Q: What are the six major controls of climate?
A: The six major controls of climate are latitude, altitude, pressure and wind system, distance from the sea (continentality), ocean currents, and relief features.
Q: How does altitude affect climate?
A: As one goes from the surface of the Earth to higher altitudes, the atmosphere becomes less dense, and temperature decreases. Therefore, higher altitudes, such as hills and mountains, tend to be cooler during summers.
Q: What is continentality?
A: Continentality refers to the condition where the moderating influence of the sea decreases as the distance from the sea increases. This leads to extreme weather conditions, with very hot summers and very cold winters.
Q: How do ocean currents and onshore winds influence coastal climate?
A: Ocean currents, along with onshore winds, affect the climate of coastal areas. Warm or cold currents flowing past a coastal area can warm or cool the region, depending on the direction of the winds.
Q: What are the two major climate categories in India based on latitude?
A: India has characteristics of both tropical and subtropical climates. The southern half of the country, below the Tropic of Cancer, belongs to the tropical area, while the remaining northern portion lies in the subtropics.
Q: How do the Himalayas affect India’s climate?
A: The Himalayas act as a barrier, preventing cold winds from Central Asia from entering the subcontinent. This results in comparatively milder winters in India compared to central Asia.
Q: What are the major atmospheric conditions that govern India’s climate?
A: The climate and associated weather conditions in India are influenced by pressure and surface winds, upper air circulation, and the impact of Western cyclonic disturbances and tropical cyclones.
Q: How many seasons are experienced in India, and what are they?
A: India experiences four main seasons: the cold weather season (winter), the hot weather season (summer), the advancing monsoon, and the retreating monsoon. Regional variations exist within these seasons.
Q: What are the characteristics of the cold weather season (winter)?
A: The cold weather season starts from mid-November in northern India and lasts until February. Temperatures decrease from south to north, with the coldest months being December and January. Frost is common in the north, and the higher slopes of the Himalayas experience snowfall. Winter rains occur due to cyclonic disturbances from the west and northwest, originating over the Mediterranean Sea and western Asia.
Q: What are the characteristics of the hot weather season (summer)?
A: The hot weather season in India occurs from March to May. Temperature increases as the global heat belt shifts northward. The highest temperatures are recorded in northwestern parts of the country, with Gujarat and Madhya Pradesh reaching around 42°C in April. Hot and dry winds called “loo” blow during the day, dust storms are common, and thunderstorms with torrential downpours occur. Pre-monsoon showers, known as “mango showers,” are common in Kerala and Karnataka.
Q: What are the characteristics of the advancing monsoon (rainy season)?
A: By early June, the low-pressure condition over the northern plains intensifies, attracting the south-east trade winds from the southern hemisphere. These winds cross the equator and enter India as the south-west monsoon. They bring abundant moisture, resulting in heavy rainfall. The windward side of the Western Ghats receives the heaviest rainfall, while the Ganga valley experiences decreasing rainfall from east to west. Rajasthan and parts of Gujarat receive scanty rainfall.
Q: What are the breaks in monsoon rainfall?
A: The monsoon rainfall has breaks or intervals of rainless periods interspersed with rainy days. These breaks are related to the movement of the monsoon trough, which determines the spatial distribution of rainfall. When the trough axis lies over the plains, there is good rainfall in those areas. However, when the axis shifts closer to the Himalayas, longer dry spells occur in the plains, while the mountainous catchment areas of the Himalayan rivers experience widespread rain.
Q: What factors influence the breaks in monsoon rainfall?
A: The movement of the monsoon trough, the frequency and intensity of tropical depressions, and the shifting of the trough axis towards or away from the Himalayas influence the breaks in monsoon rainfall. The location of the trough axis determines the distribution of rainfall, with the plains experiencing dry spells when it moves closer to the Himalayas.
Q: What are the characteristics of the retreating monsoon (transition season)?
A: The retreating monsoon occurs during October and November. As the monsoon trough weakens and is replaced by a high-pressure system, the south-west monsoon winds gradually withdraw. This period marks the transition from the rainy season to dry winter conditions. The weather becomes oppressive during the day due to high temperature and humidity, known as ‘October heat.’ In the second half of October, the mercury starts falling rapidly in northern India, and the land remains moist from the recent monsoon rains.
Q: What is the unifying influence of the monsoon on the Indian subcontinent?
A: The monsoon has a unifying influence on the Indian subcontinent. The seasonal alteration of wind systems and associated weather conditions provide a rhythmic cycle of seasons. The monsoon’s uncertainties of rain and uneven distribution are typical, and they shape the Indian landscape, plant and animal life, agricultural calendar, and people’s lives and festivities.
Q: How does the monsoon bind the whole country of India?
A: The arrival of the monsoon winds is eagerly awaited by people across India. The monsoon provides water that sets agricultural activities in motion, and the river valleys that carry this water unite as a single river valley unit. The monsoon’s arrival and the agricultural activities it enables have a unifying effect on the country.
