PRECIPITATION Flashcards
General term for all forms of moisture originating from clouds and falling to the ground
Precipitation
Precipitation happens when water falls down to the earth surface. This water might be ___ & ____
Liquid or Solid State
consists of waterdrops under 0.02-in. diameter
Drizzle
consists of drop usually greater than 0.02-in. diameter
Rain
is the ice coating formed when drizzle or rain freezes
Glaze
is frozen raindrops cool to the ice stage while falling through air at subfreezing temperatures.
Leet
precipitation in the form of Ice crystals resultung from sublimation
Snow
is made up of a number of ice crystals fused together.
Snowflake
is precipitation in the form of balls or lumps of ice over 0.2-in. diameter formed by alternative freezing and melting
Hail
Types of Precipitation
Convective precipitation
Cyclonic precipitation
Orographic precipitation
Forms of precipitation
Snow
Snowflake
Hail
is the interfere between two distinct air masses.
Front
is caused by natural rising of warmer, lighter air in colder, denser surroundings.
Convective precipitation
results from the lifting of air converging into a low-pressure area, or cyclone.
Cyclonic precipitation
results frok mechanical lifting over mountain barriers.
Orographic precipitation
is a large low pressure region with circular wind motion
Cyclone
Two types of Cyclone
Tropical cyclones
Extra tropical cyclones
are regions of high pressure, usually of harge areal extent. It cause clockwise wind circulation in the northerm hemisphere.
Anticyclones
is the amount of precipitation, the form of rain (water from clouds), that descends onto the surface of Earth
Rainfall
is falling snowflakes or snow crystals or also the accumulation of snow during a specified period of time.
Snowfall
is the simplest avareging method but can only be relied on small, flat areas.
Arithmetic mean method
is a graphical technique that considers the weights of each rain gages based on the relatice measurements of their respective area coverage.
Thiessen polygon
is also a graphical technique that involves drawing isohyets or contours that are equal to the respective rainfall gage over an area based on point measurements.
Isohyetal method
is used when the normal annual precipitation at each of the index stations is less or more than 10 percent of that for the station with the missing record.
Normal ration method
is defined as a change in the amount of precipitation that falls naturally in a certain location.
Variation of precipitation
where conditions are crucial for the formation of snowflakes
Atmosphere
the atmophere is below freezing (0 degrees Celcius or 32 degrees Fahrenheit)
Supercooling
These are microscopic particles, such as dust, pollen, or other solid particles
Ice Nuclei
when the air is holding more moisture than it can actually accmmodqte at a given temperature.
Supersaturation
When supersaturated air encounters an ice nucleus
Deposition
As the ice crystals grow, they start to consume surrounding water vapor
Vapor Diffusion
As rhe ice crustals fall through the atmosphere, they may collide woth other ice crystals
Aggregation
once the snowflake becomes too heavy for the updrafts in the atmosphere to support, it falls to the ground as snow.
Precipitation
it indicates the typical amount of snow that falls in a given period
Average Snowfall
A lower-than-average snowfall may indicate drier or milder conditions than usual.
Below-average snowfall
higher-than-average snowfall suggest wetter or colder conditions
Above-average snowfall
Examining the variability in snowfall data
Snowfall Variability
it suggests relatively consistent snowfall patterns from year to year.
Low variability
indicates significant fluctuations in snowfal amounts
high variability
measures how often snowfall events occur within a specific timeframe
Snowfall Frequency
