Upper air divergence plays a crucial role in the formation and intensification of cyclones, also known as hurricanes or typhoons. Cyclones are large-scale systems of low pressure characterized by strong winds and intense rain. Upper air divergence is an important factor in creating the conditions conducive to cyclone development.

Here's why:

To address the second part of your question, the force responsible for the deflection of wind from its intended path is the Coriolis effect. The Coriolis effect is caused by the Earth's rotation and the varying rotational speed of different latitudes. As air moves from high pressure to low pressure in the atmosphere, the Coriolis effect deflects its path to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This deflection leads to the rotation of air masses around low-pressure centers, such as those found in cyclones and other weather systems.

Dr Gaurav H Tandon thank you for your contribution to the discussion

If the upper levels are favorable for cyclone development, then there is a region of divergence aloft above the developing Low-pressure center. This will help pull the air that is converging at the surface upward and continue to develop the surface cyclone. Divergence occurs when a stronger wind moves away from a weaker wind or when air streams move in opposite directions. When divergence occurs in the upper levels of the atmosphere it leads to rising air. Divergence occurs when a stronger wind moves away from a weaker wind or when air streams move in opposite directions. When divergence occurs in the upper levels of the atmosphere it leads to rising air. The atmosphere must cool quickly enough with height to support the formation of deep convective clouds. The middle atmosphere must be relatively humid at a height of about 5,000 metres (16,000 feet) above the surface. The developing system must be at least 500 km (300 miles) away from the Equator.Upper level divergence lowers pressures and heights because some mass is removed in the upper troposphere from that region. This causes the air to rise from the lower troposphere and results in a cooling of the air. A theory of cyclone development in which upper-level divergence in the atmosphere,through the principle of mass continuity, induces low-level convergence of air that develops cyclonic circulation through the process of geostrophic adjustment.n middle and higher latitudes of both the hemispheres upper air westerlies prevail due to balancing act of pressure gradient force and coriolis force. The uniform flow of upper air westerlies is frequently disturbed by the development of large scale undulations, known as Rossby waves. When upper-level divergence is stronger than lower- level convergence, more air is taken out at the top than is brought in at the bottom. Surface pressure drops, and the low intensifies, or "deepens." If the upper levels are favorable, then the mid-latitude cyclone will continue to develop and bring up mT air in the warm sector and bring down cP air in the cold sector. It is this transfer of energy that both strengthens and propagates the mid-latitude cyclone.