The Marine Society & Sea Cadets

Our role is to provide personal development opportunities and support in a maritime context for young people and professional seafarers from all the sea services.

Measuring the weather

On Earth, regularly occurring weather phenomena includes such things are snow, cloud, wind, rain and fog. Less common events include natural disasters such as hurricanes, ice storms and tornadoes.

The study of weather - Meteorology – is based on the scientific observation of the Earth’s atmosphere. Meteorologists collect readings of temperature, wind, pressure, and other conditions from weather stations all over the world to plot as information on maps called synoptic charts (synoptic means “seen together”) and these are used by professional forecasters to create the maps and weather broadcasts that are seen on television, heard on radio or produced in newspapers or through internet sources.

Weather is normally the term given to the daily variations in rainfall, temperature, wind, sunshine and atmospheric pressure that a specific geographical region receives. In contrast, the term climate refers to the average weather that a region receives over significantly longer periods of time, several years or more.

There are six main weather components that need to be recorded to measure the weather.

Air Pressure: Measured with a barometer, recorded in millibars. The air in our atmosphere is actually pushing (or pressing) down on the Earth. This pressure is always changing – becoming a little heavier or lighter- and it causes the weather to change. Recorded as high or low pressure.

Temperature: Measured with a thermometer and recorded in degrees. Most thermometers use either the Celsius (Centigrade) scale or Fahrenheit scale and record the highest and lowest extremes of the day.

Relative humidity: Measured with a wet and dry bulb thermometer, recorded as a percentage. It records the amount of water vapour in the air relative to the maximum amount that could be held.

Wind: A weather vane shows wind direction. Wind speed is measured an anemometer in knots or kilometres per hour. It records the sideways movement of air from high to low pressure.

Clouds: A measurement of cloud cover through observation is recorded in oktas. 8 oktas is the highest cloud cover.

Precipitation: Measured with a rain gauge recorded in millimetres. It records the amount of water falling from the atmosphere as rain, hail, snow, etc. It is a feature of water’s amazing ability to transform quickly between solid (ice), liquid (rain and dew), or gas (water vapour) within a narrow temperature range.
The Marine Society & Sea Cadets, 202 Lambeth Road, London SE1 7JW

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Patron: HM The Queen
A charity registered in England and Wales 313013 and in Scotland SC037808.