Composition and Structure of Atmosphere | Class 11 Geography Notes

HEATING AND COOLING OF ATMOSPHERE

The atmosphere is heated and cooled through several processes. The Earth absorbs short wave solar radiation and warms up, then emits energy in the form of long wave radiation called terrestrial radiation. The air in contact with the Earth's surface is heated by conduction, where heat transfers from the warmer surface to the cooler air molecules. This conduction warms the lower atmosphere slowly. Convection follows, where warm air rises vertically in currents, transferring heat upward through the troposphere. Horizontal movement of air, or advection, transports heat laterally and is more significant than vertical heat transfer. For example, in middle latitudes, much of the daily weather variation is caused by advection. In northern India during summer, hot local winds called 'loo' are a result of advection. These combined processes regulate the heating and cooling of the atmosphere, influencing weather and climate patterns.

🔗 Connection: This section leads to understanding terrestrial radiation and the Earth's heat budget, explaining energy balance.