Precipitation презентация

Precipitation

Precipitation? What is precipitation?

What are the forms of precipitation?

Forms of Precipitation 3. Sleet / ice pellets - transparent / translucent spheres of frozen water - with a diameter > 5 mm - develop first as raindrops in relatively warm atmosphere (Temp: > freezing), - then raindrops descend into a colder layer of the atmosphere (Temp:<0oC) - causing the freezing into ice pellets while reaching the ground surface - like freezing rain, an air temperature inversion is required

Necessary conditions? 1. cooling of air (e.g. convectional / orographic / cyclonic (frontal) uplifting) 2. condensation and cloud formation 3. an accumulation of moisture 4. the growth of cloud droplets - the most critical stage!! Water droplets and ice crystals of clouds need to be transformed into heavier particles if they are to fall out of clouds as precipitation. Why?

Mechanism of Precipitation Development 1. Coalescence theory 2. Bergeron-Findeisen process

Mechanism of Precipitation Development 1. Coalescence theory 2. Bergeron-Findeisen process * Are these theories contradictory? Why or why not?