Important Terms and Concepts - Climate
Category : 9th Class
IMPORTANT TERMS AND CONCEPTS
- Monsoon. It is derived from an Arabic word "mausam" meaning season. Monsoon refers to the seasonal reversal in the wind direction throughout the year.
- Climate. It is the average weather conditions of a place over a long period of time, about 30-40 years.
- Continental climate. It is experienced in the interior of the continent It is very hot in summer and very cold in winter, e.g., Delhi.
- Cyclones. They have a low pressure at the centre and a circular wind motion. A eyelone is often accompanied by heavy rain.
- Range of temperature. It is the difference between maximum and minimum temperatures.
- Dry spelles. It refers to the rainless days during the monsoon season.
- Jet Streams. They are fast flowing cold air currents in a narrow zone in the upper atmosphere.
- Isobar. It is an imaginary line, drawn on the map, to join places having the same pressure above sea level. It is measured in millibar (mb).
- Isohyet. It is an imaginary line, drawn on the map, to join places having the same amount of rainfall, e.g., mm or cm.
- Isotherm It is an imaginary line, drawn on the map, joining all Ifae places having the same temperature above sea level, or .
- Leeward side. It is the rain shadow area and lies on the side which is away from the direction of the wind, e.g., Deccan Plateau is on the leeward side of the Western gnats.
- Loo. Hot and dry winds blow in the afternoon and very often continue even up to mid-night in summer. These winds are locally known as loo.
- Maritime Climate. It is experienced in coastal areas. It has cool summers and mild winters e.g., Mumbai.
- Windward. Slopes facing the wind direction. It receives heavy rains. Western ghats get heavy rain from Arabian Sea branch of the south-west monsoons.
- Breaking of monsoon. Sudden approach of the moisture laden winds is associated with violent thunder and lightning. This is known as "break" or "burst" of the monsoons. The monsoon first "break" on the south-west Coast of India around 1 st June.
- Monsoon trough. It refers to the intense low pressure area, which develops over north-western parts of the country extending from Thar Desert to Chota Nagpur Plateau.
- Transitional period. It is the period between two seasons.
- Vagaries of the monsoons refers to the uncertainties of the monsoons.
- Trade winds. They are the prevailing easterly winds, which blow from the sub-tropical high pressure belt to equatorial low pressure.
- Warm Current. Streams of water flowing in the surface or at sub-surface levels of oceans.
Warm currents are those which flow from warmer to cooler regions, e.g., warm Atlantic drift.
- Cold current. Stream of water flowing on the surface or at sub-surface levels of oceans.
Cold currents flow from colder to warmer regions, e.g., Labrador current.
- Western disturbances. Are the shallow cyclonic disturbances, which originate over the Mediterranean Sea. In India they cause light rains in the north-western parts of India and snowfall in the Himalayas.
- Mango showers. The pre-monsoon showers, which helps in the ripening of mangoes in coastal Kerala and Karnataka.
- Planetary winds. The major permanent winds, e.g.. Trades, Westerlies and Polar winds comprising a system that would prevail on any planet rotating from west to east and having an atmosphere.
- Meteorologist. A person who studies the conditions and processes within the earth's atmosphere, e.g., air pressure, temperature, wind speed, cloud formation etc. Meteorologists predict likely future weather patterns.
- Atmospheric pressure. The atmosphere is a thick gaseous envelope which surrounds the earth from all sides. Layers of atmosphere exert weight pressure. With increase in height the atmosphere decreases.
- Humidity. The amount of water-vapour present in the atmosphere is humidity.
- Precipitation. The depositing of moisture from the atmosphere into the earth's surface. Precipitation may be dew, drizzle, hail, rain or snow. It occurs when the air is cooled and can no longer carry the same volume of water.
- Rain shadow. The slopes facing the wind direction receives heavy rainfall, which is away from the direction of the wind, e.g., Deccan Plateau is the rain shadow of Western Ghats.
- October heat. The hot and humid conditions makes the weather oppressive.
