The temperature of the air that precipitation falls through is what determines its form. In fact, precipitation always starts out within the cloud as either liquid drops or snow crystals. It is the temperature and winds beneath the cloud that will determine whether this precipitation will change into one of many forms that eventually hit the earth's surface. In warmer clouds such as those over the tropics, the precipitation begins as rain and continues to grow through collision/coalescence and falls all the way to the surface as raindrops.In much of the world though, rain begins as some form of ice and melts as it falls through warmer air near the surface.还有详情和图片解释请看下列链接：http://vortex.plymouth.edu/precip/precip2a.html参考资料：http://vortex.plymouth.edu/precip/precip2a.html 已赞过已踩过<
