The weather is the day-to-day condition of the atmosphere
at a particular place and time – whether the air is warm or cool, moist
or dry, still or moving, and whether rain or snow is falling. METEOROLOGY is the study of the weather. The Sun is the driving force
behind the weather. It heats air masses in different parts of the globe
unevenly, creating differences in air pressure. This causes winds as air moves
from zones of high pressure to low pressure. WEATHER FRONTS occur
where moving masses of air collide.
Weather fronts are border zones where masses of air of
different temperatures and humidity (moisture) levels meet and push into one
another. Warm air is less dense, or lighter, than cold air, and so it rises
above the cold air. Rising warm air creates an area of low pressure or
depression. Depressions are linked with unsettled weather conditions, including
high winds and rainy spells.
A warm front occurs when a mass of warm air meets a mass of cold
air. The warm air slowly rises above the cold air, forming a low pressure zone.
As the rising warm air cools, the moisture in it condenses to form clouds,
bringing drizzle or rain.
A cold front occurs when a mass of cold air is driven towards a
mass of warm air. As they collide, a steeply sloping front is formed and the
warm air is forced to rise rapidly. This produces towering thunderclouds and
brings torrential rain showers.
Cold fronts often follow a few hours behind warm fronts.
Earth’s rotation bends the moving masses of air, causing the fronts to
spiral around one another. The warm and cold air merge to form an occluded
front, which brings cloudy skies and rain.
Meteorology is the study of atmospheric conditions and
weather systems. Meteorologists have the difficult task of predicting the
weather for the next few days (short-term forecasts) and for a week or so ahead
(long-term forecasts). We all rely on weather forecasts to help plan the day,
but they are particularly important for farmers, shipping firms, and airlines,
and also power stations, since the weather affects the amount of energy we
use.
Scientists use satellites orbiting high above Earth to track
weather systems. Satellites provide images of clouds, storms, and hurricanes.
They also monitor temperatures and humidity using sophisticated sensors.
