ESC1000 Chapter 17 Moisture, Clouds and Precipitation

English	Photos
Melting	Substance solid transforms to liquid. A cooling process.
Freezing	liquid transforms to solid. A heating process.
Evaporation	liquid transforms to vapor. A cooling process
Condensation	Vapor transforms to liquid. A heating process.
Sublimation	A solid transforms to a gas, skipping the liquid phase. A cooling process.
Deposition	A gas transforms to a solid. A heating process.
Humidity	the amount of water vapor in air.
Higher	When temperature is higher, the amount of water vapor air can hold is _______
Lower	When temperature is lower, the amount of water vapor air can hold is _______.
Unsaturated	When a given parcel of air is holding less water than it can actually hold it is___________.
Saturated	When a given parcel of air is holding all the water vapor it can hold, it is _________.
Mixing ratio	specific humidity
Specific humidity	Ratio of the amount of water vapour in air by weight, compared to the mass of air it is in. Not affected by temperature.
Absolute humidity	Ratio of the amount of water vapour in air by volume, compared to the volume of air it is in. Not affected by temperature.
Relative humidity	Ratio of the amount of water vapour in air compared to the amount needed to saturate the air at the same temperature. Given as a percentage. Is strongly affected by temperature.
Relative humidity	how much water the air is holding relative to the amount is can potentially hold, its capacity. Is strongly affected by temperature.
Increases	What happens to relative humidity when temperature increases?
Decreases	What happens to the capacity of air to hold water vapour when temperature decreases?
Increases	What happens to relative humidity when the water vapour content of the air stays the same, but the temperature drops?
Dew point	The temperature that a parcel of unsaturated air would have to fall to, in order to become saturated. Given as a temperature.
Hygrometer	A device to measure humidity
Sling psychrometer	a type of hygrometer.
Adiabatic temperature change	When a gas changes temperature because of a pressure change (either expansion or compression).
Orographic lifting	When air is forced up and over mountains
Frontal wedging	weather process where a body of cold air meets hot air, and the hot air is forced up and over the cold air, it expands, cools, condensation occurs and clouds form.
Convective lifting	weather process where the sun heats the land surface, which heats the adjacent air, and then the heated air rises.
Thermal	another name for convective lifting.
Convergence	weather process where wind (with air of similar temperatures) from two directions meet and the only way for the air to go is up.
Cirrus	Cloud that is high level and wispy or light and patchy in form, made of ice crystals and is always up high.
Cumulus	Form of cloud that is puff balls, often with a flat base (but can lose flat base due to air circulation).
Stratus	Form of cloud in sheets or layers, that may cover the whole sky, and doesn't have separate clouds.
Cirrocumulus	Form of cloud that is high in level and puff ball in form.
Cirrostratus	high level, very light layers of cloud.
Alto	general term for clouds that are at mid level
Altocumulus	mid-level puffball clouds.
Altocumulus	clouds that are mid-level, and bigger and denser than cirrocumulus.
Altostratus	clouds at mid-level that form a light sheet that lets the sun or moon show as a bright spot.
stratus	general term for clouds that are low level; often cover much of the sky
stratocumulus	clouds that are low-level layers of cumulus clouds, that begin to touch each other and fuse.
Nimbostratus	clouds that are low-level, uniform layer, usually very dark, that bring strong precipitation.
Nimbus	general term for clouds that means rainy in Latin.
Cumulonimbus	Clouds that are the product of growth of cumulus which can form huge thunderheads.
Fog	a cloud that forms at or near the ground.
Mist	precipitation that reaches the surface in liquid drops of the smallest size. 0.005-0.05mm diameter.
Drizzle	precipitation that reaches the surface in liquid form, drops 0.05-0.5mm diameter.
Rain	precipitation that reaches the surface in liquid form, drops 0.5-5mm diameter.
Snow	precipitation that reaches the surface in form of ice crystals or aggregates of crystals
Sleet	precipitation that reaches the surface in form of small ice particles. Often falls as rain but then passes through a cold layer that freezes the drops.
Hail	precipitation that reaches the surface in form of larger pieces of ice. Formed in cumulonimbus clouds in updrafts of up to 100mph.
Glaze	forms when rain freezes as it hits a freezing surface, forming a thin coating of ice. Eg black ice.
Rime	deposit of ice crystals that forms directly on cold surfaces from fog.
Graupel	Soft hail, which forms when rime coats snowflakes on their way down.
Bergeron Process	formation of precipitation, where water condenses, and freezes, then falls frozen or melted as rain.
Collision-coalescence process	formation of precipitation, where tiny droplets accumulate, fall, and collide with other small droplets until rain drops form and fall.
Atmospheric Stability	Air parcel resists upward displacement (i.e. air parcel is colder than surrounding environment or denser, when it tends to sink back to original level)