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17 Cards in this Set
- Front
- Back
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absolute humidity |
measure the mass of water vapor in a given volume of air |
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condensation |
process by which water vapor becomes a liquid 1. so much water vapor is added to it it becomes saturated and can't hold water vapor 2. temperature drops low enough that air cannot hold water vapor *measured by relative humidity* |
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relative humidity |
amount of water vapor in air /total not actual amount only relative to at it cold contain 1. adding or substance water vapor 2. changing temperature |
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influence of temp. on saturation |
the number of water vapor molecules needed to reach saturation in a given sample of air is greater in warm air than in cool air can hold more water vapor |
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absolute humidity |
not desirable measure of humidity when there is no change in actual water vapor content will change dependent on volume of air sampled |
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dew point temperature |
the temp at which air must be cooled at constant pressure in order to reach saturation -indirect measure of water vapor increase in WV= increase in DT decrease in WV= decrease in DT dew point temp can never be more than temp because when equal the are is saturated |
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Specifif humidity |
mass of h20 vapor over mass of dry air containing it *does not vary as temp or pressure of body air changes* only changes when moisture is added or subtracted is added or subtracted to it |
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vapor pressure |
each gas in atm exerts pressure - sum of all = pressure of atm mixture water vapor gas has own pressure---> partial pressure exerted by water vapor *depends on # of water vapor molecules & temp |
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wetbulb (Tw) |
the temp at which air is cooled at constant pressure by evaporating water until it is saturated
Because____ temperature is reached through a combination of addition of water vapor and cooling of the air, the temperature will always lie between the air temperature and the dewpoint temperature |
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saturated vs unsaturated |
when relative humidity is said to be 100% when air is unsaturated there is not a max of the amount of water vapor in the air increase temp. =air becomes less saturated decrease temp.= air becomes more saturated |
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stability |
air tend to cool and condense as it rises and become warm and dry as it sinks |
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cloud condensation |
are aerosols that act as initial sites for condensation of water vapor into cloud droplets or cloud ice particles * the smaller the particle the easier it is to condense on it Haze particles survive in relative humidity saturated environment |
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Types of fog |
radiation:If the air above the ground has a fairly high water vapor content, then the cooling of the ground can eventually lead to the formation advection: when moisturized air is advected over cooler surface upslope fog: cooling occurs as the air is lifted to the higher elevation steam fog:forms as cold, dry air moves over warm water-adding water vapor to the air frontal fog:formed when warm rain falls through cold, dry air or when rain falls onto a snow-covered ground |
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haze particle |
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vapor pressure |
partial pressure, the vapor pressure depends upon both the number of water vapor molecules in the air and the temperature of the air. It is the former characteristic, the number of water vapor molecules, that we are most interested in when we desire a measure of humidity.
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cloud formation |
form as the RH reaches 100%. Th ere are only two ways to increase the RH: 1) cool the air, or 2) add water vapor to the air. Most clouds form as a result of mechanism |
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Buoyancy |
“the ability to f l oat.” We say that an object is positively buoyant if it fl oats and negatively buoyant if it sinks. |
