The atmosphere

The atmosphere is divided into five layers. It is thickest near the surface and thins out with height until it eventually merges with space.

1) The troposphere	The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer. Weather in this layer affects our daily life.	Between 7 to 14 kilometres.	The higher, the colder.
2) The stratosphere	Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun.	Starts at 14 to 50 kilometres.	The higher, the hotter.
3) The mesosphere.	Meteors or rock fragments burn up in the mesosphere.	Between 50 to 85 kilometres.	The higher, the colder.
4) The thermosphere.	The thermosphere is a layer with auroras. It is also where the space shuttle orbits.	Between 85 to 640 kilometres or higher.	The higher, the hotter.
5) The exosphere.	The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.	640 kilometres or higher.

Weather forecasting

Weather
Weather is the state of the atmosphere at a given time and at any one place, with respect to heat or cold, wetness or dryness, calm or storm, clearness or cloudiness. Also, weather is the meteorological day-to-day variations of the atmosphere and their effects on life and human activity. It includes temperature, pressure, humidity, clouds, wind, precipitation and fog.


Weather forecasting
The scientific study of weather is termed meteorology. Attempts to predict future changes are known as weather forecasting. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location.

Weather forecasts are made by collecting quantitative data about the current state of the atmosphere and using scientific understanding of atmospheric processes to project how the atmosphere will evolve.


Weather station
A weather station is a facility, with instruments and equipment for observing atmospheric conditions to provide information for weather forecasts and to study the weather and climate. 

The measurements taken include: 

• temperature, 
• barometric pressure, 
• humidity, 
• wind speed, 
• wind direction, and 
• precipitation amounts. 

Weather instruments
Typical weather stations have the following instruments:

Thermometer for measuring air and sea surface temperature

Barometer for measuring atmospheric pressure

Hygrometer for measuring humidity.

Anemometer for measuring wind speed

Rain gauge for measuring liquid precipitation over a set period of time.

Weather stations often use weather balloons. A weather balloon is a balloon which carries instruments and the balloon sends back information on atmospheric pressure, temperature, humidity and wind speed. 

KNMI
The Royal Dutch Meteorological Institute (KNMI = Koninklijk Nederlands Meteorologisch Instituut) is known mainly for its weather forecasts and warnings, but is also the national knowledge centre for weather, climate research and seismology.

The KNMI was founded on 31 January 1854. Buys Ballot (1817-1890), its first general director, chose to establish KNMI at the Sonnenborgh observatory in Utrecht. In 1897, the Institute moved to De Bilt, where its headquarters is still located today.