Grounded in the chapter’s seasonal cycle.
India’s four main seasons are the cold weather season, the hot weather season, the advancing south-west monsoon or rainy season, and the retreating or north-east monsoon season.
Grounded in the air-pressure explanation.
Atmospheric pressure acts on the body from every direction, while fluids and air inside the body exert an outward pressure that balances it. Because the pressures are normally balanced and change gradually, we do not feel the enormous total force.
Grounded in the functions of atmospheric layers.
Commercial aeroplanes commonly fly in the lower stratosphere or near the tropopause because this layer is comparatively stable, has little cloud or vertical weather disturbance, and allows smoother flight than the turbulent troposphere below.
Grounded in the layer descriptions and monsoon mechanism.
a. The troposphere is the lowest layer, contains most atmospheric mass and water vapour, and is where weather occurs; temperature generally falls with height. The stratosphere lies above it, is drier and more stable, contains the ozone layer, and temperature rises upward because ozone absorbs ultraviolet radiation.
b. The south-west monsoon blows from ocean toward land mainly from June to September and supplies most of India’s annual rain through Arabian Sea and Bay of Bengal branches. The north-east or retreating monsoon blows from land toward sea mainly in October and November; after crossing the Bay of Bengal it gives important rain to the Coromandel coast, especially Tamil Nadu.
Grounded in relief effects and the path of monsoon branches.
a. Moist Bay of Bengal monsoon winds are forced to rise over the steep Khasi Hills near Shillong, cool and produce heavy orographic rain. Kolkata lies on the plains and does not receive the same intense uplift. b. Delhi receives moisture from monsoon branches advancing across the northern plains. Jodhpur lies farther west in a drier region; the Arabian Sea winds run nearly parallel to the Aravalli range and lose moisture, so uplift and rainfall are weaker.
Grounded in maritime influence, rain shadow, retreating monsoon and western disturbances.
a. Thiruvananthapuram is near the equator and the sea, whose moderating influence keeps the annual temperature range small. b. Chennai lies largely in the rain shadow during the south-west monsoon; in October–November retreating north-east winds cross the Bay of Bengal, collect moisture and rain on the Coromandel coast, often with cyclones. c. Leh lies in the Himalayan rain shadow and receives little monsoon rain; its limited precipitation is spread through occasional summer showers and winter snowfall associated with western disturbances rather than one intense rainy season.