[理学]云.ppt

Banner Cloud（旗状云） A lenticular cloud that forms downwind of a mountain peak and is regularly replenished by condensing water vapor. Pileus Cloud（伞状云） An unusual cloud that forms above a building cumulus by deflected moist winds. Mammatus Clouds An unusual cloud that hang like sacks（麻袋）, formed by sinking air with a high water content. Nacreous Clouds（珠母云） An unusual cloud best viewed at winter in the poles and forms in the stratosphere. Figure 6.26 Noctilucent Clouds（夜光云） Figure 6.27 An unusual wavy cloud that is best viewed at the poles and forms in the upper mesosphere. Altocumulus (Ac) Cirrus (Ci) Stratocumulus (Sc) Stratus (St) Cirrus (Ci) Cirrostratus (Cs) Cumulus (Cu) Altostratus (As) Stratocumulus (Sc) Cumulonimbus (Cb) How well did you learn? How should the three clouds below be labeled respectively from left to right? Click one of the choices underneath: A: Stratus, Cumulus, Cirrus B: Cirrus, Cumulus, Stratus C: Cumulus, Cirrus, Stratus 一位俄罗斯天文学家在尼泊尔拍到了珠峰上空出现的、非常罕见的彩虹云照片。现年51岁的奥列格巴图诺夫(Oleg Bartunov)是莫斯科斯特恩伯格天文研究所(Sternberg Astronomical Institute)的一名天文学家，在最近的一次赴喜马拉雅山考察活动时，他看到了珠峰上空出现的奇特云彩：阳光照射在云上，云彩却出现了类似彩虹的七彩光线。 §6 降 水 Precipitation includes rain（降雨）, sleet（雨夹雪）, snow（雪）, freezing rain（冻雨）and hail（冰雹）. Our daily outdoor activities are often greatly influenced by precipitation. Raindrops form when millions of tiny water droplets collide together in clouds to form larger ones. This process is called coalescence . Eventually, they become too heavy and fall out of the clouds as rain. Very small raindrops are called drizzle（毛毛雨） . Rain Sleet forms when a partially melted snowflake or raindrop turns back into ice as it is falling through the air. Freezing Rain happens when raindrops fall in liquid form and immediately freeze as they hit a cold surface. Sleet and Freezing Rain Snow Snow is more likely in higher places because it falls when the air temperature is below freezing. Snow forms when water freezes in a cloud and turns into snowflakes as they f