India's Monsoon and Climate Dynamics

India's Monsoon

• Monsoon is a seasonal reversal of winds.
• It originates from Arabic word "Mausim"
• Monsoon is primarily driven by temperature differences between land and sea.

Factors Affecting Indian Climate

• Latitude: Influences temperature patterns
• Altitude: Impacts temperature variation along elevation
• Pressure and Wind Systems: Air pressure and wind systems affect precipitation.
• Relief Features (Topography): Mountains and valleys affect rainfall patterns.
• Ocean Currents: Influence coastal temperatures.
• Distance from Sea: Moderates temperature extremes near the coast.

Climate and Weather

• Climate: Average weather conditions over a long period (30 years).
• Weather: Short-term atmospheric conditions, including temperature, pressure, wind, humidity, precipitation.

Winter Season

• Chilling winds from Central Asia are blocked by the Himalayas.
• Winter rainfall, also known as cyclonic disturbances or "Mahawat" in Rajasthan region.
• Rainfall occurs due to jet streams carrying Western Cyclonic Disturbances.

Summer Season

• ITCZ (Intertropical Convergence Zone): Shifts in upper regions during summer.
• Trade winds ascend as they meet warm air, creating low pressure.
• Tibetan plateau heating intensifies low pressure over India.
• Summer monsoons create high pressure from Arabian sea and Bay of Bengal.

Pre-Monsoon Showers

• Nor-Westers: Winds bringing rainfall in early parts of monsoon season.
• Blossom Showers: Early-season rainfall helps in the growth of coffee crops.
• Mango Showers: Help in early ripening of mangoes.

Monsoon and Rainfall Patterns

• The Bay of Bengal branch and Arabian Sea branch of the monsoon converge over parts of Punjab.
• Break in Monsoon: Sudden decrease in rainfall after the monsoon arrives.
• Retreating Monsoon: Also known as North-East Monsoon, it brings rainfall to Coromandel Coast.
• Highest Rainfall: Recorded in Mawsynram and Cherrapunji.

Variations in Temperature and Rainfall

• Diurnal Range of Temperature: Daily temperature variation.
• Annual Range of Temperature: Yearly temperature variation.
• Annual Range of Rainfall: Yearly rainfall variation.
• Coastal Regions: Lower ranges of temperature variation compared interior regions.
• Continentality: Extreme temperature variation in interior regions due to the landmass.

Seasons and Months

• Indian Calendar Seasons: Vasanta, Grishma, Varsha, Sharada, Hemanta, and Shishira.
• Indian Calendar Months: Chaitra-Vaisakha, Jyaistha-Asadha, Sravana-Bhadra, Asvina-Kartik, Margashirsa-Pausa, Magha-Phalguna, and equivalent months in the Gregorian calendar.

ENSO and Indian Monsoon

• La Niña: Below-average sea surface temperatures, causing cooler global temperatures and increased rainfall in some areas (Australia, India).
• El Niño: Above-average sea surface temperatures, causing drought conditions in some and increased rainfall in other areas (Asia, Australia, India).