Lecture 9: Humidity & Stability Flashcards
the heat exchanged between physical states of water provides more than ______ of the energy that powers the general circulation of the atmosphere.
30%
______ is the process by which ice changes directly to water vapour
Sublimation
______ is an important contributor to the shrinking of snowpacks in dry, windy environments.
Sublimation
True or False: Blowing snow enhances sublimation in the Canadian Rockies near Lake Louise, Banff National Park, Alberta.
True
The heat energy of a phase change is known as?
Latent heat
How many calories to change ice at 0°C to water at 0°C?
80
How many calories to change water at 0°C to water at 1°C?
100
How many calories to change water at 1°C to vapour at 100°C?
540
What is the latent heat of evaporation of 1 gram of water at 20°C?
585
True or False: evaporation can occur from a water surface at any temperature between 0 and 100 degrees Celsius and sublimation from an ices surface at any temperature below 0 °C.
True
When the phase change from liquid to vapour is induced by boiling, it requires the addition of 540 cal for each gram, this amount of energy is the ______.
latent heat of vaporization
When water vapour condenses to a liquid, each gram gives up its hidden 540 cal as the ______.
latent heat of condensation
In summary, the changing of 1 g of ice at 0°C to water and then to water vapour at 100°C—from a solid to a liquid to a gas—absorbs ______.
720 cals (80 cal + 100 cal + 540 cal)
The ______ absorbs 680 cal as a gram of ice transforms into vapour.
latent heat of sublimation
Water vapour absorbs ______, making it possible to distinguish areas of relatively high water vapour from areas of low water vapour
long wavelengths (infrared)
The amount of water vapour in the air is ______.
Humidity
_______ is a ratio (expressed as a percentage) of the amount of water vapour that is actually in the air compared to the maximum water vapour possible in the air at a given temperature.
Relative humidity
What is the equation for relative humidity?
Relative humidity = (actual vapor pressure in the air/max vapor possible in the air at that temp.) x 100%
What is the rate t which the evaporation and condensation reach equilibrium?
Saturation equilibrium
True or False: Warmer air = greater maximum water vapour possible
True