风切变，又称风切或风剪，是指大气中不同两点之间的风速或风向的剧烈变化。英语是Wind shear，或者windshear 或者wind gradient. It is a difference in wind speed and direction over a relatively short distance in the atmosphere. Wind shear can be broken down into vertical and horizontal components, with horizontal wind shear seen across fronts and near the coast, and vertical shear typically near the surface, though also at higher levels in the atmosphere near upper level jets and frontal zones aloft. 根据两点高度之间的差异，风切变可分为水平和垂直两大类。垂直风切变是指垂直于地表方向上风速或风向随高度的剧烈变化，强烈的垂直风切变的存在会对桥梁、高层建筑、飞行等造成强烈的破坏作用，可造成桥梁楼房坍塌、飞机坠毁等恶性事故，给人类生活造成严重影响。水平风切变则指与地面平行的方向上风向的急速转变