11th Geography NCERT Chapter 9

– Factors Affecting Wind Speed and Direction: Students should study the factors affecting the speed and direction of wind, including the pressure gradient force, frictional force, and Coriolis force. These forces influence the movement of air and the direction of winds on Earth【4:1†source】.

– Vertical Variation of Pressure: Understanding how pressure decreases rapidly with height in the lower atmosphere is crucial. The pressure at different elevations varies, and this variation is the primary cause of air motion, i.e., wind. Students should be familiar with the concept of pressure changes with elevation and its impact on atmospheric circulation【4:1†source】.

– General Circulation of the Atmosphere: Students should be familiar with the general circulation of the atmosphere and its effects on oceans. This includes the interaction between large-scale winds and ocean currents, such as the El Nino phenomenon, which has significant impacts on global weather patterns【4:2†source】.

– Local Deviations from General Circulation: Students should study how the pattern of wind circulation is modified in different seasons, especially focusing on the monsoon winds in regions like southeast Asia. They should also understand the formation of local winds due to differences in heating and cooling of Earth's surfaces, leading to various common and regional winds【4:3†source】.