CHAPTER- 4 , GEOGRAPHY, CLASS-9

Important Terms Of Climate

1. CLIMATE :- Climate is the sum total of the weather conditions and variations over a large area for a long period of time, generally more than 30 years.

2.Weather :- Weather is the state of the atmosphere over an area at any point of time.

3.Elements of Weather :- Temperature, Atmospheric pressure, wind, humidity and precipitation.

4.Monsoon type climate :- It is seen in India along with South and South-East India.

5.Climate Factors :- Latitude, Altitude, Pressure and Wind System, Distance from the Sea, Ocean Currents and Relief Features.

6.Coriolis Force :- Coriolis force is generated by the rotation of the Earth, it is responsible for deflecting winds towards the left in Northern Hemisphere and towards the left in Southern Hemisphere.

7.South-West Monsoon :- South-West Monsoon Winds are South-East Trade winds of Southern Hemisphere which after crossing equator, become South-Western Trade Winds(due to rightward deflection by Coriolis force). As they blow over warm ocean, they carry a lot of moisture and cause rainfall in Indian Subcontinent.

8.Jet Streams :- Jet Streams are fast blowing winds moving in the upper atmosphere. They are located at about 27⁰ – 30⁰North latitude.

9. Western Cyclonic Disturbances/Depressions :- Cyclonic Disturbances over the Mediterranean Sea are known as Western Cyclonic Disturbances. They cause Winter rainfall in North-Western parts of India.

10. Monsoon :- The term is derived from Arabic word ‘Mausam’. It refers to the seasonal reversal in wind direction throughout the year.

11. Inter Tropical Convergence Zone (ITCZ) :- It is a broad trough of Low Pressure in equatorial latitude. In ITCZ, there is convergence of North-East and South-East trade wind.

12. Southern Oscillation (SO) :- It is the reversal of pressure conditions and vice-versa in Southern Pacific Ocean and Eastern Indian Ocean.

13. EL NINO :- EL NINO is a warm ocean current that flows from the Peruvian Coast in place of Cold Peruvian current every 2 to 5 years.

14. ENSO :- ENSO is the combination of EL NINO and Southern Oscillation. The changes is pressure conditions are connected to EL NINO, hence, the phenomenon is referred to as ENSO.

15. Burst Of Monsoon :- The sudden and continuous rain associated with violent thunder and lightning. It occurs around the time of arrival of monsoon.

16. Loo :- Loo is hot and dry winds blowing during the day over the North and North-Western India in the summer season.

17. Kaal Baisakhi :- Kaal Baisakhi is a pre-monsoon shower in the West Bengal. This localized thunderstorm of the summer season is associated with violent winds, torrential downpours and is often accompanied by hail.

18. Mango Shower :- The Pre-Monsoon shower in Coastal Karnataka and Kerala. It helps in early ripening of Mangoes.

19. Monsoon Trough :- It is intense and elongated low-pressure area, which develops over North-Western India. It extends from the Thar Desert in West to Chhota Nagpur Plateau in East.

20. October Heat :- The hot and humid condition which makes the weather oppressive is called October Heat. It occurs towards the end of retreating monsoon in the month of October.