what is meant by insolation?
It is incoming short wave radiation from the sun that passes through the atmosphere of the earth.
What warms the surface of the earth.
The surface of the earth is heated when it absorbs insolation from the sun that has passed through the atmosphere.
What form of radiation does the surface of the earth emit.
The surface emits longwave radiation.
Explain how the atmosphere of the earth is heated.
It is heated when the carbon dioxide and water vapour in the air absorbs the out-going longwave radiation emitted from the surface of the earth.
Describe and explain how the temperature of air changes as it rises.
The temperature starts to decrease because of a drop in pressure.
The atmosphere may contain water vapour. Describe what happens to this water vapour when dew point is reach.
Some of the water vapour in the air starts to condense into water droplets which may form clouds.
Describe the process that takes place within a cloud that results in precipitation.
Water droplets in the cloud begin to grow in size as they collide with each other. When they are heavy enough to overcome the updraft of the rising air they will fall to the surface.
List the three main triggers that causes air to rise.
The triggers are hills or mountains, where a warmer air mass meets a cooler air mass and when heated from below by the surface of the earth.
What is meant by relative humidity?
It is the ratio of water vapour in the air compared to the maximum possible at that temperature and pressure, expressed as a percentage.
What is meant by relief rainfall?
It is rainfall that is caused when air is forced to rise over hills or mountains It is sometimes called orographic rainfall.
What is meant by frontal rainfall?
It is rainfall that is caused when warm air advances and rises over the cold, which is heavier and denser.
What is meant by convectional rainfall?
It is rainfallI that is caused when air starts to rise because the energy of the sun (insolation) heats the earth’s surface, which then emits longwave radiation which heats the air in contact with the surface which then begins to rise.
Describe and explain when convectional rainfall is most likely to happen in the UK.
It is most likely to happen in the summer when the surface of the earth in the UK is at its warmest.
What is meant by the rainshadow effect.
It is an area on the leeward side of a mountain range that experiences very little precipitation.
