Acid rain is a generic term used for precipitation that contains an abnormally high concentration of Sulfuric and Nitric acid. These acids form in the Atmosphere when industrial gas emissions combine with water, and have negative impacts on the environment and human health.

Air Pressure is the force per unit area exerted by the weight of the atmosphere above a point on or above the earth's surface. Also known as atmospheric pressure or barometric pressure.

Scientists collect and analyze samples of air in different regions of Canada on a regular basis to determine pollutant levels. This information is not only used by decision-makers to pinpoint the sources of air pollution and determine strategies for reducing it, but also to produce daily air-quality forecasts that warn Canadians when smog levels ar [..]

An Altimeter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater. Altitude can be determined based on the measurement of atmospheric pressure. The greater the altitude the lower the pressure. When [..]

An Anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind. and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. Anemometers can be divided into two classes: those that measure the wind's speed, and thos [..]

Apparent Temperature is the general term for the perceived outdoor temperature, caused by the combined effects of air temperature, relative humidity and wind speed.

Barometric pressure is the pressure exerted by the weight of the column of air above a given point, expressed in millibars (mb). Generally speaking, when the barometric pressure is high, the air is sinking, usually resulting in fair weather. When the barometric pressure is low or falling, air is rising, usually resulting in cloudy skies and precipi [..]

The Beaufort Scale is a scale for measuring wind speeds. It is based on observation rather than accurate measurement. It is the most widely used system to measure wind speed today. There are twelve (12) levels, plus 0 for "no wind". From 1946 to 1970, there were also Beaufort levels 13 to 17. All of them were labelled as Hurricane. Becaus [..]

Celsius, also known as Centigrade, is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius (1701 - 1744), who developed a similar temperature scale. The degree Celsius (°C) can refer to a specific Temperature on the Celsius scale as well as a Unit to indicate a Temperature interval, a difference b [..]

Name in the Weather Forecast for high clouds (Cirrus) through which the Sun still shines. The white cirrus clouds are usually at a 6 to 12 km altitude and consist of small ice crystals. The wispy clouds can condense into Veils. Clouds Veil, which often appear in (still) warm Weather conditions, have a thread-like structure and can also arrange in s [..]