• In 1803, Luke Howard devised the basic system of cloud classification • Still used today • Based on Latin names • Two Two par parts ts to a clou cloud’ d’ss nam name: - Shape (ex: cirrus, stratus, cumulus) - Height (cloud base & vertical extent)
How do clouds form? When water vapor in the air becomes liquid water or ice crystals.
FOG A cloud in contact with the ground.
What are clouds? • A cloud is made up of tiny water droplets and/or ice crystals, a snowflake is a collection of many ice crystals, and rain is just liquid water.
Shapes & Heights • Shapes - Cirrus = curly and wispy - Stratus = layered or stratified - Cumulus = lumpy or piled up
What do clouds tell us? • Clouds just don’t happen - there’s always a reason • A particular cloud’s shape and location depend on (and can therefore tell us about): - the movement of the air - amount of water vapor in air - stability (flat clouds = stable air while puffy clouds = unstable air)
Cumulus Clouds • Cumulus clouds are puffy (like popcorn) • Often have noticeable vertical development • Cells can be rather isolated or they can be grouped together in clusters as shown • The base of a cumulus cloud can look like a stratus cloud if it is overhead. • Thick cumulus can make skies dark (filters out sun’s rays)
Vertically Developed Cumulus Clouds • Fair weather cumulus have the appearance of floating cotton and have a lifetime of 5-40 minutes. The word cumulus comes from the Latin word for a heap or a pile. Cumulus clouds are puffy in appearance. They look like large cotton balls.
Cumulus • The clouds that produce heavy thunderstorms in summer are a form of cumulus clouds called cumulonimbus. Cumulonimbus clouds may extend upward for hundreds of meters.
Cumulus Clouds
Cap Clouds • Air containing water vapor lifted until it is saturated, producing liquid water cloud droplets which can "cap" the summit. (cap cloud over Mt. Ranier)
Contrails • Contrail is short for “condensation trails” • Formed from vapor contained in the exhaust of a jet engine when it condenses in cold air aloft