Clouds could be the most important form of flow visualization on the planet. Weather, with clouds and other thermofluid physics, affects everyone, and being able to read the sky is tremendously useful for anybody who goes outside. Clouds are also visually alluring, and affect us emotionally. Most of us have admired a beautiful sunset, and been either happily cooled or unhappily chilled to see a cloud pass in front of the sun. Perhaps you spend time looking for recognizable shapes in clouds. In any case, knowing how and why clouds exist will deepen your appreciation for them. In this section, you’ll learn to recognize the different clouds, describe the air motion and atmospheric stability that govern the appearance of clouds and even interpret weather data including Skew-T plots and wind soundings to predict and help identify likely clouds.
Names of Clouds
The first step is to recognize the basic clouds. Many of us learned the names of various types of clouds when we were children. How many can you recall?
Even if you know all the names (maybe you are a pilot), correctly identifying a cloud is no child’s game. Sometimes a cloud’s appearance will fit multiple definitions, at which point you’ll need more data to figure out what they are best named. For example, you might have to watch for a while to see how the cloud is developing; is it growing, or shrinking? Is it moving, or just seeming to move or not move? Is it changing shape, from a sheet to cloudlets or vice versa? What altitude is it at? Is that altitude changing? Is there precipitation happening?
Clouds = droplets or ice MOVING UPWARDS
Lift mechanisms determine appearance:
- Instability. Yes, basically Rayleigh-Taylor. Denser air sinks etc.
- Orographics: terrain, mountains
- Synoptic scale weather systems. Both at warm and cold fronts; cold air pushes under in a cold front, warm air overruns in a warm front.
- Convergence: shoreline temperature differences