Monsoon PDF

# Monsoon ## India Retreating Monsoon A map of India showing the retreating monsoon. - It shows the dates on which the monsoon retreats from different parts of India. - It also shows various geographical features of India such as the Arabian Sea, Bay of Bengal, Lakshadweep, Andaman & Nicobar Is...

# Monsoon ## India Retreating Monsoon A map of India showing the retreating monsoon. - It shows the dates on which the monsoon retreats from different parts of India. - It also shows various geographical features of India such as the Arabian Sea, Bay of Bengal, Lakshadweep, Andaman & Nicobar Islands, and the Tropic of Cancer. - It also shows the bordering countries, such as Pakistan, China, Nepal, Bhutan, Bangladesh, and Myanmar. # Factors Affecting Climate of India - Latitude - Altitude - Pressure and Wind System - Relief Features - Ocean Currents - Distance from Sea # Climate The average weather in a given area over a longer period of time. Data taken of 30 years. # Weather The term refers to temporary conditions of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloud cover. ## Winter Season Chilling winds from the Arctic/Central Asia affects winter season, but they are blocked to a certain extent by the Himalayas. ### Winter Rainfall It is known as Upper Atmospheric Circulation. - At 25°N latitude in February, winds blow at 9-13 km height towards the east. - This is known as Jet Stream winds. - This wind carries Western Cyclonic Disturbances, which cause rainfall in the Northern Plains. - This is known as "Mahawat" in Rajasthan. - This is beneficial for Rabi crops. - Inward of Western Disturbances through Jet Streams is marked by increase in prevailing night temperature. ## Summer Season - In upper troposphere (9-13 km) very high speed of winds, there are Jet Streams that shift north and south as they follow boundaries of hot and cold air. - These Jet Streams blow west to east. - In the Indian Peninsula, summer rays fall over the Tibetan plateau, causing intense heating, which creates low pressure. - The low pressure causes trade winds to meet in the upper region, causing air to ascend, which results in rainfall. - This happens during July, between 20-25°N. # Pre-Monsoon Showers ## Nor-Westers - Also known as Kal Baisakhi - Calamity in the month of Baisakh in West Bengal. - Helpful for the growth of jute and tea. - In Assam, called Bardoli Chheerha. ## Blossom Showers - Seen in Kerala/Karnataka. - Helps in the growth and cultivation of coffee. ## Mango Showers - Seen in Kerala. - Helps in early ripening of mangoes. # On Set of Monsoon - It is derived from the Arabic word "Mausim,' which means seasonal reversal of winds. - It begins in Kerala in the first week of June in the Western Ghats. - This is known as Orographic rainfall. - Winds from the Southwest direction, which is why it is also known as the Southwest Monsoon. - This causes windward side (on shore side) and leeward side (off shore side) effect. # Rain Bearing System - The Bay of Bengal branch and Arabian Sea branch of the Southwest monsoon meet at Punjab. - Winds move parallel to Aravallis hence no rainfall in Rajasthan desert. - The North-Eastern Hills (Khasi Hills) receive the highest rainfall, with Mawsynram/Cherapunji being the wettest place on Earth. ## Break in Monsoon A sudden decrease in rainfall after the onset of the monsoon. ## Retreating Monsoon - Also known as North-East Monsoon. - It causes rainfall over the Coromandel coast (Tamil Nadu/Andhra). - Cyclonic disturbances occur in this region. ## In North India during this season - Clear skies - October heat (oppressing heat) # La Nina vs El Nino ## La Nina **Meaning:** Small Girl - Below average sea surface temperatures in east-central equatorial Pacific (cold phase on ENSO cycle). - Trade winds strengthen, pushing warm water westward. - Seen every 2- 7 years. - Leads to cooler global temperatures. - It can cause intense rainfall in Australia and India along with heavy floods; drier conditions in South America. - Fishing industries will flourish. ## El Nino **Meaning:** Child Christ/Small Boy - Above average sea temperatures in east-central equatorial Pacific (warm phase of ENSO cycle). - Trade winds weaken, allowing warm water to spread eastwards. - Seen every 3-7 years. - Leads to warmer global temperatures. - It can cause droughts in Asia and Australia and in the US, El Nino has its strongest impact during winter. - Fishing industries won’t flourish. # Variation in Temperature/Rainfall 1. Diurnal Range of Temperature (Daily range of temperature) 2. Annual Range of Temperature 3. Annual Range of Rainfall - Extremes of climate are seen in the interior of continents. - Coastal cities do not experience extreme climate due to "moderating influence of sea." - The further we go from ocean into the continent, the more is the extremity in the climate due to the continentality effect.. # Seasons and Months | Seasons | Months (According to the Indian Calendar) | Months (According to the Indian Calendar) | |--------------------------|-----------------------------------------------|------------------------------------------------| | Vasanta | Chaitra-Vaisakha | March-April | | Grishma | Jyaistha-Asadha | May-June | | Varsha | Sravana-Bhadra | July-August | | Sharada | Asvina-Kartika | September-October | | Hemanta | Margashirsa-Pausa | November-December | | Shishira | Magha-Phalguna | January-February |