2. Lower atmosphere with sufficient water vapor: On the warm ocean surface, the water vapor content in the lower atmosphere is high. The existence of this water vapor provides water for typhoons, which is one of the important conditions for their development and enhancement.
3. Small vertical wind shear: Vertical wind shear refers to the difference of wind speed between high altitude and low altitude. Smaller vertical wind shear is beneficial to the formation and maintenance of typhoons, because it can keep the internal convection of typhoons stable and prevent typhoons from weakening or disintegration.
4. Initial disturbance: Typhoons are usually formed by initial disturbance, which can be tropical depression, easterly wave, cut-off depression, etc. This disturbance gradually developed into a typhoon under suitable environmental conditions. Once these conditions are met, the initial disturbance will gradually strengthen, forming a rotating low-pressure system. With the continuous input of heat and water vapor, typhoons will gradually strengthen and form a powerful storm system.